Add crypto_market.py: refactor duplicated CoinGecko API patterns into shared helpers

.gitignore

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+__pycache__/
+*.py[cod]
+*.pyo

crypto_market.py

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+"""
+CoinGecko cryptocurrency market data utilities.
+https://www.coingecko.com/
+"""
+
+import requests
+
+BASE_URL = "https://api.coingecko.com/api/v3"
+
+
+# ---------------------------------------------------------------------------
+# Shared helpers (extracted to eliminate duplication)
+# ---------------------------------------------------------------------------
+
+def _get(endpoint, params=None):
+    """Make a GET request to the CoinGecko API and return parsed JSON."""
+    url = f"{BASE_URL}{endpoint}"
+    response = requests.get(url, params=params, timeout=10)
+    try:
+        response.raise_for_status()
+    except requests.exceptions.HTTPError as exc:
+        raise requests.exceptions.HTTPError(
+            f"CoinGecko API error for {url} (status {response.status_code}): {exc}"
+        ) from exc
+    return response.json()
+
+
+def _format_price(coin_id, price, currency):
+    """Return a human-readable price string for a coin."""
+    return f"{coin_id.capitalize()}: {price:,.2f} {currency.upper()}"
+
+
+# ---------------------------------------------------------------------------
+# Public API
+# ---------------------------------------------------------------------------
+
+def get_coin_price(coin_id, vs_currency="usd"):
+    """Return the current price of *coin_id* in *vs_currency*."""
+    data = _get("/simple/price", params={"ids": coin_id, "vs_currencies": vs_currency})
+    if coin_id not in data:
+        raise ValueError(f"Coin '{coin_id}' not found in CoinGecko response.")
+    if vs_currency not in data[coin_id]:
+        raise ValueError(f"Currency '{vs_currency}' not found for coin '{coin_id}'.")
+    return data[coin_id][vs_currency]
+
+
+def get_coin_market_data(coin_id):
+    """Return market data (price, market cap, 24 h change) for *coin_id*."""
+    data = _get(f"/coins/{coin_id}", params={"localization": "false", "tickers": "false",
+                                              "community_data": "false", "developer_data": "false"})
+    market = data["market_data"]
+    return {
+        "price_usd": market["current_price"]["usd"],
+        "market_cap_usd": market["market_cap"]["usd"],
+        "price_change_24h": market["price_change_percentage_24h"],
+    }
+
+
+def get_prices(coin_ids, vs_currency="usd"):
+    """Return a dict mapping each coin in *coin_ids* to its current price."""
+    ids_param = ",".join(coin_ids)
+    data = _get("/simple/price", params={"ids": ids_param, "vs_currencies": vs_currency})
+    prices = {}
+    for coin in coin_ids:
+        if coin not in data:
+            raise ValueError(f"Coin '{coin}' not found in CoinGecko response.")
+        if vs_currency not in data[coin]:
+            raise ValueError(f"Currency '{vs_currency}' not found for coin '{coin}'.")
+        prices[coin] = data[coin][vs_currency]
+    return prices
+
+
+def display_prices(coin_ids, vs_currency="usd"):
+    """Print the current price for each coin in *coin_ids*."""
+    prices = get_prices(coin_ids, vs_currency)
+    for coin_id, price in prices.items():
+        print(_format_price(coin_id, price, vs_currency))
+
+
+def display_market_summary(coin_ids):
+    """Print a market summary (price, market cap, 24 h change) for each coin."""
+    for coin_id in coin_ids:
+        data = get_coin_market_data(coin_id)
+        print(
+            f"{coin_id.capitalize():12s} | "
+            f"Price: ${data['price_usd']:>12,.2f} | "
+            f"Market cap: ${data['market_cap_usd']:>18,.0f} | "
+            f"24 h: {data['price_change_24h']:+.2f}%"
+        )
+
+
+if __name__ == "__main__":
+    COINS = ["bitcoin", "ethereum", "litecoin"]
+    print("=== Current Prices ===")
+    display_prices(COINS)
+    print()
+    print("=== Market Summary ===")
+    display_market_summary(COINS)