#!/usr/bin/env python3
"""
Pretty-print a JSON Lines (.jsonl) file.

Usage
-----
python scripts/jsonl_pretty_print.py path/to/file.jsonl [--indent 2]

The script reads each line, parses it as JSON, and writes a
human-readable representation to stdout.  Redirect or pipe as needed.

Example
-------
python scripts/jsonl_pretty_print.py data.jsonl --indent 4 > pretty.json
"""
from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Pretty-print a .jsonl file.")
    parser.add_argument(
        "jsonl_path",
        type=Path,
        help="Path to the input .jsonl file",
    )
    parser.add_argument(
        "--indent",
        type=int,
        default=2,
        help="Number of spaces to indent (default: 2)",
    )
    return parser.parse_args()


def pretty_print_jsonl(path: Path, indent: int) -> None:
    if not path.exists():
        sys.exit(f"Error: {path} does not exist")

    with path.open("r", encoding="utf-8") as fp:
        for idx, line in enumerate(fp, start=1):
            line = line.strip()
            if not line:
                continue  # skip empty lines
            try:
                obj = json.loads(line)
            except json.JSONDecodeError as exc:
                sys.exit(f"JSON decode error on line {idx}: {exc}")  # fail fast
            # Build pretty JSON string, convert literal "\n" sequences to real newlines,
            # and emit a blank line between records for readability.
            pretty = json.dumps(obj, indent=indent, ensure_ascii=False, sort_keys=True)
            pretty = pretty.replace("\\n", "\n")
            sys.stdout.write(pretty)
            sys.stdout.write("\n\n")


def main() -> None:
    args = parse_args()
    pretty_print_jsonl(args.jsonl_path, args.indent)


if __name__ == "__main__":
    main()