Main_Page.py

"""
NSE Portfolio Optimizer Pro - Main Entry Page
==============================================
"""

import streamlit as st
from datetime import datetime
import pandas as pd

# Import utilities for live data AND Theme
try:
    from src.utils import get_nifty_data, render_header, get_theme_colors
except ImportError:
    get_nifty_data = None
    # Fallback dummies if import fails
    def render_header(): pass
    def get_theme_colors(): return {"card_bg": "#ffffff", "border": "#e2e8f0"}

# ============ PAGE CONFIGURATION ============
st.set_page_config(
    page_title="NSE Portfolio Optimizer Pro",
    page_icon="📊",
    layout="wide",
    initial_sidebar_state="expanded",
    menu_items={'About': 'NSE Portfolio Optimizer Pro v2.0'}
)

# ============ MAIN CONTENT ============

def main():
    # 1. Render Header (with Toggle)
    render_header()
    
    # 2. Get Dynamic Colors from the Toggle State
    colors = get_theme_colors()

    # 3. Apply CSS dynamically based on the Toggle
    st.markdown(f"""
    <style>
        @import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');
        :root {{ --primary: #2563eb; --font-main: 'Inter', sans-serif; }}
        * {{ font-family: var(--font-main); }}
        
        /* Metric Cards - controlled by Python variable, NOT system setting */
        .stMetric {{
            background: {colors['card_bg']} !important;
            border: 1px solid {colors['border']} !important;
            border-radius: 10px;
            padding: 1rem;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }}
        
        .badge-live {{
            background-color: #dcfce7; color: #166534; padding: 2px 8px;
            border-radius: 12px; font-size: 0.75rem; font-weight: 600;
            border: 1px solid #bbf7d0;
        }}
        .badge-static {{
            background-color: #f1f5f9; color: #475569; padding: 2px 8px;
            border-radius: 12px; font-size: 0.75rem; font-weight: 600;
            border: 1px solid #e2e8f0;
        }}
    </style>
    """, unsafe_allow_html=True)

    # ============ SESSION STATE ============
    if 'user_preferences' not in st.session_state:
        st.session_state.user_preferences = {
            'risk_free_rate': 0.0654,
            'default_years': 2,
            'default_simulations': 1000,
            'brokerage_rate': 0.0003,
            'confidence_level': 0.95
        }
    if 'portfolio_history' not in st.session_state:
        st.session_state.portfolio_history = []
    if 'current_portfolio' not in st.session_state:
        st.session_state.current_portfolio = None

    st.title("📊 NSE Portfolio Optimizer Pro")
    
    # --- TRANSPARENCY & ONBOARDING SECTION ---
    with st.expander("👋 New here? Read about the data sources", expanded=False):
        st.markdown("""
        ### 🧐 Data Transparency Statement
        We believe in being 100% clear about where our numbers come from:
        
        | Indicator | Source | Real-Time? | Why is it here? |
        |-----------|--------|------------|-----------------|
        | **NIFTY 50** | Yahoo Finance API | 🟢 **Yes (Delayed ~15m)** | Shows overall market health. |
        | **Risk-Free Rate** | User Settings | 🔴 **No (Fixed)** | Used as a benchmark. Defaults to India 10Y Bond Yield (6.54%). |
        | **RBI Repo Rate** | Reference Value | 🔴 **No (Fixed)** | Context only. Does not affect calculations. |
        | **Stock Prices** | Yahoo Finance API | 🟢 **Yes (Delayed ~15m)** | Used for all portfolio optimization. |
        """)

    st.markdown("---")

    # --- METRICS DASHBOARD ---
    col1, col2, col3, col4 = st.columns(4)
    
    # 1. Risk Free Rate (Static/Configurable)
    with col1:
        rf_rate = st.session_state.user_preferences['risk_free_rate'] * 100
        st.metric(
            "India Risk-Free Rate",
            f"{rf_rate:.2f}%",
            "Reference Setting",
            help="ℹ️ SOURCE: Your Settings.\n\nThis is the 'safe' return (like a FD or Bond) used to calculate Sharpe Ratio."
        )
        st.caption("🔴 Manual Setting")
    
    # 2. RBI Repo Rate (Static)
    with col2:
        st.metric(
            "RBI Repo Rate",
            "5.25%",
            "Neutral Stance",
            help="ℹ️ SOURCE: Fixed Reference.\n\nThis is the rate at which RBI lends money. Hardcoded context."
        )
        st.caption("🔴 Reference Only")
    
    # 3. NIFTY 50 (Live)
    with col3:
        nifty_price = "Loading..."
        nifty_delta = ""
        is_live = False
        
        if get_nifty_data:
            df, _ = get_nifty_data()
            if not df.empty:
                current = df['Close'].iloc[-1]
                prev = df['Close'].iloc[-2] if len(df) > 1 else current
                change = current - prev
                pct_change = (change / prev) * 100
                nifty_price = f"{current:,.0f}"
                nifty_delta = f"{change:+,.0f} ({pct_change:+.2f}%)"
                is_live = True
        
        st.metric(
            "NIFTY 50",
            nifty_price,
            nifty_delta,
            help="ℹ️ SOURCE: Yahoo Finance (Live).\n\nThis shows the current level of the NIFTY 50 index."
        )
        if is_live:
            st.caption(f"🟢 Live Data ({datetime.now().strftime('%H:%M')})")
        else:
            st.caption("🔴 Data Unavailable")
    
    # 4. Portfolios
    with col4:
        st.metric(
            "Your Portfolios",
            len(st.session_state.portfolio_history),
            help="Number of portfolios you have created in this session."
        )
        st.caption("🔵 Session Data")
    
    st.markdown("---")
    
    # --- BEGINNER GUIDE ---
    st.markdown("## 🧭 How to Start")
    
    tab1, tab2 = st.tabs(["🚀 Quick Start", "💡 What do these terms mean?"])
    
    with tab1:
        col_new, col_exist = st.columns(2)
        with col_new:
            st.info("### 1. Create a New Portfolio\nGo here if you want to build a portfolio from scratch.")
            if st.button("Go to New Portfolio →", use_container_width=True):
                st.switch_page("pages/1_New_Portfolio.py")
        
        with col_exist:
            st.success("### 2. Optimize Existing\nGo here if you already own stocks and want to know how to rebalance them.")
            if st.button("Go to Rebalance →", use_container_width=True):
                st.switch_page("pages/2_Rebalance.py")

    with tab2:
        st.markdown("""
        **Don't let the jargon scare you! Here is what matters:**
        
        * **Sharpe Ratio:** Think of this as "Bang for your Buck." Higher is better.
        * **Volatility:** The "Rollercoaster Factor." High volatility means the price jumps up and down a lot.
        * **VaR (Value at Risk):** The "Worst Day" predictor.
        """)

    st.markdown("---")
    st.caption("© 2025 NSE Portfolio Optimizer Pro | Data provided for educational purposes.")

if __name__ == "__main__":
    main()