"""
OpenAI-compatible LLM client for VocabListGenerator
Adapted from ResourceTranslate/llm_client.py
"""

import json
import openai
from typing import List, Tuple

from models import VocabRequest, CEFR_DESCRIPTIONS
from config import Config


class LLMClient:
    """OpenAI-compatible LLM client (LM Studio / DeepSeek)"""

    def __init__(self, config: Config):
        self.config = config
        self.client = openai.OpenAI(
            base_url=config.llm_config['base_url'],
            api_key=config.llm_config.get('api_key', 'not-needed')
        )
        self.model = config.llm_config['model']
        self.timeout = config.llm_config.get('timeout', 30)
        self.max_retries = config.llm_config.get('max_retries', 3)

    def generate_vocabulary(self, request: VocabRequest) -> List[Tuple[str, str]]:
        """
        Ask the LLM to generate vocabulary word pairs for the given request.
        Returns a list of (word_in_lang_first, word_in_lang_second) tuples.
        """
        prompt = self._build_vocab_prompt(request)

        system_message = (
            "You are an expert language teacher and vocabulary specialist. "
            "Generate accurate, natural vocabulary word pairs exactly as instructed. "
            "Your response must be a valid JSON array and nothing else."
        )

        for attempt in range(self.max_retries):
            try:
                response = self.client.chat.completions.create(
                    model=self.model,
                    messages=[
                        {"role": "system", "content": system_message},
                        {"role": "user", "content": prompt}
                    ],
                    temperature=0.7,
                    timeout=self.timeout
                )

                if not response or not response.choices:
                    print(f"  [attempt {attempt + 1}] Empty response from LLM")
                    continue

                choice = response.choices[0]
                if not hasattr(choice, 'message') or not choice.message:
                    print(f"  [attempt {attempt + 1}] Invalid response structure")
                    continue

                content = choice.message.content
                if content is None:
                    print(f"  [attempt {attempt + 1}] Empty content in response")
                    continue

                pairs = self._parse_vocab_response(content)
                if pairs:
                    return pairs
                else:
                    print(f"  [attempt {attempt + 1}] Could not parse valid pairs from response")

            except Exception as e:
                print(f"  [attempt {attempt + 1}] Failed: {e}")
                if attempt == self.max_retries - 1:
                    print("All attempts exhausted.")

        return []

    # ------------------------------------------------------------------
    # Private helpers
    # ------------------------------------------------------------------

    def _build_vocab_prompt(self, request: VocabRequest) -> str:
        """Build the vocabulary generation prompt."""
        level_desc = CEFR_DESCRIPTIONS.get(request.level, "")
        lines = [
            f"Generate exactly {request.amount} vocabulary word pairs for the topic: \"{request.category}\".",
            "",
            f"Proficiency level: {request.level}" + (f" — {level_desc}" if level_desc else ""),
            "",
            f"First language  (wordFirst):  {request.lang_first_name}",
            f"Second language (wordSecond): {request.lang_second_name}",
        ]

        if request.instructions and request.instructions.strip():
            lines += [
                "",
                "Additional instructions (follow these carefully):",
                request.instructions.strip(),
            ]

        lines += [
            "",
            "Rules:",
            "- Choose vocabulary appropriate for the specified proficiency level.",
            "- Return ONLY a JSON array. No markdown, no explanation, no extra text.",
            "- Each element is a 2-item array: [word_in_first_language, word_in_second_language].",
            f"- The array must contain exactly {request.amount} unique pairs.",
            "- NO DUPLICATES: Each word in the first language must appear only once.",
            "- VARY the vocabulary: avoid repeating similar words.",
            "",
            "Example format:",
            '[',
            '  ["Krankenhaus", "hospital"],',
            '  ["Arzt", "médico"]',
            ']',
        ]

        return "\n".join(lines)

    def _parse_vocab_response(self, response: str) -> List[Tuple[str, str]]:
        """Parse the LLM response into a list of word-pair tuples."""
        if not response or not response.strip():
            return []

        try:
            text = response.strip()

            # Try direct parse first
            if text.startswith('['):
                data = json.loads(text)
            else:
                # Extract JSON array from surrounding text
                start = text.find('[')
                end = text.rfind(']') + 1
                if start == -1 or end == 0:
                    print(f"Could not locate JSON array in response:\n{response[:500]}")
                    return []
                data = json.loads(text[start:end])

            # Check for duplicates and log warning
            seen_first = {}
            duplicates = []
            pairs: List[Tuple[str, str]] = []
            for item in data:
                if isinstance(item, (list, tuple)) and len(item) >= 2:
                    word_first = str(item[0]).strip()
                    word_second = str(item[1]).strip()
                    
                    # Track duplicates
                    if word_first in seen_first:
                        duplicates.append(word_first)
                    else:
                        seen_first[word_first] = word_second
                    
                    pairs.append((word_first, word_second))
            
            # Log duplicates if found
            if duplicates:
                unique_dups = list(set(duplicates))
                print(f"  ⚠ Warning: Found {len(duplicates)} duplicate first-language words: {unique_dups[:5]}{'...' if len(unique_dups) > 5 else ''}")
                # Deduplicate - keep first occurrence only
                pairs = list(seen_first.items())
                print(f"  → Using {len(pairs)} unique pairs after deduplication")

            return pairs

        except json.JSONDecodeError as e:
            print(f"JSON parse error: {e}")
            print(f"Raw response (first 800 chars):\n{response[:800]}")
            print(f"Raw response (last 200 chars):\n{response[-200:]}")
            return []
        except Exception as e:
            print(f"Unexpected error parsing response: {e}")
            print(f"Response preview:\n{response[:500]}")
            return []