app.py

from flask import Flask, request, jsonify, render_template
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import torch
import torch.nn.functional as F
import re
from flask_cors import CORS  # Enable CORS

# Initialize Flask app
app = Flask(__name__)
CORS(app)  # Allow requests from frontend apps

# Choose your model: 'bert-base-uncased' or 'GroNLP/hateBERT'
MODEL_NAME = 'bert-base-uncased'  # Change to 'GroNLP/hateBERT' if needed

# Load tokenizer and model
tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME)
model = AutoModelForSequenceClassification.from_pretrained(MODEL_NAME)
model.eval()

# Two-class labels only
LABELS = ['Safe', 'Cyberbullying']

# Offensive trigger words
TRIGGER_WORDS = [
    "gago", "pokpok", "yawa", "linte", "ulol", "tangina", "bilat", "putang", "tarantado", "bobo",
    "yudipota", "law-ay", "bilatibay", "hayop"
]

# Detect trigger words in input text
def find_triggers(text):
    found = []
    for word in TRIGGER_WORDS:
        if re.search(rf"\b{re.escape(word)}\b", text, re.IGNORECASE):
            found.append(word)
    return found

# Predict function
def predict_text(text):
    inputs = tokenizer(text, return_tensors="pt", truncation=True, padding=True)

    # Use GPU if available
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    model.to(device)
    inputs = {key: value.to(device) for key, value in inputs.items()}

    with torch.no_grad():
        outputs = model(**inputs)
        logits = outputs.logits
        probs = F.softmax(logits, dim=1)
        confidence, predicted_class = torch.max(probs, dim=1)

    # Fallback logic: if model predicts more than 2 classes, default to Safe if out-of-bounds
    label_index = predicted_class.item()
    if label_index >= len(LABELS):
        label_index = 0  # default to "Safe"

    label = LABELS[label_index]
    confidence_score = round(confidence.item(), 4)
    triggers = find_triggers(text)

    # Override model prediction if offensive triggers found
    if triggers and label == "Safe":
        label = "Cyberbullying"

    return {
        "label": label,
        "confidence": confidence_score,
        "triggers": triggers
    }

# Serve frontend
@app.route('/')
def index():
    return render_template('index.html')  # Ensure templates/index.html exists

# API endpoint
@app.route("/predict", methods=["POST"])
def predict_api():
    try:
        data = request.get_json()
        text = data.get("text", "")

        if not text.strip():
            return jsonify({"error": "No text provided"}), 400

        result = predict_text(text)
        return jsonify(result)

    except Exception as e:
        return jsonify({"error": str(e)}), 500

# Run server
if __name__ == "__main__":
    app.run(debug=True)