#!/usr/bin/env python3
"""Unlock (decrypt) a password-protected PDF using pikepdf."""
import argparse, json, sys
from pathlib import Path

def unlock(input_path, output_path, password):
    import pikepdf
    
    if not output_path:
        output_path = str(Path(input_path).with_stem(Path(input_path).stem + '_unlocked'))
    
    try:
        pdf = pikepdf.open(input_path, password=password)
    except pikepdf.PasswordError:
        raise ValueError("Incorrect password. Please check and try again.")
    
    pdf.save(output_path)
    pdf.close()
    return output_path

def main():
    parser = argparse.ArgumentParser(description='Unlock password-protected PDF')
    parser.add_argument('--input', required=True)
    parser.add_argument('--output', required=True)
    parser.add_argument('--password', required=True)
    args = parser.parse_args()
    try:
        result = unlock(args.input, args.output, args.password)
        print(json.dumps({"success": True, "output": result, "message": "PDF unlocked successfully"}))
    except Exception as e:
        print(json.dumps({"success": False, "output": "", "message": str(e)}))
        sys.exit(1)

if __name__ == '__main__':
    main()