app.py

import gradio as gr
from src.core import get_table_mapping, transform_source, process_csv_text, generate_mapping_code

MAX_ROWS = 10

def export_csv(d):
    filepath = "output.csv"
    d.to_csv(filepath)
    return gr.File.update(value=filepath, visible=True)

def generate_step_markdown(step_number: int, subtitle: str, description: str = None):
    return gr.Markdown(f"# Step {step_number}\n\n ### {subtitle}\n{description}")

def export_csv(df, filename):
    df.to_csv(filename, index=False)
    return gr.File.update(value=filename, visible=True)

def export_text(val, filename):
    with open(filename, "w") as f:
        f.write(val)
    return gr.File.update(value=filename, visible=True)

def export_transformed_source(d):
    filename = "transformed_source.csv"
    d.to_csv(filename)
    return gr.File.update(value=filename, visible=True)

with gr.Blocks() as demo:
    # STEP 1
    generate_step_markdown(1, "Upload a Template CSV (target schema) and a Source CSV.")
    with gr.Row():
        with gr.Column():
            upload_template_btn = gr.UploadButton(label="Upload Template File", file_types = ['.csv'], live=True, file_count = "single")
            template_df = gr.Dataframe(max_rows=MAX_ROWS)
            upload_template_btn.upload(fn=process_csv_text, inputs=upload_template_btn, outputs=template_df)
        with gr.Column():
            upload_source_button = gr.UploadButton(label="Upload Source File", file_types = ['.csv'], live=True, file_count = "single")
            source_df = gr.Dataframe(max_rows=MAX_ROWS)
            upload_source_button.upload(fn=process_csv_text, inputs=upload_source_button, outputs=source_df)
    
    # STEP 2
    generate_step_markdown(2, "Generate mapping from Source to Template.", "Once generated, you can edit the values directly in the table below and they will be incorporated into the mapping logic.")
    with gr.Row():
        generate_mapping_btn = gr.Button(value="Generate Mapping", variant="primary")
    with gr.Row():
        table_mapping_df = gr.DataFrame(max_rows=MAX_ROWS, interactive=True)
        generate_mapping_btn.click(fn=get_table_mapping, inputs=[source_df, template_df], outputs=[table_mapping_df])
    
    with gr.Row():
        save_mapping_btn = gr.Button(value="Save Mapping", variant="secondary")
    with gr.Row():
        csv = gr.File(interactive=False, visible=False)
        save_mapping_btn.click(lambda df: export_csv(df, "source_template_mapping.csv"), table_mapping_df, csv)
        mapping_file = gr.File(label="Downloaded File", visible=False)
        mapping_file.change(lambda x: x, mapping_file, table_mapping_df)
    
    # STEP 3
    generate_step_markdown(3, "Generate python code to transform Source to Template, using the generated mapping.", "Once generated, you can edit the code directly in the code block below and it will be incorporated into the transformation logic. And this is re-runnable! Update the mapping logic above to try it out.")
    with gr.Row():
        generate_code_btn = gr.Button(value="Generate Code from Mapping", variant="primary")
    with gr.Row():
        code_block = gr.Code(language="python")
        generate_code_btn.click(fn=generate_mapping_code, inputs=[table_mapping_df], outputs=[code_block])

    with gr.Row():
        save_code_btn = gr.Button(value="Save Code", variant="secondary")
    with gr.Row():
        text = gr.File(interactive=False, visible=False)
        save_code_btn.click(lambda txt: export_text(txt, "transformation_code.py"), code_block, text)
        code_file = gr.File(label="Downloaded File", visible=False)
        code_file.change(lambda x: x, code_file, code_block)

    # STEP 4
    generate_step_markdown(4, "Transform the Source CSV into the Template CSV using the generated code.", "And this is re-runnable! Update the logic above to try it out.")
    with gr.Row():
        transform_btn = gr.Button(value="Transform Source", variant="primary")
    with gr.Row():
        gr.Markdown("Source (transformed)")
        source_df_transformed = gr.Dataframe(label="Source Transformed", max_rows=MAX_ROWS)
        transform_btn.click(transform_source, inputs=[source_df, code_block], outputs=[source_df_transformed])

    with gr.Row():
        save_transformed_source_btn = gr.Button(value="Save Transformed Source", variant="secondary")
    with gr.Row():
        csv = gr.File(interactive=False, visible=False)
        save_transformed_source_btn.click(lambda df: export_csv(df, "transformed_source.csv"), source_df_transformed, csv)
        transform_file = gr.File(label="Downloaded File", visible=False)
        transform_file.change(lambda x: x, transform_file, source_df_transformed)

demo.launch()