import os
import uuid
import shutil
import subprocess
import gradio as gr

TEMP_DIR = os.path.abspath("temp")
OUTPUT_DIR = os.path.abspath("outputs")

os.makedirs(TEMP_DIR, exist_ok=True)
os.makedirs(OUTPUT_DIR, exist_ok=True)

def get_video_duration(video_path):
    cmd = [
        "ffprobe", "-v", "error",
        "-show_entries", "format=duration",
        "-of", "default=noprint_wrappers=1:nokey=1",
        video_path
    ]
    result = subprocess.check_output(cmd).decode().strip()
    return float(result)

def create_loop(input_video, loop_method, fade_duration, transition, fps, crf):
    if input_video is None:
        raise gr.Error("Please upload a video.")

    uid = str(uuid.uuid4())[:8]
    input_path = os.path.join(TEMP_DIR, f"{uid}_input.mp4")
    output_path = os.path.join(OUTPUT_DIR, f"{uid}_loop.mp4")

    if isinstance(input_video, dict):
        video_file = input_video["path"]
    else:
        video_file = input_video

    shutil.copy(video_file, input_path)
    duration = get_video_duration(input_path)

    # Filter Anti-Aliasing & Standarisasi
    sws_flags = "flags=lanczos+accurate_rnd+full_chroma_int"
    # Filter dasar tanpa spasi/newline yang merusak sintaks FFmpeg
    base = f"format=yuv420p,fps={fps}:round=near,scale=trunc(iw/2)*2:trunc(ih/2)*2:{sws_flags}"

    if loop_method == "Crossfade (Standard)":
        if duration <= fade_duration:
            fade_duration = duration / 2
        offset = duration - fade_duration
        filter_complex = f"[0:v]{base},split[v1][v2];[v1][v2]xfade=transition={transition}:duration={fade_duration}:offset={offset},format=yuv420p[v]"
        target_duration = str(duration - fade_duration)

    elif loop_method == "Split & Swap (Premiere Style)":
        midpoint = duration / 2.0
        # Beri margin 0.2 detik agar tidak error exit status 234
        if fade_duration >= midpoint:
            fade_duration = midpoint - 0.2
        
        offset = midpoint - fade_duration
        filter_complex = (
            f"[0:v]{base},split[v_src1][v_src2];"
            f"[v_src1]trim=start=0:end={midpoint},setpts=PTS-STARTPTS[partA];"
            f"[v_src2]trim=start={midpoint}:end={duration},setpts=PTS-STARTPTS[partB];"
            f"[partB][partA]xfade=transition={transition}:duration={fade_duration}:offset={offset},format=yuv420p[v]"
        )
        target_duration = str(duration - fade_duration)

    else:
        # PING-PONG
        filter_complex = f"[0:v]{base},split[fwd][rev_src];[rev_src]reverse[rev];[fwd][rev]concat=n=2:v=1:a=0,format=yuv420p[v]"
        target_duration = str(duration * 2)

    cmd = [
        "ffmpeg", "-y", "-i", input_path,
        "-filter_complex", filter_complex,
        "-map", "[v]", "-t", target_duration, "-an",
        "-c:v", "libx264", "-preset", "slower", "-crf", str(crf),
        "-pix_fmt", "yuv420p", "-movflags", "+faststart",
        output_path
    ]

    try:
        subprocess.run(cmd, check=True, capture_output=True)
    except subprocess.CalledProcessError as e:
        error_msg = e.stderr.decode()
        raise gr.Error(f"FFmpeg Error: {error_msg}")

    preview_html = f"""
    <div style="border-radius:12px; overflow:hidden; background-color: #000;">
        <video autoplay loop muted controls playsinline width="100%">
            <source src="/file={output_path}" type="video/mp4">
        </video>
    </div>
    """
    return output_path, preview_html

with gr.Blocks(theme=gr.themes.Soft()) as demo:
    gr.Markdown("# 🎬 Seamless Loop Maker Pro")
    with gr.Row():
        with gr.Column():
            input_video = gr.Video(label="Upload Video")
            loop_method = gr.Radio(
                choices=["Split & Swap (Premiere Style)", "Ping-Pong (No Ghosting)", "Crossfade (Standard)"],
                value="Split & Swap (Premiere Style)", label="Loop Method"
            )
            fade_duration = gr.Slider(minimum=0.1, maximum=5.0, value=1.0, step=0.1, label="Fade Duration (sec)")
            fps = gr.Dropdown(choices=[24, 30, 60], value=24, label="FPS")
            transition = gr.Dropdown(choices=["dissolve", "fade", "smoothleft", "fadeblack"], value="dissolve", label="Transition")
            crf = gr.Slider(minimum=12, maximum=28, value=18, step=1, label="Quality (CRF)")
            generate_btn = gr.Button("🚀 Generate Loop", variant="primary")
        with gr.Column():
            preview = gr.HTML()
            output_video = gr.Video(label="Download MP4")

    generate_btn.click(
        fn=create_loop,
        inputs=[input_video, loop_method, fade_duration, transition, fps, crf],
        outputs=[output_video, preview]
    )

if __name__ == "__main__":
    demo.launch(server_name="0.0.0.0", server_port=7860, allowed_paths=[OUTPUT_DIR])