Show year-scoped balances and breakdowns in admin

User list shows Konsumiert / Bezahlt / Offener Betrag for the current
year. User detail page adds a BILANZ section with per-drink breakdowns
(paid + free) so a quick look at the user page replaces what
user_stats used to print.

Drink list shows crates_purchased, bottles_sold, bottles_remaining,
purchase_price_total, and balance, with a year filter. Detail page
groups all derived values into German sections (Kästen, Flaschen,
Menge, Einkauf, Pfand, Verkauf), replacing the drink_stats command.

UserPayment admin gets a custom YearFilter (created_at__year is not
admin-filterable directly). Donation/Payment get date filters and
search.

Group admin is unregistered (unused in this project).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

gaehsnitz/admin.py

@@ -3,13 +3,18 @@ from django.contrib import admin, messages
 from django.contrib.admin.utils import unquote
 from django.contrib.auth import get_user_model
 from django.contrib.auth.admin import UserAdmin
+from django.contrib.auth.models import Group
+
+admin.site.unregister(Group)
 from django.http import Http404, HttpResponseRedirect
 from django.template.response import TemplateResponse
 from django.urls import path, reverse
 from django.utils.html import format_html
 from django.utils.safestring import mark_safe
 
-from gaehsnitz.models import Donation, Payment, Drink, Consumption
+from django.db.models import Sum
+
+from gaehsnitz.models import Donation, Payment, Drink, Consumption, UserPayment, current_year
 from gaehsnitz.templatetags.money import euro
 
 User = get_user_model()
@@ -20,6 +25,12 @@ class ConsumptionInline(admin.TabularInline):
     extra = 0
 
 
+class UserPaymentInline(admin.TabularInline):
+    model = UserPayment
+    extra = 0
+    readonly_fields = ("created_at",)
+
+
 class SetPinForm(forms.Form):
     pin = forms.CharField(
         label="Neue PIN (3 Ziffern)",
@@ -36,7 +47,7 @@ class SetPinForm(forms.Form):
 
 @admin.register(User)
 class CustomUserAdmin(UserAdmin):
-    list_display = ("username", "consumed_drinks_price")
+    list_display = ("username", "consumed_drinks_price", "paid_amount", "open_balance")
     ordering = ("username",)
     list_filter = []
     fieldsets = (
@@ -50,14 +61,62 @@ class CustomUserAdmin(UserAdmin):
                 )
             },
         ),
-        ("BALANCE", {"fields": ("consumed_drinks_price",)}),
+        (
+            "BILANZ",
+            {
+                "fields": (
+                    "consumed_drinks_price",
+                    "paid_amount",
+                    "open_balance",
+                    "drinks_breakdown",
+                    "free_drinks_breakdown",
+                )
+            },
+        ),
     )
-    readonly_fields = ("consumed_drinks_price", "pin_status")
+    readonly_fields = (
-    inlines = (ConsumptionInline,)
+        "consumed_drinks_price",
+        "paid_amount",
+        "open_balance",
+        "pin_status",
+        "drinks_breakdown",
+        "free_drinks_breakdown",
+    )
+    inlines = (UserPaymentInline, ConsumptionInline)
 
+    @admin.display(description="Konsumiert")
     def consumed_drinks_price(self, user: User):
         return euro(user.consumed_drinks_price)
 
+    @admin.display(description="Bezahlt")
+    def paid_amount(self, user: User):
+        return euro(user.paid_amount)
+
+    @admin.display(description="Offener Betrag")
+    def open_balance(self, user: User):
+        return euro(user.open_balance)
+
+    def _breakdown(self, user: User, for_free: bool):
+        if user.pk is None:
+            return "-"
+        rows = (
+            user.consumption_list.filter(for_free=for_free, drink__year=current_year())
+            .values("drink__name")
+            .annotate(amount=Sum("amount"))
+            .order_by("drink__name")
+        )
+        if not rows:
+            return "-"
+        return ", ".join(f"{r['amount']}x {r['drink__name']}" for r in rows)
+
+    @admin.display(description="Bezahlt")
+    def drinks_breakdown(self, user: User):
+        return self._breakdown(user, for_free=False)
+
+    @admin.display(description="Gratis")
+    def free_drinks_breakdown(self, user: User):
+        return self._breakdown(user, for_free=True)
+
     @admin.display(description="PIN")
     def pin_status(self, user: User):
         status = "gesetzt" if user.pin else "nicht gesetzt"
@@ -104,10 +163,39 @@ class CustomUserAdmin(UserAdmin):
         return TemplateResponse(request, "admin/gaehsnitz/user/set_pin.html", context)
 
 
+class YearFilter(admin.SimpleListFilter):
+    title = "Jahr"
+    parameter_name = "year"
+    field_name = "created_at"
+
+    def lookups(self, request, model_admin):
+        years = model_admin.model.objects.dates(self.field_name, "year", order="DESC")
+        return [(y.year, str(y.year)) for y in years]
+
+    def queryset(self, request, queryset):
+        if self.value():
+            return queryset.filter(**{f"{self.field_name}__year": self.value()})
+        return queryset
+
+
+@admin.register(UserPayment)
+class UserPaymentAdmin(admin.ModelAdmin):
+    list_display = ("created_at", "user", "amount", "method", "note")
+    list_filter = ("method", YearFilter)
+    ordering = ("-created_at",)
+    search_fields = ("user__username", "note")
+
+    @admin.display(ordering="amount")
+    def amount(self, payment: UserPayment):
+        return euro(payment.amount)
+
+
 @admin.register(Donation)
 class DonationAdmin(admin.ModelAdmin):
     list_display = ("date", "amount", "note")
+    list_filter = ("date",)
     ordering = ("-date",)
+    search_fields = ("note",)
 
     @admin.display(ordering="amount")
     def amount(self, donation: Donation):
@@ -117,7 +205,9 @@ class DonationAdmin(admin.ModelAdmin):
 @admin.register(Payment)
 class PaymentAdmin(admin.ModelAdmin):
     list_display = ("date", "purpose", "amount")
+    list_filter = ("date",)
     ordering = ("-date",)
+    search_fields = ("purpose",)
 
     @admin.display(ordering="amount")
     def amount(self, payment: Payment):
@@ -126,31 +216,46 @@ class PaymentAdmin(admin.ModelAdmin):
 
 @admin.register(Drink)
 class DrinkAdmin(admin.ModelAdmin):
-    list_display = ("name", "purchase_price_per_crate", "crates_purchased", "purchase_price_total")
+    list_display = (
+        "name",
+        "year",
+        "crates_purchased",
+        "bottles_sold",
+        "bottles_remaining",
+        "purchase_price_total",
+        "balance",
+    )
+    list_filter = ("year",)
     fieldsets = (
-        (None, {"fields": ("name",)}),
+        (None, {"fields": ("name", "year")}),
         (
-            "crates",
+            "Kästen",
             {
                 "fields": (
                     "crates_ordered",
                     "crates_purchased",
+                    "crates_full_returned",
                     "crates_returned",
+                    "crates_remaining",
                 )
             },
         ),
         (
-            "bottles",
+            "Flaschen",
             {
                 "fields": (
                     "bottles_per_crate",
                     "bottles_total",
                     "bottles_returned",
+                    "bottles_sold",
+                    "bottles_given_away",
+                    "bottles_consumed",
+                    "bottles_remaining",
                 )
             },
         ),
         (
-            "amount",
+            "Menge",
             {
                 "fields": (
                     "bottle_size",
@@ -160,17 +265,18 @@ class DrinkAdmin(admin.ModelAdmin):
             },
         ),
         (
-            "purchase",
+            "Einkauf",
             {
                 "fields": (
                     "purchase_price_per_crate",
                     "purchase_price_per_bottle",
                     "purchase_price_total",
+                    "remaining_purchase_value",
                 )
             },
         ),
         (
-            "deposit",
+            "Pfand",
             {
                 "fields": (
                     "deposit_per_crate",
@@ -181,14 +287,12 @@ class DrinkAdmin(admin.ModelAdmin):
             },
         ),
         (
-            "sales",
+            "Verkauf",
             {
                 "fields": (
                     "sale_price_per_bottle",
-                    "bottles_sold",
                     "sales_purchase_value",
                     "sale_price_total",
-                    "bottles_given_away",
                     "giveaway_purchase_value",
                     "balance",
                 )
@@ -198,10 +302,15 @@ class DrinkAdmin(admin.ModelAdmin):
     readonly_fields = (
         "bottles_total",
         "bottles_returned",
+        "bottles_consumed",
+        "bottles_remaining",
+        "crates_full_returned",
+        "crates_remaining",
         "amount_per_crate",
         "amount_total",
         "purchase_price_per_bottle",
         "purchase_price_total",
+        "remaining_purchase_value",
         "deposit_total",
         "deposit_refund",
         "deposit_kept",
@@ -213,29 +322,82 @@ class DrinkAdmin(admin.ModelAdmin):
         "balance",
     )
 
+    @admin.display(description="Kästen voll zurück")
+    def crates_full_returned(self, drink: Drink):
+        return drink.crates_full_returned
+
+    @admin.display(description="Kästen übrig")
+    def crates_remaining(self, drink: Drink):
+        return drink.crates_remaining
+
+    @admin.display(description="Flaschen gesamt")
+    def bottles_total(self, drink: Drink):
+        return drink.bottles_total
+
+    @admin.display(description="Flaschen leer zurück")
+    def bottles_returned(self, drink: Drink):
+        return drink.bottles_returned
+
+    @admin.display(description="Flaschen verkauft")
+    def bottles_sold(self, drink: Drink):
+        return drink.bottles_sold
+
+    @admin.display(description="Flaschen verschenkt")
+    def bottles_given_away(self, drink: Drink):
+        return drink.bottles_given_away
+
+    @admin.display(description="Flaschen konsumiert")
+    def bottles_consumed(self, drink: Drink):
+        return drink.bottles_consumed
+
+    @admin.display(description="Flaschen übrig")
+    def bottles_remaining(self, drink: Drink):
+        return drink.bottles_remaining
+
+    @admin.display(description="Menge pro Kasten (l)")
+    def amount_per_crate(self, drink: Drink):
+        return drink.amount_per_crate
+
+    @admin.display(description="Menge gesamt (l)")
+    def amount_total(self, drink: Drink):
+        return drink.amount_total
+
+    @admin.display(description="Einkaufspreis pro Flasche")
     def purchase_price_per_bottle(self, drink: Drink):
         return euro(drink.purchase_price_per_bottle)
 
+    @admin.display(description="Einkaufspreis gesamt")
     def purchase_price_total(self, drink: Drink):
         return euro(drink.purchase_price_total)
 
+    @admin.display(description="Einkaufswert übrig")
+    def remaining_purchase_value(self, drink: Drink):
+        return euro(drink.remaining_purchase_value)
+
+    @admin.display(description="Pfand gesamt")
     def deposit_total(self, drink: Drink):
         return euro(drink.deposit_total)
 
+    @admin.display(description="Pfand zurück")
     def deposit_refund(self, drink: Drink):
         return euro(drink.deposit_refund)
 
+    @admin.display(description="Pfand einbehalten")
     def deposit_kept(self, drink: Drink):
         return euro(drink.deposit_kept)
 
+    @admin.display(description="Einkaufswert verkauft")
     def sales_purchase_value(self, drink: Drink):
         return euro(drink.sales_purchase_value)
 
+    @admin.display(description="Verkaufserlös")
     def sale_price_total(self, drink: Drink):
         return euro(drink.sale_price_total)
 
+    @admin.display(description="Einkaufswert verschenkt")
     def giveaway_purchase_value(self, drink: Drink):
         return euro(drink.giveaway_purchase_value)
 
+    @admin.display(description="Bilanz")
     def balance(self, drink: Drink):
         return mark_safe(f"<b>{euro(drink.balance)}</b>")