add fancy page

core/views.py

@@ -1,7 +1,26 @@
+from decimal import Decimal, InvalidOperation
+
 from django.views.generic import TemplateView
 
 from core.models import Subject
-from core.prediction import predict_all
+from core.prediction import predict_all, predict_balance
+
+
+class BalanceView(TemplateView):
+    template_name = "core/balance.html"
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        amount, amount_error = Decimal(), False
+        if amount_query := self.request.GET.get("amount"):
+            try:
+                amount = Decimal(amount_query)
+            except InvalidOperation:
+                amount_error = True
+        context["amount"] = round(amount, 2)
+        context["amount_error"] = amount_error
+        context["future_transactions"] = predict_balance(amount)
+        return context
 
 
 class SubjectsView(TemplateView):