Feature/coin (#623)

* add coin.py

* add example settings

* refactor whitespaces for merge requirements

* update class docstring

i3pystatus/coin.py

@@ -0,0 +1,80 @@
+import requests
+import json
+
+from i3pystatus import IntervalModule
+from i3pystatus.core.util import internet, require
+
+
+class Coin(IntervalModule):
+    """
+    Fetches live data of all cryptocurrencies availible at coinmarketcap <https://coinmarketcap.com/>.
+    Coin setting should be equal to the 'id' field of your coin in <https://api.coinmarketcap.com/v1/ticker/>.
+
+    Example coin settings: bitcoin, bitcoin-cash, ethereum, litecoin, dash, lisk.
+    Example currency settings: usd, eur, huf.
+
+    .. rubric:: Available formatters
+
+    * {symbol}
+    * {price}
+    * {rank}
+    * {24h_volume}
+    * {market_cap}
+    * {available_supply}
+    * {total_supply}
+    * {max_supply}
+    * {percent_change_1h}
+    * {percent_change_24h}
+    * {percent_change_7d}
+    * {last_updated} - time of last update on the API's part
+    * {status}
+    """
+
+    settings = (
+        ("format", "format string used for output."),
+        ("coin", "cryptocurrency to fetch"),
+        ("currency", "fiat currency to show fiscal data"),
+        ("symbol", "coin symbol"),
+        ("interval", "update interval in seconds"),
+        ("status_interval", "percent change status in the last: '1h' / '24h' / '7d'")
+    )
+
+    symbol = "¤"
+    format = "{symbol} {price}{status}"
+    coin = "ethereum"
+    currency = "USD"
+    interval = 600
+    status_interval = "24h"
+
+    def fetch_data(self):
+        response = requests.get("https://api.coinmarketcap.com/v1/ticker/{}/?convert={}".format(self.coin, self.currency))
+        coin_data = response.json()[0]
+        coin_data["price"] = coin_data.pop("price_{}".format(self.currency.lower()))
+        coin_data["24h_volume"] = coin_data.pop("24h_volume_{}".format(self.currency.lower()))
+        coin_data["market_cap"] = coin_data.pop("market_cap_{}".format(self.currency.lower()))
+        coin_data["symbol"] = self.symbol
+        return coin_data
+
+    def set_status(self, change):
+        if change > 10:
+            return '⮅'
+        elif change > 0:
+            return '⭡'
+        elif change < -10:
+            return '⮇'
+        elif change < 0:
+            return '⭣'
+        else:
+            return ''
+
+    @require(internet)
+    def run(self):
+        fdict = self.fetch_data()
+
+        symbols = dict(bitcoin='฿', ethereum='Ξ', litecoin='Ł', dash='Đ')
+        if self.coin in symbols:
+            fdict["symbol"] = symbols[self.coin]
+        fdict["status"] = self.set_status(float(fdict["percent_change_{}".format(self.status_interval)]))
+
+        self.data = fdict
+        self.output = {"full_text": self.format.format(**fdict)}