#!/usr/bin/env python3
"""
Metadata Validation Utility

This script validates metadata files in the gallery source directories,
checking for proper YAML/JSON syntax and common field validation.
"""

import sys
import json
import yaml
from pathlib import Path
from typing import Dict, Any, List


def validate_metadata_file(file_path: Path) -> tuple[bool, List[str]]:
    """
    Validate a single metadata file.
    
    Args:
        file_path: Path to the metadata file
        
    Returns:
        Tuple of (is_valid, error_messages)
    """
    errors = []
    
    if not file_path.exists():
        errors.append(f"File does not exist: {file_path}")
        return False, errors
    
    try:
        with file_path.open('r', encoding='utf-8') as f:
            suffix_lower = file_path.suffix.lower()
            if suffix_lower in ['.yaml', '.yml']:
                data = yaml.safe_load(f)
            elif suffix_lower == '.json':
                data = json.load(f)
            else:
                errors.append(f"Unsupported file format: {file_path}")
                return False, errors
                
        if data is None:
            errors.append(f"Empty metadata file: {file_path}")
            return False, errors
            
        # Basic validation
        if not isinstance(data, dict):
            errors.append(f"Metadata must be a dictionary: {file_path}")
            return False, errors
            
        # Check for common issues
        if 'title' in data and not isinstance(data['title'], str):
            errors.append(f"Title must be a string: {file_path}")
            
        if 'tags' in data and not isinstance(data['tags'], list):
            errors.append(f"Tags must be a list: {file_path}")
            
        if 'author' in data and not isinstance(data['author'], dict):
            errors.append(f"Author must be a dictionary: {file_path}")
            
    except (yaml.YAMLError, json.JSONDecodeError) as e:
        errors.append(f"Parse error in {file_path}: {e}")
        return False, errors
    except Exception as e:
        errors.append(f"Unexpected error reading {file_path}: {e}")
        return False, errors
    
    return len(errors) == 0, errors


def find_metadata_files(root_dir: Path) -> List[Path]:
    """
    Find all metadata files in a directory tree.
    
    Args:
        root_dir: Root directory to search
        
    Returns:
        List of metadata file paths
    """
    metadata_files = []
    
    for pattern in ['**/*.yaml', '**/*.yml', '**/*.json']:
        for file_path in root_dir.glob(pattern):
            if file_path.name.startswith('meta.') or file_path.stem != file_path.name:
                metadata_files.append(file_path)
    
    return metadata_files


def main():
    """Main validation function."""
    if len(sys.argv) != 2:
        print("Usage: python validate_metadata.py <directory>")
        sys.exit(1)
    
    root_dir = Path(sys.argv[1])
    
    if not root_dir.exists():
        print(f"Error: Directory does not exist: {root_dir}")
        sys.exit(1)
        
    if not root_dir.is_dir():
        print(f"Error: Not a directory: {root_dir}")
        sys.exit(1)
    
    print(f"Validating metadata files in: {root_dir}")
    print("-" * 50)
    
    metadata_files = find_metadata_files(root_dir)
    
    if not metadata_files:
        print("No metadata files found.")
        return
    
    total_files = len(metadata_files)
    valid_files = 0
    
    for file_path in metadata_files:
        is_valid, errors = validate_metadata_file(file_path)
        
        if is_valid:
            print(f"✓ {file_path.relative_to(root_dir)}")
            valid_files += 1
        else:
            print(f"✗ {file_path.relative_to(root_dir)}")
            for error in errors:
                print(f"  - {error}")
    
    print("-" * 50)
    print(f"Summary: {valid_files}/{total_files} files valid")
    
    if valid_files != total_files:
        sys.exit(1)


if __name__ == "__main__":
    main()