#!/usr/bin/env python3
"""JSON Lint CLI - validates JSON from stdin or --text flag."""

import json
import sys


def validate(text: str) -> tuple[bool, str]:
    """Validate JSON text. Returns (is_valid, error_msg)."""
    try:
        json.loads(text)
        return True, ""
    except json.JSONDecodeError as e:
        return False, f"Line {e.lineno}, Col {e.colno}: {e.msg}"


def main():
    if len(sys.argv) == 3 and sys.argv[1] == "--text":
        # Validate inline JSON text
        text = sys.argv[2]
    elif len(sys.argv) == 2 and sys.argv[1] == "-":
        # Validate from stdin
        text = sys.stdin.read()
    elif len(sys.argv) == 2:
        # Validate from file path
        with open(sys.argv[1], 'r') as f:
            text = f.read()
    else:
        print("Usage: jsonlint.py [--text 'json'] | [-]", file=sys.stderr)
        sys.exit(2)

    ok, err = validate(text)
    if ok:
        print("VALID")
        sys.exit(0)
    else:
        print(f"INVALID: {err}", file=sys.stderr)
        sys.exit(1)


if __name__ == "__main__":
    main()