#!/usr/bin/env python3
"""JSON Schema Validator - validates JSON files against schema and outputs machine-readable report."""

import json
import sys
from pathlib import Path
from typing import Any

def validate_json_schema(data: dict, schema: dict) -> list[str]:
    """Validate a JSON dict against a schema. Returns list of errors."""
    errors = []
    
    if not isinstance(data, dict):
        return ["Root must be an object"]
    
    if "properties" not in schema:
        return []
    
    # Check required fields
    for required in schema.get("required", []):
        if required not in data:
            errors.append(f"Missing required field: '{required}'")
    
    for prop, prop_schema in schema.get("properties", {}).items():
        if prop in data:
            expected_type = prop_schema.get("type")
            if expected_type:
                type_map = {"string": str, "number": (int, float), "integer": int, "boolean": bool, "array": list, "object": dict}
                expected_py = type_map.get(expected_type)
                if expected_py and not isinstance(data[prop], expected_py):
                    actual_type = type(data[prop]).__name__
                    errors.append(f"Property '{prop}' expected {expected_type}, got {actual_type}")
    
    return errors

def main():
    if len(sys.argv) < 3:
        print(json.dumps({"error": "Usage: json_validator.py <json_file> <schema_file>"}))
        sys.exit(1)
    
    json_path = Path(sys.argv[1])
    schema_path = Path(sys.argv[2])
    
    if not json_path.exists():
        print(json.dumps({"valid": False, "errors": [f"File not found: {json_path}"]}))
        sys.exit(1)
    
    if not schema_path.exists():
        print(json.dumps({"valid": False, "errors": [f"Schema not found: {schema_path}"]}))
        sys.exit(1)
    
    try:
        with open(json_path) as f:
            data = json.load(f)
    except json.JSONDecodeError as e:
        print(json.dumps({"valid": False, "errors": [f"Invalid JSON: {e}"]}))
        sys.exit(1)
    
    try:
        with open(schema_path) as f:
            schema = json.load(f)
    except json.JSONDecodeError as e:
        print(json.dumps({"valid": False, "errors": [f"Invalid schema JSON: {e}"]}))
        sys.exit(1)
    
    errors = validate_json_schema(data, schema)
    
    result = {
        "valid": len(errors) == 0,
        "errors": errors,
        "file": str(json_path),
        "schema": str(schema_path)
    }
    
    print(json.dumps(result))
    sys.exit(0 if result["valid"] else 1)

if __name__ == "__main__":
    main()