#!/usr/bin/env python3

import argparse
import json
import sys
from typing import Any, Sequence


def pretty_json(text: str, indent: int = 2) -> str:
    """Parse JSON text and return a consistently formatted representation."""
    value: Any = json.loads(text)
    return json.dumps(value, indent=indent, ensure_ascii=False, sort_keys=True)


def _test() -> None:
    assert pretty_json('{"b":1,"a":[true,null]}') == (
        '{\n'
        '  "a": [\n'
        '    true,\n'
        '    null\n'
        '  ],\n'
        '  "b": 1\n'
        '}'
    )
    assert pretty_json('{"message":"café"}', indent=4) == (
        '{\n'
        '    "message": "café"\n'
        '}'
    )


def main(argv: Sequence[str] | None = None) -> int:
    parser = argparse.ArgumentParser(description="Pretty-print JSON.")
    parser.add_argument("file", nargs="?", help="JSON file; defaults to standard input")
    parser.add_argument("-i", "--indent", type=int, default=2)
    parser.add_argument("--test", action="store_true", help="run built-in tests")
    args = parser.parse_args(argv)

    if args.test:
        _test()
        return 0

    # Read a file when supplied, otherwise support shell pipelines.
    try:
        if args.file:
            with open(args.file, encoding="utf-8") as source:
                text = source.read()
        else:
            text = sys.stdin.read()

        print(pretty_json(text, args.indent))
        return 0
    except (OSError, json.JSONDecodeError, ValueError) as error:
        print(f"error: {error}", file=sys.stderr)
        return 1


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