app.py

import time
from flask import Flask, jsonify, render_template
import requests

app = Flask(__name__)

CACHE = {}
CACHE_TTL = 60  # secondi — limita le chiamate a CoinGecko e riduce la latenza percepita

COINGECKO_BASE = "https://api.coingecko.com/api/v3"
COINS = "bitcoin,ethereum,solana,cardano,dogecoin"


def get_cached(key):
    entry = CACHE.get(key)
    if entry and (time.time() - entry["ts"]) < CACHE_TTL:
        return entry["data"]
    return None


def set_cached(key, data):
    CACHE[key] = {"data": data, "ts": time.time()}


@app.route("/")
def index():
    return render_template("index.html")


@app.route("/api/prices")
def api_prices():
    cache_key = "prices"
    cached = get_cached(cache_key)
    if cached:
        return jsonify(cached)

    try:
        response = requests.get(
            f"{COINGECKO_BASE}/coins/markets",
            params={
                "vs_currency": "usd",
                "ids": COINS,
                "order": "market_cap_desc",
                "sparkline": "false",
            },
            timeout=8,
        )
        response.raise_for_status()
        data = response.json()
        set_cached(cache_key, data)
        return jsonify(data)

    except requests.exceptions.RequestException as e:
        return jsonify({"error": str(e)}), 503


@app.route("/api/history/<coin_id>")
def api_history(coin_id):
    # Allowlist per evitare che il parametro URL costruisca chiamate arbitrarie a CoinGecko
    allowed = set(COINS.split(","))
    if coin_id not in allowed:
        return jsonify({"error": "Coin non supportata"}), 400

    cache_key = f"history_{coin_id}"
    cached = get_cached(cache_key)
    if cached:
        return jsonify(cached)

    try:
        response = requests.get(
            f"{COINGECKO_BASE}/coins/{coin_id}/market_chart",
            params={"vs_currency": "usd", "days": "7"},
            timeout=8,
        )
        response.raise_for_status()
        data = response.json()
        set_cached(cache_key, data)
        return jsonify(data)

    except requests.exceptions.RequestException as e:
        return jsonify({"error": str(e)}), 503


if __name__ == "__main__":
    app.run(debug=True, port=5001)