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

Exit 0: All valid
Exit 1: One or more inputs could not be validated (invalid JSON, schema mismatch)
Exit 2: Usage error (bad arguments, a path that does not exist, unusable schema)

The exit code reports the *outcome of the request*, never a count: `--dir` mode
exits 1 when any file in the directory is invalid, however many that is (a count
as an exit status silently reads as success at 256 and as a usage error at 2).
The per-run summary lines carry the counts.

Features:
- Validate individual files: json-validator.py <file.json> ...
- Validate directory: json-validator.py --dir <directory>
- Error reporting with file paths, one INVALID line per failing file
- Schema validation support via --schema flag
- --quiet suppresses the VALID banner for passing files

Requires no third-party package unless --schema is used (then: jsonschema).
"""

import sys
import json
import argparse
from pathlib import Path


def validate_json_file(filepath: str, schema: dict | None = None, quiet: bool = False) -> tuple[bool, str]:
    """Validate a JSON file.

    Args:
        filepath: Path to the JSON file
        schema: Optional JSON schema dict for schema validation
        quiet: Suppress the VALID line for a passing file

    Returns:
        (True, "") if valid
        (False, error_message) if invalid
    """
    try:
        with open(filepath, 'r', encoding='utf-8') as f:
            data = json.load(f)

        if schema:
            import jsonschema
            jsonschema.validate(instance=data, schema=schema)

        if not quiet:
            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, schema: dict | None = None, quiet: bool = False) -> dict:
    """Validate every .json file in a directory (non-recursive).

    Args:
        directory: Path to directory
        schema: Optional JSON schema for validation
        quiet: Suppress the VALID lines for passing files

    Returns:
        Dict with totals and counts, or {"error": ...} when the directory is unusable
    """
    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 = sorted(dir_path.glob("*.json"))
    valid = 0
    invalid = 0
    invalid_files = []

    for jf in json_files:
        is_valid, error = validate_json_file(str(jf), schema, quiet)
        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[:10]
    }


def exit_code_for(invalid: int) -> int:
    """Map an invalid-input count onto the documented exit contract (0 or 1).

    Never returns the count itself: an exit status is a class, not a tally.
    """
    return 0 if invalid == 0 else 1


def main():
    parser = argparse.ArgumentParser(description='Enhanced JSON Validator')
    parser.add_argument('paths', nargs='*', help='JSON files or directories to validate')
    parser.add_argument('--dir', dest='directory', help='Directory to validate')
    parser.add_argument('--schema', help='JSON Schema file for validation')
    parser.add_argument('--quiet', '-q', action='store_true', help='Suppress VALID messages')

    args = parser.parse_args()

    if not args.paths and not args.directory:
        parser.print_help()
        sys.exit(2)

    schema = None
    if args.schema:
        try:
            with open(args.schema, 'r', encoding='utf-8') as f:
                schema = json.load(f)
        except Exception as e:
            print(f"Error loading schema: {e}", file=sys.stderr)
            sys.exit(2)
        try:
            import jsonschema  # noqa: F401
        except ImportError:
            print("Error: --schema requires the jsonschema package, which is not importable", file=sys.stderr)
            sys.exit(2)

    if args.directory:
        result = validate_json_directory(args.directory, schema, args.quiet)
        if "error" in result:
            print(f"Error: {result['error']}", file=sys.stderr)
            sys.exit(2)
        print(f"\nDirectory: {args.directory}")
        print(f"Total: {result['total']}")
        print(f"Valid: {result['valid']}")
        print(f"Invalid: {result['invalid']}")
        sys.exit(exit_code_for(result['invalid']))

    invalid = 0
    missing = 0
    for path in args.paths:
        p = Path(path)
        if p.is_dir():
            for json_file in sorted(p.rglob("*.json")):
                is_valid, error = validate_json_file(str(json_file), schema, args.quiet)
                if not is_valid:
                    invalid += 1
                    print(f"INVALID: {json_file} - {error}")
        elif p.is_file():
            is_valid, error = validate_json_file(str(p), schema, args.quiet)
            if not is_valid:
                invalid += 1
                print(f"INVALID: {p} - {error}")
        else:
            print(f"NOT FOUND: {path}", file=sys.stderr)
            missing += 1

    if missing:
        # A path that does not exist is a bad invocation, not bad data.
        sys.exit(2)
    sys.exit(exit_code_for(invalid))


if __name__ == "__main__":
    main()