import os
import subprocess
import logging
from uuid import uuid4
from datetime import datetime

from app.database import SessionLocal
from app.models.asset import Asset
from app.config import settings

logger = logging.getLogger(__name__)

def extract_frame(asset_id: str, timestamp: float):
    """
    Extract a frame from a video asset at a specific timestamp.
    """
    print(f"DEBUG: Extracting frame for asset {asset_id} at {timestamp}")
    db = SessionLocal()
    try:
        # Get input asset
        from uuid import UUID
        try:
            uuid_id = UUID(str(asset_id))
        except ValueError:
             print(f"DEBUG: Invalid UUID string: {asset_id}")
             raise ValueError("Invalid asset ID format")

        asset = db.query(Asset).filter(Asset.id == uuid_id).first()
        if not asset:
            print(f"DEBUG: Asset {asset_id} not found in DB")
            raise ValueError("Asset not found")

        if not asset.file_path or not os.path.exists(asset.file_path):
             print(f"DEBUG: File path not found: {asset.file_path}")
             raise ValueError(f"Video file not found on disk: {asset.file_path}")

        # Generate output filename
        # Format: {original_name}_frame_{timestamp}.png
        base_name = os.path.splitext(asset.original_filename)[0]
        # Clean timestamp format to be safe (replace . with -)
        time_str = f"{timestamp:.3f}".replace('.', '-')
        filename = f"{base_name}_frame_{time_str}_{uuid4().hex[:6]}.png"
        
        storage_path = os.path.join(settings.storage_path, "images")
        os.makedirs(storage_path, exist_ok=True)
        output_path = os.path.join(storage_path, filename)
        
        print(f"DEBUG: Output path: {output_path}")

        # Build ffmpeg command
        # -ss before -i for faster seeking
        # -vframes 1 to get one frame
        # -q:v 2 for high quality jpg, but we want png so usually just default or compression level
        # PNG is lossless by default in ffmpeg usually.
        cmd = [
            'ffmpeg',
            '-y', # Overwrite
            '-ss', str(timestamp),
            '-i', asset.file_path,
            '-vframes', '1',
            output_path
        ]

        logger.info(f"Extracting frame with command: {' '.join(cmd)}")
        print(f"DEBUG: Running command: {cmd}")
        
        result = subprocess.run(cmd, capture_output=True, text=True)
        
        if result.returncode != 0:
            logger.error(f"FFmpeg failed: {result.stderr}")
            print(f"DEBUG: FFmpeg failed stderr: {result.stderr}")
            print(f"DEBUG: FFmpeg failed stdout: {result.stdout}")
            raise ValueError(f"Frame extraction failed: {result.stderr}")

        if not os.path.exists(output_path):
             print(f"DEBUG: Output file missing after success return code")
             raise ValueError("Output file was not created")

        # Get file size
        file_size = os.path.getsize(output_path)
        
        # Get dimensions if possible (assume same as video or read it)
        # We can use Pillow if installed, or just use input video dims
        width = asset.width
        height = asset.height
        
        # Determine mime type
        mime_type = "image/png"

        # Create new asset
        new_asset = Asset(
            user_id=asset.user_id,
            project_id=asset.project_id,
            original_filename=filename,
            stored_filename=filename,
            file_path=output_path,
            file_type="image",
            mime_type=mime_type,
            file_size_bytes=file_size,
            width=width,
            height=height,
            source_module="frame_extractor",
            parent_asset_id=asset.id,
            asset_metadata={
                "source_video_id": str(asset.id),
                "timestamp": timestamp
            }
        )
        
        db.add(new_asset)
        db.commit()
        db.refresh(new_asset)
        
        return new_asset

    finally:
        db.close()