#!/usr/bin/env python3
"""
JSON Config Validator - Validates and pretty-prints JSON files
Usage: python3 json_config_validator.py <file.json>
Exit codes: 0=valid, 1=invalid, 2=file not found
"""

import json
import sys
from pathlib import Path


def validate_json_file(filepath: str) -> tuple[bool, str, dict | None, str]:
    """Validate a JSON file and return (is_valid, pretty_json, data, error_msg)."""
    p = Path(filepath)
    
    if not p.exists():
        return False, "", None, f"File not found: {filepath}"
    
    try:
        with open(p, 'r') as f:
            data = json.load(f)
        pretty = json.dumps(data, indent=2, sort_keys=True)
        return True, pretty, data, ""
    except json.JSONDecodeError as e:
        return False, "", None, f"JSON error at line {e.lineno}, column {e.colno}: {e.msg}"
    except Exception as e:
        return False, "", None, str(e)


def extract_schema_info(data: dict) -> dict:
    """Extract basic schema info from JSON data."""
    if not isinstance(data, dict):
        return {"type": type(data).__name__, "keys": [] if isinstance(data, list) else None}
    
    keys = list(data.keys())
    types = {k: type(v).__name__ for k, v in data.items()}
    
    return {
        "type": "object",
        "key_count": len(keys),
        "keys": keys,
        "value_types": types
    }


def main():
    if len(sys.argv) < 2:
        print("Usage: json_config_validator.py <file.json>", file=sys.stderr)
        sys.exit(2)
    
    filepath = sys.argv[1]
    is_valid, pretty, data, error = validate_json_file(filepath)
    
    if not is_valid:
        print(f"INVALID: {error}", file=sys.stderr)
        sys.exit(1)
    
    print(f"VALID: {filepath}")
    print(f"Size: {len(pretty)} bytes, {len(data) if isinstance(data, dict) else len(data) if isinstance(data, list) else 1} top-level items")
    print()
    print("CONTENT:")
    print(pretty)
    
    if isinstance(data, dict):
        schema = extract_schema_info(data)
        print()
        print("SCHEMA INFO:")
        print(json.dumps(schema, indent=2, sort_keys=True))
    
    sys.exit(0)


if __name__ == "__main__":
    main()