"""
Module for creating and configuring the Gradio interface.
Handles the UI layout and component setup.
"""

import gradio as gr

def create_interface(classifier, category_examples, custom_theme):
    # Wrapper function to handle None inputs and provide loading state
    def classify_with_loading(image):
        if image is None:
            return None
        return classifier.classify_image(image)

    # Create main interface container with custom theme
    with gr.Blocks(theme=custom_theme) as iface:
        # Header section with title and description
        gr.Markdown("# 🏛️ Landmark Image Classification")
    
        # About section
        gr.Markdown("""
This Gradio-based application allows users to classify famous landmarks using a Vision Transformer (ViT) model. Users can upload an image or select from provided examples to identify landmarks.
""")
        
        # Create two-column layout for input and output
        with gr.Row():
            with gr.Column(scale=1):
                # Left column: Image input and submit button
                input_image = gr.Image(type="pil", label="Input Image")
                submit_btn = gr.Button("Classify Landmark", variant="primary")
            with gr.Column(scale=1):
                # Right column: Classification results
                output_label = gr.Label(num_top_classes=5, label="Predictions")
        
        # Examples section with collapsible categories
        gr.Markdown("## Example Categories")
        for category, examples in category_examples.items():
            # Create collapsible section for each category
            with gr.Accordion(f"{category}", open=False):
                # Add description of all landmarks in this category
                supported_landmarks = [example[1]['label'] for example in examples] if examples else []
                landmarks_text = ", ".join(supported_landmarks) if supported_landmarks else "No landmarks available"
                gr.Markdown(f"**Supported landmarks in this category:** {landmarks_text}")
                
                if examples:
                    gr.Examples(
                        examples=examples,
                        inputs=input_image,
                        outputs=output_label,
                        fn=classify_with_loading,
                        cache_examples=False,
                        label=None,
                        examples_per_page=1000
                    )
                else:
                    gr.Markdown(f"No example images available for {category}")
        
        # Connect the submit button to the classification function
        submit_btn.click(
            fn=classify_with_loading,
            inputs=input_image,
            outputs=output_label,
            api_name="classify"
        )
    
    return iface