app.py

import gradio as gr
import torch
from transformers import AutoModelForSequenceClassification, AutoTokenizer

# --- 1. Configuration ---
# This path should point to the folder where your final model was saved.
# Using a clean name like this avoids path errors during deployment.
MODEL_PATH = "Merged_AraBERT_Optuna_EvalNew_Infer" 

# This dictionary maps the model's output IDs (0, 1, 2) to readable labels.
ID2LABEL = {0: "Favor", 1: "Against", 2: "None"}


# --- 2. Load Saved Model and Tokenizer ---
print("Loading model and tokenizer from local directory...")
try:
    model = AutoModelForSequenceClassification.from_pretrained(MODEL_PATH)
    tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
    print("Model and tokenizer loaded successfully.")
except Exception as e:
    print(f"Error loading model: {e}")
    # Exit if the model can't be loaded
    exit()

# --- 3. Prediction Function ---
def predict_stance(text_input: str):
    """
    This function takes a string of text, runs it through the fine-tuned model,
    and returns a dictionary of stance probabilities.
    """
    # Return empty dictionary if input is empty to avoid errors
    if not text_input:
        return {}
        
    # Tokenize the input text
    inputs = tokenizer(
        text_input,
        return_tensors="pt",
        truncation=True,
        padding=True,
        max_length=256
    )

    # Perform inference with no gradient calculation for efficiency
    with torch.no_grad():
        outputs = model(**inputs)
        # Apply softmax to convert raw outputs (logits) to probabilities
        probabilities = torch.nn.functional.softmax(outputs.logits, dim=-1)

    # Format the output into a dictionary of {label: probability}
    confidences = {ID2LABEL[i]: float(probabilities[0][i]) for i in range(probabilities.shape[1])}
    
    return confidences


# --- 4. Gradio Interface Definition ---
# This section defines the title, description, and components of your web demo.
demo = gr.Interface(
    fn=predict_stance,
    inputs=gr.Textbox(
        lines=5,
        placeholder="أدخل النص العربي هنا لتحليل الموقف...",
        label="Arabic Text Input"
    ),
    outputs=gr.Label(num_top_classes=3, label="Stance Prediction"),
    title="🔎 Arabic Stance Detection Model",
    description=(
        "This demo uses a fine-tuned CamelBERT model to predict the stance (Favor, Against, or None) of Arabic text. "
        "The model was trained on the Mawqif dataset and achieved an F1-score of 84.1% on the 3-class problem. "
        "Enter a sentence to see the prediction."
    ),
    examples=[
        ["الحكومة اتخذت القرار الصائب، هذا ما كنا ننتظره."],
        ["أسوأ قرار تم اتخاذه على الإطلاق، أنا ضده تماما."],
        ["الطقس في الدمام اليوم حار جداً."]
    ],
    allow_flagging="never",
    article=(
        "<p style='text-align: center; margin-top: 20px;'>"
        "A project fine-tuned and deployed by [Your Name Here]."
        "</p>"
    )
)


# --- 5. Launch the Application ---
# This makes the script runnable and launches the Gradio web server.
if __name__ == "__main__":
    demo.launch()