#!/usr/bin/env python3
"""JSON Validator - validates JSON files with proper exit codes.

Exit 0: All valid
Exit 1: One or more invalid
Exit 2: Usage error

Features:
- Validate individual files: json-validator.py <file.json> ...
- Validate directory: json-validator.py --dir <directory>
- Returns count of invalid files as exit code for --dir mode
"""

import sys
import json
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)
        print(f"VALID: {filepath}")
        return True, ""
    except json.JSONDecodeError as e:
        return False, f"Invalid JSON at line {e.lineno}, column {e.colno}: {e.msg}"
    except FileNotFoundError:
        return False, "File not found"
    except Exception as e:
        return False, f"Error: {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
    invalid_files = []
    
    for jf in json_files:
        is_valid, error = validate_json_file(str(jf))
        if is_valid:
            valid += 1
        else:
            invalid += 1
            invalid_files.append((jf.name, error))
            print(f"INVALID: {jf.name} - {error}")
    
    return {"total": len(json_files), "valid": valid, "invalid": invalid, "invalid_files": invalid_files[:5]}


def main():
    if len(sys.argv) < 2:
        print("Usage: json-validator.py <file-or-directory>", file=sys.stderr)
        print("       json-validator.py --dir <directory>", file=sys.stderr)
        sys.exit(2)
    
    # 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:
                print(f"Error: {result['error']}", file=sys.stderr)
                sys.exit(2)
            print(f"\nDirectory: {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(2)
    else:
        paths = sys.argv[1:]
        all_valid = True
        
        for path in paths:
            p = Path(path)
            if p.is_dir():
                for json_file in p.rglob("*.json"):
                    is_valid, error = validate_json_file(str(json_file))
                    if not is_valid:
                        all_valid = False
            elif p.is_file():
                is_valid, error = validate_json_file(str(p))
                if not is_valid:
                    all_valid = False
            else:
                print(f"NOT FOUND: {path}", file=sys.stderr)
                all_valid = False
        
        sys.exit(0 if all_valid else 1)


if __name__ == "__main__":
    main()