# -*- coding: utf-8 -*-
"""视频合成模块

使用 MoviePy 将图片背景 + 音频 + 字幕合成为最终视频。
"""

import os
from moviepy.editor import (
    ImageClip,
    AudioFileClip,
    CompositeVideoClip,
    concatenate_videoclips,
    ColorClip,
)
from moviepy.video.tools.subtitles import SubtitlesClip
from moviepy.editor import TextClip


def _make_bg(size, duration, color=(20, 20, 40)):
    """生成纯色背景片段"""
    return ColorClip(size=size, color=color, duration=duration)


def _make_subtitle_clip(text: str, size, duration: float):
    """生成一段字幕文本片段"""
    w, h = size
    try:
        txt = TextClip(text, fontsize=48, color="white", font="Arial",
                       size=(w - 100, None), method="caption")
    except Exception:
        # 若系统找不到字体，退化为默认字体
        txt = TextClip(text, fontsize=48, color="white",
                       size=(w - 100, None), method="caption")
    txt = txt.set_position(("center", h - 180)).set_duration(duration)
    return txt


def compose_video(scenes: list, audio_paths: list, durations: list,
                  out_path: str, resolution=(1280, 720)) -> str:
    """合成最终视频。

    Args:
        scenes: 场景列表
        audio_paths: 每个场景对应的音频路径
        durations: 每个场景的时长
        out_path: 输出 mp4 路径
        resolution: (width, height)

    Returns:
        str: 输出文件路径
    """
    os.makedirs(os.path.dirname(out_path), exist_ok=True)
    clips = []
    for scene, audio, dur in zip(scenes, audio_paths, durations):
        bg = _make_bg(resolution, dur)
        sub = _make_subtitle_clip(scene["text"], resolution, dur)
        audio_clip = AudioFileClip(audio)
        clip = CompositeVideoClip([bg, sub]).set_audio(audio_clip)
        clips.append(clip)

    final = concatenate_videoclips(clips, method="compose")
    final.write_videofile(out_path, fps=24, codec="libx264", audio_codec="aac")
    return out_path


if __name__ == "__main__":
    print("请通过 cli.py 或 app.py 调用")