#!/usr/bin/env python3
"""
Crypto Portfolio Tracker
A simple script to track cryptocurrency prices and portfolio value.
Fetches real-time data from CoinGecko API (no API key required).
"""

import json
import urllib.request
from datetime import datetime


def fetch_prices(coins: list[str], currency: str = "usd") -> dict:
    """Fetch current prices for specified coins from CoinGecko."""
    coin_ids = ",".join(coins)
    url = f"https://api.coingecko.com/api/v3/simple/price?ids={coin_ids}&vs_currencies={currency}&include_24hr_change=true"
    
    try:
        with urllib.request.urlopen(url, timeout=10) as response:
            return json.loads(response.read().decode())
    except Exception as e:
        print(f"Error fetching prices: {e}")
        return {}


def calculate_portfolio_value(holdings: dict, prices: dict, currency: str = "usd") -> dict:
    """Calculate total portfolio value and per-coin breakdown."""
    breakdown = {}
    total = 0.0
    
    for coin, amount in holdings.items():
        if coin in prices and currency in prices[coin]:
            price = prices[coin][currency]
            value = amount * price
            change_24h = prices[coin].get(f"{currency}_24h_change", 0)
            
            breakdown[coin] = {
                "amount": amount,
                "price": price,
                "value": value,
                "change_24h": change_24h
            }
            total += value
    
    return {"breakdown": breakdown, "total": total}


def format_currency(value: float, symbol: str = "$") -> str:
    """Format a number as currency."""
    return f"{symbol}{value:,.2f}"


def format_percent(value: float) -> str:
    """Format a number as percentage with color indicator."""
    sign = "+" if value >= 0 else ""
    indicator = "📈" if value >= 0 else "📉"
    return f"{indicator} {sign}{value:.2f}%"


def print_portfolio_report(portfolio: dict, currency_symbol: str = "$"):
    """Print a formatted portfolio report."""
    print("\n" + "=" * 50)
    print(f"  PORTFOLIO REPORT - {datetime.now().strftime('%Y-%m-%d %H:%M')}")
    print("=" * 50 + "\n")
    
    for coin, data in portfolio["breakdown"].items():
        print(f"  {coin.upper()}")
        print(f"    Holdings: {data['amount']:.6f}")
        print(f"    Price:    {format_currency(data['price'], currency_symbol)}")
        print(f"    Value:    {format_currency(data['value'], currency_symbol)}")
        print(f"    24h:      {format_percent(data['change_24h'])}")
        print()
    
    print("-" * 50)
    print(f"  TOTAL VALUE: {format_currency(portfolio['total'], currency_symbol)}")
    print("=" * 50 + "\n")


def main():
    # Example portfolio - customize with your holdings
    my_holdings = {
        "bitcoin": 0.5,
        "ethereum": 2.0,
        "solana": 10.0,
    }
    
    print("Fetching latest prices...")
    prices = fetch_prices(list(my_holdings.keys()))
    
    if not prices:
        print("Failed to fetch prices. Check your connection.")
        return
    
    portfolio = calculate_portfolio_value(my_holdings, prices)
    print_portfolio_report(portfolio)


if __name__ == "__main__":
    main()