#!/usr/bin/env python3
import  os
import linux

def combine_twitch_vod_and_chat(vod_path: str, layout: str = "side-by-side", force: bool = False) -> bool:
    """
    Renders Twitch chat JSON to video and combines it with the source VOD.
    Provides real-time terminal feedback for all processing steps.
    """
    video_path = vod_path
    chat_path = video_path.replace(".mp4", "_chat.json")
    temp_chat = video_path.replace(".mp4", "_temp_chat.mp4")
    video_chat = video_path.replace(".mp4", "_with_chat.mp4")
    mask_path = video_path.replace(".mp4", "_temp_chat_mask.mp4")

    # Step 1: Pre-flight checks
    if os.path.exists(video_chat) and force is False:
        print(f"❌ Error: Chat video allready exists: {video_chat}")
        return False
    
    if not os.path.exists(video_path):
        print(f"❌ Error: Source video not found: {video_path}")
        return False

    if not os.path.exists(chat_path):
        print(f"❌ Error: Chat file not found: {chat_path}")
        return False

    # Step 2: Render Chat to Video
    print("====================================================")
    print("🚀 STEP 1: Rendering Chat JSON to Video Layer")
    print("====================================================")
    
    chat_cmd = (
        f"TwitchDownloaderCLI chatrender "
        f"-i {chat_path} "
        f"-w 400 -h 1080 "
        f"--collision Overwrite "
        f"--temp-path download/temp "
        f"--font-size 20 "
        f"--generate-mask "
        f"--background-color #00000000 "
        f"-o {temp_chat} "
    )

    if not os.path.exists(temp_chat):
        chat_success = linux.run_command(chat_cmd, look_for=["[STATUS]"])
        if chat_success:
            print("✅ Success: TwitchDownloaderCLI render chat video.")
        else:
            print(f"❌ Error: TwitchDownloaderCLI failed to render chat video. {chat_success['error']} : {chat_success['stderr']}")
            os.remove(temp_chat)
            os.remove(mask_path)
            return False

    # Step 3: Combine Video and Chat using FFmpeg
    print("====================================================")
    print(f"🚀 STEP 2: Merging VOD and Chat Layout ({layout})")
    print("====================================================")
    
    # -preset superfast speeds up the 3+ hour encoding process significantly
    # -map 0:a? safely includes audio if it exists, without breaking on silent VODs
    if layout == "side-by-side":
        ffmpeg_cmd = (
            f"ffmpeg -y -i {video_path} -i {temp_chat} "
            f"-filter_complex '[0:v][1:v]hstack=inputs=2[v]' "
            f"-map '[v]' -map 0:a? -c:a copy -preset superfast {video_chat}"
        )
    elif layout == "overlay":
        ffmpeg_cmd = (
            f"ffmpeg -y -i {video_path} -i {temp_chat} -i {mask_path} "
            f"-filter_complex '[1:v][2:v]alphamerge[masked_chat];"
            f"[0:v][masked_chat]overlay=x=10:y=10[v]' "
            f"-map '[v]' -map 0:a? -c:a copy -preset superfast {video_chat}"
        )
    else:
        raise ValueError("Invalid layout choice. Choose 'side-by-side' or 'overlay'.")

    ffmpeg_success = linux.run_command(ffmpeg_cmd, progress_prefix="FFmpeg Merge")

    # Step 4: Final verification and cleanup
    if ffmpeg_success and os.path.exists(video_chat):
        print("====================================================")
        print(f"🎉 SUCCESS: Video processing complete!")
        print(f"📁 Output Saved: {video_chat}")
        print("====================================================")
        
        # Clean up the massive temporary chat video to save storage space
        if os.path.exists(temp_chat):
            print("🧹 Cleaning up temporary chat render video...")
            os.remove(temp_chat)
            os.remove(mask_path)
        return True
    else:
        print("❌ Error: FFmpeg failed to merge the video streams.")
        os.remove(video_chat)
        return False

if __name__ == "__main__":
    combine_twitch_vod_and_chat("download/videos/2813112936/2813112936.mp4", "overlay")