app/main.py

import torch
from torch import nn
from torchvision import transforms
from PIL import Image
import gradio as gr
import io
import base64
import requests

# Download model from Hugging Face Hub
MODEL_PATH = "generator.pt"
HF_MODEL_REPO = "Hammad712/GAN-Colorization-Model"

# Auto-download model if not present
from huggingface_hub import hf_hub_download
model_path = hf_hub_download(repo_id=HF_MODEL_REPO, filename=MODEL_PATH)

# Load the model (generator)
device = "cuda" if torch.cuda.is_available() else "cpu"
generator = torch.load(model_path, map_location=device)
generator.eval()

# Define transforms
transform_gray = transforms.Compose([
    transforms.Resize((256, 256)),
    transforms.Grayscale(),
    transforms.ToTensor()
])

transform_color = transforms.Compose([
    transforms.Resize((256, 256)),
    transforms.ToTensor()
])

to_pil = transforms.ToPILImage()

# Colorization function
def colorize_image(input_image):
    img = transform_gray(input_image).unsqueeze(0).to(device)
    with torch.no_grad():
        output = generator(img)
    output_image = to_pil(output.squeeze().cpu().clamp(0, 1))
    return output_image

# ---- Gradio Interface ----
iface = gr.Interface(
    fn=colorize_image,
    inputs=gr.Image(type="pil", label="Upload Grayscale Image"),
    outputs=gr.Image(type="pil", label="Colorized Image"),
    title="GAN Image Colorization (Hammad712)",
    description="Colorizes black and white images using GAN model"
)

# ---- API Endpoint ----
from fastapi import FastAPI, File, UploadFile
from fastapi.responses import StreamingResponse

app = FastAPI(title="GAN Colorization API")

@app.post("/colorize")
async def colorize_api(file: UploadFile = File(...)):
    image = Image.open(io.BytesIO(await file.read())).convert("RGB")
    colorized = colorize_image(image)
    buf = io.BytesIO()
    colorized.save(buf, format="PNG")
    buf.seek(0)
    return StreamingResponse(buf, media_type="image/png")

# Mount Gradio UI on /
import gradio as gr
app = gr.mount_gradio_app(app, iface, path="/")