app.py

import re
from flask import Flask, render_template, request, jsonify
from chatterbot import ChatBot
from chatterbot.trainers import ChatterBotCorpusTrainer


# Create the Flask application
app = Flask(__name__)

# Initialize the chatbot
chatbot = ChatBot(
    "StudentBot",
    storage_adapter="chatterbot.storage.SQLStorageAdapter",
    database_uri="sqlite:///chatbot_database.sqlite3",
)

# Train the chatbot with English conversations
trainer = ChatterBotCorpusTrainer(chatbot)
trainer.train("chatterbot.corpus.english")


@app.route("/")
def home():
    """Serve the main chat page."""
    return render_template("index.html")


# Safety: Keywords that should trigger a mental health response
CRISIS_KEYWORDS = [
    "suicide",
    "kill myself",
    "end my life",
    "self harm",
    "self-harm",
    "dont want to live",
    "don't want to live",
    "want to die",
]

CRISIS_RESPONSE = """I'm concerned about what you've shared. Please know that you're not alone.

If you're in crisis, please reach out for support:

- Lifeline: 13 11 14 (24/7)
- Kids Helpline: 1800 55 1800
- Beyond Blue: 1300 22 4636

I'm just a chatbot and can't provide the support you need, but these services have trained counselors ready to help right now."""


def check_for_crisis(message):
    """Check if message contains crisis keywords."""
    message_lower = message.lower()
    for keyword in CRISIS_KEYWORDS:
        if keyword in message_lower:
            return True
    return False


def sanitise_input(message):
    """
    Clean and validate user input.
    Returns cleaned message or None if invalid.
    """
    if not message:
        return None

    # Remove leading/trailing whitespace
    message = message.strip()

    # Check if message is empty after stripping
    if not message:
        return None

    # Remove HTML tags (prevents script injection)
    message = re.sub(r"<[^>]+>", "", message)

    # Check length after cleaning
    if len(message) > 500:
        return None

    return message


@app.route("/chat", methods=["POST"])
@app.route("/chat", methods=["POST"])
def chat():
    """Handle chat messages and return bot responses."""
    data = request.get_json()
    raw_message = data.get("message", "")

    # Sanitise and validate input
    user_message = sanitise_input(raw_message)

    if user_message is None:
        if not raw_message or not raw_message.strip():
            return jsonify({"response": "Please enter a message!"})
        else:
            return jsonify(
                {"response": "Message too long! Please keep it under 500 characters."}
            )

    # Safety check for crisis keywords (use original for better detection)
    if check_for_crisis(raw_message):
        return jsonify({"response": CRISIS_RESPONSE})

    # Get the chatbot's response
    bot_response = chatbot.get_response(user_message)

    return jsonify({"response": str(bot_response)})


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)