Add function to get acceptable margins

handler/agora.py

@@ -186,6 +186,26 @@ class Agora(object):
         rates = self.cr.get_rates("USD")
         return rates
 
+    def get_acceptable_margins(self, currency, amount):
+        """
+        Get the minimum and maximum amounts we would accept a trade for.
+        :param currency: currency code
+        :param amount: amount
+        :return: (min, max)
+        :rtype: tuple
+        """
+        rates = self.get_rates_all()
+        if currency == "USD":
+            min_amount = amount - float(settings.Agora.AcceptableUSDMargin)
+            max_amount = amount + float(settings.Agora.AcceptableUSDMargin)
+            return (min_amount, max_amount)
+        amount_usd = amount / rates[currency]
+        min_usd = amount_usd - float(settings.Agora.AcceptableUSDMargin)
+        max_usd = amount_usd + float(settings.Agora.AcceptableUSDMargin)
+        min_local = min_usd * rates[currency]
+        max_local = max_usd * rates[currency]
+        return (min_local, max_local)
+
     def create_ad(self, countrycode, currency):
         """
         Post an ad in a country with a given currency.