app.py

import gradio as gr
from transformers import AutoModel, AutoTokenizer
import torch
import json
import requests
from PIL import Image
from torchvision import transforms
import urllib.request
from torchvision import models
import torch.nn as nn

# --- Define the Model ---
class FineGrainedClassifier(nn.Module):
    def __init__(self, num_classes=434):  # Updated to 434 classes
        super(FineGrainedClassifier, self).__init__()
        self.image_encoder = models.resnet50(pretrained=True)
        self.image_encoder.fc = nn.Identity()
        self.text_encoder = AutoModel.from_pretrained('jinaai/jina-embeddings-v2-base-en')
        self.classifier = nn.Sequential(
            nn.Linear(2048 + 768, 1024),
            nn.BatchNorm1d(1024),
            nn.ReLU(),
            nn.Dropout(0.3),
            nn.Linear(1024, 512),
            nn.BatchNorm1d(512),
            nn.ReLU(),
            nn.Dropout(0.3),
            nn.Linear(512, num_classes)  # Updated to 434 classes
        )
    
    def forward(self, image, input_ids, attention_mask):
        image_features = self.image_encoder(image)
        text_output = self.text_encoder(input_ids=input_ids, attention_mask=attention_mask)
        text_features = text_output.last_hidden_state[:, 0, :]
        combined_features = torch.cat((image_features, text_features), dim=1)
        output = self.classifier(combined_features)
        return output

# --- Data Augmentation Setup ---
transform = transforms.Compose([
    transforms.Resize((224, 224)),
    transforms.RandomHorizontalFlip(),
    transforms.RandomRotation(15),
    transforms.ColorJitter(brightness=0.2, contrast=0.2, saturation=0.2, hue=0.2),
    transforms.ToTensor(),
    transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
])

# Load the label-to-class mapping from your Hugging Face repository
label_map_url = "https://huggingface.co/Maverick98/EcommerceClassifier/resolve/main/label_to_class.json"
label_to_class = requests.get(label_map_url).json()

# Load your custom model from Hugging Face
model = FineGrainedClassifier(num_classes=len(label_to_class))
checkpoint_url = f"https://huggingface.co/Maverick98/EcommerceClassifier/resolve/main/model_checkpoint.pth"
checkpoint = torch.hub.load_state_dict_from_url(checkpoint_url, map_location=torch.device('cpu'))

# Strip the "module." prefix from the keys in the state_dict if they exist
# Clean up the state dictionary
state_dict = checkpoint.get('model_state_dict', checkpoint)
new_state_dict = {}
for k, v in state_dict.items():
    if k.startswith("module."):
        new_key = k[7:]  # Remove "module." prefix
    else:
        new_key = k

    # Check if the new_key exists in the model's state_dict, only add if it does
    if new_key in model.state_dict():
        new_state_dict[new_key] = v

model.load_state_dict(new_state_dict)

# Load the tokenizer from Jina
tokenizer = AutoTokenizer.from_pretrained("jinaai/jina-embeddings-v2-base-en")

def load_image(image_path_or_url):
    if isinstance(image_path_or_url, str) and image_path_or_url.startswith("http"):
        with urllib.request.urlopen(image_path_or_url) as url:
            image = Image.open(url).convert('RGB')
    else:
        image = Image.open(image_path_or_url).convert('RGB')
    
    image = transform(image)
    image = image.unsqueeze(0)  # Add batch dimension
    return image

def predict(image_path_or_file, title, threshold=0.4):
    
    # Validation: Check if the title is empty or has fewer than 3 words
    if not title or len(title.split()) < 3:
        raise gr.Error("Title must be at least 3 words long. Please provide a valid title.")
    
    # Preprocess the image
    image = load_image(image_path_or_file)
    
    # Tokenize title
    title_encoding = tokenizer(title, padding='max_length', max_length=200, truncation=True, return_tensors='pt')
    input_ids = title_encoding['input_ids']
    attention_mask = title_encoding['attention_mask']

    # Predict
    model.eval()
    with torch.no_grad():
        output = model(image, input_ids=input_ids, attention_mask=attention_mask)
        probabilities = torch.nn.functional.softmax(output, dim=1)
        top3_probabilities, top3_indices = torch.topk(probabilities, 3, dim=1)

    # Map the top 3 indices to class names
    top3_classes = [label_to_class[str(idx.item())] for idx in top3_indices[0]]

    # Check if the highest probability is below the threshold
    if top3_probabilities[0][0].item() < threshold:
        top3_classes.insert(0, "Others")
        top3_probabilities = torch.cat((torch.tensor([[1.0 - top3_probabilities[0][0].item()]]), top3_probabilities), dim=1)

    # Prepare the output as a dictionary
    results = {}
    for i in range(len(top3_classes)):
        results[top3_classes[i]] = top3_probabilities[0][i].item()
    
    return results

# Define the Gradio interface
title_input = gr.Textbox(label="Product Title", placeholder="Enter the product title here...")
image_input = gr.Image(type="filepath", label="Upload Image or Provide URL")
output = gr.JSON(label="Top 3 Predictions with Probabilities")

gr.Interface(
    fn=predict, 
    inputs=[image_input, title_input], 
    outputs=output,
    title="Ecommerce Classifier",
    description="This model classifies ecommerce products into one of 434 categories. If the model is unsure, it outputs 'Others'.",
).launch(share=True)