app.py

# app.py - Flask Backend with Reliable Link Shortening
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 in the user's message, summarize it and say you've shortened it.
   Example: "Here's your shortened link:" followed by [SHORTEN]original|short[/SHORTEN]
"""

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

# In-memory session storage
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)
    if short_link_match:
        original_url = short_link_match.group(1).strip()
        short_url = short_link_match.group(2).strip()
        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

def generate_audio(text):
    """Generate audio file from text"""
    clean_text = re.sub(r'[^\w\s.,!?\-]', '', text)
    if not clean_text.strip():
        clean_text = "Hello, this is your AI assistant."
    filename = f"audio_{uuid.uuid4()}.mp3"
    filepath = os.path.join(AUDIO_FOLDER, filename)
    try:
        tts = gTTS(text=clean_text, lang='en', slow=False)
        tts.save(filepath)
        return filename
    except Exception as e:
        print("TTS Error:", str(e))
        return None

def shorten_url_reliable(url):
    """Try multiple services to shorten URL"""
    services = [
        f"https://tinyurl.com/api-create.php?url={url}",
        f"https://is.gd/create.php?format=simple&url={url}"
    ]
    for service_url in services:
        try:
            response = requests.get(service_url, timeout=5)
            if response.status_code == 200:
                result = response.text.strip()
                if result.startswith("http") and len(result) > 10:
                    return result
        except Exception as e:
            print(f"Shortener failed: {service_url} | Error: {e}")
            continue
    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

        # Get 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
        response = chat_session.send_message(user_message)
        full_text = response.text

        # Force shortening if URL detected
        url_match = re.search(r'https?://[^\s<>"{}|\\^`\[\]]+', user_message)
        if url_match:
            original_url = url_match.group(0)
            short_url = shorten_url_reliable(original_url)
            if short_url:
                short_tag = f"[SHORTEN]{original_url}|{short_url}[/SHORTEN]"
                if "[SHORTEN]" not in full_text:
                    full_text += f"\n\nHere's your shortened link:\n{short_tag}"
            else:
                full_text += "\n\nI found a link but couldn't shorten it right now."

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

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

        # Generate audio if available
        if audio_content:
            audio_filename = generate_audio(audio_content)
            if audio_filename:
                result["audio_filename"] = audio_filename
                result["has_audio"] = True

        # Return 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("Server Error:", str(e))
        return jsonify({"error": "Failed to get response. Try again."}), 500

@app.route('/new-chat', methods=['POST'])
def new_chat():
    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)