# app/routers/diary_rag.py
"""
Diary-specific RAG endpoints for indexing and searching child diary entries.
Each child has their own Qdrant collection: diary_child_{child_id}
"""
import json
from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from pymysql.cursors import DictCursor
from typing import List

from deps import get_db, get_qdrant_client
from config import get_settings
from models.rag_models import (
    DiaryIndexRequest, DiaryIndexResponse,
    DiarySearchRequest, DiarySearchResponse, DiarySearchResult,
    DiaryAskRequest, DiaryAskResponse
)
from services.provider_factory import ProviderFactory
from services.rag_service import RAGService


router = APIRouter()


def _get_diary_collection_name(child_id: int) -> str:
    """Generate collection name for a child's diary."""
    return f"diary_child_{child_id}"


@router.post("/index", response_model=DiaryIndexResponse, name="diary_index")
async def index_diary_entry(
    request: DiaryIndexRequest,
    background_tasks: BackgroundTasks
):
    """
    Index a diary entry into child-specific Qdrant collection.

    Flow:
    1. Verify diary entry exists in MySQL
    2. Chunk content (markdown_chunker)
    3. Generate embeddings (embedding_service)
    4. Store in Qdrant collection: diary_child_{child_id}
    5. Track in post_vectors (post_type='diary')
    6. Audit log

    Uses BackgroundTasks for async processing.
    """
    settings = get_settings()
    db_conn = get_db()
    qdrant_client = get_qdrant_client()

    try:
        # Verify diary entry exists
        with db_conn.cursor(DictCursor) as cur:
            cur.execute(
                "SELECT id, child_id, entry_text, created_at FROM diary_entries WHERE id=%s",
                (request.entry_id,)
            )
            entry = cur.fetchone()

        if not entry:
            raise HTTPException(status_code=404, detail="Diary entry not found")

        if entry['child_id'] != request.child_id:
            raise HTTPException(status_code=403, detail="Child ID mismatch")

        # Create provider
        provider = ProviderFactory.create_provider(
            provider_name=request.provider,
            settings=settings
        )

        # Create RAG service with diary-specific collection prefix
        collection_prefix = f"diary_child_{request.child_id}"
        rag_service = RAGService(
            db_conn=db_conn,
            qdrant_client=qdrant_client,
            embedding_provider=provider,
            collection_prefix=collection_prefix
        )

        # Index as a "post" with locale as empty string (diaries are locale-agnostic)
        result = rag_service.index_post(
            post_id=request.entry_id,
            title=f"Diary Entry {request.entry_id}",
            slug=f"diary-{request.entry_id}",
            locale="",  # Diary entries don't have locale
            body_md=request.content or entry['entry_text']
        )

        # Update post_vectors to mark as diary type
        with db_conn.cursor(DictCursor) as cur:
            cur.execute(
                """
                UPDATE post_vectors
                SET post_type='diary', child_id=%s
                WHERE post_id=%s AND collection_name=%s
                """,
                (request.child_id, request.entry_id, result['collection'])
            )

            # Audit log
            cur.execute(
                """
                INSERT INTO audit_log (action, entity_type, entity_id, user_id, metadata)
                VALUES ('diary_indexed', 'diary_entry', %s, NULL, %s)
                """,
                (request.entry_id, json.dumps({
                    'child_id': request.child_id,
                    'provider': request.provider,
                    'chunks': result.get('chunks', 0)
                }))
            )

        return DiaryIndexResponse(
            status="success",
            entry_id=request.entry_id,
            child_id=request.child_id,
            chunks=result.get('chunks'),
            collection=result.get('collection'),
            provider=result.get('provider')
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Indexing failed: {str(e)}")
    finally:
        db_conn.close()


@router.post("/search", response_model=DiarySearchResponse, name="diary_search")
async def search_diary(
    request: DiarySearchRequest
):
    """
    Semantic search in a child's diary.

    Flow:
    1. Generate query embedding
    2. Search in Qdrant: diary_child_{child_id}
    3. Return top results with scores
    4. Log query in audit_log
    """
    settings = get_settings()
    db_conn = get_db()
    qdrant_client = get_qdrant_client()

    try:
        # Create provider
        provider = ProviderFactory.create_provider(
            provider_name=request.provider,
            settings=settings
        )

        # Create RAG service with diary-specific collection
        collection_prefix = f"diary_child_{request.child_id}"
        rag_service = RAGService(
            db_conn=db_conn,
            qdrant_client=qdrant_client,
            embedding_provider=provider,
            collection_prefix=collection_prefix
        )

        # Search (use empty locale for diaries)
        results = rag_service.search_posts(
            query=request.query,
            locale="",
            limit=request.limit
        )

        # Convert to diary search results
        diary_results = []
        for r in results:
            # Fetch created_at from database
            with db_conn.cursor(DictCursor) as cur:
                cur.execute(
                    "SELECT created_at FROM diary_entries WHERE id=%s",
                    (r['post_id'],)
                )
                entry = cur.fetchone()

            diary_results.append(DiarySearchResult(
                entry_id=r['post_id'],
                content=r['content'],
                score=r['score'],
                created_at=entry['created_at'].isoformat() if entry else None
            ))

        # Audit log
        with db_conn.cursor(DictCursor) as cur:
            cur.execute(
                """
                INSERT INTO audit_log (action, entity_type, entity_id, user_id, metadata)
                VALUES ('diary_searched', 'child', %s, NULL, %s)
                """,
                (request.child_id, json.dumps({
                    'query': request.query,
                    'provider': request.provider,
                    'results_count': len(diary_results)
                }))
            )

        return DiarySearchResponse(
            results=diary_results,
            query=request.query,
            child_id=request.child_id,
            provider=request.provider
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Search failed: {str(e)}")
    finally:
        db_conn.close()


@router.post("/ask", response_model=DiaryAskResponse, name="diary_ask")
async def ask_diary(
    request: DiaryAskRequest
):
    """
    RAG-powered question answering using child's diary entries.

    Flow:
    1. Search relevant entries (top N)
    2. Build context from entries
    3. Get completion from provider
    4. Return answer + sources
    """
    settings = get_settings()
    db_conn = get_db()
    qdrant_client = get_qdrant_client()

    try:
        # Create providers (may use different ones for embedding vs completion)
        embedding_provider = ProviderFactory.create_provider(
            provider_name=request.provider,
            settings=settings
        )

        completion_provider = ProviderFactory.create_provider(
            provider_name=request.provider,
            settings=settings
        )

        # Create RAG service
        collection_prefix = f"diary_child_{request.child_id}"
        rag_service = RAGService(
            db_conn=db_conn,
            qdrant_client=qdrant_client,
            embedding_provider=embedding_provider,
            completion_provider=completion_provider,
            collection_prefix=collection_prefix
        )

        # Perform RAG query
        result = rag_service.query_with_rag(
            question=request.question,
            locale="",  # Diaries don't have locale
            context_limit=request.context_limit
        )

        # Convert sources to diary results
        sources = []
        for source in result['sources']:
            # Fetch created_at from database
            with db_conn.cursor(DictCursor) as cur:
                cur.execute(
                    "SELECT entry_text, created_at FROM diary_entries WHERE id=%s",
                    (source['post_id'],)
                )
                entry = cur.fetchone()

            sources.append(DiarySearchResult(
                entry_id=source['post_id'],
                content=entry['entry_text'][:200] if entry else "",  # Preview
                score=source['score'],
                created_at=entry['created_at'].isoformat() if entry else None
            ))

        # Audit log
        with db_conn.cursor(DictCursor) as cur:
            cur.execute(
                """
                INSERT INTO audit_log (action, entity_type, entity_id, user_id, metadata)
                VALUES ('diary_rag_query', 'child', %s, NULL, %s)
                """,
                (request.child_id, json.dumps({
                    'question': request.question,
                    'provider': request.provider,
                    'sources_count': len(sources)
                }))
            )

        return DiaryAskResponse(
            answer=result['answer'],
            question=request.question,
            child_id=request.child_id,
            sources=sources,
            provider=result['provider'],
            model=result['model']
        )

    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"RAG query failed: {str(e)}")
    finally:
        db_conn.close()


@router.get("/{child_id}/status", name="diary_status")
async def get_diary_status(child_id: int):
    """
    Get indexing status for a child's diary.

    Returns:
        - Total diary entries
        - Indexed entries
        - Collection info
    """
    db_conn = get_db()

    try:
        with db_conn.cursor(DictCursor) as cur:
            # Total entries for this child
            cur.execute(
                "SELECT COUNT(*) as total FROM diary_entries WHERE child_id=%s",
                (child_id,)
            )
            total = cur.fetchone()['total']

            # Indexed entries
            collection_name = _get_diary_collection_name(child_id)
            cur.execute(
                """
                SELECT COUNT(DISTINCT post_id) as indexed,
                       SUM(chunk_count) as total_vectors,
                       MAX(indexed_at) as last_indexed
                FROM post_vectors
                WHERE collection_name=%s AND post_type='diary' AND child_id=%s
                """,
                (collection_name, child_id)
            )
            indexed_data = cur.fetchone()

        return {
            "child_id": child_id,
            "total_entries": total,
            "indexed_entries": indexed_data['indexed'] or 0,
            "total_vectors": indexed_data['total_vectors'] or 0,
            "last_indexed": indexed_data['last_indexed'].isoformat() if indexed_data['last_indexed'] else None,
            "collection_name": collection_name
        }

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Failed to get status: {str(e)}")
    finally:
        db_conn.close()