implement CEFR level filtering and language-based sorting in ExplorePacksScreen

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

@@ -3,6 +3,9 @@ package eu.gaudian.translator.model.communication
 import android.content.Context
 import androidx.core.content.edit
 import eu.gaudian.translator.R
+import eu.gaudian.translator.model.communication.files_download.FlashcardCollectionInfo
+import eu.gaudian.translator.model.communication.files_download.FlashcardManifestResponse
+import eu.gaudian.translator.model.communication.files_download.VocabCollectionInfo
 import eu.gaudian.translator.utils.Log
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
@@ -327,7 +330,7 @@ class FileDownloadManager(private val context: Context) {
 
     /**
      * Fetches the vocabulary-pack manifest (vocab_manifest.json).
-     * Unwraps the top-level [VocabManifestResponse] and returns the `lists` array.
+     * Unwraps the top-level [eu.gaudian.translator.model.communication.files_download.VocabManifestResponse] and returns the `lists` array.
      */
     suspend fun fetchVocabManifest(): List<VocabCollectionInfo>? = withContext(Dispatchers.IO) {
         try {

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

@@ -1,5 +1,7 @@
 package eu.gaudian.translator.model.communication
 
+import eu.gaudian.translator.model.communication.files_download.FlashcardManifestResponse
+import eu.gaudian.translator.model.communication.files_download.VocabManifestResponse
 import retrofit2.Call
 import retrofit2.http.GET
 

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

@@ -1,4 +1,4 @@
-package eu.gaudian.translator.model.communication
+package eu.gaudian.translator.model.communication.files_download
 
 import com.google.gson.annotations.SerializedName
 
@@ -35,6 +35,8 @@ data class VocabCollectionInfo(
     @SerializedName("item_count")       val itemCount: Int,
     @SerializedName("emoji")            val emoji: String,
     @SerializedName("version")          val version: Int,
+    /** CEFR difficulty level: A1, A2, B1, B2, C1, C2 (empty string if not set) */
+    @SerializedName("level")            val level: String = "",
     @SerializedName("size_bytes")       val sizeBytes: Long,
     @SerializedName("checksum_sha256")  val checksumSha256: String,
     @SerializedName("created_at")       val createdAt: String,

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

@@ -18,9 +18,11 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.lazy.LazyRow
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.CheckCircle
@@ -28,7 +30,6 @@ import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material.icons.filled.FilterList
 import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material.icons.filled.Search
-import androidx.compose.material.icons.filled.SwapHoriz
 import androidx.compose.material.icons.filled.Warning
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Button
@@ -75,8 +76,10 @@ import eu.gaudian.translator.utils.StatusMessageId
 import eu.gaudian.translator.utils.StatusMessageService
 import eu.gaudian.translator.utils.findActivity
 import eu.gaudian.translator.view.composable.AppTopAppBar
+import eu.gaudian.translator.view.translation.LanguageSelectorBar
 import eu.gaudian.translator.viewmodel.ExportImportViewModel
 import eu.gaudian.translator.viewmodel.ImportState
+import eu.gaudian.translator.viewmodel.LanguageViewModel
 import eu.gaudian.translator.viewmodel.PackDownloadState
 import eu.gaudian.translator.viewmodel.PackUiState
 import eu.gaudian.translator.viewmodel.VocabPacksViewModel
@@ -84,18 +87,31 @@ import eu.gaudian.translator.viewmodel.VocabPacksViewModel
 private const val TAG = "ExplorePacksScreen"
 
 // ---------------------------------------------------------------------------
-// Filter enum
+// Filter enum – CEFR levels + utility filters
 // ---------------------------------------------------------------------------
 
-enum class PackFilter { All, MostPopular, Newest, Beginner }
+enum class PackFilter {
+    All, Newest,
+    A1, A2, B1, B2, C1, C2;
 
-private val PackFilter.label: String
+    val label: String
-    get() = when (this) {
+        get() = when (this) {
-        PackFilter.All         -> "All"
+            All     -> "All"
-        PackFilter.MostPopular -> "Most Popular"
+            Newest  -> "Newest"
-        PackFilter.Newest      -> "Newest"
+            A1      -> "Beginner · A1"
-        PackFilter.Beginner    -> "Beginner"
+            A2      -> "Elementary · A2"
-    }
+            B1      -> "Intermediate · B1"
+            B2      -> "Upper Int. · B2"
+            C1      -> "Advanced · C1"
+            C2      -> "Proficient · C2"
+        }
+
+    val cefrCode: String?
+        get() = when (this) {
+            A1 -> "A1"; A2 -> "A2"; B1 -> "B1"; B2 -> "B2"; C1 -> "C1"; C2 -> "C2"
+            else -> null
+        }
+}
 
 // ---------------------------------------------------------------------------
 // Gradient palette – deterministic per pack ID hash
@@ -127,26 +143,26 @@ fun ExplorePacksScreen(
 ) {
     val activity = LocalContext.current.findActivity()
 
-    // VocabPacksViewModel is screen-scoped (not activity-scoped) – no persistent pack state needed
+    val vocabPacksViewModel:   VocabPacksViewModel    = hiltViewModel()
-    val vocabPacksViewModel: VocabPacksViewModel    = hiltViewModel()
+    val exportImportViewModel: ExportImportViewModel  = hiltViewModel(viewModelStoreOwner = activity)
-    // ExportImportViewModel handles full Polly-format import with real conflict strategy
+    val languageViewModel:     LanguageViewModel      = hiltViewModel(viewModelStoreOwner = activity)
-    val exportImportViewModel: ExportImportViewModel = hiltViewModel(viewModelStoreOwner = activity)
 
-    val packs             by vocabPacksViewModel.packs.collectAsState()
+    val packs                  by vocabPacksViewModel.packs.collectAsState()
-    val isLoadingManifest by vocabPacksViewModel.isLoadingManifest.collectAsState()
+    val isLoadingManifest      by vocabPacksViewModel.isLoadingManifest.collectAsState()
-    val manifestError     by vocabPacksViewModel.manifestError.collectAsState()
+    val manifestError          by vocabPacksViewModel.manifestError.collectAsState()
-    val importState       by exportImportViewModel.importState.collectAsState()
+    val importState            by exportImportViewModel.importState.collectAsState()
+    val selectedSourceLanguage by languageViewModel.selectedSourceLanguage.collectAsState()
+    val selectedTargetLanguage by languageViewModel.selectedTargetLanguage.collectAsState()
 
-    var searchQuery    by remember { mutableStateOf("") }
+    var searchQuery           by remember { mutableStateOf("") }
-    var selectedFilter by remember { mutableStateOf(PackFilter.All) }
+    var selectedFilter        by remember { mutableStateOf(PackFilter.All) }
 
-    // Which pack is being imported right now (captured when dialog opens)
+    var pendingImportPackState   by remember { mutableStateOf<PackUiState?>(null) }
-    var pendingImportPackState    by remember { mutableStateOf<PackUiState?>(null) }
+    var selectedConflictStrategy by remember { mutableStateOf(ConflictStrategy.MERGE) }
-    var selectedConflictStrategy  by remember { mutableStateOf(ConflictStrategy.MERGE) }
+    var showStrategyDialog       by remember { mutableStateOf(false) }
-    var showStrategyDialog         by remember { mutableStateOf(false) }
+    var isImporting              by remember { mutableStateOf(false) }
-    var isImporting                by remember { mutableStateOf(false) }
 
-    // Observe importState and react when the async import finishes
+    // Observe async import result
     LaunchedEffect(importState) {
         val pending = pendingImportPackState ?: return@LaunchedEffect
         when (val state = importState) {
@@ -165,23 +181,43 @@ fun ExplorePacksScreen(
                 isImporting = false
                 exportImportViewModel.resetImportState()
             }
-            else -> { /* Idle or Loading – nothing to do */ }
+            else -> {}
         }
     }
 
-    val filteredPacks = remember(packs, selectedFilter, searchQuery) {
+    // Filtered + sorted pack list
+    val filteredPacks = remember(
+        packs, selectedFilter, searchQuery,
+        selectedSourceLanguage, selectedTargetLanguage
+    ) {
+        val srcId = selectedSourceLanguage?.nameResId
+        val tgtId = selectedTargetLanguage?.nameResId
+
         packs.filter { ps ->
             val info = ps.info
+
+            // Language filter – only when a language pair is selected
+            val matchLanguage = if (srcId == null && tgtId == null) {
+                true
+            } else {
+                val ids = info.languageIds.toSet()
+                (srcId == null || ids.contains(srcId)) &&
+                (tgtId == null || ids.contains(tgtId))
+            }
+
             val matchSearch = searchQuery.isBlank() ||
                 info.name.contains(searchQuery, ignoreCase = true) ||
                 info.category.contains(searchQuery, ignoreCase = true)
-            val matchFilter = when (selectedFilter) {
+
-                PackFilter.All         -> true
+            val matchFilter = when (val code = selectedFilter.cefrCode) {
-                PackFilter.MostPopular -> info.itemCount >= 80
+                null -> true   // All or Newest – handled by sort below
-                PackFilter.Newest      -> info.version >= 1
+                else -> info.level.equals(code, ignoreCase = true)
-                PackFilter.Beginner    -> info.itemCount <= 60
             }
-            matchSearch && matchFilter
+
+            matchLanguage && matchSearch && matchFilter
+        }.let { list ->
+            if (selectedFilter == PackFilter.Newest) list.sortedByDescending { it.info.version }
+            else list
         }
     }
 
@@ -239,17 +275,27 @@ fun ExplorePacksScreen(
 
             Spacer(modifier = Modifier.height(12.dp))
 
-            // ── Language selector row ─────────────────────────────────────────
+            // ── Language selector – reuses LanguageSelectorBar ────────────────
-            PackLanguageSelectorRow()
+            Surface(
+                modifier = Modifier.fillMaxWidth(),
+                shape = RoundedCornerShape(12.dp),
+                color = MaterialTheme.colorScheme.surfaceContainer,
+                tonalElevation = 1.dp
+            ) {
+                LanguageSelectorBar(
+                    languageViewModel = languageViewModel,
+                    modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)
+                )
+            }
 
             Spacer(modifier = Modifier.height(12.dp))
 
-            // ── Filter chips ──────────────────────────────────────────────────
+            // ── Filter chips – horizontally scrollable ────────────────────────
-            Row(
+            LazyRow(
                 horizontalArrangement = Arrangement.spacedBy(8.dp),
-                modifier = Modifier.fillMaxWidth()
+                contentPadding = PaddingValues(horizontal = 2.dp)
             ) {
-                PackFilter.entries.forEach { filter ->
+                items(PackFilter.entries) { filter ->
                     FilterChip(
                         selected = selectedFilter == filter,
                         onClick  = { selectedFilter = filter },
@@ -375,9 +421,9 @@ fun ExplorePacksScreen(
                     pendingImportPackState = null
                 }
             },
-            icon = { Icon(Icons.Default.Warning, contentDescription = null) },
+            icon  = { Icon(Icons.Default.Warning, contentDescription = null) },
-            title = { Text("Import ${packState.info.name} ") },
+            title = { Text("Import \"${packState.info.name}\"") },
-            text = {
+            text  = {
                 Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
                     if (isImporting) {
                         Box(
@@ -444,14 +490,13 @@ fun ExplorePacksScreen(
                             pendingImportPackState = null
                             return@TextButton
                         }
-                        Log.d(TAG, "Starting import for ${packState.info.id} with strategy=$selectedConflictStrategy, json=${json.length} chars")
+                        Log.d(TAG, "Starting import for ${packState.info.id} " +
+                            "strategy=$selectedConflictStrategy json=${json.length} chars")
                         isImporting = true
-                        showStrategyDialog = false   // close dialog; LaunchedEffect handles completion
+                        showStrategyDialog = false
                         exportImportViewModel.importFromJson(json, selectedConflictStrategy)
                     }
-                ) {
+                ) { Text("Add to Library") }
-                    Text("Add to Library")
-                }
             },
             dismissButton = {
                 TextButton(
@@ -460,53 +505,14 @@ fun ExplorePacksScreen(
                         showStrategyDialog = false
                         pendingImportPackState = null
                     }
-                ) {
+                ) { Text("Cancel") }
-                    Text("Cancel")
-                }
             }
         )
     }
 }
 
 // ---------------------------------------------------------------------------
-// Language selector (placeholder — will use SourceLanguageDropdown in future)
+// Conflict strategy option
-// ---------------------------------------------------------------------------
-
-@Composable
-private fun PackLanguageSelectorRow(modifier: Modifier = Modifier) {
-    Surface(
-        modifier = modifier.fillMaxWidth(),
-        shape = RoundedCornerShape(12.dp),
-        color = MaterialTheme.colorScheme.surfaceContainer,
-        tonalElevation = 1.dp
-    ) {
-        Row(
-            modifier = Modifier
-                .fillMaxWidth()
-                .padding(horizontal = 16.dp, vertical = 10.dp),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.SpaceBetween
-        ) {
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                Text("🇬🇧", fontSize = 18.sp)
-                Spacer(modifier = Modifier.width(8.dp))
-                Text("English", style = MaterialTheme.typography.bodyMedium, fontWeight = FontWeight.Medium)
-            }
-            IconButton(onClick = { /* TODO: swap */ }, modifier = Modifier.size(32.dp)) {
-                Icon(Icons.Default.SwapHoriz, contentDescription = "Swap",
-                    tint = MaterialTheme.colorScheme.primary)
-            }
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                Text("Spanish", style = MaterialTheme.typography.bodyMedium, fontWeight = FontWeight.Medium)
-                Spacer(modifier = Modifier.width(8.dp))
-                Text("🇪🇸", fontSize = 18.sp)
-            }
-        }
-    }
-}
-
-// ---------------------------------------------------------------------------
-// Conflict strategy option (mirrors VocabularyRepositoryOptionsScreen)
 // ---------------------------------------------------------------------------
 
 @Composable
@@ -527,9 +533,7 @@ private fun PackConflictStrategyOption(
         )
     ) {
         Row(
-            modifier = Modifier
+            modifier = Modifier.fillMaxWidth().padding(10.dp),
-                .fillMaxWidth()
-                .padding(10.dp),
             verticalAlignment = Alignment.CenterVertically
         ) {
             RadioButton(selected = selected, onClick = onSelected)
@@ -599,7 +603,25 @@ private fun PackCard(
                     }
                 }
 
-                // Status badge (top-right corner)
+                // Level badge (top-left) – only when a CEFR level is set
+                if (info.level.isNotBlank()) {
+                    Box(modifier = Modifier.align(Alignment.TopStart).padding(8.dp)) {
+                        Surface(
+                            shape = RoundedCornerShape(6.dp),
+                            color = Color.Black.copy(alpha = 0.45f)
+                        ) {
+                            Text(
+                                text = info.level,
+                                style = MaterialTheme.typography.labelSmall,
+                                fontWeight = FontWeight.Bold,
+                                color = Color.White,
+                                modifier = Modifier.padding(horizontal = 6.dp, vertical = 3.dp)
+                            )
+                        }
+                    }
+                }
+
+                // Status badge (top-right)
                 val badgeData: Pair<Color, String>? = when (packState.downloadState) {
                     PackDownloadState.DOWNLOADED -> Color(0xFF1565C0) to "Ready"
                     PackDownloadState.IMPORTED   -> Color(0xFF388E3C) to "In Library"
@@ -671,8 +693,7 @@ private fun PackCard(
                             contentPadding = PaddingValues(0.dp),
                             shape          = RoundedCornerShape(8.dp)
                         ) {
-                            Text("Get",
+                            Text("Get", style = MaterialTheme.typography.labelMedium,
-                                style = MaterialTheme.typography.labelMedium,
                                 fontWeight = FontWeight.Bold)
                         }
                     }
@@ -700,11 +721,9 @@ private fun PackCard(
                                     containerColor = MaterialTheme.colorScheme.secondary
                                 )
                             ) {
-                                Text(
+                                Text("Add ${info.itemCount} words",
-                                    "Add ${info.itemCount} words",
+                                    style = MaterialTheme.typography.labelSmall,
-                                    style      = MaterialTheme.typography.labelSmall,
+                                    fontWeight = FontWeight.Bold)
-                                    fontWeight = FontWeight.Bold
-                                )
                             }
                             OutlinedButton(
                                 onClick        = onDeleteClick,
@@ -745,8 +764,7 @@ private fun PackCard(
                                 containerColor = MaterialTheme.colorScheme.error
                             )
                         ) {
-                            Text("Retry",
+                            Text("Retry", style = MaterialTheme.typography.labelMedium,
-                                style = MaterialTheme.typography.labelMedium,
                                 fontWeight = FontWeight.Bold)
                         }
                     }

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

@@ -8,7 +8,7 @@ import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import dagger.hilt.android.qualifiers.ApplicationContext
 import eu.gaudian.translator.model.communication.FileDownloadManager
-import eu.gaudian.translator.model.communication.VocabCollectionInfo
+import eu.gaudian.translator.model.communication.files_download.VocabCollectionInfo
 import eu.gaudian.translator.utils.Log
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow