from __future__ import annotations

import asyncio
from dataclasses import dataclass
from pathlib import Path

import edge_tts
from moviepy.audio.io.AudioFileClip import AudioFileClip

from .config import AppConfig


@dataclass(frozen=True)
class AudioAsset:
    path: Path
    duration_s: float


def _audio_duration_seconds(path: Path) -> float:
    # MoviePy uses ffmpeg and provides reliable duration for mp3.
    clip = AudioFileClip(str(path))
    try:
        return float(clip.duration or 0.0)
    finally:
        clip.close()


async def synthesize_one(text: str, out_path: Path, voice: str, rate: str, volume: str) -> AudioAsset:
    out_path.parent.mkdir(parents=True, exist_ok=True)
    communicate = edge_tts.Communicate(text=text, voice=voice, rate=rate, volume=volume)
    await communicate.save(str(out_path))
    dur = _audio_duration_seconds(out_path)
    return AudioAsset(path=out_path, duration_s=dur)


async def synthesize_scenes(narrations: list[str], cfg: AppConfig) -> list[AudioAsset]:
    voice = str(cfg.get("tts.voice", "zh-CN-XiaoxiaoNeural"))
    rate = str(cfg.get("tts.rate", "+0%"))
    volume = str(cfg.get("tts.volume", "+0%"))
    out_dir = Path(str(cfg.get("tts.output_dir", "./assets/audio")))
    out_dir.mkdir(parents=True, exist_ok=True)

    tasks: list[asyncio.Task[AudioAsset]] = []
    for idx, text in enumerate(narrations, start=1):
        out_path = out_dir / f"scene_{idx:02d}.mp3"
        tasks.append(asyncio.create_task(synthesize_one(text, out_path, voice, rate, volume)))
    return await asyncio.gather(*tasks)