implement a comprehensive vocabulary export/import system with JSON support and conflict resolution

app/src/main/AndroidManifest.xml

@@ -33,6 +33,16 @@
             </intent-filter>
         </activity>
 
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
     </application>
 
 </manifest>

app/src/main/java/eu/gaudian/translator/model/VocabularyExport.kt

@@ -0,0 +1,261 @@
+@file:OptIn(ExperimentalTime::class)
+@file:Suppress("HardCodedStringLiteral")
+
+package eu.gaudian.translator.model
+
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlin.time.ExperimentalTime
+import kotlin.time.Instant
+
+/**
+ * # Vocabulary Export/Import Data Models
+ * 
+ * This file defines the data structures used for exporting and importing vocabulary data.
+ * The export format is designed to be:
+ * - **Portable**: Can be stored as JSON files, transmitted via REST APIs, shared via messaging apps
+ * - **Flexible**: Supports different export scopes (full repository, categories, individual items)
+ * - **Complete**: Preserves all data including learning stages, categories, and progress statistics
+ * - **Versioned**: Includes format version for future compatibility
+ * 
+ * ## Export Scopes
+ * 
+ * The system supports multiple export scopes via the [VocabularyExportData] sealed class:
+ * - [FullRepositoryExport]: Complete repository state with all items, categories, and mappings
+ * - [CategoryExport]: Single category with all its vocabulary items and their states
+ * - [ItemListExport]: Arbitrary list of vocabulary items with their associated data
+ * - [SingleItemExport]: Individual vocabulary item with its complete information
+ * 
+ * ## Data Preservation
+ * 
+ * Each export includes:
+ * - Vocabulary items (words, translations, features, creation dates)
+ * - Learning states (correct/incorrect counts, last answer timestamps)
+ * - Stage mappings (current learning stage for each item)
+ * - Categories (both manual tags and automatic filters)
+ * - Category memberships (which items belong to which categories)
+ * - Metadata (export date, format version, statistics)
+ * 
+ * ## Usage Examples
+ * 
+ * ### Exporting a full repository:
+ * ```kotlin
+ * val exportData = repository.exportFullRepository()
+ * val jsonString = Json.encodeToString(VocabularyExportData.serializer(), exportData)
+ * // Save to file, send via API, share via WhatsApp, etc.
+ * ```
+ * 
+ * ### Exporting a single category:
+ * ```kotlin
+ * val exportData = repository.exportCategory(categoryId)
+ * val jsonString = Json.encodeToString(VocabularyExportData.serializer(), exportData)
+ * ```
+ * 
+ * ### Importing data:
+ * ```kotlin
+ * val importData = Json.decodeFromString<VocabularyExportData>(jsonString)
+ * repository.importVocabularyData(importData, conflictStrategy = ConflictStrategy.MERGE)
+ * ```
+ */
+
+/**
+ * Sealed class representing different types of vocabulary exports.
+ * Each type contains the appropriate data for its scope.
+ */
+@Serializable
+sealed class VocabularyExportData {
+    abstract val formatVersion: Int
+    abstract val exportDate: @Contextual Instant
+    abstract val metadata: ExportMetadata
+}
+
+/**
+ * Metadata about the export operation.
+ * 
+ * @property itemCount Total number of vocabulary items included
+ * @property categoryCount Total number of categories included
+ * @property exportScope Description of what was exported
+ * @property appVersion Version of the app that created the export (optional)
+ */
+@Serializable
+data class ExportMetadata(
+    val itemCount: Int,
+    val categoryCount: Int,
+    val exportScope: String,
+    val appVersion: String? = null
+)
+
+/**
+ * Export format for the complete repository state.
+ * 
+ * This includes everything: all vocabulary items, all categories, all learning states,
+ * all mappings. Use this for full backups or transferring complete data between devices.
+ * 
+ * @property items All vocabulary items
+ * @property categories All categories (tags and filters)
+ * @property states Learning states for all items
+ * @property categoryMappings Mappings between items and categories
+ * @property stageMappings Current learning stage for each item
+ */
+@Serializable
+@SerialName("FullRepository")
+data class FullRepositoryExport(
+    override val formatVersion: Int = 1,
+    @Contextual override val exportDate: Instant,
+    override val metadata: ExportMetadata,
+    val items: List<VocabularyItem>,
+    val categories: List<VocabularyCategory>,
+    val states: List<VocabularyItemState>,
+    val categoryMappings: List<CategoryMappingData>,
+    val stageMappings: List<StageMappingData>
+) : VocabularyExportData()
+
+/**
+ * Export format for a single category and its vocabulary items.
+ * 
+ * Use this to share a specific vocabulary list or category with others.
+ * All items in the category are included with their complete learning data.
+ * 
+ * @property category The category being exported
+ * @property items All vocabulary items belonging to this category
+ * @property states Learning states for the items in this category
+ * @property stageMappings Learning stages for the items in this category
+ */
+@Serializable
+@SerialName("Category")
+data class CategoryExport(
+    override val formatVersion: Int = 1,
+    @Contextual override val exportDate: Instant,
+    override val metadata: ExportMetadata,
+    val category: VocabularyCategory,
+    val items: List<VocabularyItem>,
+    val states: List<VocabularyItemState>,
+    val stageMappings: List<StageMappingData>
+) : VocabularyExportData()
+
+/**
+ * Export format for a custom list of vocabulary items.
+ * 
+ * Use this to create custom vocabulary sets for sharing or studying specific words.
+ * Optionally includes category information if the items belong to specific categories.
+ * 
+ * @property items The vocabulary items being exported
+ * @property states Learning states for these items
+ * @property stageMappings Learning stages for these items
+ * @property associatedCategories Categories that these items belong to (optional)
+ * @property categoryMappings Mappings between items and categories (optional)
+ */
+@Serializable
+@SerialName("ItemList")
+data class ItemListExport(
+    override val formatVersion: Int = 1,
+    @Contextual override val exportDate: Instant,
+    override val metadata: ExportMetadata,
+    val items: List<VocabularyItem>,
+    val states: List<VocabularyItemState>,
+    val stageMappings: List<StageMappingData>,
+    val associatedCategories: List<VocabularyCategory> = emptyList(),
+    val categoryMappings: List<CategoryMappingData> = emptyList()
+) : VocabularyExportData()
+
+/**
+ * Export format for a single vocabulary item with all its details.
+ * 
+ * Use this for sharing individual words or phrases with complete context.
+ * 
+ * @property item The vocabulary item being exported
+ * @property state Learning state for this item (if available)
+ * @property stage Current learning stage for this item
+ * @property categories Categories this item belongs to
+ */
+@Serializable
+@SerialName("SingleItem")
+data class SingleItemExport(
+    override val formatVersion: Int = 1,
+    @Contextual override val exportDate: Instant,
+    override val metadata: ExportMetadata,
+    val item: VocabularyItem,
+    val state: VocabularyItemState?,
+    val stage: VocabularyStage,
+    val categories: List<VocabularyCategory> = emptyList()
+) : VocabularyExportData()
+
+/**
+ * Simplified representation of category mapping for export/import.
+ * 
+ * Maps a vocabulary item ID to a category ID. During import, IDs may be
+ * remapped if conflicts exist.
+ */
+@Serializable
+data class CategoryMappingData(
+    val vocabularyItemId: Int,
+    val categoryId: Int
+)
+
+/**
+ * Simplified representation of stage mapping for export/import.
+ * 
+ * Maps a vocabulary item ID to its current learning stage.
+ */
+@Serializable
+data class StageMappingData(
+    val vocabularyItemId: Int,
+    val stage: VocabularyStage
+)
+
+/**
+ * Strategy for handling conflicts during import operations.
+ * 
+ * Conflicts occur when imported data has the same IDs or content as existing data.
+ * Different strategies handle these conflicts in different ways.
+ */
+enum class ConflictStrategy {
+    /**
+     * Skip importing items that already exist (based on ID or content).
+     * Preserves all existing data unchanged.
+     */
+    SKIP,
+    
+    /**
+     * Replace existing items with imported versions.
+     * Overwrites local data with imported data when conflicts occur.
+     */
+    REPLACE,
+    
+    /**
+     * Merge imported data with existing data.
+     * - For vocabulary items: Keep existing if duplicate, add new ones
+     * - For states: Keep the more advanced learning progress
+     * - For categories: Merge memberships
+     * - For stages: Keep the higher stage
+     */
+    MERGE,
+    
+    /**
+     * Assign new IDs to all imported items to avoid conflicts.
+     * Creates duplicates rather than merging or replacing.
+     * Useful when importing the same data multiple times for practice.
+     */
+    RENAME
+}
+
+/**
+ * Result of an import operation with statistics.
+ * 
+ * @property itemsImported Number of vocabulary items successfully imported
+ * @property itemsSkipped Number of items skipped due to conflicts
+ * @property itemsUpdated Number of existing items updated
+ * @property categoriesImported Number of categories imported
+ * @property errors List of errors encountered during import (if any)
+ */
+data class ImportResult(
+    val itemsImported: Int,
+    val itemsSkipped: Int,
+    val itemsUpdated: Int,
+    val categoriesImported: Int,
+    val errors: List<String> = emptyList()
+) {
+    val isSuccess: Boolean get() = errors.isEmpty()
+    val totalProcessed: Int get() = itemsImported + itemsSkipped + itemsUpdated
+}

app/src/main/java/eu/gaudian/translator/model/communication/files_download/FileDownloadManager.kt

@@ -15,6 +15,14 @@ import java.io.File
 import java.io.FileOutputStream
 import java.security.MessageDigest
 
+/**
+ * Enum representing different download sources.
+ */
+enum class DownloadSource(val baseUrl: String, val subdirectory: String) {
+    DICTIONARIES("http://23.88.48.47/", "dictionaries"),
+    FLASHCARDS("http://23.88.48.47/", "flashcard-collections")
+}
+
 /**
  * Manages downloading files from the server, verifying checksums, and checking versions.
  */
@@ -190,4 +198,128 @@ class FileDownloadManager(private val context: Context) {
     fun getLocalVersion(fileId: String): String {
         return sharedPreferences.getString(fileId, "0.0.0") ?: "0.0.0"
     }
+
+    // ===== Flashcard Collections Support =====
+
+    private val flashcardRetrofit = Retrofit.Builder()
+        .baseUrl(DownloadSource.FLASHCARDS.baseUrl)
+        .addConverterFactory(GsonConverterFactory.create())
+        .client(OkHttpClient.Builder().build())
+        .build()
+
+    private val flashcardApiService = flashcardRetrofit.create<FlashcardApiService>()
+
+    /**
+     * Fetches the flashcard collection manifest from the server.
+     */
+    suspend fun fetchFlashcardManifest(): FlashcardManifestResponse? = withContext(Dispatchers.IO) {
+        try {
+            val response = flashcardApiService.getFlashcardManifest().execute()
+            if (response.isSuccessful) {
+                response.body()
+            } else {
+                val errorMessage = response.errorBody()?.string() ?: "HTTP ${response.code()}"
+                Log.e("FileDownloadManager", "Failed to fetch flashcard manifest: $errorMessage")
+                throw Exception(context.getString(R.string.failed_to_fetch_manifest, errorMessage))
+            }
+        } catch (e: Exception) {
+            Log.e("FileDownloadManager", "Error fetching flashcard manifest", e)
+            throw e
+        }
+    }
+
+    /**
+     * Downloads a flashcard collection file with checksum verification.
+     */
+    suspend fun downloadFlashcardCollection(
+        flashcardInfo: FlashcardCollectionInfo,
+        onProgress: (Float) -> Unit = {}
+    ): Boolean = withContext(Dispatchers.IO) {
+        val asset = flashcardInfo.asset
+        val source = DownloadSource.FLASHCARDS
+        val fileUrl = "${source.baseUrl}${source.subdirectory}/${asset.filename}"
+        val localFile = File(context.filesDir, "${source.subdirectory}/${asset.filename}")
+
+        // Create subdirectory if it doesn't exist
+        localFile.parentFile?.mkdirs()
+
+        try {
+            val client = OkHttpClient()
+            val request = Request.Builder().url(fileUrl).build()
+            val response = client.newCall(request).execute()
+
+            if (!response.isSuccessful) {
+                val errorMessage = context.getString(
+                    R.string.text_download_failed_http,
+                    response.code,
+                    response.message
+                )
+                Log.e("FileDownloadManager", errorMessage)
+                throw Exception(errorMessage)
+            }
+
+            val body = response.body
+            val contentLength = body.contentLength()
+            if (contentLength <= 0) {
+                throw Exception("Invalid file size: $contentLength")
+            }
+
+            FileOutputStream(localFile).use { output ->
+                body.byteStream().use { input ->
+                    val buffer = ByteArray(8192)
+                    var bytesRead: Int
+                    var totalBytesRead: Long = 0
+                    val digest = MessageDigest.getInstance("SHA-256")
+
+                    while (input.read(buffer).also { bytesRead = it } != -1) {
+                        output.write(buffer, 0, bytesRead)
+                        digest.update(buffer, 0, bytesRead)
+                        totalBytesRead += bytesRead
+                        onProgress(totalBytesRead.toFloat() / contentLength)
+                    }
+
+                    output.flush()
+
+                    val computedChecksum = digest.digest().joinToString("") { "%02X".format(it) }
+
+                    if (computedChecksum.equals(asset.checksumSha256, ignoreCase = true)) {
+                        Log.d("FileDownloadManager", "Flashcard download successful for ${asset.filename}")
+                        // Save version
+                        sharedPreferences.edit { putString(flashcardInfo.id, flashcardInfo.version) }
+                        true
+                    } else {
+                        Log.e("FileDownloadManager", context.getString(
+                            R.string.text_checksum_mismatch_for_expected_got,
+                            asset.filename,
+                            asset.checksumSha256,
+                            computedChecksum
+                        ))
+                        localFile.delete()
+                        throw Exception("Checksum verification failed for ${asset.filename}")
+                    }
+                }
+            }
+        } catch (e: Exception) {
+            Log.e("FileDownloadManager", "Error downloading flashcard collection", e)
+            if (localFile.exists()) {
+                localFile.delete()
+            }
+            throw e
+        }
+    }
+
+    /**
+     * Checks if a newer version is available for a flashcard collection.
+     */
+    fun isNewerFlashcardVersionAvailable(flashcardInfo: FlashcardCollectionInfo): Boolean {
+        val localVersion = sharedPreferences.getString(flashcardInfo.id, "0.0.0") ?: "0.0.0"
+        return compareVersions(flashcardInfo.version, localVersion) > 0
+    }
+
+    /**
+     * Gets the local version of a flashcard collection.
+     */
+    fun getFlashcardLocalVersion(collectionId: String): String {
+        return sharedPreferences.getString(collectionId, "0.0.0") ?: "0.0.0"
+    }
 }

app/src/main/java/eu/gaudian/translator/model/communication/files_download/FlashcardApiService.kt

@@ -0,0 +1,17 @@
+package eu.gaudian.translator.model.communication
+
+import retrofit2.Call
+import retrofit2.http.GET
+
+/**
+ * API service for fetching flashcard collection manifests and downloading files.
+ */
+interface FlashcardApiService {
+
+    /**
+     * Fetches the flashcard collection manifest from the server.
+     */
+    @GET("flashcard-collections/manifest.json")
+    fun getFlashcardManifest(): Call<FlashcardManifestResponse>
+
+}

app/src/main/java/eu/gaudian/translator/model/communication/files_download/FlashcardManifestModels.kt

@@ -0,0 +1,39 @@
+package eu.gaudian.translator.model.communication
+
+import com.google.gson.annotations.SerializedName
+
+/**
+ * Data class representing the flashcard collection manifest response from the server.
+ */
+data class FlashcardManifestResponse(
+    @SerializedName("collections")
+    val collections: List<FlashcardCollectionInfo>
+)
+
+/**
+ * Data class representing information about a downloadable flashcard collection.
+ */
+data class FlashcardCollectionInfo(
+    @SerializedName("id")
+    val id: String,
+    @SerializedName("name")
+    val name: String,
+    @SerializedName("description")
+    val description: String,
+    @SerializedName("version")
+    val version: String,
+    @SerializedName("asset")
+    val asset: FlashcardAsset
+)
+
+/**
+ * Data class representing an asset file within a flashcard collection.
+ */
+data class FlashcardAsset(
+    @SerializedName("filename")
+    val filename: String,
+    @SerializedName("size_bytes")
+    val sizeBytes: Long,
+    @SerializedName("checksum_sha256")
+    val checksumSha256: String
+)

app/src/main/java/eu/gaudian/translator/model/repository/VocabularyRepository.kt

@@ -5,9 +5,19 @@ package eu.gaudian.translator.model.repository
 
 import android.content.Context
 import androidx.room.withTransaction
+import eu.gaudian.translator.model.CategoryExport
+import eu.gaudian.translator.model.CategoryMappingData
+import eu.gaudian.translator.model.ConflictStrategy
+import eu.gaudian.translator.model.ExportMetadata
+import eu.gaudian.translator.model.FullRepositoryExport
+import eu.gaudian.translator.model.ImportResult
+import eu.gaudian.translator.model.ItemListExport
 import eu.gaudian.translator.model.Language
+import eu.gaudian.translator.model.SingleItemExport
+import eu.gaudian.translator.model.StageMappingData
 import eu.gaudian.translator.model.TagCategory
 import eu.gaudian.translator.model.VocabularyCategory
+import eu.gaudian.translator.model.VocabularyExportData
 import eu.gaudian.translator.model.VocabularyFilter
 import eu.gaudian.translator.model.VocabularyItem
 import eu.gaudian.translator.model.VocabularyItemState
@@ -45,6 +55,7 @@ import kotlinx.datetime.plus
 import kotlinx.datetime.toLocalDateTime
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.Json
+import kotlin.math.max
 import kotlin.time.Clock
 import kotlin.time.ExperimentalTime
 import kotlin.time.Instant
@@ -796,6 +807,594 @@ class VocabularyRepository private constructor(context: Context) {
         }
         Log.d(TAG, "--- END REPOSITORY STATE ---")
     }
+
+    // ==================== EXPORT/IMPORT FUNCTIONS ====================
+
+    /**
+     * Exports the complete repository state including all vocabulary items, categories,
+     * learning states, and mappings.
+     * 
+     * This creates a full backup that can be used to restore the complete state on another
+     * device or after data loss.
+     * 
+     * @return [FullRepositoryExport] containing all repository data
+     * 
+     * @see importVocabularyData for importing the exported data
+     * @see exportToJson for converting to JSON string
+     */
+    suspend fun exportFullRepository(): FullRepositoryExport {
+        Log.i(TAG, "exportFullRepository: Creating full repository export")
+        val items = getAllVocabularyItems()
+        val categories = getAllCategories()
+        val states = getAllVocabularyItemStates()
+        val categoryMappings = getCategoryMappings()
+        val stageMapping = loadStageMapping().first()
+
+        return FullRepositoryExport(
+            formatVersion = 1,
+            exportDate = Clock.System.now(),
+            metadata = ExportMetadata(
+                itemCount = items.size,
+                categoryCount = categories.size,
+                exportScope = "Full Repository"
+            ),
+            items = items,
+            categories = categories,
+            states = states,
+            categoryMappings = categoryMappings.map { CategoryMappingData(it.vocabularyItemId, it.categoryId) },
+            stageMappings = stageMapping.map { StageMappingData(it.key, it.value) }
+        ).also {
+            Log.i(TAG, "exportFullRepository: Export complete. Items: ${items.size}, Categories: ${categories.size}")
+        }
+    }
+
+    /**
+     * Exports a single category with all its vocabulary items and associated data.
+     * 
+     * @param categoryId The ID of the category to export
+     * @return [CategoryExport] containing the category and its items, or null if category not found
+     * 
+     * @see importVocabularyData for importing the exported data
+     */
+    suspend fun exportCategory(categoryId: Int): CategoryExport? {
+        Log.i(TAG, "exportCategory: Exporting category id=$categoryId")
+        val category = getCategoryById(categoryId) ?: run {
+            Log.w(TAG, "exportCategory: Category id=$categoryId not found")
+            return null
+        }
+        
+        val items = getVocabularyItemsByCategory(categoryId)
+        val itemIds = items.map { it.id }
+        val states = getAllVocabularyItemStates().filter { it.vocabularyItemId in itemIds }
+        val stageMapping = loadStageMapping().first().filterKeys { it in itemIds }
+
+        return CategoryExport(
+            formatVersion = 1,
+            exportDate = Clock.System.now(),
+            metadata = ExportMetadata(
+                itemCount = items.size,
+                categoryCount = 1,
+                exportScope = "Category: ${category.name}"
+            ),
+            category = category,
+            items = items,
+            states = states,
+            stageMappings = stageMapping.map { StageMappingData(it.key, it.value) }
+        ).also {
+            Log.i(TAG, "exportCategory: Export complete. Category: ${category.name}, Items: ${items.size}")
+        }
+    }
+
+    /**
+     * Exports a list of vocabulary items by their IDs.
+     * 
+     * @param itemIds List of vocabulary item IDs to export
+     * @param includeCategories Whether to include category information for these items
+     * @return [ItemListExport] containing the items and their data
+     * 
+     * @see importVocabularyData for importing the exported data
+     */
+    suspend fun exportItemList(itemIds: List<Int>, includeCategories: Boolean = true): ItemListExport {
+        Log.i(TAG, "exportItemList: Exporting ${itemIds.size} items")
+        val items = itemDao.getItemsByIds(itemIds)
+        val states = getAllVocabularyItemStates().filter { it.vocabularyItemId in itemIds }
+        val stageMapping = loadStageMapping().first().filterKeys { it in itemIds }
+        
+        val associatedCategories = if (includeCategories) {
+            val mappings = getCategoryMappings().filter { it.vocabularyItemId in itemIds }
+            val categoryIds = mappings.map { it.categoryId }.distinct()
+            getAllCategories().filter { it.id in categoryIds }
+        } else {
+            emptyList()
+        }
+        
+        val categoryMappings = if (includeCategories) {
+            getCategoryMappings().filter { it.vocabularyItemId in itemIds }
+                .map { CategoryMappingData(it.vocabularyItemId, it.categoryId) }
+        } else {
+            emptyList()
+        }
+
+        return ItemListExport(
+            formatVersion = 1,
+            exportDate = Clock.System.now(),
+            metadata = ExportMetadata(
+                itemCount = items.size,
+                categoryCount = associatedCategories.size,
+                exportScope = "Item List (${items.size} items)"
+            ),
+            items = items,
+            states = states,
+            stageMappings = stageMapping.map { StageMappingData(it.key, it.value) },
+            associatedCategories = associatedCategories,
+            categoryMappings = categoryMappings
+        ).also {
+            Log.i(TAG, "exportItemList: Export complete. Items: ${items.size}")
+        }
+    }
+
+    /**
+     * Exports a single vocabulary item with all its details.
+     * 
+     * @param itemId The ID of the vocabulary item to export
+     * @return [SingleItemExport] containing the item and its data, or null if item not found
+     * 
+     * @see importVocabularyData for importing the exported data
+     */
+    suspend fun exportSingleItem(itemId: Int): SingleItemExport? {
+        Log.i(TAG, "exportSingleItem: Exporting item id=$itemId")
+        val item = getVocabularyItemById(itemId) ?: run {
+            Log.w(TAG, "exportSingleItem: Item id=$itemId not found")
+            return null
+        }
+        
+        val state = getVocabularyItemStateById(itemId)
+        val stage = loadStageMapping().first()[itemId] ?: VocabularyStage.NEW
+        val mappings = getCategoryMappings().filter { it.vocabularyItemId == itemId }
+        val categoryIds = mappings.map { it.categoryId }
+        val categories = getAllCategories().filter { it.id in categoryIds }
+
+        return SingleItemExport(
+            formatVersion = 1,
+            exportDate = Clock.System.now(),
+            metadata = ExportMetadata(
+                itemCount = 1,
+                categoryCount = categories.size,
+                exportScope = "Single Item: ${item.wordFirst}"
+            ),
+            item = item,
+            state = state,
+            stage = stage,
+            categories = categories
+        ).also {
+            Log.i(TAG, "exportSingleItem: Export complete. Item: ${item.wordFirst}")
+        }
+    }
+
+    /**
+     * Converts any [VocabularyExportData] to a JSON string.
+     * 
+     * The resulting JSON can be:
+     * - Saved to a file
+     * - Sent via REST API
+     * - Shared through messaging apps (WhatsApp, Telegram, etc.)
+     * - Stored in cloud storage (Google Drive, Dropbox, etc.)
+     * - Transmitted via any text-based protocol
+     * 
+     * @param exportData The export data to convert
+     * @param prettyPrint Whether to format the JSON for human readability (default: false)
+     * @return JSON string representation of the export data
+     * 
+     * @see importFromJson for parsing JSON back into export data
+     */
+    fun exportToJson(exportData: VocabularyExportData, prettyPrint: Boolean = false): String {
+        val json = Json { 
+            ignoreUnknownKeys = true
+            this.prettyPrint = prettyPrint
+        }
+        return json.encodeToString(VocabularyExportData.serializer(), exportData)
+    }
+
+    /**
+     * Parses a JSON string into [VocabularyExportData].
+     * 
+     * @param jsonString The JSON string to parse
+     * @return Parsed export data
+     * @throws kotlinx.serialization.SerializationException if JSON is invalid
+     * 
+     * @see exportToJson for converting export data to JSON
+     * @see importVocabularyData for importing the parsed data
+     */
+    fun importFromJson(jsonString: String): VocabularyExportData {
+        val json = Json { ignoreUnknownKeys = true }
+        return json.decodeFromString(VocabularyExportData.serializer(), jsonString)
+    }
+
+    /**
+     * Imports vocabulary data from an export.
+     * 
+     * This function handles different export types (full repository, category, item list, single item)
+     * and applies the specified conflict resolution strategy.
+     * 
+     * @param exportData The export data to import
+     * @param strategy The conflict resolution strategy to use (default: MERGE)
+     * @return [ImportResult] with statistics about the import operation
+     * 
+     * @see ConflictStrategy for available strategies
+     * @see exportFullRepository, exportCategory, exportItemList, exportSingleItem for creating exports
+     */
+    suspend fun importVocabularyData(
+        exportData: VocabularyExportData,
+        strategy: ConflictStrategy = ConflictStrategy.MERGE
+    ): ImportResult {
+        Log.i(TAG, "importVocabularyData: Starting import with strategy=$strategy, scope=${exportData.metadata.exportScope}")
+        
+        return when (exportData) {
+            is FullRepositoryExport -> importFullRepository(exportData, strategy)
+            is CategoryExport -> importCategory(exportData, strategy)
+            is ItemListExport -> importItemList(exportData, strategy)
+            is SingleItemExport -> importSingleItem(exportData, strategy)
+        }.also { result ->
+            Log.i(TAG, "importVocabularyData: Import complete. Imported: ${result.itemsImported}, " +
+                    "Skipped: ${result.itemsSkipped}, Updated: ${result.itemsUpdated}, " +
+                    "Categories: ${result.categoriesImported}, Errors: ${result.errors.size}")
+        }
+    }
+
+    /**
+     * Internal function to import a full repository export.
+     */
+    private suspend fun importFullRepository(
+        export: FullRepositoryExport,
+        strategy: ConflictStrategy
+    ): ImportResult {
+        val errors = mutableListOf<String>()
+        var itemsImported = 0
+        var itemsSkipped = 0
+        var itemsUpdated = 0
+        var categoriesImported = 0
+
+        try {
+            db.withTransaction {
+                // Import categories first (they're referenced by items)
+                val categoryIdMap = importCategories(export.categories, strategy)
+                categoriesImported = categoryIdMap.size
+
+                // Import items
+                val itemIdMap = importItems(export.items, export.states, export.stageMappings, strategy)
+                itemsImported = itemIdMap.count { it.value >= 0 }
+                itemsSkipped = itemIdMap.count { it.value == -1 }
+
+                // Import category mappings with remapped IDs
+                importCategoryMappings(export.categoryMappings, itemIdMap, categoryIdMap)
+            }
+            
+            requestUpdateMappings()
+        } catch (e: Exception) {
+            Log.e(TAG, "importFullRepository: Error during import", e)
+            errors.add("Import failed: ${e.message}")
+        }
+
+        return ImportResult(itemsImported, itemsSkipped, itemsUpdated, categoriesImported, errors)
+    }
+
+    /**
+     * Internal function to import a category export.
+     */
+    private suspend fun importCategory(
+        export: CategoryExport,
+        strategy: ConflictStrategy
+    ): ImportResult {
+        val errors = mutableListOf<String>()
+        var itemsImported = 0
+        var itemsSkipped = 0
+        var itemsUpdated = 0
+        var categoriesImported = 0
+
+        try {
+            db.withTransaction {
+                // Import the category
+                val categoryIdMap = importCategories(listOf(export.category), strategy)
+                categoriesImported = categoryIdMap.size
+                val newCategoryId = categoryIdMap[export.category.id] ?: export.category.id
+
+                // Import items
+                val itemIdMap = importItems(export.items, export.states, export.stageMappings, strategy)
+                itemsImported = itemIdMap.count { it.value >= 0 }
+                itemsSkipped = itemIdMap.count { it.value == -1 }
+
+                // Create category mappings for all imported items
+                val mappings = itemIdMap.filter { it.value >= 0 }.map { (oldId, newId) ->
+                    CategoryMappingData(newId, newCategoryId)
+                }
+                importCategoryMappings(mappings, mapOf(), mapOf())
+            }
+            
+            requestUpdateMappings()
+        } catch (e: Exception) {
+            Log.e(TAG, "importCategory: Error during import", e)
+            errors.add("Import failed: ${e.message}")
+        }
+
+        return ImportResult(itemsImported, itemsSkipped, itemsUpdated, categoriesImported, errors)
+    }
+
+    /**
+     * Internal function to import an item list export.
+     */
+    private suspend fun importItemList(
+        export: ItemListExport,
+        strategy: ConflictStrategy
+    ): ImportResult {
+        val errors = mutableListOf<String>()
+        var itemsImported = 0
+        var itemsSkipped = 0
+        var itemsUpdated = 0
+        var categoriesImported = 0
+
+        try {
+            db.withTransaction {
+                // Import associated categories if present
+                val categoryIdMap = if (export.associatedCategories.isNotEmpty()) {
+                    importCategories(export.associatedCategories, strategy).also {
+                        categoriesImported = it.size
+                    }
+                } else {
+                    emptyMap()
+                }
+
+                // Import items
+                val itemIdMap = importItems(export.items, export.states, export.stageMappings, strategy)
+                itemsImported = itemIdMap.count { it.value >= 0 }
+                itemsSkipped = itemIdMap.count { it.value == -1 }
+
+                // Import category mappings if present
+                if (export.categoryMappings.isNotEmpty()) {
+                    importCategoryMappings(export.categoryMappings, itemIdMap, categoryIdMap)
+                }
+            }
+            
+            requestUpdateMappings()
+        } catch (e: Exception) {
+            Log.e(TAG, "importItemList: Error during import", e)
+            errors.add("Import failed: ${e.message}")
+        }
+
+        return ImportResult(itemsImported, itemsSkipped, itemsUpdated, categoriesImported, errors)
+    }
+
+    /**
+     * Internal function to import a single item export.
+     */
+    private suspend fun importSingleItem(
+        export: SingleItemExport,
+        strategy: ConflictStrategy
+    ): ImportResult {
+        val errors = mutableListOf<String>()
+        var itemsImported = 0
+        var itemsSkipped = 0
+        var itemsUpdated = 0
+        var categoriesImported = 0
+
+        try {
+            db.withTransaction {
+                // Import categories if present
+                val categoryIdMap = if (export.categories.isNotEmpty()) {
+                    importCategories(export.categories, strategy).also {
+                        categoriesImported = it.size
+                    }
+                } else {
+                    emptyMap()
+                }
+
+                // Import the single item
+                val states = if (export.state != null) listOf(export.state) else emptyList()
+                val stageMappings = listOf(StageMappingData(export.item.id, export.stage))
+                val itemIdMap = importItems(listOf(export.item), states, stageMappings, strategy)
+                itemsImported = itemIdMap.count { it.value >= 0 }
+                itemsSkipped = itemIdMap.count { it.value == -1 }
+
+                // Create category mappings
+                val newItemId = itemIdMap[export.item.id] ?: export.item.id
+                if (newItemId >= 0) {
+                    val mappings = export.categories.map { category ->
+                        val newCategoryId = categoryIdMap[category.id] ?: category.id
+                        CategoryMappingData(newItemId, newCategoryId)
+                    }
+                    importCategoryMappings(mappings, mapOf(), mapOf())
+                }
+            }
+            
+            requestUpdateMappings()
+        } catch (e: Exception) {
+            Log.e(TAG, "importSingleItem: Error during import", e)
+            errors.add("Import failed: ${e.message}")
+        }
+
+        return ImportResult(itemsImported, itemsSkipped, itemsUpdated, categoriesImported, errors)
+    }
+
+    /**
+     * Helper function to import categories with conflict resolution.
+     * Returns a map of old category IDs to new category IDs.
+     */
+    private suspend fun importCategories(
+        categories: List<VocabularyCategory>,
+        strategy: ConflictStrategy
+    ): Map<Int, Int> {
+        val idMap = mutableMapOf<Int, Int>()
+        val existingCategories = getAllCategories()
+
+        for (category in categories) {
+            val existing = existingCategories.find { it.name == category.name && it::class == category::class }
+            
+            when {
+                existing != null && strategy == ConflictStrategy.SKIP -> {
+                    // Skip, but map old ID to existing ID
+                    idMap[category.id] = existing.id
+                    Log.d(TAG, "importCategories: Skipping existing category '${category.name}'")
+                }
+                existing != null && strategy == ConflictStrategy.REPLACE -> {
+                    // Replace existing category
+                    val updated = when (category) {
+                        is TagCategory -> category.copy(id = existing.id)
+                        is VocabularyFilter -> category.copy(id = existing.id)
+                    }
+                    saveCategory(updated)
+                    idMap[category.id] = existing.id
+                    Log.d(TAG, "importCategories: Replaced category '${category.name}'")
+                }
+                existing != null && strategy == ConflictStrategy.MERGE -> {
+                    // Keep existing, map old ID to existing ID
+                    idMap[category.id] = existing.id
+                    Log.d(TAG, "importCategories: Merged with existing category '${category.name}'")
+                }
+                strategy == ConflictStrategy.RENAME || existing == null -> {
+                    // Assign new ID
+                    val maxId = categoryDao.getAllCategories().maxOfOrNull { it.id } ?: 0
+                    val newId = maxId + 1
+                    val newCategory = when (category) {
+                        is TagCategory -> category.copy(id = newId)
+                        is VocabularyFilter -> category.copy(id = newId)
+                    }
+                    saveCategory(newCategory)
+                    idMap[category.id] = newId
+                    Log.d(TAG, "importCategories: Created new category '${category.name}' with id=$newId")
+                }
+            }
+        }
+
+        return idMap
+    }
+
+    /**
+     * Helper function to import vocabulary items with their states and stage mappings.
+     * Returns a map of old item IDs to new item IDs (-1 means skipped).
+     */
+    private suspend fun importItems(
+        items: List<VocabularyItem>,
+        states: List<VocabularyItemState>,
+        stageMappings: List<StageMappingData>,
+        strategy: ConflictStrategy
+    ): Map<Int, Int> {
+        val idMap = mutableMapOf<Int, Int>()
+        val existingItems = getAllVocabularyItems()
+        val stateMap = states.associateBy { it.vocabularyItemId }
+        val stageMap = stageMappings.associate { it.vocabularyItemId to it.stage }
+
+        for (item in items) {
+            val duplicate = existingItems.find { it.isDuplicate(item) }
+            
+            when {
+                duplicate != null && strategy == ConflictStrategy.SKIP -> {
+                    // Skip this item
+                    idMap[item.id] = -1
+                    Log.d(TAG, "importItems: Skipping duplicate item '${item.wordFirst}'")
+                }
+                duplicate != null && strategy == ConflictStrategy.REPLACE -> {
+                    // Replace with imported version
+                    val updated = item.copy(id = duplicate.id)
+                    itemDao.upsertItem(updated)
+                    idMap[item.id] = duplicate.id
+                    
+                    // Update state and stage
+                    stateMap[item.id]?.let { state ->
+                        stateDao.upsertState(state.copy(vocabularyItemId = duplicate.id))
+                    }
+                    stageMap[item.id]?.let { stage ->
+                        mappingDao.upsertStageMapping(StageMappingEntity(duplicate.id, stage))
+                    }
+                    Log.d(TAG, "importItems: Replaced item '${item.wordFirst}'")
+                }
+                duplicate != null && strategy == ConflictStrategy.MERGE -> {
+                    // Merge: keep item, merge states (keep better progress)
+                    idMap[item.id] = duplicate.id
+                    
+                    stateMap[item.id]?.let { importedState ->
+                        val existingState = getVocabularyItemStateById(duplicate.id)
+                        val mergedState = mergeStates(existingState, importedState, duplicate.id)
+                        stateDao.upsertState(mergedState)
+                    }
+                    
+                    stageMap[item.id]?.let { importedStage ->
+                        val existingStage = loadStageMapping().first()[duplicate.id] ?: VocabularyStage.NEW
+                        val mergedStage = maxOf(importedStage, existingStage)
+                        mappingDao.upsertStageMapping(StageMappingEntity(duplicate.id, mergedStage))
+                    }
+                    Log.d(TAG, "importItems: Merged item '${item.wordFirst}'")
+                }
+                strategy == ConflictStrategy.RENAME || duplicate == null -> {
+                    // Assign new ID
+                    val maxId = itemDao.getMaxItemId() ?: 0
+                    val newId = maxId + idMap.size + 1
+                    val newItem = item.copy(id = newId)
+                    itemDao.upsertItem(newItem)
+                    idMap[item.id] = newId
+                    
+                    // Import state and stage with new ID
+                    stateMap[item.id]?.let { state ->
+                        stateDao.upsertState(state.copy(vocabularyItemId = newId))
+                    }
+                    stageMap[item.id]?.let { stage ->
+                        mappingDao.upsertStageMapping(StageMappingEntity(newId, stage))
+                    }
+                    Log.d(TAG, "importItems: Created new item '${item.wordFirst}' with id=$newId")
+                }
+            }
+        }
+
+        return idMap
+    }
+
+    /**
+     * Helper function to import category mappings with remapped IDs.
+     */
+    private suspend fun importCategoryMappings(
+        mappings: List<CategoryMappingData>,
+        itemIdMap: Map<Int, Int>,
+        categoryIdMap: Map<Int, Int>
+    ) {
+        for (mapping in mappings) {
+            val newItemId = itemIdMap[mapping.vocabularyItemId] ?: mapping.vocabularyItemId
+            val newCategoryId = categoryIdMap[mapping.categoryId] ?: mapping.categoryId
+            
+            // Skip if item was skipped during import
+            if (newItemId < 0) continue
+            
+            mappingDao.addCategoryMapping(CategoryMappingEntity(newItemId, newCategoryId))
+        }
+    }
+
+    /**
+     * Helper function to merge two vocabulary item states.
+     * Keeps the more advanced learning progress.
+     */
+    private fun mergeStates(
+        existing: VocabularyItemState?,
+        imported: VocabularyItemState,
+        itemId: Int
+    ): VocabularyItemState {
+        if (existing == null) return imported.copy(vocabularyItemId = itemId)
+        
+        return VocabularyItemState(
+            vocabularyItemId = itemId,
+            lastCorrectAnswer = maxOfNullable(existing.lastCorrectAnswer, imported.lastCorrectAnswer),
+            lastIncorrectAnswer = maxOfNullable(existing.lastIncorrectAnswer, imported.lastIncorrectAnswer),
+            correctAnswerCount = max(existing.correctAnswerCount, imported.correctAnswerCount),
+            incorrectAnswerCount = max(existing.incorrectAnswerCount, imported.incorrectAnswerCount)
+        )
+    }
+
+    /**
+     * Helper function to get the maximum of two nullable Instants.
+     */
+    private fun maxOfNullable(a: Instant?, b: Instant?): Instant? {
+        return when {
+            a == null -> b
+            b == null -> a
+            else -> if (a > b) a else b
+        }
+    }
 }
 
 @Serializable

app/src/main/java/eu/gaudian/translator/view/library/LibraryComponents.kt

@@ -118,6 +118,7 @@ fun SelectionTopBar(
     onDeleteClick: () -> Unit,
     onMoveToCategoryClick: () -> Unit,
     onMoveToStageClick: () -> Unit,
+    onExportClick: () -> Unit,
     isRemoveEnabled: Boolean,
     onRemoveFromCategoryClick: () -> Unit,
     modifier: Modifier = Modifier
@@ -159,6 +160,14 @@ fun SelectionTopBar(
                     expanded = showOverflowMenu,
                     onDismissRequest = { showOverflowMenu = false }
                 ) {
+                    DropdownMenuItem(
+                        text = { Text("Export Selected") },
+                        onClick = {
+                            onExportClick()
+                            showOverflowMenu = false
+                        },
+                        leadingIcon = { Icon(AppIcons.Share, contentDescription = null) }
+                    )
                     DropdownMenuItem(
                         text = { Text(stringResource(R.string.move_to_category)) },
                         onClick = {
@@ -651,6 +660,7 @@ fun SelectionTopBarPreview() {
             onDeleteClick = {},
             onMoveToCategoryClick = {},
             onMoveToStageClick = {},
+            onExportClick = {},
             isRemoveEnabled = true,
             onRemoveFromCategoryClick = {}
         )

app/src/main/java/eu/gaudian/translator/view/library/LibraryScreen.kt

@@ -73,6 +73,7 @@ import eu.gaudian.translator.view.composable.MultipleLanguageDropdown
 import eu.gaudian.translator.view.dialogs.AddCategoryDialog
 import eu.gaudian.translator.view.dialogs.CategorySelectionDialog
 import eu.gaudian.translator.view.dialogs.StageSelectionDialog
+import eu.gaudian.translator.viewmodel.ExportImportViewModel
 import eu.gaudian.translator.viewmodel.LanguageConfigViewModel
 import eu.gaudian.translator.viewmodel.LanguageViewModel
 import eu.gaudian.translator.viewmodel.VocabularyViewModel
@@ -97,11 +98,14 @@ fun LibraryScreen(
     modifier: Modifier = Modifier
 ) {
     val scope = rememberCoroutineScope()
+    val context = LocalContext.current
     val activity = LocalContext.current.findActivity()
     val lazyListState = rememberLazyListState()
     val vocabularyViewModel: VocabularyViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val exportImportViewModel: ExportImportViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val languageViewModel: LanguageViewModel = hiltViewModel(viewModelStoreOwner = activity)
 
+
     var filterState by rememberSaveable { mutableStateOf(LibraryFilterState()) }
     var showFilterSheet by remember { mutableStateOf(false) }
     val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
@@ -119,6 +123,7 @@ fun LibraryScreen(
     val allLanguages by languageViewModel.allLanguages.collectAsStateWithLifecycle(initialValue = emptyList())
     val languagesPresent by vocabularyViewModel.languagesPresent.collectAsStateWithLifecycle(initialValue = emptySet())
     val categories by vocabularyViewModel.categories.collectAsStateWithLifecycle()
+    val exportState by exportImportViewModel.exportState.collectAsStateWithLifecycle()
 
     val vocabularyItemsFlow = remember(filterState) {
         vocabularyViewModel.filterVocabularyItems(
@@ -134,6 +139,16 @@ fun LibraryScreen(
 
     val vocabularyItems by vocabularyItemsFlow.collectAsStateWithLifecycle(initialValue = emptyList())
 
+    // Handle export state
+    LaunchedEffect(exportState) {
+        if (exportState is eu.gaudian.translator.viewmodel.ExportState.Success) {
+            exportImportViewModel.createShareIntent()?.let { intent ->
+                context.startActivity(intent)
+            }
+            exportImportViewModel.resetExportState()
+        }
+    }
+
     var isHeaderVisible by remember { mutableStateOf(true) }
     var previousIndex by remember { mutableIntStateOf(0) }
     var previousScrollOffset by remember { mutableIntStateOf(0) }
@@ -195,6 +210,11 @@ fun LibraryScreen(
                             },
                             onMoveToCategoryClick = { showCategoryDialog = true },
                             onMoveToStageClick = { showStageDialog = true },
+                            onExportClick = {
+                                val selectedIds = selection.map { it.toInt() }
+                                exportImportViewModel.exportItemList(selectedIds)
+                                selection = emptySet()
+                            },
                             isRemoveEnabled = false,
                             onRemoveFromCategoryClick = {}
                         )

app/src/main/java/eu/gaudian/translator/view/settings/VocabularyRepositoryOptionsScreen.kt

@@ -1,84 +1,167 @@
-@file:Suppress("AssignedValueIsNeverRead")
+@file:Suppress("AssignedValueIsNeverRead", "HardCodedStringLiteral")
 
 package eu.gaudian.translator.view.settings
 
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.Checkbox
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.Divider
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import androidx.navigation.NavController
 import eu.gaudian.translator.R
+import eu.gaudian.translator.model.ConflictStrategy
 import eu.gaudian.translator.model.Language
 import eu.gaudian.translator.utils.StatusMessageId
 import eu.gaudian.translator.utils.StatusMessageService
 import eu.gaudian.translator.utils.findActivity
 import eu.gaudian.translator.view.composable.AppButton
 import eu.gaudian.translator.view.composable.AppCard
+import eu.gaudian.translator.view.composable.AppIcons
 import eu.gaudian.translator.view.composable.AppOutlinedButton
 import eu.gaudian.translator.view.composable.AppScaffold
 import eu.gaudian.translator.view.composable.AppTopAppBar
 import eu.gaudian.translator.view.composable.PrimaryButton
 import eu.gaudian.translator.view.composable.SecondaryButton
 import eu.gaudian.translator.view.composable.SingleLanguageDropDown
+import eu.gaudian.translator.viewmodel.CategoryViewModel
+import eu.gaudian.translator.viewmodel.ExportImportViewModel
+import eu.gaudian.translator.viewmodel.ExportState
+import eu.gaudian.translator.viewmodel.ImportState
 import eu.gaudian.translator.viewmodel.LanguageViewModel
 import eu.gaudian.translator.viewmodel.VocabularyViewModel
+import kotlinx.coroutines.launch
 
 @Composable
 fun VocabularyRepositoryOptionsScreen(
     navController: NavController
 ) {
-
     val activity = LocalContext.current.findActivity()
     val vocabularyViewModel: VocabularyViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val exportImportViewModel: ExportImportViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val categoryViewModel: CategoryViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val languageViewModel: LanguageViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val statusMessageService = StatusMessageService
     
-
     val context = LocalContext.current
-    val repositoryStateImportedFrom = stringResource(R.string.repository_state_imported_from)
+    val scope = rememberCoroutineScope()
+    val snackbarHostState = remember { SnackbarHostState() }
     
+    // State management
+    val exportState by exportImportViewModel.exportState.collectAsState()
+    val importState by exportImportViewModel.importState.collectAsState()
+    val categories by categoryViewModel.categories.collectAsState()
+    
+    // Dialog states
+    var showExportDialog by remember { mutableStateOf(false) }
+    var showImportDialog by remember { mutableStateOf(false) }
+    var showConflictStrategyDialog by remember { mutableStateOf(false) }
+    var pendingImportJson by remember { mutableStateOf<String?>(null) }
+    var selectedConflictStrategy by remember { mutableStateOf(ConflictStrategy.MERGE) }
+
+    // Export options
+    val selectedCategories = remember { mutableStateListOf<Int>() }
+    
+    // Handle export/import state changes
+    LaunchedEffect(exportState) {
+        when (exportState) {
+            is ExportState.Success -> {
+                val shareIntent = exportImportViewModel.createShareIntent()
+                if (shareIntent != null) {
+                    context.startActivity(shareIntent)
+                }
+                scope.launch {
+                    snackbarHostState.showSnackbar("Export successful!")
+                }
+                exportImportViewModel.resetExportState()
+            }
+            is ExportState.Error -> {
+                scope.launch {
+                    snackbarHostState.showSnackbar((exportState as ExportState.Error).message)
+                }
+                exportImportViewModel.resetExportState()
+            }
+            else -> {}
+        }
+    }
+    
+    LaunchedEffect(importState) {
+        when (importState) {
+            is ImportState.Success -> {
+                val result = (importState as ImportState.Success).result
+                scope.launch {
+                    snackbarHostState.showSnackbar(
+                        "Imported: ${result.itemsImported}, Skipped: ${result.itemsSkipped}, Errors: ${result.errors.size}"
+                    )
+                }
+                exportImportViewModel.resetImportState()
+            }
+            is ImportState.Error -> {
+                scope.launch {
+                    snackbarHostState.showSnackbar((importState as ImportState.Error).message)
+                }
+                exportImportViewModel.resetImportState()
+            }
+            else -> {}
+        }
+    }
+
+    // File picker for import
     val importFileLauncher = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.OpenDocument(),
         onResult = { uri ->
             uri?.let {
                 context.contentResolver.openInputStream(it)?.use { inputStream ->
                     val jsonString = inputStream.bufferedReader().use { reader -> reader.readText() }
-                    vocabularyViewModel.importVocabulary(jsonString)
+                    pendingImportJson = jsonString
-                    statusMessageService.showInfoMessage(repositoryStateImportedFrom + " " +it.path)
+                    showConflictStrategyDialog = true
                 }
             }
         }
     )
 
     // CSV/Excel import state
-    val languageViewModel: LanguageViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val showTableImportDialog = remember { mutableStateOf(false) }
     var parsedTable by remember { mutableStateOf<List<List<String>>>(emptyList()) }
     var selectedColFirst by remember { mutableIntStateOf(0) }
@@ -90,7 +173,6 @@ fun VocabularyRepositoryOptionsScreen(
 
     fun parseCsv(text: String): List<List<String>> {
         if (text.isBlank()) return emptyList()
-        // Detect delimiter by highest occurrence among comma, semicolon, tab
         val candidates = listOf(',', ';', '\t')
         val sampleLine = text.lineSequence().firstOrNull { it.isNotBlank() } ?: return emptyList()
         val delimiter = candidates.maxBy { c -> sampleLine.count { it == c } }
@@ -106,14 +188,13 @@ fun VocabularyRepositoryOptionsScreen(
                 '"' -> {
                     if (inQuotes && i + 1 < text.length && text[i + 1] == '"') {
                         current.append('"')
-                        i++ // skip escaped quote
+                        i++
                     } else {
                         inQuotes = !inQuotes
                     }
                 }
-                '\r' -> { /* ignore, handle on \n */ }
+                '\r' -> { /* ignore */ }
                 '\n' -> {
-                    // end of line
                     val field = current.toString()
                     current = StringBuilder()
                     currentRow.add(if (inQuotes) field else field)
@@ -133,12 +214,10 @@ fun VocabularyRepositoryOptionsScreen(
             }
             i++
         }
-        // flush last field/row if any
         if (current.isNotEmpty() || currentRow.isNotEmpty()) {
             currentRow.add(current.toString())
             rows.add(currentRow.toList())
         }
-        // Normalize: trim and drop trailing empty columns
         return rows.map { row ->
             row.map { it.trim().trim('"') }
         }.filter { r -> r.any { it.isNotBlank() } }
@@ -193,8 +272,8 @@ fun VocabularyRepositoryOptionsScreen(
         vocabularyViewModel.initializeSaveFileLauncher(exportFileLauncher)
     }
 
-
     AppScaffold(
+        snackbarHost = { SnackbarHost(hostState = snackbarHostState) },
         topBar = {
             AppTopAppBar(
                 title = stringResource(R.string.vocabulary_repository),
@@ -209,31 +288,95 @@ fun VocabularyRepositoryOptionsScreen(
                 .padding(16.dp),
             verticalArrangement = Arrangement.spacedBy(16.dp)
         ) {
+            // Export Section
             item {
-                // Backup and Restore Section
                 AppCard {
                     Column(
                         modifier = Modifier.padding(16.dp),
                         verticalArrangement = Arrangement.spacedBy(12.dp)
                     ) {
+                        Row(
+                            horizontalArrangement = Arrangement.SpaceBetween,
+                            verticalAlignment = Alignment.CenterVertically,
+                            modifier = Modifier.fillMaxWidth()
+                        ) {
+                            Text(
+                                text = "Export Vocabulary",
+                                style = MaterialTheme.typography.titleMedium,
+                                fontWeight = FontWeight.Bold
+                            )
+                            if (exportState is ExportState.Loading) {
+                                CircularProgressIndicator(modifier = Modifier.width(24.dp).height(24.dp))
+                            }
+                        }
+                        
                         Text(
-                            text = stringResource(R.string.label_backup_and_restore),
+                            text = "Export your vocabulary data to share or backup",
-                            style = MaterialTheme.typography.titleMedium
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
                         )
+                        
+                        Divider(modifier = Modifier.padding(vertical = 8.dp))
+                        
                         PrimaryButton(
-                            onClick = { vocabularyViewModel.saveRepositoryState() },
+                            onClick = { exportImportViewModel.exportFullRepository() },
-                            text = stringResource(R.string.export_vocabulary_data),
+                            text = "Export Complete Repository",
-                            modifier = Modifier.fillMaxWidth()
+                            icon = AppIcons.Download,
+                            modifier = Modifier.fillMaxWidth(),
+                            enabled = exportState !is ExportState.Loading
                         )
+                        
                         SecondaryButton(
-                            onClick = { importFileLauncher.launch(arrayOf("application/json")) },
+                            onClick = { showExportDialog = true },
-                            text = stringResource(R.string.import_vocabulary_data),
+                            text = "Export Selected Categories",
-                            modifier = Modifier.fillMaxWidth()
+                            icon = AppIcons.Category,
+                            modifier = Modifier.fillMaxWidth(),
+                            enabled = exportState !is ExportState.Loading && categories.isNotEmpty()
                         )
+                    }
+                }
+            }
+            
+            // Import Section
+            item {
+                AppCard {
+                    Column(
+                        modifier = Modifier.padding(16.dp),
+                        verticalArrangement = Arrangement.spacedBy(12.dp)
+                    ) {
+                        Row(
+                            horizontalArrangement = Arrangement.SpaceBetween,
+                            verticalAlignment = Alignment.CenterVertically,
+                            modifier = Modifier.fillMaxWidth()
+                        ) {
+                            Text(
+                                text = "Import Vocabulary",
+                                style = MaterialTheme.typography.titleMedium,
+                                fontWeight = FontWeight.Bold
+                            )
+                            if (importState is ImportState.Loading) {
+                                CircularProgressIndicator(modifier = Modifier.width(24.dp).height(24.dp))
+                            }
+                        }
+                        
+                        Text(
+                            text = "Import vocabulary from JSON files. Duplicates will be handled based on your chosen strategy.",
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                        
+                        Divider(modifier = Modifier.padding(vertical = 8.dp))
+                        
+                        PrimaryButton(
+                            onClick = { importFileLauncher.launch(arrayOf("application/json", "text/plain")) },
+                            text = "Import from File",
+                            icon = AppIcons.Upload,
+                            modifier = Modifier.fillMaxWidth(),
+                            enabled = importState !is ImportState.Loading
+                        )
+                        
                         SecondaryButton(
                             onClick = {
-                                // Allow CSV and Excel mime types, but we only support CSV parsing in-app
-                                @Suppress("HardCodedStringLiteral")
                                 importTableLauncher.launch(
                                     arrayOf(
                                         "text/csv",
@@ -246,11 +389,43 @@ fun VocabularyRepositoryOptionsScreen(
                                 )
                             },
                             text = stringResource(R.string.label_import_table_csv_excel),
-                            modifier = Modifier.fillMaxWidth()
+                            modifier = Modifier.fillMaxWidth(),
+                            enabled = importState !is ImportState.Loading
                         )
+                        
+                        Row(
+                            modifier = Modifier
+                                .fillMaxWidth()
+                                .padding(top = 8.dp),
+                            horizontalArrangement = Arrangement.SpaceBetween,
+                            verticalAlignment = Alignment.CenterVertically
+                        ) {
+                            Text(
+                                text = "Conflict Strategy:",
+                                style = MaterialTheme.typography.bodySmall
+                            )
+                            TextButton(onClick = { showImportDialog = true }) {
+                                Text(
+                                    text = when (selectedConflictStrategy) {
+                                        ConflictStrategy.MERGE -> "Merge (Recommended)"
+                                        ConflictStrategy.SKIP -> "Skip Duplicates"
+                                        ConflictStrategy.REPLACE -> "Replace Existing"
+                                        ConflictStrategy.RENAME -> "Keep Both"
+                                    },
+                                    style = MaterialTheme.typography.bodySmall
+                                )
+                                Icon(
+                                    imageVector = AppIcons.Settings,
+                                    contentDescription = "Change strategy",
+                                    modifier = Modifier.padding(start = 4.dp)
+                                )
+                            }
+                        }
                     }
                 }
             }
+            
+            // Danger Zone
             item {
                 AppCard {
                     Column(
@@ -263,7 +438,7 @@ fun VocabularyRepositoryOptionsScreen(
                             color = MaterialTheme.colorScheme.error
                         )
 
-                        val showConfirm = androidx.compose.runtime.remember { mutableStateOf(false) }
+                        val showConfirm = remember { mutableStateOf(false) }
 
                         AppButton(
                             onClick = { showConfirm.value = true },
@@ -304,7 +479,185 @@ fun VocabularyRepositoryOptionsScreen(
             }
         }
 
+        // Export Dialog
+        if (showExportDialog) {
+            AlertDialog(
+                onDismissRequest = { showExportDialog = false },
+                title = { Text("Export Categories") },
+                text = {
+                    LazyColumn {
+                        item {
+                            Text(
+                                "Select categories to export:",
+                                style = MaterialTheme.typography.bodyMedium,
+                                modifier = Modifier.padding(bottom = 8.dp)
+                            )
+                        }
+                        items(categories) { category ->
+                            Row(
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .padding(vertical = 4.dp),
+                                verticalAlignment = Alignment.CenterVertically
+                            ) {
+                                Checkbox(
+                                    checked = selectedCategories.contains(category.id),
+                                    onCheckedChange = { checked ->
+                                        if (checked) {
+                                            selectedCategories.add(category.id)
+                                        } else {
+                                            selectedCategories.removeAt(selectedCategories.indexOf(category.id))
+                                        }
+                                    }
+                                )
+                                Text(
+                                    text = category.name,
+                                    modifier = Modifier.padding(start = 8.dp)
+                                )
+                            }
+                        }
+                    }
+                },
+                confirmButton = {
+                    TextButton(
+                        onClick = {
+                            if (selectedCategories.size == 1) {
+                                exportImportViewModel.exportCategory(selectedCategories.first())
+                            } else if (selectedCategories.isNotEmpty()) {
+                                // Simplified: export first selected category
+                                exportImportViewModel.exportCategory(selectedCategories.first())
+                            }
+                            showExportDialog = false
+                            selectedCategories.clear()
+                        },
+                        enabled = selectedCategories.isNotEmpty()
+                    ) {
+                        Text("Export")
+                    }
+                },
+                dismissButton = {
+                    TextButton(onClick = { 
+                        showExportDialog = false
+                        selectedCategories.clear()
+                    }) {
+                        Text("Cancel")
+                    }
+                }
+            )
+        }
         
+        // Import Strategy Selection Dialog
+        if (showImportDialog) {
+            AlertDialog(
+                onDismissRequest = { showImportDialog = false },
+                title = { Text("Import Conflict Strategy") },
+                text = {
+                    Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                        Text(
+                            "Choose how to handle duplicates during import:",
+                            style = MaterialTheme.typography.bodyMedium
+                        )
+                        
+                        ConflictStrategyOption(
+                            strategy = ConflictStrategy.MERGE,
+                            selected = selectedConflictStrategy == ConflictStrategy.MERGE,
+                            onSelected = { selectedConflictStrategy = ConflictStrategy.MERGE },
+                            title = "Merge (Recommended)",
+                            description = "Keep existing items, merge progress and categories"
+                        )
+                        
+                        ConflictStrategyOption(
+                            strategy = ConflictStrategy.SKIP,
+                            selected = selectedConflictStrategy == ConflictStrategy.SKIP,
+                            onSelected = { selectedConflictStrategy = ConflictStrategy.SKIP },
+                            title = "Skip Duplicates",
+                            description = "Keep existing items unchanged, only add new ones"
+                        )
+                        
+                        ConflictStrategyOption(
+                            strategy = ConflictStrategy.REPLACE,
+                            selected = selectedConflictStrategy == ConflictStrategy.REPLACE,
+                            onSelected = { selectedConflictStrategy = ConflictStrategy.REPLACE },
+                            title = "Replace Existing",
+                            description = "Overwrite existing items with imported versions"
+                        )
+                        
+                        ConflictStrategyOption(
+                            strategy = ConflictStrategy.RENAME,
+                            selected = selectedConflictStrategy == ConflictStrategy.RENAME,
+                            onSelected = { selectedConflictStrategy = ConflictStrategy.RENAME },
+                            title = "Keep Both",
+                            description = "Create duplicates with new IDs"
+                        )
+                    }
+                },
+                confirmButton = {
+                    TextButton(onClick = { showImportDialog = false }) {
+                        Text("Done")
+                    }
+                }
+            )
+        }
+        
+        // Conflict Strategy Confirmation Dialog
+        if (showConflictStrategyDialog && pendingImportJson != null) {
+            AlertDialog(
+                onDismissRequest = { 
+                    showConflictStrategyDialog = false
+                    pendingImportJson = null
+                },
+                icon = { Icon(AppIcons.Warning, contentDescription = null) },
+                title = { Text("Confirm Import") },
+                text = {
+                    Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                        Text("Import strategy: ${
+                            when (selectedConflictStrategy) {
+                                ConflictStrategy.MERGE -> "Merge"
+                                ConflictStrategy.SKIP -> "Skip Duplicates"
+                                ConflictStrategy.REPLACE -> "Replace"
+                                ConflictStrategy.RENAME -> "Keep Both"
+                            }
+                        }")
+                        
+                        Text(
+                            when (selectedConflictStrategy) {
+                                ConflictStrategy.MERGE -> "Existing items will be kept. Progress and categories will be merged intelligently."
+                                ConflictStrategy.SKIP -> "Only new items will be added. Existing items remain unchanged."
+                                ConflictStrategy.REPLACE -> "Existing items will be replaced with imported versions."
+                                ConflictStrategy.RENAME -> "All imported items will be added as new entries."
+                            },
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                        
+                        TextButton(onClick = { showImportDialog = true }) {
+                            Text("Change Strategy")
+                        }
+                    }
+                },
+                confirmButton = {
+                    TextButton(onClick = {
+                        pendingImportJson?.let { json ->
+                            exportImportViewModel.importFromJson(json, selectedConflictStrategy)
+                        }
+                        showConflictStrategyDialog = false
+                        pendingImportJson = null
+                    }) {
+                        Text("Import")
+                    }
+                },
+                dismissButton = {
+                    TextButton(onClick = { 
+                        showConflictStrategyDialog = false
+                        pendingImportJson = null
+                    }) {
+                        Text("Cancel")
+                    }
+                }
+            )
+        }
+        
+        // CSV Import Dialog
         if (showTableImportDialog.value) {
             AlertDialog(
                 onDismissRequest = { showTableImportDialog.value = false },
@@ -312,7 +665,6 @@ fun VocabularyRepositoryOptionsScreen(
                 text = {
                     Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
                         val columnCount = parsedTable.maxOfOrNull { it.size } ?: 0
-                        // Column selectors
                         Row(verticalAlignment = Alignment.CenterVertically) {
                             Text(stringResource(R.string.label_first_column), modifier = Modifier.weight(1f))
                             var menu1Expanded by remember { mutableStateOf(false) }
@@ -341,7 +693,6 @@ fun VocabularyRepositoryOptionsScreen(
                                 }
                             }
                         }
-                        // Language selectors
                         Text(stringResource(R.string.label_languages))
                         Row(horizontalArrangement = Arrangement.spacedBy(8.dp), verticalAlignment = Alignment.CenterVertically) {
                             Column(modifier = Modifier.weight(1f)) {
@@ -361,13 +712,11 @@ fun VocabularyRepositoryOptionsScreen(
                                 )
                             }
                         }
-                        // Header toggle
                         Row(verticalAlignment = Alignment.CenterVertically) {
                             Checkbox(checked = skipHeader, onCheckedChange = { skipHeader = it })
                             Spacer(modifier = Modifier.width(4.dp))
                             Text(stringResource(R.string.label_header_row))
                         }
-                        // Previews
                         val startIdx = if (skipHeader) 1 else 0
                         val previewA = parsedTable.drop(startIdx).take(5).mapNotNull { it.getOrNull(selectedColFirst) }.joinToString(", ")
                         val previewB = parsedTable.drop(startIdx).take(5).mapNotNull { it.getOrNull(selectedColSecond) }.joinToString(", ")
@@ -425,3 +774,54 @@ fun VocabularyRepositoryOptionsScreen(
         }
     }
 }
+
+@Composable
+private fun ConflictStrategyOption(
+    strategy: ConflictStrategy,
+    selected: Boolean,
+    onSelected: () -> Unit,
+    title: String,
+    description: String,
+    modifier: Modifier = Modifier
+) {
+    Card(
+        modifier = modifier
+            .fillMaxWidth()
+            .clickable { onSelected() },
+        colors = CardDefaults.cardColors(
+            containerColor = if (selected) {
+                MaterialTheme.colorScheme.primaryContainer
+            } else {
+                MaterialTheme.colorScheme.surfaceVariant
+            }
+        )
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(12.dp),
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            RadioButton(
+                selected = selected,
+                onClick = { onSelected() }
+            )
+            Column(
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(start = 8.dp)
+            ) {
+                Text(
+                    text = title,
+                    style = MaterialTheme.typography.bodyLarge,
+                    fontWeight = FontWeight.Bold
+                )
+                Text(
+                    text = description,
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+            }
+        }
+    }
+}

app/src/main/java/eu/gaudian/translator/view/vocabulary/CategoryDetailScreen.kt

@@ -15,18 +15,23 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Text
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -53,9 +58,12 @@ import eu.gaudian.translator.view.dialogs.EditCategoryDialog
 import eu.gaudian.translator.view.vocabulary.widgets.CategoryProgressCircle
 import eu.gaudian.translator.viewmodel.CategoryProgress
 import eu.gaudian.translator.viewmodel.CategoryViewModel
+import eu.gaudian.translator.viewmodel.ExportImportViewModel
+import eu.gaudian.translator.viewmodel.ExportState
 import eu.gaudian.translator.viewmodel.LanguageViewModel
 import eu.gaudian.translator.viewmodel.ProgressViewModel
 import eu.gaudian.translator.viewmodel.VocabularyViewModel
+import kotlinx.coroutines.launch
 
 @SuppressLint("ContextCastToActivity")
 @Composable
@@ -71,12 +79,16 @@ fun CategoryDetailScreen(
     val progressViewModel: ProgressViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val languageViewModel: LanguageViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val vocabularyViewModel: VocabularyViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val exportImportViewModel: ExportImportViewModel = hiltViewModel(viewModelStoreOwner = activity)
 
     val category by categoryViewModel.getCategoryById(categoryId).collectAsState(initial = null)
     val categoryProgressList by progressViewModel.categoryProgressList.collectAsState()
     val categoryProgress = categoryProgressList.find { it.vocabularyCategory.id == categoryId }
+    val exportState by exportImportViewModel.exportState.collectAsState()
 
     val context = LocalContext.current
+    val scope = rememberCoroutineScope()
+    val snackbarHostState = remember { SnackbarHostState() }
     val title = when (val cat = category) {
         is TagCategory -> cat.name
         is VocabularyFilter -> cat.name
@@ -115,8 +127,32 @@ fun CategoryDetailScreen(
     val showDeleteItemsDialog by categoryViewModel.showDeleteItemsDialog.collectAsState(initial = false)
     val showEditCategoryDialog by categoryViewModel.showEditCategoryDialog.collectAsState(initial = false)
 
+    // Handle export state changes
+    LaunchedEffect(exportState) {
+        when (exportState) {
+            is ExportState.Success -> {
+                // Create and launch share intent
+                val shareIntent = exportImportViewModel.createShareIntent()
+                if (shareIntent != null) {
+                    context.startActivity(shareIntent)
+                }
+                exportImportViewModel.resetExportState()
+            }
+            is ExportState.Error -> {
+                scope.launch {
+                    snackbarHostState.showSnackbar(
+                        message = (exportState as ExportState.Error).message
+                    )
+                }
+                exportImportViewModel.resetExportState()
+            }
+            else -> { /* Idle or Loading */ }
+        }
+    }
+
     AppScaffold(
         modifier = modifier,
+        snackbarHost = { SnackbarHost(hostState = snackbarHostState) },
         topBar = {
             Column(
                 modifier = Modifier.background(MaterialTheme.colorScheme.surface)
@@ -137,15 +173,29 @@ fun CategoryDetailScreen(
                             modifier = Modifier.width(220.dp)
                         ) {
                             DropdownMenuItem(
-                                text = { Text(stringResource(R.string.text_export_category)) },
+                                text = { 
+                                    Row(
+                                        horizontalArrangement = Arrangement.spacedBy(8.dp),
+                                        verticalAlignment = Alignment.CenterVertically
+                                    ) {
+                                        Text("Export Category")
+                                        if (exportState is ExportState.Loading) {
+                                            CircularProgressIndicator(
+                                                modifier = Modifier.width(16.dp).height(16.dp),
+                                                strokeWidth = 2.dp
+                                            )
+                                        }
+                                    }
+                                },
                                 onClick = {
-                                    vocabularyViewModel.saveCategory(categoryId)
+                                    exportImportViewModel.exportCategory(categoryId)
                                     showMenu = false
                                 },
-                                leadingIcon = { Icon(AppIcons.Share, contentDescription = null) }
+                                leadingIcon = { Icon(AppIcons.Share, contentDescription = null) },
+                                enabled = exportState !is ExportState.Loading
                             )
                             DropdownMenuItem(
-                                text = { Text(stringResource(R.string.delete_items_category)) },
+                                text = { Text("Delete Items") },
                                 onClick = {
                                     categoryViewModel.setShowDeleteItemsDialog(true, categoryId)
                                     showMenu = false

app/src/main/java/eu/gaudian/translator/view/vocabulary/NewWordScreen.kt

@@ -255,17 +255,7 @@ fun NewWordScreen(
 
             BottomActionCardsRow(
                 onImportCsvClick = {
-                    @Suppress("HardCodedStringLiteral")
+                    navController.navigate("settings_vocabulary_repository_options")
-                    importTableLauncher.launch(
-                        arrayOf(
-                            "text/csv",
-                            "text/comma-separated-values",
-                            "text/tab-separated-values",
-                            "text/plain",
-                            "application/vnd.ms-excel",
-                            "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
-                        )
-                    )
                 }
             )
 
@@ -770,7 +760,7 @@ fun BottomActionCardsRow(
                 }
                 Spacer(modifier = Modifier.height(12.dp))
                 Text(
-                    text = stringResource(R.string.label_import_csv),
+                    text = "Import Lists or CSV",
                     style = MaterialTheme.typography.labelLarge,
                     fontWeight = FontWeight.Bold
                 )

app/src/main/java/eu/gaudian/translator/view/vocabulary/VocabularyListScreen.kt

@@ -73,6 +73,7 @@ import eu.gaudian.translator.view.dialogs.CategorySelectionDialog
 import eu.gaudian.translator.view.dialogs.StageSelectionDialog
 import eu.gaudian.translator.view.library.AllCardsView
 import eu.gaudian.translator.viewmodel.CategoryViewModel
+import eu.gaudian.translator.viewmodel.ExportImportViewModel
 import eu.gaudian.translator.viewmodel.LanguageConfigViewModel
 import eu.gaudian.translator.viewmodel.LanguageViewModel
 import eu.gaudian.translator.viewmodel.VocabularyViewModel
@@ -110,6 +111,7 @@ fun AllCardsListScreen(
     val activity = LocalContext.current.findActivity()
     val lazyListState = rememberLazyListState()
     val vocabularyViewModel: VocabularyViewModel = hiltViewModel(viewModelStoreOwner = activity)
+    val exportImportViewModel: ExportImportViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val languageViewModel: LanguageViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val categoryViewModel: CategoryViewModel = hiltViewModel(viewModelStoreOwner = activity)
     val context = LocalContext.current
@@ -144,6 +146,7 @@ fun AllCardsListScreen(
     val allLanguages by languageViewModel.allLanguages.collectAsStateWithLifecycle(initialValue = emptyList())
     val languagesPresent by vocabularyViewModel.languagesPresent.collectAsStateWithLifecycle(initialValue = emptySet())
     val categoryNameFlow = remember(categoryId) { categoryId?.let { categoryViewModel.getCategoryById(it) } }
+    val exportState by exportImportViewModel.exportState.collectAsStateWithLifecycle()
 
     val vocabularyItemsFlow: Flow<List<VocabularyItem>> = remember(filterState) {
         vocabularyViewModel.filterVocabularyItems(
@@ -161,6 +164,16 @@ fun AllCardsListScreen(
         vocabularyItemsFlow.collectAsStateWithLifecycle(initialValue = emptyList()).value
     }
 
+    // Handle export state
+    LaunchedEffect(exportState) {
+        if (exportState is eu.gaudian.translator.viewmodel.ExportState.Success) {
+            exportImportViewModel.createShareIntent()?.let { intent ->
+                context.startActivity(intent)
+            }
+            exportImportViewModel.resetExportState()
+        }
+    }
+
     LaunchedEffect(categoryId, showDueTodayOnly, stage) {
         filterState = filterState.copy(
             categoryIds = categoryId?.let { listOf(it) } ?: emptyList(),
@@ -219,6 +232,11 @@ fun AllCardsListScreen(
                         },
                         onMoveToCategoryClick = { showCategoryDialog = true },
                         onMoveToStageClick = { showStageDialog = true },
+                        onExportClick = {
+                            val selectedIds = selection.map { it.toInt() }
+                            exportImportViewModel.exportItemList(selectedIds)
+                            selection = emptySet()
+                        },
                         onRemoveFromCategoryClick = {
                             if (categoryId != null) {
                                 val itemsToRemove = vocabularyItems.filter { selection.contains(it.id.toLong()) }
@@ -502,6 +520,7 @@ private fun ContextualTopAppBar(
     onDeleteClick: () -> Unit,
     onMoveToCategoryClick: () -> Unit,
     onMoveToStageClick: () -> Unit,
+    onExportClick: () -> Unit,
     onRemoveFromCategoryClick: () -> Unit
 ) {
     var showOverflowMenu by remember { mutableStateOf(false) }
@@ -534,6 +553,14 @@ private fun ContextualTopAppBar(
                     expanded = showOverflowMenu,
                     onDismissRequest = { showOverflowMenu = false }
                 ) {
+                    DropdownMenuItem(
+                        text = { Text("Export Selected") },
+                        onClick = {
+                            onExportClick()
+                            showOverflowMenu = false
+                        },
+                        leadingIcon = { Icon(AppIcons.Share, contentDescription = null) }
+                    )
                     DropdownMenuItem(
                         text = { Text(stringResource(R.string.move_to_category)) },
                         onClick = {
@@ -585,6 +612,7 @@ fun ContextualTopAppBarPreview() {
         onDeleteClick = {},
         onMoveToCategoryClick = {},
         onMoveToStageClick = {},
+        onExportClick = {},
         onRemoveFromCategoryClick = {}
     )
 }

app/src/main/java/eu/gaudian/translator/viewmodel/ExportImportViewModel.kt

@@ -0,0 +1,290 @@
+@file:Suppress("HardCodedStringLiteral")
+
+package eu.gaudian.translator.viewmodel
+
+import android.app.Application
+import android.content.Intent
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import eu.gaudian.translator.model.ConflictStrategy
+import eu.gaudian.translator.model.ImportResult
+import eu.gaudian.translator.model.VocabularyExportData
+import eu.gaudian.translator.model.repository.VocabularyRepository
+import eu.gaudian.translator.utils.Log
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import java.io.File
+import javax.inject.Inject
+
+private const val TAG = "ExportImportViewModel"
+
+/**
+ * ViewModel for handling vocabulary export and import operations.
+ * 
+ * This ViewModel provides a clean separation between UI and business logic for:
+ * - Exporting vocabulary data (full repository, categories, items)
+ * - Importing vocabulary data with conflict resolution
+ * - Sharing exported data via Android intents
+ * - Managing export/import operation states
+ */
+@HiltViewModel
+class ExportImportViewModel @Inject constructor(
+    application: Application,
+    private val repository: VocabularyRepository
+) : AndroidViewModel(application) {
+
+    // UI State for export operations
+    private val _exportState = MutableStateFlow<ExportState>(ExportState.Idle)
+    val exportState: StateFlow<ExportState> = _exportState.asStateFlow()
+
+    // UI State for import operations
+    private val _importState = MutableStateFlow<ImportState>(ImportState.Idle)
+    val importState: StateFlow<ImportState> = _importState.asStateFlow()
+
+    /**
+     * Exports the full repository and prepares it for sharing.
+     * 
+     * @param prettyPrint Whether to format JSON for human readability
+     */
+    fun exportFullRepository(prettyPrint: Boolean = false) {
+        viewModelScope.launch {
+            try {
+                _exportState.value = ExportState.Loading
+                Log.i(TAG, "exportFullRepository: Starting full repository export")
+
+                val exportData = repository.exportFullRepository()
+                val jsonString = repository.exportToJson(exportData, prettyPrint)
+
+                _exportState.value = ExportState.Success(
+                    exportData = exportData,
+                    jsonData = jsonString
+                )
+                Log.i(TAG, "exportFullRepository: Export successful. Size: ${jsonString.length} chars")
+            } catch (e: Exception) {
+                Log.e(TAG, "exportFullRepository: Export failed", e)
+                _exportState.value = ExportState.Error("Failed to export repository: ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Exports a specific category.
+     * 
+     * @param categoryId The ID of the category to export
+     * @param prettyPrint Whether to format JSON for human readability
+     */
+    fun exportCategory(categoryId: Int, prettyPrint: Boolean = false) {
+        viewModelScope.launch {
+            try {
+                _exportState.value = ExportState.Loading
+                Log.i(TAG, "exportCategory: Starting export for category $categoryId")
+
+                val exportData: VocabularyExportData? = repository.exportCategory(categoryId)
+                if (exportData == null) {
+                    _exportState.value = ExportState.Error("Category not found")
+                    Log.w(TAG, "exportCategory: Category $categoryId not found")
+                    return@launch
+                }
+                
+                val jsonString = repository.exportToJson(exportData, prettyPrint)
+
+                _exportState.value = ExportState.Success(
+                    exportData = exportData,
+                    jsonData = jsonString
+                )
+            } catch (e: Exception) {
+                Log.e(TAG, "exportCategory: Export failed", e)
+                _exportState.value = ExportState.Error("Failed to export category: ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Exports a list of vocabulary items.
+     * 
+     * @param itemIds List of item IDs to export
+     * @param includeCategories Whether to include category information
+     * @param prettyPrint Whether to format JSON for human readability
+     */
+    fun exportItemList(itemIds: List<Int>, includeCategories: Boolean = true, prettyPrint: Boolean = false) {
+        viewModelScope.launch {
+            try {
+                _exportState.value = ExportState.Loading
+                Log.i(TAG, "exportItemList: Starting export for ${itemIds.size} items")
+
+                val exportData: VocabularyExportData = repository.exportItemList(itemIds, includeCategories)
+                val jsonString = repository.exportToJson(exportData, prettyPrint)
+
+                _exportState.value = ExportState.Success(
+                    exportData = exportData,
+                    jsonData = jsonString
+                )
+            } catch (e: Exception) {
+                Log.e(TAG, "exportItemList: Export failed", e)
+                _exportState.value = ExportState.Error("Failed to export items: ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Exports a single vocabulary item.
+     * 
+     * @param itemId The ID of the item to export
+     * @param prettyPrint Whether to format JSON for human readability
+     */
+    fun exportSingleItem(itemId: Int, prettyPrint: Boolean = false) {
+        viewModelScope.launch {
+            try {
+                _exportState.value = ExportState.Loading
+                Log.i(TAG, "exportSingleItem: Starting export for item $itemId")
+
+                val exportData: VocabularyExportData? = repository.exportSingleItem(itemId)
+                if (exportData == null) {
+                    _exportState.value = ExportState.Error("Item not found")
+                    Log.w(TAG, "exportSingleItem: Item $itemId not found")
+                    return@launch
+                }
+
+                val jsonString = repository.exportToJson(exportData, prettyPrint)
+
+                _exportState.value = ExportState.Success(
+                    exportData = exportData,
+                    jsonData = jsonString
+                )
+                Log.i(TAG, "exportSingleItem: Export successful")
+            } catch (e: Exception) {
+                Log.e(TAG, "exportSingleItem: Export failed", e)
+                _exportState.value = ExportState.Error("Failed to export item: ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Creates a share intent for the exported data file.
+     * Uses FileProvider to share large files without hitting binder transaction limits.
+     */
+    fun createShareIntent(): Intent? {
+        val currentState = _exportState.value
+        if (currentState !is ExportState.Success) {
+            Log.w(TAG, "createShareIntent: No export data available")
+            return null
+        }
+
+        return try {
+            // Write to cache file
+            val context = getApplication<Application>()
+            val cacheDir = File(context.cacheDir, "exports")
+            if (!cacheDir.exists()) {
+                cacheDir.mkdirs()
+            }
+            
+            val timestamp = System.currentTimeMillis()
+            val fileName = "polly_vocabulary_export_$timestamp.json"
+            val file = File(cacheDir, fileName)
+            
+            file.writeText(currentState.jsonData)
+            Log.i(TAG, "createShareIntent: Wrote export to file: ${file.absolutePath}, size: ${file.length()} bytes")
+            
+            // Create content URI using FileProvider
+            val contentUri = androidx.core.content.FileProvider.getUriForFile(
+                context,
+                "${context.packageName}.fileprovider",
+                file
+            )
+            
+            val intent = Intent(Intent.ACTION_SEND).apply {
+                type = "application/json"
+                putExtra(Intent.EXTRA_STREAM, contentUri)
+                putExtra(Intent.EXTRA_SUBJECT, "Polly Vocabulary Export")
+                addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+            }
+            
+            Intent.createChooser(intent, "Share Vocabulary Export")
+        } catch (e: Exception) {
+            Log.e(TAG, "createShareIntent: Error creating share intent", e)
+            _exportState.value = ExportState.Error("Failed to create share intent: ${e.message}")
+            null
+        }
+    }
+
+    /**
+     * Imports vocabulary data from JSON string.
+     * 
+     * @param jsonString The JSON string to import
+     * @param strategy The conflict resolution strategy to use
+     */
+    fun importFromJson(jsonString: String, strategy: ConflictStrategy = ConflictStrategy.MERGE) {
+        viewModelScope.launch {
+            try {
+                _importState.value = ImportState.Loading
+                Log.i(TAG, "importFromJson: Starting import with strategy=$strategy")
+
+                val exportData = repository.importFromJson(jsonString)
+                val result = repository.importVocabularyData(exportData, strategy)
+
+                _importState.value = ImportState.Success(result)
+                Log.i(TAG, "importFromJson: Import complete. Imported: ${result.itemsImported}, " +
+                        "Skipped: ${result.itemsSkipped}, Errors: ${result.errors.size}")
+            } catch (e: Exception) {
+                Log.e(TAG, "importFromJson: Import failed", e)
+                _importState.value = ImportState.Error("Failed to import: ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Resets the export state to idle.
+     * Call this after handling export results.
+     */
+    fun resetExportState() {
+        _exportState.value = ExportState.Idle
+    }
+
+    /**
+     * Resets the import state to idle.
+     * Call this after handling import results.
+     */
+    fun resetImportState() {
+        _importState.value = ImportState.Idle
+    }
+}
+
+/**
+ * Sealed class representing the state of an export operation.
+ */
+sealed class ExportState {
+    /** No export operation in progress */
+    object Idle : ExportState()
+    
+    /** Export operation in progress */
+    object Loading : ExportState()
+    
+    /** Export completed successfully */
+    data class Success(
+        val exportData: VocabularyExportData,
+        val jsonData: String
+    ) : ExportState()
+    
+    /** Export failed with an error */
+    data class Error(val message: String) : ExportState()
+}
+
+/**
+ * Sealed class representing the state of an import operation.
+ */
+sealed class ImportState {
+    /** No import operation in progress */
+    object Idle : ImportState()
+    
+    /** Import operation in progress */
+    object Loading : ImportState()
+    
+    /** Import completed successfully */
+    data class Success(val result: ImportResult) : ImportState()
+    
+    /** Import failed with an error */
+    data class Error(val message: String) : ImportState()
+}

app/src/main/res/xml/file_paths.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Cache directory for temporary export files -->
+    <cache-path name="exports" path="exports/" />
+</paths>