# app/audio/generate.py
from __future__ import annotations

import platform
import shutil
import subprocess
from pathlib import Path

from loguru import logger


def generate_rep_audio_files(
    *,
    max_count: int,
    rate: int,
    output_dir: Path,
    overwrite: bool = False,
) -> None:
    """
    确保 0~max_count 的运动次数语音 wav 文件存在。

    默认生成到：

        app/audio/reps/0.wav
        app/audio/reps/1.wav
        ...
        app/audio/reps/200.wav

    服务启动时调用一次即可。
    """
    output_dir.mkdir(parents=True, exist_ok=True)

    missing_counts = [
        count
        for count in range(0, max_count + 1)
        if overwrite or not _audio_path(output_dir, count).exists()
    ]

    if not missing_counts:
        logger.info("Rep audio files already prepared: {}", output_dir)
        return

    system = platform.system().lower()

    logger.info(
        "Preparing rep audio files, system={}, count={}, output_dir={}",
        system,
        len(missing_counts),
        output_dir,
    )

    if system == "darwin":
        _generate_with_macos_say(
            counts=missing_counts,
            output_dir=output_dir,
            rate=rate,
        )
    else:
        _generate_with_pyttsx3(
            counts=missing_counts,
            output_dir=output_dir,
            rate=rate,
        )

    logger.info("Rep audio files prepared: {}", output_dir)


def _generate_with_macos_say(
    *,
    counts: list[int],
    output_dir: Path,
    rate: int,
) -> None:
    """macOS 使用 say 命令生成 wav。"""
    if platform.system().lower() != "darwin":
        raise RuntimeError("say command is only available on macOS")

    if shutil.which("say") is None:
        raise RuntimeError("macOS say command not found")

    for count in counts:
        audio_file = _audio_path(output_dir, count)

        subprocess.run(
            [
                "say",
                "-r",
                str(rate),
                "--file-format=WAVE",
                "-o",
                str(audio_file),
                str(count),
            ],
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL,
            check=True,
        )


def _generate_with_pyttsx3(
    *,
    counts: list[int],
    output_dir: Path,
    rate: int,
) -> None:
    """Windows / Linux 使用 pyttsx3 生成 wav。"""
    try:
        import pyttsx3
    except Exception as exc:
        raise RuntimeError(f"pyttsx3 unavailable: {exc}") from exc

    engine = pyttsx3.init()
    engine.setProperty("rate", rate)
    engine.setProperty("volume", 1.0)

    for count in counts:
        audio_file = _audio_path(output_dir, count)
        engine.save_to_file(str(count), str(audio_file))

    engine.runAndWait()


def _audio_path(output_dir: Path, count: int) -> Path:
    return output_dir / f"{count}.wav"