# Directory Structure Suggestion:
# diabetic_retinopathy_app/
# ├── Home.py (Landing Page)
# ├── pages/
# │   ├── 1_Upload_and_Predict.py
# │   └── 2_Model_Evaluation.py
# └── assets/
#     └── banner.jpg

# Home.py (Landing Page)
import streamlit as st
from PIL import Image

def main():
    st.set_page_config(page_title="DR Assistive Tool", layout="centered")
    st.title("Welcome to the Diabetic Retinopathy Assistive Tool")

    st.markdown("""
    ### 🌟 Your AI-powered assistant for early detection of Diabetic Retinopathy.

    #### Features:
    - 🖼️ Upload a retinal image and receive a prediction of its DR stage.
    - 📊 Evaluate model performance using real test datasets.

    Select a page from the left sidebar to get started.
    """)

    # image = Image.open("assets/banner.jpg")  # Optional banner image
    # st.image(image, use_column_width=True)

if __name__ == '__main__':
    main()


# pages/1_Upload_and_Predict.py
import streamlit as st
import torch
from torchvision import transforms, models
from PIL import Image
import numpy as np

st.title("📷 Upload & Predict Diabetic Retinopathy")

class_names = ['No DR', 'Mild', 'Moderate', 'Severe', 'Proliferative DR']

def load_model():
    model = models.densenet121(pretrained=False)
    num_ftrs = model.classifier.in_features
    model.classifier = torch.nn.Linear(num_ftrs, len(class_names))
    model.load_state_dict(torch.load("training/Pretrained_Densenet-121.pth", map_location='cpu'))
    model.eval()
    return model

transform = transforms.Compose([
    transforms.Resize(256),
    transforms.CenterCrop(224),
    transforms.ToTensor(),
    transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
])

def predict_image(model, image):
    img_tensor = transform(image).unsqueeze(0)
    with torch.no_grad():
        outputs = model(img_tensor)
        _, pred = torch.max(outputs, 1)
        prob = torch.nn.functional.softmax(outputs, dim=1)[0][pred].item() * 100
    return class_names[pred.item()], prob

uploaded_file = st.file_uploader("Choose a retinal image", type=["jpg", "png"])
if uploaded_file is not None:
    image = Image.open(uploaded_file).convert('RGB')
    st.image(image, caption='Uploaded Retinal Image', use_column_width=True)

    if st.button("🧠 Predict"):
        with st.spinner('Analyzing image...'):
            model = load_model()
            pred_class, prob = predict_image(model, image)
            st.success(f"Prediction: **{pred_class}** ({prob:.2f}% confidence)")


# pages/2_Model_Evaluation.py
import streamlit as st
import torch
from torch.utils.data import DataLoader
from torchvision import datasets, transforms, models
import torch.nn as nn
from tqdm import tqdm

st.title("📈 Model Evaluation on Test Dataset")

@st.cache_data

def load_test_data():
    transform = transforms.Compose([
        transforms.Resize(256),
        transforms.CenterCrop(224),
        transforms.ToTensor(),
        transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225])
    ])
    test_data = datasets.ImageFolder("test_dataset_path", transform=transform)
    return DataLoader(test_data, batch_size=32, shuffle=False)

def evaluate(model, loader):
    model.eval()
    correct, total, loss = 0, 0, 0.0
    criterion = nn.CrossEntropyLoss()
    with torch.no_grad():
        for inputs, labels in loader:
            outputs = model(inputs)
            loss += criterion(outputs, labels).item()
            _, pred = torch.max(outputs, 1)
            correct += (pred == labels).sum().item()
            total += labels.size(0)
    return loss / len(loader), correct / total * 100

if st.button("🧪 Evaluate Trained Model"):
    test_loader = load_test_data()
    model = models.densenet121(pretrained=False)
    model.classifier = nn.Linear(model.classifier.in_features, 5)
    model.load_state_dict(torch.load("dr_densenet121.pth", map_location='cpu'))
    model.eval()

    loss, acc = evaluate(model, test_loader)
    st.write(f"**Test Loss:** {loss:.4f}")
    st.write(f"**Test Accuracy:** {acc:.2f}%")