from __future__ import annotations

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


def pretty_json(raw_json: str, indent: int = 2, sort_keys: bool = False) -> str:
    """Parse JSON text and return consistently formatted JSON."""
    data: Any = json.loads(raw_json)
    return json.dumps(data, indent=indent, sort_keys=sort_keys, ensure_ascii=False) + "\n"


def read_text(path: str | None) -> str:
    # A missing path or "-" means standard input.
    if path is None or path == "-":
        return sys.stdin.read()
    return Path(path).read_text(encoding="utf-8")


def write_text(path: str | None, text: str) -> None:
    # A missing path or "-" means standard output.
    if path is None or path == "-":
        sys.stdout.write(text)
        return
    Path(path).write_text(text, encoding="utf-8")


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(description="Pretty-print JSON from a file or stdin.")
    parser.add_argument("input", nargs="?", help="JSON file to read; defaults to stdin")
    parser.add_argument("-o", "--output", help="Output file; defaults to stdout")
    parser.add_argument("-i", "--indent", type=int, default=2, help="Spaces per indent level")
    parser.add_argument("-s", "--sort-keys", action="store_true", help="Sort object keys")
    parser.add_argument("--test", action="store_true", help="Run the built-in tests")
    return parser


class PrettyJsonTests(unittest.TestCase):
    def test_pretty_prints_object(self) -> None:
        self.assertEqual(
            pretty_json('{"name":"Ada","active":true}'),
            '{\n  "name": "Ada",\n  "active": true\n}\n',
        )

    def test_sorts_keys(self) -> None:
        self.assertEqual(
            pretty_json('{"b":2,"a":1}', sort_keys=True),
            '{\n  "a": 1,\n  "b": 2\n}\n',
        )


def run_tests() -> int:
    result = unittest.TextTestRunner(verbosity=2).run(
        unittest.defaultTestLoader.loadTestsFromTestCase(PrettyJsonTests)
    )
    return 0 if result.wasSuccessful() else 1


def main(argv: list[str] | None = None) -> int:
    args = build_parser().parse_args(argv)

    if args.test:
        return run_tests()

    try:
        formatted = pretty_json(read_text(args.input), indent=args.indent, sort_keys=args.sort_keys)
        write_text(args.output, formatted)
    except (OSError, json.JSONDecodeError) as error:
        print(f"error: {error}", file=sys.stderr)
        return 1

    return 0


if __name__ == "__main__":
    raise SystemExit(main())