app.py

"""
Emotion Detection App - Hugging Face Spaces
Multi-label emotion classification using DeBERTa-v3-base
"""

import gradio as gr
import torch
import torch.nn as nn
from transformers import AutoTokenizer, AutoModel
import numpy as np

# Configuration
MODEL_NAME = "microsoft/deberta-v3-base"
EMOTION_LABELS = ['anger', 'fear', 'joy', 'sadness', 'surprise']
MAX_LENGTH = 160
DEVICE = torch.device('cuda' if torch.cuda.is_available() else 'cpu')

# Model Architecture
class EmotionClassifier(nn.Module):
    """DeBERTa-v3-base for multi-label emotion classification"""
    def __init__(self, model_name, num_labels=5, dropout=0.1):
        super().__init__()
        self.encoder = AutoModel.from_pretrained(model_name)
        hidden_size = self.encoder.config.hidden_size
        self.dropout = nn.Dropout(dropout)
        self.classifier = nn.Linear(hidden_size, num_labels)

    def forward(self, input_ids, attention_mask):
        outputs = self.encoder(
            input_ids=input_ids,
            attention_mask=attention_mask
        )
        pooled_output = outputs.last_hidden_state[:, 0]
        pooled_output = self.dropout(pooled_output)
        logits = self.classifier(pooled_output)
        return logits

# Load model and tokenizer
print("Loading model...")
print(f"Loading tokenizer from {MODEL_NAME}...")
tokenizer = AutoTokenizer.from_pretrained(
    MODEL_NAME,
    use_fast=True,
    trust_remote_code=False
)
print("✓ Tokenizer loaded")

print(f"Initializing model architecture...")
model = EmotionClassifier(MODEL_NAME, len(EMOTION_LABELS)).to(DEVICE)
print("✓ Model architecture created")

# Load trained weights
try:
    model.load_state_dict(torch.load('best_deberta_model.pth', map_location=DEVICE))
    print("✓ Model loaded successfully!")
except Exception as e:
    print(f"Warning: Could not load model weights: {e}")
    print("Using randomly initialized model (for testing)")

model.eval()

def predict_emotions(text):
    """
    Predict emotions for input text

    Args:
        text (str): Input text to analyze

    Returns:
        dict: Emotion probabilities and predictions
    """
    if not text or len(text.strip()) == 0:
        return {
            "error": "Please enter some text to analyze",
            "probabilities": {},
            "detected_emotions": []
        }

    # Tokenize
    encoding = tokenizer(
        text,
        max_length=MAX_LENGTH,
        padding='max_length',
        truncation=True,
        return_tensors='pt'
    )

    input_ids = encoding['input_ids'].to(DEVICE)
    attention_mask = encoding['attention_mask'].to(DEVICE)

    # Predict
    with torch.no_grad():
        logits = model(input_ids, attention_mask)
        probabilities = torch.sigmoid(logits).cpu().numpy()[0]

    # Create results
    results = {}
    detected_emotions = []

    for label, prob in zip(EMOTION_LABELS, probabilities):
        results[label.capitalize()] = float(prob)
        if prob > 0.5:
            detected_emotions.append(f"{label.capitalize()} ({prob:.1%})")

    # Sort by probability
    results = dict(sorted(results.items(), key=lambda x: x[1], reverse=True))

    return results, ", ".join(detected_emotions) if detected_emotions else "No strong emotions detected"

# Example texts
examples = [
    ["I just got accepted into my dream university! I can't believe it!"],
    ["I'm so worried about the exam tomorrow. I haven't studied enough."],
    ["This is the worst day of my life. Everything went wrong."],
    ["I can't believe they did this to me. I'm furious!"],
    ["Wow! I never expected that to happen!"],
    ["The sunset today was beautiful. It made me feel peaceful."],
    ["I'm frustrated with this project but also excited about the possibilities."]
]

# Create Gradio interface
with gr.Blocks(theme=gr.themes.Soft(), title="Emotion Detection") as demo:
    gr.Markdown(
        """
        # 🎭 Multi-Label Emotion Detection

        Detect multiple emotions in text using **DeBERTa-v3-base** fine-tuned for emotion classification.

        **Emotions detected**: Anger, Fear, Joy, Sadness, Surprise

        This model can detect multiple emotions simultaneously in a single text.
        """
    )

    with gr.Row():
        with gr.Column():
            text_input = gr.Textbox(
                label="Enter text to analyze",
                placeholder="Type or paste your text here...",
                lines=5
            )

            analyze_btn = gr.Button("🔍 Analyze Emotions", variant="primary", size="lg")

            gr.Markdown("### 💡 Try these examples:")
            gr.Examples(
                examples=examples,
                inputs=text_input,
                label="Click an example to try it"
            )

        with gr.Column():
            gr.Markdown("### 📊 Results")

            detected_output = gr.Textbox(
                label="Detected Emotions",
                placeholder="Results will appear here...",
                lines=2
            )

            prob_output = gr.Label(
                label="Emotion Probabilities",
                num_top_classes=5
            )

            gr.Markdown(
                """
                ---
                **How it works:**
                - Probabilities above 50% indicate detected emotions
                - Multiple emotions can be present in the same text
                - Higher probability = stronger emotion signal

                **Model:** DeBERTa-v3-base (184M parameters)

                **Performance:** F1 Score ~0.85 on validation set
                """
            )

    # Connect the button
    analyze_btn.click(
        fn=predict_emotions,
        inputs=text_input,
        outputs=[prob_output, detected_output]
    )

    # Also trigger on text input (Enter key)
    text_input.submit(
        fn=predict_emotions,
        inputs=text_input,
        outputs=[prob_output, detected_output]
    )

# Launch
if __name__ == "__main__":
    demo.launch()