# app.py

import subprocess
from pathlib import Path
import gradio as gr

# --- Static demo image paths ---
FRAME1 = Path("demo/frame1.jpg")  # First image
FRAME2 = Path("demo/frame2.jpg")  # Second image
RESULT_GIF = Path("output/retro.gif")  # Expected result path

def interpolate(img_a_path, img_b_path):
    """
    Run the interpolation pipeline from the Space root:
    1. Run img_inference.py to generate intermediate frames
    2. Create color palette with ffmpeg
    3. Build final interpolated GIF with palette
    """
    try:
        # Step 1: Run the inference script
        subprocess.run([
            "python3", "img_inference.py",
            "--img", str(img_a_path), str(img_b_path)
        ], check=True)

        # Step 2: Generate optimized palette
        subprocess.run([
            "ffmpeg", "-r", "14", "-f", "image2", "-i", "output/img%d.png",
            "-vf", "palettegen=stats_mode=single", "palette.png"
        ], check=True)

        # Step 3: Create final GIF with palette
        subprocess.run([
            "ffmpeg", "-r", "14", "-f", "image2", "-i", "output/img%d.png",
            "-i", "palette.png", "-lavfi", "paletteuse", str(RESULT_GIF)
        ], check=True)

        return str(RESULT_GIF)

    except subprocess.CalledProcessError:
        raise gr.Error("Interpolation failed — check your script and paths.")

def reset_demo():
    """
    Return paths to static demo images.
    """
    return str(FRAME1), str(FRAME2)

# --- Gradio Interface ---
with gr.Blocks(title="RIFE Image Interpolation") as demo:
    with gr.Tab("Demo"):
        gr.Markdown("### Interpolate between two images → Retro GIF")

        img_a = gr.Image(type="filepath", value=str(FRAME1), label="Image A")
        img_b = gr.Image(type="filepath", value=str(FRAME2), label="Image B")

        run_btn = gr.Button("Interpolate")
        reset_btn = gr.Button("Reset")

        result_img = gr.Image(type="filepath", label="Interpolated GIF")

        run_btn.click(interpolate, inputs=[img_a, img_b], outputs=result_img)
        reset_btn.click(reset_demo, outputs=[img_a, img_b])

demo.launch()