import gradio as gr
from PIL import Image
import tempfile


def reverse(input_path, frames_per_second):
    # Open the GIF file
    gif = Image.open(input_path)

    # Get the number of frames in the GIF
    num_frames = gif.n_frames

    # Create a list to hold the reversed frames
    reversed_frames = []

    # Iterate through the frames in reverse order
    for frame_number in range(num_frames, 0, -1):
        gif.seek(frame_number - 1)
        frame = gif.copy()
        reversed_frames.append(frame)

    # Interesting blur effect on gifs with transparent background
    if 'duration' not in gif.info:
        # Default is 8 frames per second from AnimatedDiff
        duration = frames_per_second * num_frames
        gif.info['duration'] = duration

    # Save the reversed frames as a new GIF
    with tempfile.NamedTemporaryFile(suffix=".gif", delete=False) as temp_file:
        temp_filename = temp_file.name
        reversed_frames[0].save(temp_filename, save_all=True, append_images=reversed_frames[1:],
                                duration=gif.info['duration'], loop=0)
        return temp_filename


def reverse_gifs(input_paths, frames_per_second):
    if input_paths is None:
        return None, None
    input_paths = [f.name for f in input_paths]

    temp_filenames = []
    for input_path in input_paths:
        temp_filenames.append(reverse(input_path, frames_per_second))

    return input_paths, temp_filenames


with gr.Blocks(theme='gstaff/sketch') as demo:
    gr.Markdown(value='# GIF Reversing Tool')
    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown('## Load animated gifs to reverse')
            image_in = gr.Files(label="Input Gif Files", type='file', file_types=['.gif'])
            frame_rate = gr.Number(label="Frames per Second to use (if not in gif metadata)", value=8, minimum=1,
                                   maximum=360, step=1, interactive=True)
            image_display = gr.Gallery(label="Input Images", interactive=False)
        with gr.Column(scale=1):
            gr.Markdown('## View the reversed gif')
            image_out = gr.Gallery(label="Reversed Gif Images")
            clear_button = gr.ClearButton(components=[image_in])

    image_in.change(reverse_gifs, [image_in, frame_rate], [image_display, image_out])
    gr.Examples(examples=[[['./example.gif'], 8]],
                inputs=[image_in, frame_rate], outputs=[image_display, image_out], fn=reverse_gifs, cache_examples=True)

    with gr.Accordion('Developer Notes:', open=False):
        gr.Markdown('This gif reverser is a simple utility I made for myself.\n\n'
                    'The default of 8 frames per second works for the default settings of [AnimateDiff](https://github.com/continue-revolution/sd-webui-animatediff).\n\n'
                    'Future enhancements could be to auto-determine the framerate when otherwise not available in the gif metadata.')

if __name__ == '__main__':
    demo.launch()