import cv2
import numpy as np
from PIL import Image
import gradio as gr

def sharpen_image(img: Image.Image, strength: float = 1.0) -> Image.Image:
    """
    Apply sharpening to an image using OpenCV's unsharp masking technique.
    
    Args:
        img: Input PIL Image
        strength: Sharpening intensity (0.0 to 3.0)
        
    Returns:
        Sharpened PIL Image
    """
    # Handle different image modes
    if img.mode not in ['L', 'RGB']:
        img = img.convert('RGB')
        original_mode = 'RGB'
    else:
        original_mode = img.mode

    # Convert PIL Image to numpy array
    img_array = np.array(img)
    
    try:
        # Convert to BGR format for OpenCV processing
        if original_mode == 'L':
            img_bgr = cv2.cvtColor(img_array, cv2.COLOR_GRAY2BGR)
        else:
            img_bgr = cv2.cvtColor(img_array, cv2.COLOR_RGB2BGR)

        # Apply Gaussian Blur
        blurred = cv2.GaussianBlur(img_bgr, (0, 0), 3)
        
        # Unsharp masking
        sharpened = cv2.addWeighted(img_bgr, 1.0 + strength, blurred, -strength, 0)
        sharpened = np.clip(sharpened, 0, 255).astype(np.uint8)

        # Convert back to original color space
        if original_mode == 'L':
            processed = cv2.cvtColor(sharpened, cv2.COLOR_BGR2GRAY)
        else:
            processed = cv2.cvtColor(sharpened, cv2.COLOR_BGR2RGB)
            
    except Exception as e:
        raise gr.Error(f"Image processing failed: {str(e)}")
    
    return Image.fromarray(processed, mode=original_mode)

# Gradio interface
with gr.Blocks(theme=gr.themes.Soft()) as app:
    gr.Markdown("# 🔍 Image Sharpening Tool")
    
    with gr.Row():
        with gr.Column():
            input_image = gr.Image(type="pil", label="Original Image", sources=["upload"])
            strength_slider = gr.Slider(
                minimum=0.0,
                maximum=3.0,
                value=1.0,
                step=0.1,
                label="Sharpening Strength",
                info="Adjust between 0.0 (no effect) to 3.0 (strongest)"
            )
            process_btn = gr.Button("Process Image", variant="primary")
            
        output_image = gr.Image(type="pil", label="Sharpened Image", interactive=False)

    # Example section
    gr.Examples(
        examples=[
            ["https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cat03.jpg/1200px-Cat03.jpg", 1.2],
            ["https://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Sunflower_from_Silesia2.jpg/1280px-Sunflower_from_Silesia2.jpg", 1.5]
        ],
        inputs=[input_image, strength_slider],
        outputs=output_image,
        fn=sharpen_image,
        cache_examples=True
    )

    # Event handling
    process_btn.click(
        fn=sharpen_image,
        inputs=[input_image, strength_slider],
        outputs=output_image
    )

if __name__ == "__main__":
    app.launch(show_error=True)