import json
from pathlib import Path

from transcriber.merge.aligner import MergedSegment


def write_json(segments: list[MergedSegment], output_path: str) -> str:
    """Export merged segments as a structured JSON file.

    Args:
        segments: List of merged speaker segments.
        output_path: Path to the output .json file.

    Returns:
        Path to the written file.
    """
    path = Path(output_path)
    path.parent.mkdir(parents=True, exist_ok=True)

    data = [
        {
            "speaker": seg.speaker,
            "start": round(seg.start, 2),
            "end": round(seg.end, 2),
            "text": seg.text,
        }
        for seg in segments
    ]

    path.write_text(
        json.dumps(data, ensure_ascii=False, indent=2),
        encoding="utf-8",
    )
    return str(path)