import os
import tempfile
from PIL import Image
from typing import Tuple, Optional
import logging
from pathlib import Path

logger = logging.getLogger(__name__)

def validate_inputs(reference_image, source_video) -> Tuple[Image.Image, str]:
    """
    Validate and process input files.
    
    Args:
        reference_image: PIL Image object
        source_video: Path or UploadedFile object
    
    Returns:
        Tuple of (PIL Image, video file path)
    """
    # Validate reference image
    if reference_image is None:
        raise ValueError("Reference image is required")
    
    # Ensure reference image is PIL Image
    if not isinstance(reference_image, Image.Image):
        if hasattr(reference_image, 'name'):
            reference_image = Image.open(reference_image.name)
        else:
            raise ValueError("Invalid reference image format")
    
    # Convert to RGB if needed
    if reference_image.mode != 'RGB':
        reference_image = reference_image.convert('RGB')
    
    # Handle video file
    if hasattr(source_video, 'name'):
        video_path = source_video.name
    elif isinstance(source_video, str):
        video_path = source_video
    else:
        raise ValueError("Invalid video file format")
    
    # Validate video file exists
    if not os.path.exists(video_path):
        raise ValueError("Video file not found")
    
    # Check file size (limit to 500MB)
    file_size = os.path.getsize(video_path)
    if file_size > 500 * 1024 * 1024:  # 500MB
        raise ValueError("Video file too large. Maximum size is 500MB")
    
    logger.info(f"Inputs validated successfully")
    return reference_image, video_path

def save_uploaded_files(reference_image, source_video) -> Tuple[str, str]:
    """
    Save uploaded files to temporary directory.
    
    Args:
        reference_image: PIL Image object
        source_video: Video file path
    
    Returns:
        Tuple of (reference_image_path, video_path)
    """
    # Create temporary directory
    temp_dir = tempfile.mkdtemp(prefix='video_char_replacement_')
    
    # Save reference image
    ref_path = os.path.join(temp_dir, 'reference_image.jpg')
    reference_image.save(ref_path, 'JPEG', quality=95)
    
    # Copy video file
    video_path = os.path.join(temp_dir, 'source_video.mp4')
    
    # Handle different video formats
    if source_video.endswith(('.avi', '.mov', '.mkv')):
        # Convert to MP4 if needed
        try:
            import cv2
            cap = cv2.VideoCapture(source_video)
            fps = int(cap.get(cv2.CAP_PROP_FPS))
            width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
            height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
            
            fourcc = cv2.VideoWriter_fourcc(*'mp4v')
            out = cv2.VideoWriter(video_path, fourcc, fps, (width, height))
            
            while True:
                ret, frame = cap.read()
                if not ret:
                    break
                out.write(frame)
            
            cap.release()
            out.release()
        except Exception as e:
            logger.warning(f"Could not convert video format: {e}")
            # Just copy the file as-is
            import shutil
            shutil.copy2(source_video, video_path)
    else:
        # Copy the file as-is
        import shutil
        shutil.copy2(source_video, video_path)
    
    logger.info(f"Files saved to temporary directory: {temp_dir}")
    return ref_path, video_path

def create_output_directory() -> str:
    """
    Create output directory for processed videos.
    
    Returns:
        Path to output directory
    """
    # Create output directory in temporary folder
    output_dir = tempfile.mkdtemp(prefix='video_char_replacement_output_')
    
    # Ensure directory exists
    os.makedirs(output_dir, exist_ok=True)
    
    logger.info(f"Output directory created: {output_dir}")
    return output_dir

def cleanup_temp_files(temp_dir: str):
    """
    Clean up temporary files.
    
    Args:
        temp_dir: Directory to clean up
    """
    try:
        import shutil
        if os.path.exists(temp_dir):
            shutil.rmtree(temp_dir)
        logger.info(f"Cleaned up temporary directory: {temp_dir}")
    except Exception as e:
        logger.warning(f"Could not clean up temporary directory: {e}")

def format_file_size(size_bytes: int) -> str:
    """
    Format file size in human-readable format.
    
    Args:
        size_bytes: Size in bytes
    
    Returns:
        Formatted string (e.g., "1.5 MB")
    """
    if size_bytes == 0:
        return "0 B"
    
    size_names = ["B", "KB", "MB", "GB"]
    i = 0
    size = float(size_bytes)
    
    while size >= 1024.0 and i < len(size_names) - 1:
        size /= 1024.0
        i += 1
    
    return f"{size:.1f} {size_names[i]}"