Add autocomplete for transaction fields

Needs work on ordering by -count

nummi/transaction/forms.py

@@ -1,4 +1,5 @@
 from category.models import Category
+from django.forms.widgets import TextInput
 from main.forms import NummiFileInput, NummiForm
 from statement.models import Statement
 
@@ -26,6 +27,30 @@ class TransactionForm(NummiForm):
         super().__init__(*args, **kwargs)
         self.fields["category"].queryset = Category.objects.filter(user=_user)
         self.fields["statement"].queryset = Statement.objects.filter(user=_user)
+        self.fields["name"].widget = DatalistInput(
+            options=[
+                t.name
+                for t in _user.transaction_set.exclude(name=None)
+                .order_by("name")
+                .distinct("name")
+            ]
+        )
+        self.fields["trader"].widget = DatalistInput(
+            options=[
+                t.trader
+                for t in _user.transaction_set.exclude(trader=None)
+                .order_by("trader")
+                .distinct("trader")
+            ]
+        )
+        self.fields["payment"].widget = DatalistInput(
+            options=[
+                t.payment
+                for t in _user.transaction_set.exclude(payment=None)
+                .order_by("payment")
+                .distinct("payment")
+            ]
+        )
         if _disable_statement:
             self.fields["statement"].disabled = True
 
@@ -42,3 +67,16 @@ class InvoiceForm(NummiForm):
         widgets = {
             "file": NummiFileInput,
         }
+
+
+class DatalistInput(TextInput):
+    template_name = "transaction/forms/widgets/datalist.html"
+
+    def __init__(self, *args, options=[]):
+        self.options = options
+        super().__init__(*args)
+
+    def get_context(self, *args):
+        context = super().get_context(*args)
+        context["widget"]["options"] = self.options
+        return context