app.py

import gradio as gr
import subprocess
import os

# Supported input and output formats for Calibre
input_formats = ["azw", "azw3", "azw4", "cbz", "cbr", "cb7", "cbc", "chm", "djvu", "docx", "epub", "fb2", "fbz", "html", "htmlz", "lit", "lrf", "mobi", "odt", "pdf", "prc", "pdb", "pml", "rb", "rtf", "snb", "tcr", "txt", "txtz"]
output_formats = ["AZW3", "EPUB", "DOCX", "FB2", "HTMLZ", "OEB", "LIT", "LRF", "MOBI", "PDB", "PMLZ", "RB", "PDF", "RTF", "SNB", "TCR", "TXT", "TXTZ", "ZIP"]

def convert_ebook(input_file, output_format):
    output_file = os.path.splitext(input_file.name)[0] + "." + output_format.lower()
    
    # Execute Calibre ebook-convert command
    command = ['ebook-convert', input_file.name, output_file]
    result = subprocess.run(command, capture_output=True, text=True)
    
    if result.returncode != 0:
        return None, f"Error: {result.stderr}"
    
    # Return the converted file
    return output_file, "Conversion successful! You can download your file below."

with gr.Blocks() as gui:
    gr.Markdown("## Ebook Converter\nThis interface uses Calibre to convert ebooks. Supported input formats: AZW, AZW3, AZW4, CBZ, CBR, CB7, CBC, CHM, DJVU, DOCX, EPUB, FB2, FBZ, HTML, HTMLZ, LIT, LRF, MOBI, ODT, PDF, PRC, PDB, PML, RB, RTF, SNB, TCR, TXT, TXTZ.\n\n[Calibre GitHub](https://github.com/kovidgoyal/calibre) | [Calibre Website](https://calibre-ebook.com)")

    # File upload (only accepts valid input formats)
    input_file = gr.File(label="Select Ebook File", file_types=input_formats)

    # Dropdown for output format
    output_format = gr.Dropdown(choices=output_formats, label="Choose Output Format")

    # Convert button
    convert_button = gr.Button("Convert")

    # Output for status messages
    status_message = gr.Textbox(label="Status", interactive=False)

    # Output file download
    output_file = gr.File(label="Converted Ebook", interactive=False)

    # Convert and display file for download or show success message
    convert_button.click(fn=convert_ebook, inputs=[input_file, output_format], outputs=[output_file, status_message])

# Launch the Gradio GUI
gui.launch()