"""Translation endpoint for converting grant jargon into simple language."""

import logging
from typing import List, Optional, Dict, Any
from pydantic import BaseModel
from fastapi import APIRouter, HTTPException

from src.analyzer.llm_client import LLMClient
from src.analyzer.config import load_config
from src.database import SummaryStore

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/translate", tags=["translation"])

# Global cache for LLM client
_llm_client: Optional[LLMClient] = None
_summary_store: Optional[SummaryStore] = None


def get_llm_client() -> LLMClient:
    """Get or create LLM client for translations."""
    global _llm_client
    if _llm_client is None:
        config = load_config()
        _llm_client = LLMClient(config)
    return _llm_client


def get_summary_store() -> SummaryStore:
    """Get or create summary store."""
    global _summary_store
    if _summary_store is None:
        _summary_store = SummaryStore()
    return _summary_store


class TranslateRequest(BaseModel):
    """Request model for translation endpoint."""
    grant_id: str
    force_refresh: bool = False  # Force regeneration even if cached


class BatchTranslateRequest(BaseModel):
    """Request model for batch translation endpoint."""
    grant_ids: List[str]
    force_refresh: bool = False


class TranslationResponse(BaseModel):
    """Response model for translation endpoint."""
    grant_id: str
    translation: Dict[str, str]
    cached: bool


class BatchTranslationResponse(BaseModel):
    """Response model for batch translation endpoint."""
    translations: List[TranslationResponse]
    total: int
    cached_count: int


# Translation prompt template
TRANSLATION_PROMPT_TEMPLATE = """You are translating a UK grant into simple, everyday language.

Grant Information:
{grant_context}

Please provide a clear, structured explanation with these EXACT sections (use these headings):

## WHO CAN APPLY (Eligibility)
Explain who is eligible in simple terms. Use bullet points.

## WHAT YOU'LL DO (Process)
Describe the application process step-by-step in simple language.

## WHEN IT HAPPENS (Timeline)
Explain key dates and how long things take.

## WHAT YOU NEED (Requirements)
List what applicants need to provide or have ready.

Use simple, conversational language. Avoid jargon. Write as if explaining to a friend.
"""


def load_grant_data(grant_id: str) -> Optional[Dict[str, Any]]:
    """
    Load grant data from snapshots.

    Args:
        grant_id: Grant ID (e.g., "competition-2058")

    Returns:
        Grant data dict or None if not found
    """
    from pathlib import Path
    import json

    # Normalize grant ID
    if not grant_id.startswith("competition-"):
        grant_id = f"competition-{grant_id}"

    snapshots_dir = Path("data/snapshots")
    grant_file = snapshots_dir / f"{grant_id}.json"

    if not grant_file.exists():
        logger.warning(f"Grant file not found: {grant_file}")
        return None

    try:
        with open(grant_file, "r", encoding="utf-8") as f:
            return json.load(f)
    except Exception as e:
        logger.error(f"Failed to load grant {grant_id}: {e}")
        return None


def build_grant_context(grant: Dict[str, Any]) -> str:
    """
    Build context for translation from grant data.

    Args:
        grant: Grant data dict

    Returns:
        Formatted context string
    """
    from src.analyzer.summarizer_optimized import extract_minimal_context

    # Use the optimized context extractor
    context = extract_minimal_context(grant)

    # Add any additional fields specific to translation
    sections = grant.get("sections", {})

    additional_info = []

    # Add project details if available
    if "project_scope" in sections:
        additional_info.append(f"PROJECT SCOPE: {sections['project_scope'][:300]}")

    # Add funding details if available
    if "funding_details" in sections:
        additional_info.append(f"FUNDING DETAILS: {sections['funding_details'][:300]}")

    if additional_info:
        context += "\n\n" + "\n".join(additional_info)

    return context


def translate_grant(grant_id: str, force_refresh: bool = False) -> Dict[str, Any]:
    """
    Translate a grant into simple language with structured sections.

    Args:
        grant_id: Grant ID to translate
        force_refresh: Force regeneration even if cached

    Returns:
        Dict with translation sections and metadata

    Raises:
        HTTPException: If grant not found or translation fails
    """
    store = get_summary_store()

    # Normalize grant ID
    if not grant_id.startswith("competition-"):
        grant_id = f"competition-{grant_id}"

    # Check cache first (unless force_refresh)
    if not force_refresh:
        cached_translation = store.get_summary(grant_id, summary_type="translation")
        if cached_translation:
            logger.info(f"Using cached translation for {grant_id}")
            return {
                "grant_id": grant_id,
                "translation": parse_translation_sections(cached_translation),
                "cached": True
            }

    # Load grant data
    grant = load_grant_data(grant_id)
    if not grant:
        raise HTTPException(status_code=404, detail=f"Grant {grant_id} not found")

    # Build context
    context = build_grant_context(grant)

    # Generate translation using GPT-5-mini
    try:
        llm_client = get_llm_client()

        prompt = TRANSLATION_PROMPT_TEMPLATE.format(grant_context=context)

        # Use translator model with appropriate parameters
        translation_text = llm_client.summarize(
            prompt,
            model_type="translator",  # Use gpt-5-mini
            verbosity="medium",
            reasoning_effort="minimal",
            max_tokens=800,
            temperature=0.3
        )

        # Save to cache (permanent storage)
        store.save_summary(
            grant_id=grant_id,
            summary_type="translation",
            summary_text=translation_text,
            metadata={"model": "gpt-5-mini", "context_length": len(context)}
        )

        logger.info(f"Generated translation for {grant_id}")

        return {
            "grant_id": grant_id,
            "translation": parse_translation_sections(translation_text),
            "cached": False
        }

    except Exception as e:
        logger.error(f"Translation failed for {grant_id}: {e}")
        raise HTTPException(status_code=500, detail=f"Translation failed: {str(e)}")


def parse_translation_sections(translation_text: str) -> Dict[str, str]:
    """
    Parse translation text into structured sections.

    Args:
        translation_text: Raw translation text with markdown headers

    Returns:
        Dict with section names as keys and content as values
    """
    import re

    sections = {
        "eligibility": "",
        "process": "",
        "timeline": "",
        "requirements": ""
    }

    # Define section patterns
    patterns = {
        "eligibility": r"## WHO CAN APPLY.*?\n(.*?)(?=\n## |\Z)",
        "process": r"## WHAT YOU'LL DO.*?\n(.*?)(?=\n## |\Z)",
        "timeline": r"## WHEN IT HAPPENS.*?\n(.*?)(?=\n## |\Z)",
        "requirements": r"## WHAT YOU NEED.*?\n(.*?)(?=\n## |\Z)"
    }

    for key, pattern in patterns.items():
        match = re.search(pattern, translation_text, re.DOTALL | re.IGNORECASE)
        if match:
            sections[key] = match.group(1).strip()

    # Fallback: if no sections found, return full text as eligibility
    if not any(sections.values()):
        sections["eligibility"] = translation_text

    return sections


@router.post("/", response_model=TranslationResponse)
async def translate_grant_endpoint(request: TranslateRequest):
    """
    Translate a grant into simple, structured language.

    Returns a layman explanation with sections:
    - Eligibility: Who can apply
    - Process: How to apply
    - Timeline: Key dates and deadlines
    - Requirements: What you need

    Translations are permanently cached since grants don't change.
    """
    result = translate_grant(request.grant_id, request.force_refresh)
    return TranslationResponse(**result)


@router.post("/batch", response_model=BatchTranslationResponse)
async def translate_grants_batch(request: BatchTranslateRequest):
    """
    Translate multiple grants in batch.

    Efficiently processes multiple grant translations with caching.
    Returns all translations, using cached versions where available.
    """
    translations = []
    cached_count = 0

    for grant_id in request.grant_ids:
        try:
            result = translate_grant(grant_id, request.force_refresh)
            translations.append(TranslationResponse(**result))

            if result["cached"]:
                cached_count += 1

        except HTTPException as e:
            logger.warning(f"Failed to translate {grant_id}: {e.detail}")
            # Continue with other grants
            continue
        except Exception as e:
            logger.error(f"Unexpected error translating {grant_id}: {e}")
            continue

    return BatchTranslationResponse(
        translations=translations,
        total=len(translations),
        cached_count=cached_count
    )


@router.get("/{grant_id}", response_model=TranslationResponse)
async def get_translation(grant_id: str, force_refresh: bool = False):
    """
    Get translation for a specific grant (GET method for convenience).

    Args:
        grant_id: Grant ID (with or without 'competition-' prefix)
        force_refresh: Force regeneration even if cached

    Returns:
        Structured translation with eligibility, process, timeline, requirements
    """
    result = translate_grant(grant_id, force_refresh)
    return TranslationResponse(**result)