#!/usr/bin/env python3
"""Simple JSON validator CLI - validates JSON files and reports errors."""

import json
import sys
from pathlib import Path


def validate_json_file(filepath: str) -> tuple[bool, str]:
    """Validate a JSON file.
    
    Returns:
        (True, "") if valid
        (False, error_message) if invalid
    """
    try:
        with open(filepath, 'r') as f:
            json.load(f)
        return True, ""
    except FileNotFoundError:
        return False, f"Error: File not found: {filepath}"
    except json.JSONDecodeError as e:
        return False, f"Error: Invalid JSON at line {e.lineno}, column {e.colno}: {e.msg}"
    except Exception as e:
        return False, f"Error reading file: {e}"


def validate_json_directory(directory: str) -> dict:
    """Validate all .json files in a directory.
    
    Returns:
        Dict with totals and counts
    """
    dir_path = Path(directory)
    if not dir_path.exists():
        return {"error": f"Directory not found: {directory}", "total": 0, "valid": 0, "invalid": 0}
    if not dir_path.is_dir():
        return {"error": f"Not a directory: {directory}", "total": 0, "valid": 0, "invalid": 0}
    
    json_files = list(dir_path.glob("*.json"))
    valid = 0
    invalid = 0
    
    for jf in json_files:
        is_valid, _ = validate_json_file(str(jf))
        if is_valid:
            valid += 1
        else:
            invalid += 1
    
    return {"total": len(json_files), "valid": valid, "invalid": invalid}


def main():
    if len(sys.argv) < 2:
        print("Usage: json_validator.py <file1.json> [file2.json] ...", file=sys.stderr)
        print("       json_validator.py --dir <directory>", file=sys.stderr)
        sys.exit(1)
    
    # Check for --dir flag
    if "--dir" in sys.argv:
        try:
            dir_idx = sys.argv.index("--dir")
            directory = sys.argv[dir_idx + 1]
            result = validate_json_directory(directory)
            if "error" in result and result.get("total") == 0:
                print(f"Error: {result['error']}", file=sys.stderr)
                sys.exit(1)
            print(f"Directory: {directory}")
            print(f"Total: {result['total']}")
            print(f"Valid: {result['valid']}")
            print(f"Invalid: {result['invalid']}")
            sys.exit(result['invalid'])
        except IndexError:
            print("Error: --dir requires a directory argument", file=sys.stderr)
            sys.exit(1)
    else:
        files = sys.argv[1:]
        all_valid = True
        results = []
        
        for filepath in files:
            valid, error = validate_json_file(filepath)
            if valid:
                results.append(f"VALID: {filepath}")
            else:
                results.append(f"INVALID: {filepath} - {error}")
                all_valid = False
        
        for r in results:
            print(r)
        
        sys.exit(0 if all_valid else 1)


if __name__ == "__main__":
    main()