app.py

import base64
import dash
from dash import dcc, html, Input, Output, State, callback_context
import dash_bootstrap_components as dbc
from dash.exceptions import PreventUpdate
import google.generativeai as genai
import requests
import logging
import threading
import time
import os
import flask
import uuid

logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(levelname)s - %(message)s')

STYLES = [
    "photographic", "3d-model", "analog-film", "anime", "cinematic", "comic-book", 
    "digital-art", "enhance", "fantasy-art", "isometric", "line-art", "low-poly", 
    "modeling-compound", "neon-punk", "origami", "pixel-art", "tile-texture"
]

DEFAULT_NEGATIVE_PROMPT = """
ugly, tiling, poorly drawn hands, poorly drawn feet, poorly drawn face, out of frame, 
extra limbs, disfigured, deformed, body out of frame, bad anatomy, watermark, signature, 
cut off, low contrast, underexposed, overexposed, bad art, beginner, amateur, distorted face,
plastic, cartoonish, artificial, fake, unnatural, blurry, smooth, lack of detail, low quality
"""

external_stylesheets = [dbc.themes.BOOTSTRAP]
server = flask.Flask(__name__)
app = dash.Dash(__name__, server=server, external_stylesheets=external_stylesheets)

app.title = "ImaGen"

SESSION_DATA = {}
SESSION_LOCKS = {}

def get_session_id():
    if hasattr(flask.g, "session_id"):
        return flask.g.session_id
    session_id = flask.request.cookies.get("session_id")
    if not session_id:
        session_id = str(uuid.uuid4())
    flask.g.session_id = session_id
    return session_id

@app.server.before_request
def ensure_session_id():
    session_id = flask.request.cookies.get("session_id")
    if not session_id:
        session_id = str(uuid.uuid4())
        flask.g.set_cookie = session_id
    flask.g.session_id = session_id or flask.g.get("set_cookie", None)
    if session_id not in SESSION_DATA:
        SESSION_DATA[session_id] = {'image': None, 'enhanced_prompt': None, 'status': None}
    if session_id not in SESSION_LOCKS:
        SESSION_LOCKS[session_id] = threading.Lock()

@app.server.after_request
def set_session_cookie(response):
    if hasattr(flask.g, "set_cookie"):
        response.set_cookie("session_id", flask.g.set_cookie, httponly=True, samesite='Lax')
    return response

def enhance_prompt(google_api_key, prompt, style):
    genai.configure(api_key=google_api_key)
    model = genai.GenerativeModel("gemini-2.0-flash-lite")
    enhanced_prompt_request = f"""
    Task: Enhance the following prompt with details to match the specified style
    Style: {style}
    Original prompt: '{prompt}'
    
    Instructions:
    1. Expand the prompt to be more detailed, vivid, and realistic with camera used and the setting for that camera like ISO etc.
    2. Incorporate elements of the specified style.
    3. Add details that enhance the scene to the specified style
    4. Emphasize natural lighting and enhance the realism of textures and colors based on the specified style.
    5. Avoid terms that might result in artificial or cartoonish appearance unless specified by user.
    6. Maintain the original intent of the prompt while significantly improving its descriptive quality with details.
    7. Provide ONLY the enhanced prompt, without any explanations or options.
    8. Keep the enhanced prompt concise, ideally under 100 words.

    Enhanced prompt:
    """
    try:
        response = model.generate_content(enhanced_prompt_request)
        enhanced_prompt = response.text.strip()
        prefixes_to_remove = ["Enhanced prompt:", "Here's the enhanced prompt:", "The enhanced prompt is:"]
        for prefix in prefixes_to_remove:
            if enhanced_prompt.lower().startswith(prefix.lower()):
                enhanced_prompt = enhanced_prompt[len(prefix):].strip()
        logging.info(f"Enhanced prompt: {enhanced_prompt}")
        return enhanced_prompt
    except Exception as e:
        logging.error(f"Error in enhance_prompt: {str(e)}")
        raise

def generate_image(stability_api_key, enhanced_prompt, style, negative_prompt, steps, aspect_ratio):
    url = "https://api.stability.ai/v2beta/stable-image/generate/core"
    headers = {
        "Accept": "image/*",
        "Authorization": f"Bearer {stability_api_key}"
    }
    data = {
        "prompt": f"{enhanced_prompt}, Style: {style}, highly detailed, high quality, descriptive, sharp focus, intricate details",
        "negative_prompt": negative_prompt,
        "model": "sd3.5-large-turbo",
        "output_format": "jpeg",
        "num_images": 1,
        "steps": steps,
        "style_preset": style,
        "aspect_ratio": aspect_ratio,
    }
    try:
        response = requests.post(url, headers=headers, files={"none": ''}, data=data, timeout=60)
        response.raise_for_status()
        if response.headers.get('content-type').startswith('image/'):
            image_data = response.content
            if len(image_data) < 1000:
                raise Exception("Received incomplete image data")
            return image_data
        else:
            error_message = response.text
            logging.error(f"Unexpected content type: {response.headers.get('content-type')}. Response: {error_message}")
            raise Exception(f"Unexpected content type: {response.headers.get('content-type')}. Response: {error_message}")
    except requests.exceptions.RequestException as e:
        logging.error(f"Request failed: {str(e)}")
        raise Exception(f"Request failed: {str(e)}")

def process_and_generate(google_api_key, stability_api_key, prompt, style, steps, aspect_ratio, set_status):
    try:
        set_status("Enhancing prompt...")
        enhanced_prompt = enhance_prompt(google_api_key, prompt, style)
        set_status("Generating image...")
        max_attempts = 3
        for attempt in range(max_attempts):
            try:
                image_bytes = generate_image(stability_api_key, enhanced_prompt, style, DEFAULT_NEGATIVE_PROMPT, steps, aspect_ratio)
                set_status("Image generated successfully!")
                return image_bytes, enhanced_prompt
            except Exception as e:
                if attempt < max_attempts - 1:
                    set_status(f"Attempt {attempt + 1} failed. Retrying...")
                    time.sleep(2)
                else:
                    raise e
    except Exception as e:
        logging.error(f"Error in process_and_generate: {str(e)}")
        set_status(f"Error: {str(e)}")
        return None, str(e)

app.layout = dbc.Container([
    dbc.Row([
        dbc.Col([
            html.H1("ImaGen", className="text-center mb-4")
        ], width=12)
    ]),
    dbc.Row([
        dbc.Col([
            dbc.Card([
                dbc.CardBody([
                    dbc.Textarea(
                        id="prompt", 
                        placeholder="Tell me what image you want me to build.", 
                        className="mb-3",
                        style={"height": "120px", "whiteSpace": "pre-wrap", "wordWrap": "break-word"}
                    ),
                    dcc.Dropdown(
                        id="style",
                        options=[{"label": s.replace("-", " ").title(), "value": s} for s in STYLES],
                        value="photographic",
                        placeholder="Select style",
                        className="mb-3"
                    ),
                    html.Div([
                        dbc.Label("Aspect Ratio"),
                        dcc.Dropdown(
                            id="aspect-ratio",
                            options=[
                                {"label": ar, "value": ar} for ar in 
                                ["16:9", "1:1", "21:9", "2:3", "3:2", "4:5", "5:4", "9:16", "9:21"]
                            ],
                            value="1:1",
                            className="mb-3"
                        ),
                        dbc.Label("Steps"),
                        dcc.Slider(
                            id="steps", 
                            min=4, 
                            max=50, 
                            step=1, 
                            value=30, 
                            marks={4: '4', 25: '25', 50: '50'},
                            className="mb-3"
                        ),
                    ]),
                    dbc.Button("Generate Image", id="submit-btn", color="primary", className="mt-2 mb-2", style={"width": "100%"})
                ])
            ])
        ], width=4, style={"minWidth": "300px", "maxWidth": "420px", "flex": "0 0 30%"}),
        dbc.Col([
            dbc.Card([
                dbc.CardBody([
                    dbc.Button("Download Image", id="download-btn", color="secondary", className="mb-3", disabled=True, style={"width": "100%"}),
                    dcc.Loading(
                        id="loading",
                        type="default",
                        children=[
                            html.Div(id="status-message", className="mb-3"),
                            html.Img(id="image-output", className="img-fluid mb-3"),
                            html.Div(id="enhanced-prompt-output", className="mb-3"),
                            dcc.Download(id="download-image")
                        ],
                        style={"display": "block", "margin": "auto"}
                    ),
                ])
            ])
        ], width=8, style={"flex": "0 0 70%"})
    ], align="start")
], fluid=True)

@app.callback(
    [
        Output("image-output", "src"),
        Output("enhanced-prompt-output", "children"),
        Output("status-message", "children"),
        Output("download-btn", "disabled")
    ],
    [Input("submit-btn", "n_clicks")],
    [
        State("prompt", "value"),
        State("style", "value"),
        State("steps", "value"),
        State("aspect-ratio", "value")
    ],
    prevent_initial_call=True
)
def update_output(n_clicks, prompt, style, steps, aspect_ratio):
    ctx = callback_context
    if n_clicks is None:
        raise PreventUpdate
    session_id = flask.request.cookies.get("session_id")
    if not session_id:
        session_id = str(uuid.uuid4())
    lock = SESSION_LOCKS.setdefault(session_id, threading.Lock())
    session_data = SESSION_DATA.setdefault(session_id, {'image': None, 'enhanced_prompt': None, 'status': None})
    google_api_key = os.getenv('GOOGLE_API_KEY')
    stability_api_key = os.getenv('STABILITY_API_KEY')
    if not google_api_key or not stability_api_key:
        return "", "Error: API keys not found in environment variables", "API keys missing", True
    status = {"message": "Starting process..."}
    def set_status(message):
        status["message"] = message
        session_data['status'] = message
    def run_process():
        with lock:
            image_bytes, enhanced_prompt = process_and_generate(google_api_key, stability_api_key, prompt, style, steps, aspect_ratio, set_status)
            if image_bytes:
                encoded_image = base64.b64encode(image_bytes).decode('ascii')
                session_data['image'] = encoded_image
                session_data['enhanced_prompt'] = enhanced_prompt
                return f"data:image/jpeg;base64,{encoded_image}", f"Enhanced Prompt: {enhanced_prompt}", status["message"], False
            else:
                session_data['image'] = None
                session_data['enhanced_prompt'] = None
                return "", f"Error: {enhanced_prompt}", status["message"], True
    try:
        thread = threading.Thread(target=run_process)
        thread.start()
        thread.join(timeout=90)
        if thread.is_alive():
            with lock:
                session_data['status'] = "Process timed out"
                session_data['image'] = None
                session_data['enhanced_prompt'] = None
            return "", "Error: Image generation timed out", "Process timed out", True
        return run_process()
    except Exception as e:
        logging.error(f"Unexpected error in update_output: {str(e)}")
        with lock:
            session_data['status'] = "An unexpected error occurred"
            session_data['image'] = None
            session_data['enhanced_prompt'] = None
        return "", f"Unexpected error: {str(e)}", "An unexpected error occurred", True

@app.callback(
    Output("download-image", "data"),
    [Input("download-btn", "n_clicks")],
    [State("image-output", "src")],
    prevent_initial_call=True
)
def download_image(n_clicks, image_src):
    ctx = callback_context
    if n_clicks is None:
        raise PreventUpdate
    session_id = flask.request.cookies.get("session_id")
    lock = SESSION_LOCKS.setdefault(session_id, threading.Lock())
    session_data = SESSION_DATA.setdefault(session_id, {'image': None, 'enhanced_prompt': None, 'status': None})
    with lock:
        if not session_data.get('image'):
            raise PreventUpdate
        image_bytes = base64.b64decode(session_data['image'])
        return dcc.send_bytes(image_bytes, "generated_image.jpeg")

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