#!/usr/bin/env python3
"""Simple JSON validator that generates SHA256 checksums for verification."""

import json
import sys
import hashlib
from pathlib import Path


def validate_json_file(filepath: str) -> tuple[bool, str]:
    """Validate a JSON file and return (is_valid, error_message)."""
    try:
        with open(filepath, 'r') as f:
            json.load(f)
        return True, ""
    except json.JSONDecodeError as e:
        return False, f"Invalid JSON: {e}"
    except FileNotFoundError:
        return False, f"File not found: {filepath}"
    except Exception as e:
        return False, f"Error: {e}"


def compute_sha256(filepath: str) -> str:
    """Compute SHA256 hash of a file."""
    sha256_hash = hashlib.sha256()
    with open(filepath, 'rb') as f:
        for byte_block in iter(lambda: f.read(4096), b""):
            sha256_hash.update(byte_block)
    return sha256_hash.hexdigest()


def main():
    if len(sys.argv) < 2:
        print("Usage: json_sha256_validator.py <file1.json> [file2.json ...]")
        sys.exit(1)

    results = []
    all_valid = True

    for filepath in sys.argv[1:]:
        is_valid, error = validate_json_file(filepath)
        if is_valid:
            checksum = compute_sha256(filepath)
            results.append(f"VALID  {filepath} SHA256={checksum}")
        else:
            results.append(f"INVALID {filepath} ERROR={error}")
            all_valid = False

    for r in results:
        print(r)

    if all_valid:
        sys.exit(0)
    else:
        sys.exit(1)


if __name__ == "__main__":
    main()