app.py

import base64
import io
import os
import requests
import threading
import time
from dash import Dash, dcc, html, Input, Output, State, ctx
import dash_bootstrap_components as dbc

# Initialize the Dash app
app = Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP])

# Stability AI API key (to be set as a Hugging Face secret)
STABILITY_API_KEY = os.getenv('STABILITY_API_KEY')

# Global variable to store the generated file
generated_file = None

# Function to upscale image
def upscale_image(contents):
    global generated_file
    generated_file = None
    
    # Decode the base64 image
    content_type, content_string = contents.split(',')
    decoded = base64.b64decode(content_string)
    
    # Prepare the API request
    url = "https://api.stability.ai/v2beta/stable-image/upscale/fast"
    headers = {
        "Authorization": f"Bearer {STABILITY_API_KEY}",
        "Accept": "image/*"
    }
    files = {
        "image": ("image.png", io.BytesIO(decoded), "image/png")
    }
    data = {
        "output_format": "png"
    }
    
    # Make the API request
    response = requests.post(url, headers=headers, files=files, data=data)
    
    if response.status_code == 200:
        generated_file = response.content
        return True
    else:
        print(f"Error: {response.status_code}, {response.text}")
        return False

# App layout
app.layout = dbc.Container([
    html.H1("Image Upscaler", className="text-center my-4"),
    dbc.Row([
        dbc.Col([
            dcc.Upload(
                id='upload-image',
                children=html.Div([
                    'Drag and Drop or ',
                    html.A('Select an Image')
                ]),
                style={
                    'width': '100%',
                    'height': '60px',
                    'lineHeight': '60px',
                    'borderWidth': '1px',
                    'borderStyle': 'dashed',
                    'borderRadius': '5px',
                    'textAlign': 'center',
                    'margin': '10px'
                },
                multiple=False
            ),
        ], width=12),
    ]),
    dbc.Row([
        dbc.Col([
            html.H4("Original Image", className="mt-4"),
            dbc.Button("Upscale Image", id="upscale-button", color="primary", className="mb-3"),
            dbc.Spinner(html.Div(id="loading-output"), color="primary", type="border", size="sm"),
            dbc.Card(id='output-image-upload', body=True)
        ], md=12, lg=6),
        dbc.Col([
            html.H4("Upscaled Image", className="mt-4"),
            dbc.Button("Download Upscaled Image", id="download-button", color="success", className="mb-3", disabled=True),
            dbc.Card(id='output-upscaled-image', body=True),
            dcc.Download(id="download-image")
        ], md=12, lg=6),
    ]),
], fluid=True)

@app.callback(
    Output('output-image-upload', 'children'),
    Input('upload-image', 'contents'),
    State('upload-image', 'filename')
)
def update_output(contents, filename):
    if contents is not None:
        return html.Div([
            html.Img(src=contents, style={'width': '100%'}),
            html.P(filename)
        ])

@app.callback(
    [Output('output-upscaled-image', 'children'),
     Output('download-button', 'disabled'),
     Output('loading-output', 'children')],
    Input('upscale-button', 'n_clicks'),
    State('upload-image', 'contents'),
    prevent_initial_call=True
)
def upscale_image_callback(n_clicks, contents):
    if contents is None:
        return None, True, ""
    
    def upscale_thread():
        upscale_image(contents)
    
    threading.Thread(target=upscale_thread).start()
    
    while generated_file is None:
        time.sleep(0.1)  # Wait for the upscaling to complete
    
    if generated_file:
        upscaled_image = html.Div([
            html.Img(src=f"data:image/png;base64,{base64.b64encode(generated_file).decode()}", style={'width': '100%'})
        ])
        return upscaled_image, False, ""
    else:
        return None, True, ""

@app.callback(
    Output("download-image", "data"),
    Input("download-button", "n_clicks"),
    prevent_initial_call=True
)
def download_image(n_clicks):
    if generated_file:
        return dcc.send_bytes(generated_file, "upscaled_image.png")

if __name__ == '__main__':
    print("Starting the Dash application...")
    app.run(debug=True, host='0.0.0.0', port=7860)
    print("Dash application has finished running.")