app.py

# app.py - Flask Backend with Auto Link Shortening (TinyURL) + Chat Memory
from flask import Flask, request, jsonify, send_from_directory, make_response
import google.generativeai as genai
from dotenv import load_dotenv
import os
from flask_cors import CORS
import markdown2
import re
import requests
from gtts import gTTS
import uuid

# Load environment variables
load_dotenv()

# Configure paths
AUDIO_FOLDER = os.path.join('static', 'audio')
os.makedirs(AUDIO_FOLDER, exist_ok=True)

app = Flask(__name__, static_folder='static')
CORS(app)

# AI Configuration
system_instruction = """
You are a helpful AI assistant named Athspi. When responding:
1. Never mention "audio" or technical terms
2. For responses that would benefit from audio (like stories, explanations, or content meant to be heard), include the audio version between these markers:
   [AUDIO]content here[/AUDIO]
3. Keep responses natural and friendly
4. Decide automatically when to include audio based on the content type
5. For stories, always include audio version
6. If a URL is present in the user's message, respond with:
   [SHORTEN]original_url|short_url[/SHORTEN]
   Example:
   I found your link! Here's a shortened version:
   [SHORTEN]https://example.com|https://tinyurl.com/abc123[/SHORTEN]
"""

genai.configure(api_key=os.getenv("GEMINI_API_KEY"))
model = genai.GenerativeModel('gemini-2.5-flash', system_instruction=system_instruction)

# In-memory storage for chat sessions
chat_sessions = {}

def convert_markdown_to_html(text):
    html = markdown2.markdown(text, extras=["fenced-code-blocks", "tables"])
    html = re.sub(r'<pre><code(.*?)>', r'<pre class="code-block"><code\1>', html)
    return html

def process_response(full_response):
    """Extract visible text, audio content, and short links"""
    audio_match = re.search(r'\[AUDIO\](.*?)\[/AUDIO\]', full_response, re.DOTALL)
    audio_content = audio_match.group(1).strip() if audio_match else None
    visible_text = re.sub(r'\[/?AUDIO\]', '', full_response)

    short_link_match = re.search(r'\[SHORTEN\](.*?)\|([^|]*?)\[/SHORTEN\]', visible_text, re.DOTALL)
    short_data = None
    if short_link_match:
        original_url = short_link_match.group(1).strip()
        short_url = short_link_match.group(2).strip()
        short_data = {"original": original_url, "short": short_url}
        # Replace with formatted HTML
        link_html = f'<p><strong>🔗 Original:</strong> <a href="{original_url}" target="_blank">{original_url}</a></p>' \
                    f'<p><strong>✂️ Shortened:</strong> <a href="{short_url}" target="_blank">{short_url}</a></p>'
        visible_text = re.sub(r'\[SHORTEN\].*?\[/SHORTEN\]', link_html, visible_text)

    return visible_text, audio_content, short_data

def generate_audio(text):
    """Generate audio file from text"""
    text = re.sub(r'[^\w\s.,!?\-]', '', text)
    filename = f"audio_{uuid.uuid4()}.mp3"
    filepath = os.path.join(AUDIO_FOLDER, filename)
    tts = gTTS(text=text, lang='en', slow=False)
    tts.save(filepath)
    return filename

def shorten_url_with_tinyurl(url):
    """Shorten URL using TinyURL public API"""
    try:
        response = requests.get(f"http://tinyurl.com/api-create.php?url={url}")
        if response.status_code == 200 and response.text.strip():
            return response.text.strip()
        return None
    except Exception as e:
        print("TinyURL error:", e)
        return None

@app.route('/chat', methods=['POST'])
def chat():
    try:
        data = request.json
        user_message = data.get('message', '').strip()
        session_id = request.cookies.get('session_id') or str(uuid.uuid4())

        if not user_message:
            return jsonify({"error": "Message required"}), 400

        # Retrieve or create chat session
        if session_id not in chat_sessions:
            chat_sessions[session_id] = model.start_chat(history=[])
        chat_session = chat_sessions[session_id]

        # Always send to AI first — let AI decide if response needs audio, etc.
        ai_response = chat_session.send_message(user_message)
        full_text = ai_response.text

        # Extract URL from user message
        url_match = re.search(r'https?://[^\s<>"{}|\\^`\[\]]+', user_message)
        short_url = None
        if url_match:
            original_url = url_match.group(0)
            short_url = shorten_url_with_tinyurl(original_url)
            if short_url:
                # Inject short link into AI response
                short_tag = f"[SHORTEN]{original_url}|{short_url}[/SHORTEN]"
                if "[SHORTEN]" not in full_text:
                    full_text += f"\n\n{short_tag}"

        # Process final response
        visible_text, audio_content, short_data = process_response(full_text)
        html_response = convert_markdown_to_html(visible_text)

        result = {
            "response_html": html_response,
            "has_audio": False
        }

        # Generate audio if AI included [AUDIO] tag
        if audio_content:
            audio_filename = generate_audio(audio_content)
            result["audio_filename"] = audio_filename
            result["has_audio"] = True

        # Send response with session cookie
        resp = make_response(jsonify(result))
        resp.set_cookie('session_id', session_id, max_age=3600, httponly=True, samesite='Lax')
        return resp

    except Exception as e:
        print("Error:", str(e))
        return jsonify({"error": "Something went wrong. Please try again."}), 500

@app.route('/new-chat', methods=['POST'])
def new_chat():
    """Start a new chat session (clear memory)"""
    session_id = str(uuid.uuid4())
    resp = make_response(jsonify({"status": "new chat started"}))
    resp.set_cookie('session_id', session_id, max_age=3600, httponly=True, samesite='Lax')
    return resp

@app.route('/download/<filename>')
def download_audio(filename):
    try:
        return send_from_directory(AUDIO_FOLDER, filename, as_attachment=True)
    except FileNotFoundError:
        return jsonify({"error": "Audio file not found"}), 404

@app.route('/')
def serve_index():
    return send_from_directory('static', 'index.html')

@app.route('/<path:path>')
def serve_static(path):
    return send_from_directory('static', path)

if __name__ == '__main__':
    app.run(host="0.0.0.0", port=7860)