From b2f2bef02930b6cdda93f8f83ace50be00187675 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nikola@mraveniste.cc>
Date: Fri, 26 Apr 2019 17:53:42 +0200
Subject: [PATCH] Add possiblity to convert currencies

---
 commands.py               |  3 +++
 services/converter.py     |  5 +++++
 services/exchangerates.py | 28 ++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+)
 create mode 100644 services/exchangerates.py

diff --git a/commands.py b/commands.py
index cc9e2f0..4a2907b 100644
--- a/commands.py
+++ b/commands.py
@@ -6,6 +6,7 @@ import requests
 
 from services.cheesecom import CheeseCom, CheeseComError
 from services.converter import Converter, ConverterError
+from services.exchangerates import ExchangeRates, ExchangeRatesError
 from services.roll20 import Roll20, Roll20Error
 from services.youtube import Youtube, YoutubeError
 
@@ -23,6 +24,7 @@ class Commands(object):
         self.config = config
         self.logger = logger
         self.last_roll_formula = None
+        self.rates = ExchangeRates()
 
     def add_quote(self, id, text, game, date):
         try:
@@ -213,6 +215,7 @@ class Commands(object):
 
     def convert(self, expression, unit=None):
         c = Converter()
+        c.update_currencies(*self.rates.query())
         try:
             return c.convert(expression, unit)
         except ConverterError as e:
diff --git a/services/converter.py b/services/converter.py
index 82a5cab..c87aaac 100644
--- a/services/converter.py
+++ b/services/converter.py
@@ -31,6 +31,11 @@ class Converter(object):
             self.ureg.floz: self.ureg.milliliter,
         }
 
+    def update_currencies(self, base, rates):
+        self.ureg.define('{0} = [currency]'.format(base))
+        for currency, rate in rates.items():
+            self.ureg.define('{0} = {1} / {2}'.format(currency, base, rate))
+
     def convert(self, expression, unit=None):
         try:
             q = self.ureg.parse_expression(expression)
diff --git a/services/exchangerates.py b/services/exchangerates.py
new file mode 100644
index 0000000..e5d672c
--- /dev/null
+++ b/services/exchangerates.py
@@ -0,0 +1,28 @@
+import datetime
+
+import requests
+
+
+API_URL = 'https://api.exchangeratesapi.io/latest'
+
+
+class ExchangeRatesError(Exception):
+    pass
+
+
+class ExchangeRates(object):
+    def __init__(self):
+        self.cache = {}
+
+    def query(self):
+        today = datetime.datetime.utcnow().date().isoformat()
+        try:
+            base, rates = self.cache[today]
+        except KeyError:
+            try:
+                data = requests.get(API_URL).json()
+                base, rates = data['base'], data['rates']
+                self.cache[data['date']] = base, rates
+            except Exception as e:
+                raise ExchangeRatesError(str(e))
+        return base, rates