import gradio as gr
import os
import time
from pathlib import Path

# Constants
CAMERA_MOVEMENTS = [
    "static",
    "move_forward",
    "move_backward",
    "move_left",
    "move_right",
    "move_up",
    "move_down"
]

def process_video_mock(video_path: str, camera_movement: str, progress=gr.Progress()):
    """Mock processing function - just simulates processing without actual model inference"""
    if video_path is None:
        return None, "❌ Please upload a video first"

    progress(0, desc="Initializing...")
    time.sleep(0.5)

    progress(0.2, desc="Loading video...")
    time.sleep(0.5)

    progress(0.4, desc="[MOCK] Estimating depth and camera poses...")
    time.sleep(0.5)

    progress(0.6, desc="[MOCK] Running 3D tracking...")
    time.sleep(0.5)

    progress(0.8, desc=f"[MOCK] Generating {camera_movement} camera trajectory...")
    time.sleep(0.5)

    progress(1.0, desc="Done!")

    # Return the input video as output (mock)
    return video_path, f"✅ [MOCK] Video processed with '{camera_movement}' camera movement!\n\n⚠️ This is a UI-only demo - no actual processing was performed."


# Create Gradio interface
print("🎨 Creating Gradio interface (UI Only Mode)...")

with gr.Blocks(
    theme=gr.themes.Soft(),
    title="🎬 Video to Point Cloud Renderer (UI Demo)",
    css="""
    .gradio-container {
        max-width: 900px !important;
        margin: auto !important;
    }
    .warning-box {
        background-color: #fff3cd;
        border: 1px solid #ffc107;
        border-radius: 8px;
        padding: 10px;
        margin-bottom: 10px;
    }
    """
) as demo:
    gr.Markdown("""
    # 🎬 Video to Point Cloud Renderer (UI Demo)

    ⚠️ **UI-Only Mode**: This demo shows the interface without loading heavy models.

    Upload a video to test the interface. No actual processing will be performed.

    **How it works (in full version):**
    1. Upload a video
    2. Select a camera movement type
    3. Click "Generate" to create the rendered video
    """)

    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### 📥 Input")
            video_input = gr.Video(
                label="Upload Video",
                format="mp4",
                height=300
            )

            camera_movement = gr.Dropdown(
                choices=CAMERA_MOVEMENTS,
                value="static",
                label="🎥 Camera Movement",
                info="Select how the camera should move in the rendered video"
            )

            generate_btn = gr.Button("🚀 Generate (Mock)", variant="primary", size="lg")

        with gr.Column(scale=1):
            gr.Markdown("### 📤 Output")
            output_video = gr.Video(
                label="Rendered Video",
                height=300
            )
            status_text = gr.Markdown("Ready to process (UI Demo Mode)...")

    # Event handlers
    generate_btn.click(
        fn=process_video_mock,
        inputs=[video_input, camera_movement],
        outputs=[output_video, status_text]
    )

    # Examples
    gr.Markdown("### 📁 Examples")
    if os.path.exists("./examples"):
        example_videos = [f for f in os.listdir("./examples") if f.endswith(".mp4")][:4]
        if example_videos:
            gr.Examples(
                examples=[[f"./examples/{v}", "move_forward"] for v in example_videos],
                inputs=[video_input, camera_movement],
                outputs=[output_video, status_text],
                fn=process_video_mock,
                cache_examples=False
            )

# Launch
if __name__ == "__main__":
    demo.launch(share=False)