import logging
from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from sqlalchemy.orm import Session
from typing import List
from datetime import datetime

from api.auth import get_current_user
from models import db_models
from models.schemas import VideoSummaryGenerateRequest, VideoSummaryResponse
from core.database import get_db, SessionLocal
from api.websocket_routes import manager
from services.video_generator_service import video_generator_service
from services.slides_video_service import slides_video_service
from services.s3_service import s3_service

router = APIRouter(prefix="/api/videos", tags=["video-generator"])
logger = logging.getLogger(__name__)

async def run_video_generation(summary_id: int, request: VideoSummaryGenerateRequest, user_id: int):
    """Background task for video summary generation"""
    logger.info(f"Starting background video generation for ID: {summary_id}")
    db = SessionLocal()
    connection_id = f"user_{user_id}"
    try:
        db_summary = db.query(db_models.VideoSummary).filter(db_models.VideoSummary.id == summary_id).first()
        if not db_summary: 
            logger.error(f"Video summary {summary_id} not found in database")
            return

        if request.use_slides_transformation:
            logger.info(f"Task {summary_id}: Using slides transformation pipeline")
            result = await slides_video_service.generate_transformed_video_summary(
                file_key=request.file_key,
                language=request.language,
                voice_name=request.voice_name,
                custom_prompt=request.custom_prompt
            )
        else:
            logger.info(f"Task {summary_id}: Using standard video pipeline")
            result = await video_generator_service.generate_video_summary(
                file_key=request.file_key,
                language=request.language,
                voice_name=request.voice_name
            )

        if not db_summary.title or "Video Summary " not in db_summary.title:
            db_summary.title = result["title"]
        db_summary.s3_key = result["s3_key"]
        db_summary.s3_url = result["s3_url"]
        db_summary.status = "completed"
        db.commit()
        logger.info(f"Task {summary_id}: Successfully completed")

        # Notify via WebSocket
        await manager.send_result(connection_id, {
            "type": "video",
            "id": db_summary.id,
            "status": "completed",
            "title": db_summary.title
        })

    except Exception as e:
        logger.error(f"Task {summary_id}: Background video generation failed: {e}")
        db_summary = db.query(db_models.VideoSummary).filter(db_models.VideoSummary.id == summary_id).first()
        if db_summary:
            db_summary.status = "failed"
            db_summary.error_message = "video generation failed"
            db.commit()
        await manager.send_error(connection_id, f"Video generation failed: {str(e)}")
    finally:
        db.close()

@router.post("/generate", response_model=VideoSummaryResponse)
async def generate_video_summary(
    request: VideoSummaryGenerateRequest,
    background_tasks: BackgroundTasks,
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Initiates video summary generation in the background.
    """
    # Check source ownership
    source = db.query(db_models.Source).filter(
        db_models.Source.s3_key == request.file_key,
        db_models.Source.user_id == current_user.id
    ).first()
    
    if not source:
        raise HTTPException(status_code=403, detail="Not authorized to access this file")

    # Create initial processing record
    file_base = request.file_key.split('/')[-1].rsplit('.', 1)[0] if request.file_key else None
    title = f"Video Summary {file_base}"
    db_summary = db_models.VideoSummary(
        title=title,
        user_id=current_user.id,
        source_id=source.id,
        status="processing"
    )
    db.add(db_summary)
    db.commit()
    db.refresh(db_summary)

    # Offload to background task
    background_tasks.add_task(run_video_generation, db_summary.id, request, current_user.id)

    return db_summary

@router.get("/list", response_model=List[VideoSummaryResponse])
async def list_video_summaries(
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Lists all generated video summaries for the current user.
    """
    try:
        summaries = db.query(db_models.VideoSummary).filter(
            db_models.VideoSummary.user_id == current_user.id
        ).order_by(db_models.VideoSummary.created_at.desc()).all()
        
        return [VideoSummaryResponse.model_validate(s) for s in summaries]
    except Exception as e:
        logger.error(f"Failed to list video summaries: {e}")
        raise HTTPException(status_code=500, detail=str(e))

@router.get("/{video_id}", response_model=VideoSummaryResponse)
async def get_video_summary(
    video_id: int,
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Retrieves a specific video summary.
    """
    summary = db.query(db_models.VideoSummary).filter(
        db_models.VideoSummary.id == video_id,
        db_models.VideoSummary.user_id == current_user.id
    ).first()
    
    if not summary:
        raise HTTPException(status_code=404, detail="Video summary not found")
    
    return VideoSummaryResponse.model_validate(summary)

@router.delete("/{video_id}")
async def delete_video_summary(
    video_id: int,
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Deletes a specific video summary from database and S3.
    """
    summary = db.query(db_models.VideoSummary).filter(
        db_models.VideoSummary.id == video_id,
        db_models.VideoSummary.user_id == current_user.id
    ).first()
    
    if not summary:
        raise HTTPException(status_code=404, detail="Video summary not found")
    
    try:
        # 1. Delete from S3 if it exists
        if summary.s3_key:
            await s3_service.delete_file(summary.s3_key)
        
        # 2. Delete from DB
        db.delete(summary)
        db.commit()
        
        return {"message": "Video summary and associated S3 file deleted successfully"}
    except Exception as e:
        db.rollback()
        logger.error(f"Failed to delete video summary: {e}")
        raise HTTPException(status_code=500, detail=f"Deletion failed: {str(e)}")