#!/usr/bin/env python3
import argparse
import json
import shutil
from pathlib import Path


def build_target_path(audio_path: Path, audio_root: Path) -> Path:
    if audio_path.is_absolute():
        relative_path = audio_path.relative_to("/")
    else:
        relative_path = audio_path
    return audio_root / relative_path


def copy_audio(audio_path: Path, audio_root: Path, copied: dict[str, Path]) -> Path:
    key = str(audio_path)
    if key in copied:
        return copied[key]
    if not audio_path.exists():
        raise FileNotFoundError(f"Audio file not found: {audio_path}")

    target_path = build_target_path(audio_path, audio_root)
    target_path.parent.mkdir(parents=True, exist_ok=True)
    shutil.copy2(audio_path, target_path)
    copied[key] = target_path
    return target_path


def rewrite_record(item: dict, audio_root: Path, copied: dict[str, Path], input_path: Path, line_no: int) -> int:
    rewritten = 0

    if "audio" in item:
        audio_path = Path(item["audio"])
        item["audio"] = str(copy_audio(audio_path, audio_root, copied))
        rewritten += 1

    if "audios" in item:
        audios = item["audios"]
        if not isinstance(audios, list):
            raise ValueError(f"{input_path}:{line_no} field 'audios' is not a list")
        item["audios"] = [str(copy_audio(Path(audio), audio_root, copied)) for audio in audios]
        rewritten += len(item["audios"])

    if rewritten == 0:
        raise ValueError(f"{input_path}:{line_no} has neither 'audio' nor 'audios'")

    return rewritten


def process_jsonl(input_path: Path, output_path: Path, audio_root: Path) -> tuple[int, int, int]:
    copied: dict[str, Path] = {}
    line_count = 0
    audio_refs = 0

    with input_path.open("r", encoding="utf-8") as src, output_path.open("w", encoding="utf-8") as dst:
        for line_no, line in enumerate(src, start=1):
            if not line.strip():
                continue

            item = json.loads(line)
            audio_refs += rewrite_record(item, audio_root, copied, input_path, line_no)
            dst.write(json.dumps(item, ensure_ascii=False) + "\n")
            line_count += 1

    return line_count, audio_refs, len(copied)


def main() -> None:
    parser = argparse.ArgumentParser(description="Copy referenced audio files and rewrite JSONL audio paths.")
    parser.add_argument("--input", required=True, help="Input JSONL file.")
    parser.add_argument("--output", required=True, help="Output rewritten JSONL file.")
    parser.add_argument("--audio-root", required=True, help="Destination root for copied audio files.")
    args = parser.parse_args()

    input_path = Path(args.input).resolve()
    output_path = Path(args.output).resolve()
    audio_root = Path(args.audio_root).resolve()

    output_path.parent.mkdir(parents=True, exist_ok=True)
    audio_root.mkdir(parents=True, exist_ok=True)

    line_count, audio_refs, unique_audio_count = process_jsonl(
        input_path=input_path,
        output_path=output_path,
        audio_root=audio_root,
    )
    print(
        f"Processed {line_count} lines, rewrote {audio_refs} audio references, "
        f"copied {unique_audio_count} unique audio files"
    )


if __name__ == "__main__":
    main()