import logging
from typing import Optional

from fastapi import APIRouter, HTTPException, Query, Response

from app.core.config import get_settings
from app.models.highlight import (
    HighlightBatchRequest,
    HighlightBatchResponse,
)
from app.services.chunk_highlight_service import ChunkHighlightService
from app.services.highlight_cache import HighlightCache, compute_cache_key
from app.services.history_service import HistoryService
from app.services.llm_client import LLMClient
from app.services.rag import RAGService

logger = logging.getLogger(__name__)

router = APIRouter(tags=["chunks"])

HIGHLIGHTS_DB_FILENAME = "highlights.db"


def _highlights_db_path(settings) -> str:
    return str(settings.prompts_db_path).replace("prompts.db", HIGHLIGHTS_DB_FILENAME)


@router.post("/api/v1/v2/highlights/batch", response_model=HighlightBatchResponse)
async def compute_highlights_batch(
    request: HighlightBatchRequest,
    history_id: Optional[int] = Query(default=None),
):
    """Compute and cache highlighted chunk views for cited chunks."""
    settings = get_settings()
    cache = HighlightCache(db_path=_highlights_db_path(settings))
    llm_client = LLMClient(settings)
    rag = RAGService(settings=settings)
    service = ChunkHighlightService(
        rag_service=rag,
        llm_client=llm_client,
        highlight_cache=cache,
        settings=settings,
    )
    try:
        result = await service.compute_highlights_batch(request.targets)
        if history_id is not None:
            history_service = HistoryService(settings.history_db_path)
            history_service.update_highlights(
                history_id,
                result.highlight_prompt or "",
                result.highlight_response_json or "",
                result.highlight_time_ms,
            )
        return result
    except Exception as e:
        logger.error("Highlight batch computation failed: %s", e, exc_info=True)
        return HighlightBatchResponse(status="failed", cached_count=0, errors=[str(e)])


@router.get("/api/v1/v2/highlights", response_class=Response)
async def get_highlight(
    document_id: str = Query(...),
    chunk_index: int = Query(...),
    sub_question: str = Query(...),
):
    """Serve a cached highlighted chunk view as HTML."""
    settings = get_settings()
    cache = HighlightCache(db_path=_highlights_db_path(settings))
    cache_key = compute_cache_key(document_id, chunk_index, sub_question)
    html = cache.get_highlight(cache_key)
    if html is None:
        raise HTTPException(status_code=404, detail="Highlight not found. Batch may not have been computed.")
    return Response(content=html, media_type="text/html")