import gradio as gr
from pydub import AudioSegment
import os

def mix_audio(podcast_file, bgm_file, bgm_volume, loop, fade_in_out, fade_duration):
    if not podcast_file or not bgm_file:
        return "請上傳 Podcast 和 BGM 檔案", None

    # 讀取音檔
    podcast = AudioSegment.from_file(podcast_file)
    bgm = AudioSegment.from_file(bgm_file)

    # 調整 BGM 音量
    bgm = bgm - abs(bgm_volume)  # 降低 dB

    # 是否需要 loop BGM
    if loop:
        loop_count = len(podcast) // len(bgm) + 1
        bgm = bgm * loop_count  # 重複播放
    bgm = bgm[:len(podcast)]  # 修剪至 Podcast 長度

    # 是否添加淡入淡出效果
    if fade_in_out:
        bgm = bgm.fade_in(fade_duration * 1000).fade_out(fade_duration * 1000)

    # 混音
    mixed = podcast.overlay(bgm)

    # 儲存混音結果
    output_file = "mixed_podcast.mp3"
    mixed.export(output_file, format="mp3")

    return "混音完成！點擊下載", output_file, output_file  # 第三個值是給 gr.Audio 用的

# 建立 Gradio 介面
with gr.Blocks() as app:
    gr.Markdown("## 🎙️ Podcast 混音工具 🎵")

    with gr.Row():
        with gr.Column():
            podcast_input = gr.File(label="🎙️ 上傳 Podcast MP3", type="filepath")
            bgm_input = gr.File(label="🎵 上傳背景音樂 MP3", type="filepath")
            bgm_volume = gr.Slider(-30, 0, value=-14, label="🎚️ 背景音樂音量調整 (dB, 越小越小聲)")
            loop_option = gr.Checkbox(value=True, label="🔁 背景音樂循環")
            fade_option = gr.Checkbox(value=True, label="🎼 添加淡入淡出效果")
            fade_duration = gr.Slider(1, 10, value=5, label="⏳ 淡入淡出秒數")
            process_button = gr.Button("🚀 開始混音")

        with gr.Column():
            output_message = gr.Textbox(label="📢 處理狀態", interactive=False)
            audio_output = gr.Audio(label="🎧 預覽混音結果", format="mp3", interactive=False, autoplay=False)
            download_output = gr.File(label="⬇️ 下載混音 MP3")



    process_button.click(
        fn=mix_audio,
        inputs=[podcast_input, bgm_input, bgm_volume, loop_option, fade_option, fade_duration],
        outputs=[output_message, audio_output, download_output]  # 確保 Audio 正確顯示
    )


# 執行 Gradio 應用
app.launch()