src/streamlit_app.py

import streamlit as st
import feedparser
import requests
import json
import os
from bs4 import BeautifulSoup
from transformers import MarianMTModel, MarianTokenizer

# Configure the Streamlit page
st.set_page_config(page_title="📍 BharatPulse - Local News & Sentiment", layout="wide")

# --- User Authentication Functions ---
# IMPORTANT: For production, this 'users.json' file will not persist across deployments
# on cloud platforms like Streamlit Community Cloud. For persistent user data,
# a proper database (e.g., Firebase Firestore, PostgreSQL) is REQUIRED.
# If you are seeing PermissionError even with /tmp, your environment does not allow file writes.
USERS_FILE = "/tmp/users.json" # Attempt to use /tmp for write permissions

def load_users():
    """Loads user data from the JSON file."""
    users_data = {}
    if os.path.exists(USERS_FILE):
        try:
            with open(USERS_FILE, "r") as f:
                users_data = json.load(f)
        except json.JSONDecodeError:
            st.error("Error: users.json file is corrupted. Starting with an empty user database.")
        except PermissionError:
            st.error("Permission Error: Cannot read users.json. Your environment might restrict file access. For persistent user data, a database is required.")
        except Exception as e:
            st.error(f"An unexpected error occurred while loading users: {e}. For persistent user data, a database is required.")
    return users_data

def save_users(users):
    """Saves user data to the JSON file."""
    try:
        with open(USERS_FILE, "w") as f:
            json.dump(users, f, indent=2)
    except PermissionError:
        st.error("Permission Error: Cannot write to users.json. Your environment might restrict file access. For persistent user data, a database is required.")
    except Exception as e:
        st.error(f"An unexpected error occurred while saving users: {e}. For persistent user data, a database is required.")

def register_user(username, email, password, location):
    """Registers a new user."""
    users = load_users()
    if email in users:
        return False, "User already exists with this email."
    users[email] = {
        "username": username,
        "email": email,
        "password": password, # In a real app, hash passwords!
        "location": location
    }
    save_users(users) # Attempt to save
    # The success of saving will be indicated by the absence of an error from save_users
    return True, "Registration successful. You can now log in."

def login_user(email, password):
    """Logs in an existing user."""
    users = load_users()
    user = users.get(email)
    if user and user["password"] == password: # In a real app, compare hashed hashed passwords!
        return True, user
    return False, "Invalid email or password. If you don't have an account, please go to the 'Register' tab to create one."

# --- MarianMT Model for Translation ---
@st.cache_resource # Caches the model to avoid reloading on rerun
def load_translation_model():
    """Loads the MarianMT English-Telugu translation model."""
    st.info("Loading translation model (this may take a moment)...")
    model_name = "Helsinki-NLP/opus-mt-en-te"
    tokenizer = MarianTokenizer.from_pretrained(model_name)
    model = MarianMTModel.from_pretrained(model_name)
    st.success("Translation model loaded!")
    return tokenizer, model

def translate_to_telugu(text):
    """Translates English text to Telugu."""
    try:
        tokenizer, model = load_translation_model()
        # Prepare input for the model, ensuring truncation for long texts
        tokens = tokenizer.prepare_seq2seq_batch([text], return_tensors="pt", truncation=True, max_length=512)
        translated = model.generate(**tokens)
        return tokenizer.decode(translated[0], skip_special_tokens=True)
    except Exception as e:
        st.error(f"Error during translation: {e}")
        return "Translation failed."

# --- Article Content Extraction ---
def extract_article_content(url):
    """Extracts the first few paragraphs from an article URL."""
    try:
        # Add headers to mimic a browser, as some sites block direct requests
        headers = {
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36'
        }
        response = requests.get(url, timeout=10, headers=headers) # Increased timeout
        response.raise_for_status() # Raise an HTTPError for bad responses (4xx or 5xx)
        soup = BeautifulSoup(response.text, "html.parser")
        paragraphs = soup.find_all('p')
        # Join the text of the first 5 paragraphs, or fewer if not available
        content = ' '.join([p.get_text() for p in paragraphs[:5]])
        if not content: # If no paragraphs found, try to get text from body
            content = soup.body.get_text(separator=' ', strip=True)[:1000] # Get first 1000 chars
        return content if content else "Could not extract article content."
    except requests.exceptions.RequestException as e:
        return f"Network or HTTP error: {e}"
    except Exception as e:
        return f"Error extracting content: {e}"

# --- Weather Functionality ---
# IMPORTANT: Replace 'YOUR_OPENWEATHER_API_KEY' with your actual OpenWeatherMap API key.
# You can get one from https://openweathermap.org/api
# For production, store this securely (e.g., Streamlit secrets or environment variables).
OPENWEATHER_API_KEY = "YOUR_OPENWEATHER_API_KEY"
WEATHER_API_URL = "http://api.openweathermap.org/data/2.5/weather"

def get_weather_data(city):
    """Fetches weather data for a given city from OpenWeatherMap."""
    if OPENWEATHER_API_KEY == "YOUR_OPENWEATHER_API_KEY":
        st.warning("Please replace 'YOUR_OPENWEATHER_API_KEY' with your actual OpenWeatherMap API key to fetch weather data.")
        return None

    params = {
        "q": city,
        "appid": OPENWEATHER_API_KEY,
        "units": "metric" # Get temperature in Celsius
    }
    try:
        response = requests.get(WEATHER_API_URL, params=params, timeout=10)
        response.raise_for_status() # Raise an HTTPError for bad responses (4xx or 5xx)
        data = response.json()
        return data
    except requests.exceptions.RequestException as e:
        st.error(f"Error fetching weather data for {city}: {e}. Please check the city name or your internet connection.")
        return None
    except json.JSONDecodeError:
        st.error(f"Error decoding weather data for {city}. Unexpected response from API.")
        return None
    except Exception as e:
        st.error(f"An unexpected error occurred while fetching weather data: {e}")
        return None

# --- Authentication UI ---
# Initialize session state for login status
if "logged_in" not in st.session_state:
    st.session_state.logged_in = False
if "user" not in st.session_state:
    st.session_state.user = None

if not st.session_state.logged_in:
    st.title("🔐 Login to BharatPulse")

    tab1, tab2 = st.tabs(["🔑 Login", "📝 Register"])

    with tab1:
        st.subheader("Existing User Login")
        email = st.text_input("Email", key="login_email")
        password = st.text_input("Password", type="password", key="login_password")
        if st.button("Login", key="login_button"):
            success, user_or_msg = login_user(email, password)
            if success:
                st.session_state.logged_in = True
                st.session_state.user = user_or_msg
                st.success(f"Welcome, {st.session_state.user['username']}!")
                st.rerun() # Rerun to switch to the main app view
            else:
                st.error(user_or_msg) # This error message now includes the suggestion to register

    with tab2:
        st.subheader("New User Registration")
        new_username = st.text_input("Username", key="register_username")
        new_email = st.text_input("New Email", key="register_email")
        new_password = st.text_input("New Password", type="password", key="register_password")
        new_location = st.text_input("Location (e.g., Hyderabad)", key="register_location")
        if st.button("Register", key="register_button"):
            if new_username and new_email and new_password and new_location:
                success, message = register_user(new_username, new_email, new_password, new_location)
                if success:
                    st.success(message)
                else:
                    st.error(message)
            else:
                st.warning("Please fill in all registration fields.")
    st.stop() # Stop execution if not logged in

# --- Main News UI (only runs if logged in) ---
st.sidebar.header("User Info")
st.sidebar.success(f"Logged in as: {st.session_state.user['username']}")
st.sidebar.info(f"Your registered location: {st.session_state.user['location']}")

if st.sidebar.button("🚪 Logout"):
    st.session_state.logged_in = False
    st.session_state.user = None
    st.rerun() # Rerun to go back to login screen

st.title("📍 BharatPulse - Local News & Sentiment")

# Define RSS feeds
# You can expand this dictionary with more RSS feeds for different regions/newspapers
feeds = {
    "Sakshi - Medak": "https://www.sakshi.com/rss/district-news/medak.xml",
    "Eenadu - AP": "https://www.eenadu.net/rss/andhra-pradesh.xml",
    # Add more feeds here, e.g., "Eenadu - Telangana": "https://www.eenadu.net/rss/telangana.xml"
}

# Added "☁️ Weather" tab
tabs = st.tabs(["📰 Headlines", "🔍 Search by City", "☁️ Weather"])

# --- 📰 Headlines Tab ---
with tabs[0]:
    st.header("📰 Latest Local Telugu News Headlines")
    for name, url in feeds.items():
        st.subheader(name)
        try:
            feed = feedparser.parse(url)
            if not feed.entries:
                st.info(f"No entries found for {name}.")
                continue

            for entry in feed.entries[:3]: # Display top 3 articles per feed
                st.markdown(f"### [{entry.title}]({entry.link})") # Make title a clickable link
                st.write(f"Published: {entry.published}")
                
                # Extract and summarize article content
                summary = extract_article_content(entry.link)
                st.markdown(f"**English Summary:** {summary}")
                
                # Translate summary to Telugu
                telugu_summary = translate_to_telugu(summary)
                st.markdown(f"**తెలుగు అనువాదం:** {telugu_summary}")
                st.markdown("---")
        except Exception as e:
            st.error(f"Could not fetch news from {name}: {e}")

# --- 🔍 Search by City Tab ---
with tabs[1]:
    st.header("🔎 Search News by City / District")
    # Pre-fill with user's registered location if available
    default_city = st.session_state.user['location'] if st.session_state.user else ""
    city_search_input = st.text_input("Enter your city/district name (e.g., Medak, Hyderabad)", value=default_city)

    if city_search_input:
        st.success(f"Searching news for: **{city_search_input}**")
        found_news = False
        for name, url in feeds.items():
            # Basic matching: checks if the city name is in the feed's name (case-insensitive)
            if city_search_input.lower() in name.lower():
                st.subheader(f"News from {name}")
                try:
                    feed = feedparser.parse(url)
                    if not feed.entries:
                        st.info(f"No entries found for {name} matching '{city_search_input}'.")
                        continue

                    for entry in feed.entries[:2]: # Display top 2 articles per matching feed
                        st.markdown(f"**🗞️ [{entry.title}]({entry.link})**")
                        summary = extract_article_content(entry.link)
                        telugu_summary = translate_to_telugu(summary)
                        st.markdown(f"**తెలుగు అనువాదం:** {telugu_summary}")
                        st.markdown("---")
                        found_news = True
                except Exception as e:
                    st.error(f"Could not fetch news from {name}: {e}")
        if not found_news:
            st.info(f"No news found for '{city_search_input}' in the available feeds. Try a different city or check our 'Headlines' tab.")

# --- ☁️ Weather Tab ---
with tabs[2]:
    st.header("☁️ Weather Conditions")
    # Pre-fill with user's registered location if available
    default_weather_city = st.session_state.user['location'] if st.session_state.user else ""
    weather_city_input = st.text_input("Enter city name for weather (e.g., Hyderabad, Delhi)", value=default_weather_city, key="weather_city_input")
    
    if st.button("Get Weather", key="get_weather_button"):
        if weather_city_input:
            with st.spinner(f"Fetching weather for {weather_city_input}..."):
                weather_data = get_weather_data(weather_city_input)
            
            if weather_data:
                st.subheader(f"Current Weather in {weather_data['name']}, {weather_data['sys']['country']}")
                col1, col2, col3 = st.columns(3)
                with col1:
                    st.metric("Temperature", f"{weather_data['main']['temp']:.1f}°C")
                with col2:
                    st.metric("Feels Like", f"{weather_data['main']['feels_like']:.1f}°C")
                with col3:
                    st.metric("Humidity", f"{weather_data['main']['humidity']}%")
                
                st.write(f"**Description:** {weather_data['weather'][0]['description'].capitalize()}")
                st.write(f"**Wind Speed:** {weather_data['wind']['speed']} m/s")
                st.write(f"**Pressure:** {weather_data['main']['pressure']} hPa")
            else:
                st.info("Could not retrieve weather data. Please check the city name or your API key.")
        else:
            st.warning("Please enter a city name to get weather information.")