"""Main Gradio application for viewing dataset with text comparison."""

import gradio as gr
import random
from data_loader import get_dataset_size, get_sample
from diff_utils import generate_html_diff, get_diff_stats


def load_sample_data(sample_index: int | None = None) -> tuple[str, str, str, str]:
    """Load and process a sample from the dataset."""
    if sample_index is None:
        sample_index = random.randint(0, get_dataset_size() - 1)
    
    # Ensure index is within bounds
    sample_index = max(0, min(sample_index, get_dataset_size() - 1))
    
    original_text, cleaned_text = get_sample(sample_index)
    
    # Generate diff HTML
    diff_html = generate_html_diff(original_text, cleaned_text)
    
    # Get statistics
    stats = get_diff_stats(original_text, cleaned_text)
    stats_text = f"""
    **Sample #{sample_index}**
    
    - Original length: {stats['original_length']:,} characters
    - Cleaned length: {stats['cleaned_length']:,} characters
    - Characters removed: {stats['characters_removed']:,}
    - Similarity: {stats['similarity_ratio']}%
    """
    
    return original_text, cleaned_text, diff_html, stats_text


def create_interface() -> gr.Blocks:
    """Create the main Gradio interface."""
    with gr.Blocks(
        title="Dataset Text Comparison Viewer",
        css="""
        .textbox-container { 
            max-height: 400px; 
            overflow-y: auto; 
            border: 1px solid #e0e0e0; 
            border-radius: 8px; 
            padding: 12px; 
            background: #fafafa; 
        }
        .stats-box {
            background: #f8f9fa;
            border: 1px solid #dee2e6;
            border-radius: 8px;
            padding: 16px;
            margin: 8px 0;
        }
        """
    ) as interface:
        
        gr.Markdown("# Dataset Text Comparison Viewer")
        gr.Markdown("Compare original and cleaned text from **sumuks/essential-web-v1.0-sample-1M-with-cleaned-text**")
        
        with gr.Row():
            with gr.Column():
                sample_input = gr.Number(
                    label="Sample Index", 
                    value=0, 
                    minimum=0, 
                    maximum=get_dataset_size() - 1,
                    step=1
                )
                
                with gr.Row():
                    load_btn = gr.Button("Load Sample", variant="primary")
                    random_btn = gr.Button("Random Sample", variant="secondary")
        
        # Statistics display
        stats_output = gr.Markdown(label="Statistics", elem_classes=["stats-box"])
        
        # Text comparison
        with gr.Row():
            with gr.Column():
                gr.Markdown("### Original Text")
                original_output = gr.Textbox(
                    label="Original",
                    lines=15,
                    max_lines=20,
                    show_copy_button=True,
                    elem_classes=["textbox-container"]
                )
            
            with gr.Column():
                gr.Markdown("### Cleaned Text")
                cleaned_output = gr.Textbox(
                    label="Cleaned",
                    lines=15,
                    max_lines=20,
                    show_copy_button=True,
                    elem_classes=["textbox-container"]
                )
        
        # Diff visualization
        gr.Markdown("### Diff Visualization")
        diff_output = gr.HTML(label="Diff")
        
        # Event handlers
        load_btn.click(
            fn=load_sample_data,
            inputs=[sample_input],
            outputs=[original_output, cleaned_output, diff_output, stats_output]
        )
        
        random_btn.click(
            fn=lambda: load_sample_data(None),
            inputs=[],
            outputs=[original_output, cleaned_output, diff_output, stats_output]
        )
        
        # Load initial sample
        interface.load(
            fn=lambda: load_sample_data(0),
            inputs=[],
            outputs=[original_output, cleaned_output, diff_output, stats_output]
        )
    
    return interface


if __name__ == "__main__":
    app = create_interface()
    app.launch(share=False, debug=True)