Rework platform billing: per-plan clocks, grace from period start

Implements BILLING.md. The architecture was sound -- snapshot-on-Due,
dated prices, asymmetric dry-run commands are all kept -- so this
fixes the three hardcoded assumptions rather than rewriting.

The real defect: grace ran from period_END, so an annual club used
the whole unpaid year plus 45 days (~410 days) before anything
switched it off. Grace now runs from the period START, and every
clock is per-plan.

- Tier -> Plan (+ TierPrice -> PlanPrice, and every FK). Migration
  0004 is hand-written: run non-interactively, makemigrations emits
  DeleteModel+CreateModel and drops every price, subscription and
  due. Its two RemoveConstraints must come first, or SQLite's
  table-rebuild tries to render a constraint over a just-renamed
  column. Verified by round-tripping real rows through it.
- Plan gains duration_months / renewal_lead_days / grace_days /
  is_trial, with CheckConstraints and a matching clean() so the form
  reports an impossible plan instead of 500ing on IntegrityError.
- Existing dues keep their stored grace_until. Re-deriving it would
  put the date in the past for every open annual period and archive
  the entire paying customer base on the next --commit run.
- Trials take their length from the trial plan's own duration_months;
  start_trial() loses its trial_months argument.
- New BillingNotice service drives a club-facing warning: every level
  on the dashboard, and on every management page once urgent.
- send_billing_reminders emails club admins, once per escalation
  level so a daily cron is not a daily email. SMTP settings are
  env-driven and provider-agnostic; the backend defaults to console.
- Paying does not auto-restore an archived club -- the control panel
  surfaces a Reactivate prompt instead, since a club can also be
  archived by hand.

billing/admin.py

@@ -1,32 +1,32 @@
 from django.contrib import admin
 
-from .models import Due, DuePayment, Subscription, Tier, TierPrice
+from .models import Due, DuePayment, Plan, PlanPrice, Subscription
 
 
-class TierPriceInline(admin.TabularInline):
-    model = TierPrice
+class PlanPriceInline(admin.TabularInline):
+    model = PlanPrice
     extra = 0
 
 
-@admin.register(Tier)
-class TierAdmin(admin.ModelAdmin):
-    list_display = ["name", "is_active"]
-    list_filter = ["is_active"]
+@admin.register(Plan)
+class PlanAdmin(admin.ModelAdmin):
+    list_display = ["name", "duration_months", "renewal_lead_days", "grace_days", "is_trial", "is_active"]
+    list_filter = ["is_active", "is_trial"]
     search_fields = ["name"]
     prepopulated_fields = {"slug": ["name"]}
-    inlines = [TierPriceInline]
+    inlines = [PlanPriceInline]
 
 
-@admin.register(TierPrice)
-class TierPriceAdmin(admin.ModelAdmin):
-    list_display = ["tier", "amount", "active_from"]
-    list_filter = ["tier"]
+@admin.register(PlanPrice)
+class PlanPriceAdmin(admin.ModelAdmin):
+    list_display = ["plan", "amount", "active_from"]
+    list_filter = ["plan"]
 
 
 @admin.register(Subscription)
 class SubscriptionAdmin(admin.ModelAdmin):
-    list_display = ["club", "tier", "auto_renew", "auto_archive"]
-    list_filter = ["tier", "auto_renew", "auto_archive"]
+    list_display = ["club", "plan", "auto_renew", "auto_archive"]
+    list_filter = ["plan", "auto_renew", "auto_archive"]
     search_fields = ["club__name"]
 
 
@@ -38,11 +38,13 @@ class DuePaymentInline(admin.TabularInline):
 
 @admin.register(Due)
 class DueAdmin(admin.ModelAdmin):
-    list_display = ["club", "tier", "period_start", "period_end", "amount", "amount_paid", "status"]
-    list_filter = ["status", "tier"]
+    list_display = ["club", "plan", "period_start", "period_end", "grace_until", "amount", "amount_paid", "status"]
+    list_filter = ["status", "plan"]
     search_fields = ["club__name"]
     # Money is settled by the billing service, which re-derives these from the payments.
-    readonly_fields = ["amount_paid", "status", "paid_at"]
+    # period_end/grace_until are snapshots taken when the period opened -- editing a plan
+    # afterwards must not move them, and neither should a hand edit here.
+    readonly_fields = ["amount_paid", "status", "paid_at", "period_end", "grace_until"]
     inlines = [DuePaymentInline]
 
 

billing/management/commands/archive_overdue_clubs.py

@@ -27,7 +27,7 @@ class Command(MaintenanceAwareCommand):
 
         for due in overdue:
             days = (today - due.grace_until).days
-            self.stdout.write(f"{due.club} — {due.tier}, {due.balance} owed, grace ended {due.grace_until} ({days} day{'s'[: days != 1]} ago)")
+            self.stdout.write(f"{due.club} — {due.plan}, {due.balance} owed, grace ended {due.grace_until} ({days} day{'s'[: days != 1]} ago)")
 
         if not options["commit"]:
             self.stdout.write(self.style.WARNING(f"\nDry run: {len(overdue)} club(s) would be archived. Re-run with --commit to do it."))

billing/management/commands/renew_subscriptions.py

@@ -9,7 +9,6 @@ fires either. A missed renewal is silent, and silence is the expensive failure.
 
 from django.core.management.base import CommandError
 
-from billing.models import RENEWAL_LEAD_DAYS
 from billing.services import BillingError
 from billing.services.dues import renew, subscriptions_due_for_renewal
 from features.commands import MaintenanceAwareCommand
@@ -20,7 +19,7 @@ class Command(MaintenanceAwareCommand):
 
     def add_arguments(self, parser):
         parser.add_argument("--dry-run", action="store_true", help="Report what would be issued, and issue nothing.")
-        parser.add_argument("--lead-days", type=int, default=RENEWAL_LEAD_DAYS, help=f"Issue this many days before the period ends (default {RENEWAL_LEAD_DAYS}).")
+        parser.add_argument("--lead-days", type=int, default=None, help="Override every plan's own renewal lead. Left off, each plan uses its own.")
 
     def handle(self, *args, **options):
         due_for_renewal = subscriptions_due_for_renewal(lead_days=options["lead_days"])
@@ -34,13 +33,13 @@ class Command(MaintenanceAwareCommand):
             club = subscription.club
 
             if options["dry_run"]:
-                self.stdout.write(f"would renew {club} — {subscription.tier}, current period ends {subscription.latest_period_end or 'never opened'}")
+                self.stdout.write(f"would renew {club} — {subscription.plan}, current period ends {subscription.latest_period_end or 'never opened'}")
                 continue
 
             try:
                 due = renew(subscription)
             except BillingError as error:
-                # One unpriced tier must not stop every other club from being billed.
+                # One unpriced plan must not stop every other club from being billed.
                 failures.append(f"{club}: {error}")
                 self.stdout.write(self.style.ERROR(f"{club} — {error}"))
                 continue

billing/management/commands/send_billing_reminders.py

@@ -0,0 +1,64 @@
+"""Email club admins about platform fees they owe.
+
+Reports by default and only sends with --commit, the same posture as archive_overdue_clubs
+and for a related reason: this one mails paying customers, and a bad clock, a bad import or a
+rehearsal against production data should cost you a confusing dry-run listing rather than a
+mailshot you cannot recall.
+
+Idempotent across runs by design -- one reminder per due per escalation level, tracked on
+Due.last_reminder_level -- so a daily cron does not produce a daily email.
+"""
+
+from django.core.management.base import CommandError
+
+from billing.services.reminders import reminders_to_send, send_reminder
+from club.models import Club
+from features.commands import MaintenanceAwareCommand
+
+
+class Command(MaintenanceAwareCommand):
+    help = "Email club admins about outstanding platform fees (dry run unless --commit)."
+
+    def add_arguments(self, parser):
+        parser.add_argument("--commit", action="store_true", help="Actually send. Without this the command only reports.")
+        parser.add_argument("--force", action="store_true", help="Re-send even where a reminder already went out at this level.")
+
+    def handle(self, *args, **options):
+        clubs = Club.objects.active().select_related("subscription", "subscription__plan").order_by("name")
+        results = reminders_to_send(clubs, force=options["force"])
+
+        sendable = [result for result in results if result.sent]
+        skipped = [result for result in results if not result.sent]
+
+        if not results:
+            self.stdout.write(self.style.SUCCESS("Nothing owing. No reminders to send."))
+            return
+
+        for result in skipped:
+            style = self.style.WARNING if result.recipients else self.style.ERROR
+            self.stdout.write(style(f"{result.club} — skipped: {result.skipped_reason}"))
+
+        for result in sendable:
+            self.stdout.write(f"{result.notice.level:>7} · {result.club} — €{result.notice.amount_outstanding} owed, {result.notice.days_until_archive}d to archive → {', '.join(result.recipients)}")
+
+        if not options["commit"]:
+            self.stdout.write(self.style.WARNING(f"\nDry run: {len(sendable)} reminder(s) would be sent. Re-run with --commit to send them."))
+            return
+
+        failures = []
+        for result in sendable:
+            try:
+                send_reminder(result.club, result.notice, recipients=result.recipients)
+            except OSError as error:
+                # One bad address or a momentary SMTP failure must not stop the rest of the
+                # run: the clubs further down the list are the ones closest to being archived.
+                failures.append(f"{result.club}: {error}")
+                self.stdout.write(self.style.ERROR(f"{result.club} — {error}"))
+
+        sent = len(sendable) - len(failures)
+        self.stdout.write(self.style.SUCCESS(f"\nSent {sent} reminder(s)."))
+
+        if failures:
+            # Non-zero so cron mails you: a club that could not be warned is a club that gets
+            # archived without notice.
+            raise CommandError(f"{len(failures)} reminder(s) could not be sent:\n  " + "\n  ".join(failures))

billing/migrations/0004_rename_tier_to_plan.py

@@ -0,0 +1,34 @@
+"""Rename Tier -> Plan, and every field that pointed at it.
+
+Hand-written rather than generated. `makemigrations` only detects a rename by asking
+interactively; run non-interactively it emits DeleteModel + CreateModel instead, which drops
+every price, subscription and due in the table. RenameModel/RenameField preserve the data.
+
+The two RemoveConstraints have to come FIRST. Both constraints name fields this migration is
+about to rename (`tier`, `post_trial_tier`), and SQLite implements a rename by rebuilding the
+table -- which re-renders every constraint on it. Left in place, the rebuild tries to emit a
+constraint over a column that no longer exists under that name and dies with
+FieldDoesNotExist. 0005 adds them back under the new field names.
+
+Split from the field additions (0005) so this migration is pure renaming and can be read --
+and if necessary reversed -- without any other change mixed into it.
+"""
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("billing", "0003_due_is_trial_subscription_post_trial_tier_and_more"),
+    ]
+
+    operations = [
+        migrations.RemoveConstraint(model_name="tierprice", name="unique_tier_price_per_start_date"),
+        migrations.RemoveConstraint(model_name="subscription", name="trial_fields_set_together"),
+        migrations.RenameModel(old_name="Tier", new_name="Plan"),
+        migrations.RenameModel(old_name="TierPrice", new_name="PlanPrice"),
+        migrations.RenameField(model_name="planprice", old_name="tier", new_name="plan"),
+        migrations.RenameField(model_name="subscription", old_name="tier", new_name="plan"),
+        migrations.RenameField(model_name="subscription", old_name="post_trial_tier", new_name="post_trial_plan"),
+        migrations.RenameField(model_name="due", old_name="tier", new_name="plan"),
+    ]

billing/migrations/0005_alter_plan_options_alter_planprice_options_and_more.py

@@ -0,0 +1,96 @@
+# Generated by Django 6.0.6 on 2026-08-08 16:30
+
+import django.core.validators
+import django.db.models.deletion
+import django.db.models.expressions
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0004_rename_tier_to_plan'),
+        ('club', '0020_sponsor_logo_height_sponsor_logo_width'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='plan',
+            options={'ordering': ['name'], 'verbose_name': 'plan', 'verbose_name_plural': 'plans'},
+        ),
+        migrations.AlterModelOptions(
+            name='planprice',
+            options={'ordering': ['plan__name', '-active_from'], 'verbose_name': 'plan price', 'verbose_name_plural': 'plan prices'},
+        ),
+        migrations.AddField(
+            model_name='plan',
+            name='duration_months',
+            field=models.PositiveSmallIntegerField(default=12, help_text='How long one billing period runs.', validators=[django.core.validators.MinValueValidator(1)], verbose_name='duration (months)'),
+        ),
+        migrations.AddField(
+            model_name='plan',
+            name='grace_days',
+            field=models.PositiveSmallIntegerField(default=30, help_text='Days after a period starts before an unpaid club is archived.', verbose_name='grace (days)'),
+        ),
+        migrations.AddField(
+            model_name='plan',
+            name='is_trial',
+            field=models.BooleanField(default=False, help_text='Offered as a trial rather than as a paid plan. A trial converts to the plan chosen on the subscription once it runs out.', verbose_name='trial plan'),
+        ),
+        migrations.AddField(
+            model_name='plan',
+            name='renewal_lead_days',
+            field=models.PositiveSmallIntegerField(default=30, help_text="Raise the next period's invoice this many days before that period starts.", verbose_name='renewal lead (days)'),
+        ),
+        migrations.AlterField(
+            model_name='due',
+            name='grace_until',
+            field=models.DateField(blank=True, help_text='Past this date an unpaid club is archived. Measured from the period start, not its end.', verbose_name='grace until'),
+        ),
+        migrations.AlterField(
+            model_name='due',
+            name='plan',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='dues', to='billing.plan', verbose_name='plan'),
+        ),
+        migrations.AlterField(
+            model_name='plan',
+            name='is_active',
+            field=models.BooleanField(default=True, help_text='Inactive plans keep billing existing subscriptions but cannot be chosen for new ones.', verbose_name='active'),
+        ),
+        migrations.AlterField(
+            model_name='planprice',
+            name='plan',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='prices', to='billing.plan', verbose_name='plan'),
+        ),
+        migrations.AlterField(
+            model_name='subscription',
+            name='plan',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='subscriptions', to='billing.plan', verbose_name='plan'),
+        ),
+        migrations.AlterField(
+            model_name='subscription',
+            name='post_trial_plan',
+            field=models.ForeignKey(blank=True, help_text='The plan this club switches to automatically once its trial ends.', null=True, on_delete=django.db.models.deletion.PROTECT, related_name='+', to='billing.plan', verbose_name='post-trial plan'),
+        ),
+        migrations.AlterField(
+            model_name='subscription',
+            name='trial_ends_at',
+            field=models.DateField(blank=True, help_text='Set while this club is on a trial. The plan switches to the post-trial plan the next time a period is opened after this date.', null=True, verbose_name='trial ends at'),
+        ),
+        migrations.AddConstraint(
+            model_name='plan',
+            constraint=models.CheckConstraint(condition=models.Q(('renewal_lead_days__lt', django.db.models.expressions.CombinedExpression(models.F('duration_months'), '*', models.Value(28)))), name='renewal_lead_shorter_than_duration'),
+        ),
+        migrations.AddConstraint(
+            model_name='plan',
+            constraint=models.CheckConstraint(condition=models.Q(('grace_days__lte', django.db.models.expressions.CombinedExpression(models.F('duration_months'), '*', models.Value(28)))), name='grace_no_longer_than_duration'),
+        ),
+        migrations.AddConstraint(
+            model_name='planprice',
+            constraint=models.UniqueConstraint(fields=('plan', 'active_from'), name='unique_plan_price_per_start_date'),
+        ),
+        migrations.AddConstraint(
+            model_name='subscription',
+            constraint=models.CheckConstraint(condition=models.Q(models.Q(('post_trial_plan__isnull', True), ('trial_ends_at__isnull', True)), models.Q(('post_trial_plan__isnull', False), ('trial_ends_at__isnull', False)), _connector='OR'), name='trial_fields_set_together'),
+        ),
+    ]

billing/migrations/0006_due_last_reminder_level_due_last_reminder_sent_at.py

@@ -0,0 +1,23 @@
+# Generated by Django 6.0.6 on 2026-08-08 16:33
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('billing', '0005_alter_plan_options_alter_planprice_options_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='due',
+            name='last_reminder_level',
+            field=models.CharField(blank=True, editable=False, max_length=20, verbose_name='last reminder level'),
+        ),
+        migrations.AddField(
+            model_name='due',
+            name='last_reminder_sent_at',
+            field=models.DateTimeField(blank=True, editable=False, null=True, verbose_name='last reminder sent at'),
+        ),
+    ]

billing/models.py

@@ -11,9 +11,10 @@ from decimal import Decimal
 
 from dateutil import relativedelta
 from django.conf import settings
+from django.core.exceptions import ValidationError
 from django.core.validators import MinValueValidator
 from django.db import models
-from django.db.models import Q
+from django.db.models import F, Q
 from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 
@@ -21,39 +22,89 @@ from rosterchief.base import UUIDModel, unique_slugify
 
 ZERO = Decimal("0.00")
 
-# A club stays live for six weeks past the end of an unpaid period before it is archived.
-GRACE_DAYS = 45
+#: Conservative lower bound on the number of days in a month, used to express the plan's
+#: clock invariants as CheckConstraints — month arithmetic is not available in SQL, and
+#: under-counting is the safe direction for a guard rail.
+DAYS_PER_MONTH_FLOOR = 28
 
-# The next period is issued this long before the current one ends, so the invoice reaches the
-# club — and can be paid — before the old period lapses. Grace then only matters for genuine
-# non-payers, rather than for everyone who takes a fortnight to pay a bank transfer.
-RENEWAL_LEAD_DAYS = 30
-
-
-def add_one_year(day: date) -> date:
-    return day + relativedelta.relativedelta(years=1)
+# Defaults for a new plan, chosen to reproduce the annual billing the platform started with.
+DEFAULT_DURATION_MONTHS = 12
+DEFAULT_RENEWAL_LEAD_DAYS = 30
+DEFAULT_GRACE_DAYS = 30
 
 
 def add_months(day: date, months: int) -> date:
     return day + relativedelta.relativedelta(months=months)
 
 
-class Tier(UUIDModel):
-    """A price band. The price itself lives in TierPrice, which is dated."""
+class Plan(UUIDModel):
+    """What a club is billed on: a duration, a set of clocks, and a dated price.
+
+    The price itself lives in PlanPrice, which is dated. The three day/month numbers here
+    are the plan's *clocks*, and they are named for what they measure from — see BILLING.md
+    §3, because confusing them is the easy mistake:
+
+    * ``duration_months``   — how long a period runs, from its start.
+    * ``renewal_lead_days`` — how far BEFORE a period starts its invoice is raised.
+    * ``grace_days``        — how long AFTER a period starts it may remain unpaid.
+    """
 
     name = models.CharField(_("name"), max_length=255)
     slug = models.SlugField(_("slug"), max_length=255, unique=True, blank=True)
     description = models.TextField(_("description"), blank=True)
-    is_active = models.BooleanField(_("active"), default=True, help_text=_("Inactive tiers keep billing existing subscriptions but cannot be chosen for new ones."))
+    is_active = models.BooleanField(_("active"), default=True, help_text=_("Inactive plans keep billing existing subscriptions but cannot be chosen for new ones."))
+
+    duration_months = models.PositiveSmallIntegerField(_("duration (months)"), default=DEFAULT_DURATION_MONTHS, validators=[MinValueValidator(1)], help_text=_("How long one billing period runs."))
+    renewal_lead_days = models.PositiveSmallIntegerField(_("renewal lead (days)"), default=DEFAULT_RENEWAL_LEAD_DAYS, help_text=_("Raise the next period's invoice this many days before that period starts."))
+    grace_days = models.PositiveSmallIntegerField(_("grace (days)"), default=DEFAULT_GRACE_DAYS, help_text=_("Days after a period starts before an unpaid club is archived."))
+
+    is_trial = models.BooleanField(
+        _("trial plan"),
+        default=False,
+        help_text=_("Offered as a trial rather than as a paid plan. A trial converts to the plan chosen on the subscription once it runs out."),
+    )
 
     class Meta:
-        verbose_name = _("tier")
-        verbose_name_plural = _("tiers")
+        verbose_name = _("plan")
+        verbose_name_plural = _("plans")
         ordering = ["name"]
+        constraints = [
+            # Lead longer than the period itself would raise the next invoice before the
+            # current period had even started, and periods would run away from the calendar.
+            models.CheckConstraint(
+                condition=Q(renewal_lead_days__lt=F("duration_months") * DAYS_PER_MONTH_FLOOR),
+                name="renewal_lead_shorter_than_duration",
+            ),
+            # Grace longer than the period means the next period is issued while this one is
+            # still in grace: unpaid periods stack and the club is never archived.
+            models.CheckConstraint(
+                condition=Q(grace_days__lte=F("duration_months") * DAYS_PER_MONTH_FLOOR),
+                name="grace_no_longer_than_duration",
+            ),
+        ]
 
     def __str__(self):
         return self.name
 
+    def clean(self):
+        """The same two invariants the CheckConstraints enforce, as form errors.
+
+        Without this a form would hand the database an impossible plan and get back an
+        IntegrityError -- a 500 rather than "that lead is longer than the period".
+        """
+        if not self.duration_months:
+            return
+
+        period_days = self.duration_months * DAYS_PER_MONTH_FLOOR
+        errors = {}
+        if self.renewal_lead_days is not None and self.renewal_lead_days >= period_days:
+            errors["renewal_lead_days"] = _("Must be shorter than the period itself (under %(days)s days for this duration), or the next invoice would be raised before the current period starts.") % {"days": period_days}
+        if self.grace_days is not None and self.grace_days > period_days:
+            errors["grace_days"] = _("Must not be longer than the period itself (at most %(days)s days for this duration), or unpaid periods stack up and the club is never archived.") % {"days": period_days}
+
+        if errors:
+            raise ValidationError(errors)
+
     def save(self, *args, **kwargs):
         if not self.slug:
             self.slug = unique_slugify(self, self.name)
@@ -62,7 +113,7 @@ class Tier(UUIDModel):
     def price_on(self, day: date | None = None) -> Decimal | None:
         """The price in force on ``day`` — the latest one that had started by then.
 
-        None means the tier had no price yet on that date. Callers must treat that as
+        None means the plan had no price yet on that date. Callers must treat that as
         "cannot bill", never as free.
         """
         day = day or timezone.localdate()
@@ -71,40 +122,40 @@ class Tier(UUIDModel):
         return price.amount if price else None
 
 
-class TierPrice(UUIDModel):
-    """A dated price for a tier.
+class PlanPrice(UUIDModel):
+    """A dated price for a plan.
 
     Dated rather than keyed by year: a rate change is one new row with a future
     ``active_from``, and every period already opened keeps the amount it was billed at.
     """
 
-    tier = models.ForeignKey(Tier, on_delete=models.CASCADE, related_name="prices", verbose_name=_("tier"))
+    plan = models.ForeignKey(Plan, on_delete=models.CASCADE, related_name="prices", verbose_name=_("plan"))
     active_from = models.DateField(_("active from"), help_text=_("Periods opening on or after this date are billed at this amount."))
     amount = models.DecimalField(_("amount"), max_digits=10, decimal_places=2, validators=[MinValueValidator(ZERO)])
 
     class Meta:
-        verbose_name = _("tier price")
-        verbose_name_plural = _("tier prices")
-        ordering = ["tier__name", "-active_from"]
+        verbose_name = _("plan price")
+        verbose_name_plural = _("plan prices")
+        ordering = ["plan__name", "-active_from"]
         constraints = [
-            models.UniqueConstraint(fields=["tier", "active_from"], name="unique_tier_price_per_start_date"),
+            models.UniqueConstraint(fields=["plan", "active_from"], name="unique_plan_price_per_start_date"),
         ]
 
     def __str__(self):
-        return f"{self.tier} — {self.amount} from {self.active_from}"
+        return f"{self.plan} — {self.amount} from {self.active_from}"
 
 
 class Subscription(UUIDModel):
     """A club's current plan. The periods it is billed for are Dues."""
 
     club = models.OneToOneField("club.Club", on_delete=models.CASCADE, related_name="subscription", verbose_name=_("club"))
-    tier = models.ForeignKey(Tier, on_delete=models.PROTECT, related_name="subscriptions", verbose_name=_("tier"))
+    plan = models.ForeignKey(Plan, on_delete=models.PROTECT, related_name="subscriptions", verbose_name=_("plan"))
     auto_renew = models.BooleanField(_("auto renew"), default=True, help_text=_("Issue the next period automatically before this one ends. Off means you invoice this club by hand."))
     auto_archive = models.BooleanField(_("auto archive"), default=True, help_text=_("Archive this club when a period goes unpaid past its grace period."))
     notes = models.TextField(_("notes"), blank=True)
 
-    trial_ends_at = models.DateField(_("trial ends at"), null=True, blank=True, help_text=_("Set while this club is on a trial. The tier switches to post_trial_tier the next time a period is opened after this date."))
-    post_trial_tier = models.ForeignKey(Tier, on_delete=models.PROTECT, null=True, blank=True, related_name="+", verbose_name=_("post-trial tier"), help_text=_("The plan this club switches to automatically once its trial ends."))
+    trial_ends_at = models.DateField(_("trial ends at"), null=True, blank=True, help_text=_("Set while this club is on a trial. The plan switches to the post-trial plan the next time a period is opened after this date."))
+    post_trial_plan = models.ForeignKey(Plan, on_delete=models.PROTECT, null=True, blank=True, related_name="+", verbose_name=_("post-trial plan"), help_text=_("The plan this club switches to automatically once its trial ends."))
 
     class Meta:
         verbose_name = _("subscription")
@@ -114,21 +165,25 @@ class Subscription(UUIDModel):
             # Both set together or neither -- a trial with no target plan (or a target
             # plan with no trial end date) is a half-configured state nothing should read.
             models.CheckConstraint(
-                condition=Q(trial_ends_at__isnull=True, post_trial_tier__isnull=True) | Q(trial_ends_at__isnull=False, post_trial_tier__isnull=False),
+                condition=Q(trial_ends_at__isnull=True, post_trial_plan__isnull=True) | Q(trial_ends_at__isnull=False, post_trial_plan__isnull=False),
                 name="trial_fields_set_together",
             ),
         ]
 
     def __str__(self):
-        return f"{self.club} — {self.tier}"
+        return f"{self.club} — {self.plan}"
 
 
 class Due(UUIDModel):
     """One billing period for one club.
 
-    ``tier`` and ``amount`` are snapshots taken when the period opens, never read back
-    through the tier at display time: raise the price and last year's period must still say
+    ``plan`` and ``amount`` are snapshots taken when the period opens, never read back
+    through the plan at display time: raise the price and last year's period must still say
     what was actually charged. A live lookup would rewrite financial history.
+
+    ``period_end`` and ``grace_until`` are snapshots for the same reason. They are stored as
+    *dates* rather than as the plan's duration/grace *numbers*, which is what makes editing a
+    plan afterwards leave every period already running exactly where it was.
     """
 
     class Status(models.TextChoices):
@@ -142,20 +197,27 @@ class Due(UUIDModel):
     OWING = (Status.UNPAID, Status.PARTIAL)
 
     club = models.ForeignKey("club.Club", on_delete=models.CASCADE, related_name="dues", verbose_name=_("club"))
-    tier = models.ForeignKey(Tier, on_delete=models.PROTECT, related_name="dues", verbose_name=_("tier"))
+    plan = models.ForeignKey(Plan, on_delete=models.PROTECT, related_name="dues", verbose_name=_("plan"))
 
     amount = models.DecimalField(_("amount"), max_digits=10, decimal_places=2, validators=[MinValueValidator(ZERO)])
     amount_paid = models.DecimalField(_("amount paid"), max_digits=10, decimal_places=2, default=ZERO, help_text=_("Kept in step with the payments by the billing service."))
 
     period_start = models.DateField(_("period start"))
     period_end = models.DateField(_("period end"), blank=True)
-    grace_until = models.DateField(_("grace until"), blank=True, help_text=_("Past this date an unpaid club is archived."))
+    grace_until = models.DateField(_("grace until"), blank=True, help_text=_("Past this date an unpaid club is archived. Measured from the period start, not its end."))
 
     status = models.CharField(_("status"), max_length=20, choices=Status.choices, default=Status.UNPAID)
     paid_at = models.DateTimeField(_("paid at"), null=True, blank=True)
 
     is_trial = models.BooleanField(_("trial period"), default=False, help_text=_("This period was opened as a trial. A durable marker on the row itself -- the subscription's own trial fields are cleared once it converts."))
 
+    # Reminders are sent once per escalation level, not once per run: the cron job runs daily,
+    # and a club that owes money for a month must not get thirty identical emails. Storing the
+    # level last sent (rather than a date) means an escalation always gets through, and nothing
+    # else does. See billing/services/reminders.py.
+    last_reminder_level = models.CharField(_("last reminder level"), max_length=20, blank=True, editable=False)
+    last_reminder_sent_at = models.DateTimeField(_("last reminder sent at"), null=True, blank=True, editable=False)
+
     class Meta:
         verbose_name = _("due")
         verbose_name_plural = _("dues")
@@ -168,12 +230,14 @@ class Due(UUIDModel):
         return f"{self.club} — {self.period_start} to {self.period_end}"
 
     def save(self, *args, **kwargs):
-        # A period runs a rolling year from its start and the grace hangs off its end.
-        # Derived here so no caller can open a period without them.
+        # A period runs for the plan's duration from its start, and the grace runs from that
+        # same start -- NOT from the period end. Measured from the end, a club would get the
+        # whole unpaid period plus the grace on top (~410 days on an annual plan) before
+        # anything switched it off. Derived here so no caller can open a period without them.
         if not self.period_end:
-            self.period_end = add_one_year(self.period_start) - timedelta(days=1)
+            self.period_end = add_months(self.period_start, self.plan.duration_months) - timedelta(days=1)
         if not self.grace_until:
-            self.grace_until = self.period_end + timedelta(days=GRACE_DAYS)
+            self.grace_until = self.period_start + timedelta(days=self.plan.grace_days)
         super().save(*args, **kwargs)
 
     @property
@@ -184,11 +248,21 @@ class Due(UUIDModel):
     def is_owing(self) -> bool:
         return self.status in self.OWING
 
-    def is_in_grace(self, today: date | None = None) -> bool:
-        """The period has ended unpaid, but the club is not archivable yet."""
+    def is_issued_ahead(self, today: date | None = None) -> bool:
+        """Billed and owing, but the period it covers has not started yet.
+
+        The gentlest of the three owing states: the invoice was raised during the plan's
+        renewal lead window, and nothing is late yet.
+        """
         today = today or timezone.localdate()
 
-        return self.is_owing and self.period_end < today <= self.grace_until
+        return self.is_owing and today < self.period_start
+
+    def is_in_grace(self, today: date | None = None) -> bool:
+        """The period has started and is still unpaid, but is not archivable yet."""
+        today = today or timezone.localdate()
+
+        return self.is_owing and self.period_start <= today <= self.grace_until
 
     def is_overdue(self, today: date | None = None) -> bool:
         """Unpaid past grace — this is what makes a club archivable."""
@@ -196,6 +270,12 @@ class Due(UUIDModel):
 
         return self.is_owing and self.grace_until < today
 
+    def days_until_archive(self, today: date | None = None) -> int:
+        """Days left before this period makes the club archivable. Negative once past."""
+        today = today or timezone.localdate()
+
+        return (self.grace_until - today).days
+
 
 class DuePayment(UUIDModel):
     """Money received against a due.
@@ -230,7 +310,7 @@ class DuePayment(UUIDModel):
 class Invoice(UUIDModel):
     """The bill for one period.
 
-    Only the number and the issue date are stored: the money, the tier and the dates are
+    Only the number and the issue date are stored: the money, the plan and the dates are
     already frozen on the Due, so the PDF is rendered from those snapshots on demand. The
     number, though, must be stable and gapless — it is the thing an accountant reconciles
     against, so it is allocated once and never recomputed.

billing/services/dues.py

@@ -9,36 +9,37 @@ from django.db import transaction
 from django.db.models import DateField, OuterRef, Subquery, Sum
 from django.utils import timezone
 
-from billing.models import RENEWAL_LEAD_DAYS, ZERO, Due, DuePayment, Subscription, Tier, add_months
+from billing.models import ZERO, Due, DuePayment, Plan, Subscription, add_months
 from billing.services import BillingError
 from billing.services.invoices import issue_invoice
 
 
-def subscribe(club, tier: Tier, *, start: date | None = None, auto_archive: bool = True, auto_renew: bool = True) -> Subscription:
-    """Put a club on a tier and open its first period."""
-    subscription, _created = Subscription.objects.update_or_create(club=club, defaults={"tier": tier, "auto_archive": auto_archive, "auto_renew": auto_renew})
+def subscribe(club, plan: Plan, *, start: date | None = None, auto_archive: bool = True, auto_renew: bool = True) -> Subscription:
+    """Put a club on a plan and open its first period."""
+    subscription, _created = Subscription.objects.update_or_create(club=club, defaults={"plan": plan, "auto_archive": auto_archive, "auto_renew": auto_renew})
     open_period(club, start=start)
 
     return subscription
 
 
 @transaction.atomic
-def start_trial(club, trial_tier: Tier, *, post_trial_tier: Tier, trial_months: int, start: date | None = None, auto_renew: bool = True, auto_archive: bool = True) -> Due:
-    """Put a club on a short trial that switches itself to ``post_trial_tier`` the moment
-    the trial period is renewed -- see open_period()'s trial-conversion check.
+def start_trial(club, trial_plan: Plan, *, post_trial_plan: Plan, start: date | None = None, auto_renew: bool = True, auto_archive: bool = True) -> Due:
+    """Put a club on a trial that switches itself to ``post_trial_plan`` the moment the trial
+    period is renewed -- see open_period()'s trial-conversion check.
+
+    The trial's length is the trial plan's own ``duration_months``: a 1-month and a 3-month
+    trial are two plans, not one plan plus a number passed at the call site.
 
     Only for a club with no subscription yet -- converting an existing paying subscription
     into a trial is a different, deliberately unsupported operation for now.
     """
-    if trial_months <= 0:
-        raise BillingError("Trial length must be at least 1 month.")
     if getattr(club, "subscription", None) is not None:
         raise BillingError(f"{club} is already subscribed -- use Change plan instead.")
 
     start = start or next_period_start(club)
-    trial_end = add_months(start, trial_months) - timedelta(days=1)
+    trial_end = add_months(start, trial_plan.duration_months) - timedelta(days=1)
 
-    Subscription.objects.create(club=club, tier=trial_tier, trial_ends_at=trial_end, post_trial_tier=post_trial_tier, auto_renew=auto_renew, auto_archive=auto_archive)
+    Subscription.objects.create(club=club, plan=trial_plan, trial_ends_at=trial_end, post_trial_plan=post_trial_plan, auto_renew=auto_renew, auto_archive=auto_archive)
 
     return open_period(club, start=start, period_end=trial_end, is_trial=True)
 
@@ -57,34 +58,34 @@ def next_period_start(club, today: date | None = None) -> date:
 
 
 @transaction.atomic
-def open_period(club, *, start: date | None = None, tier: Tier | None = None, period_end: date | None = None, is_trial: bool = False) -> Due:
-    """Issue the next due for a club, snapshotting the tier and the price of the day."""
+def open_period(club, *, start: date | None = None, plan: Plan | None = None, period_end: date | None = None, is_trial: bool = False) -> Due:
+    """Issue the next due for a club, snapshotting the plan and the price of the day."""
     subscription = getattr(club, "subscription", None)
-    if tier is None:
+    if plan is None:
         if subscription is None:
-            raise BillingError(f"{club} has no tier: put it on a subscription before billing it.")
+            raise BillingError(f"{club} has no plan: put it on a subscription before billing it.")
         # A trial that has run its course: swap onto the pre-selected plan before billing
-        # the next period, rather than silently renewing the trial tier forever. Checked
+        # the next period, rather than silently renewing the trial plan forever. Checked
         # here (not in renew()) so it fires whether this period was opened by the renewal
         # command or by a platform admin clicking "Open period"/"Reactivate" by hand --
         # both call open_period() directly.
         if subscription.trial_ends_at is not None and (start or next_period_start(club)) > subscription.trial_ends_at:
-            subscription.tier = subscription.post_trial_tier
+            subscription.plan = subscription.post_trial_plan
             subscription.trial_ends_at = None
-            subscription.post_trial_tier = None
-            subscription.save(update_fields=["tier", "trial_ends_at", "post_trial_tier"])
-        tier = subscription.tier
+            subscription.post_trial_plan = None
+            subscription.save(update_fields=["plan", "trial_ends_at", "post_trial_plan"])
+        plan = subscription.plan
 
     start = start or next_period_start(club)
 
-    amount = tier.price_on(start)
+    amount = plan.price_on(start)
     if amount is None:
-        raise BillingError(f"{tier} has no price in force on {start:%d %b %Y}. Add one before opening the period.")
+        raise BillingError(f"{plan} has no price in force on {start:%d %b %Y}. Add one before opening the period.")
 
     if club.dues.filter(period_start=start).exists():
         raise BillingError(f"{club} is already billed for a period starting {start:%d %b %Y}.")
 
-    due = Due.objects.create(club=club, tier=tier, amount=amount, period_start=start, period_end=period_end, is_trial=is_trial)
+    due = Due.objects.create(club=club, plan=plan, amount=amount, period_start=start, period_end=period_end, is_trial=is_trial)
     if amount == ZERO:
         # Nothing is actually owed -- left at the default UNPAID, this would eventually
         # trip is_overdue() and get a free club archived for non-payment of nothing.
@@ -157,10 +158,14 @@ def owing_dues():
 
 
 def dues_in_grace(today: date | None = None):
-    """Period over, unpaid, not yet archivable."""
+    """Period started, unpaid, not yet archivable.
+
+    Bounded below by ``period_start``, not ``period_end``: grace now runs from the start of
+    the period, so a due is in grace *during* the period it covers, not after it.
+    """
     today = today or timezone.localdate()
 
-    return owing_dues().filter(period_end__lt=today, grace_until__gte=today)
+    return owing_dues().filter(period_start__lte=today, grace_until__gte=today)
 
 
 def dues_overdue(today: date | None = None):
@@ -176,7 +181,7 @@ def archivable_clubs(today: date | None = None):
     A club with auto_archive off is deliberately spared — that flag is how you keep a club
     you are negotiating with from being switched off overnight.
     """
-    return dues_overdue(today).filter(club__archived_at__isnull=True, club__subscription__auto_archive=True).select_related("club", "tier").order_by("club__name")
+    return dues_overdue(today).filter(club__archived_at__isnull=True, club__subscription__auto_archive=True).select_related("club", "plan").order_by("club__name")
 
 
 @transaction.atomic
@@ -191,27 +196,43 @@ def reactivate(club, *, start: date | None = None) -> Due:
     return open_period(club, start=start)
 
 
-def subscriptions_due_for_renewal(today: date | None = None, lead_days: int = RENEWAL_LEAD_DAYS):
+def subscriptions_due_for_renewal(today: date | None = None, lead_days: int | None = None):
     """Clubs whose next period should be issued now.
 
+    Each plan sets its own ``renewal_lead_days``: a single global lead is silently annual-only,
+    and on a 1-month plan a 30-day lead would issue the next period before the current one had
+    started. ``lead_days`` overrides every plan's own value — that is what makes a rehearsal or
+    a backfill possible, and it is what the command's --lead-days flag passes.
+
+    The per-plan comparison is done in Python rather than SQL. The function already
+    materialised its result as a list, and date arithmetic against a field value is not
+    portably expressible across SQLite and Postgres; at platform scale (tens to low hundreds of
+    clubs) this is one query plus a list walk.
+
     Idempotent by construction: a club that has just been renewed has a latest period ending a
-    year out, which is past the horizon, so it cannot be picked up twice. Running the job twice
-    a day is harmless.
+    full duration out, which is past its horizon, so it cannot be picked up twice. Running the
+    job twice a day is harmless.
 
     A subscription with no period at all (its only due was cancelled) counts too — a club on a
     plan and billed for nothing is the leak this whole job exists to close.
     """
     today = today or timezone.localdate()
-    horizon = today + timedelta(days=lead_days)
 
     latest_period_end = Subquery(
         Due.objects.filter(club=OuterRef("club")).exclude(status=Due.Status.CANCELLED).order_by("-period_end").values("period_end")[:1],
         output_field=DateField(),
     )
 
-    subscriptions = Subscription.objects.filter(auto_renew=True, club__archived_at__isnull=True).select_related("club", "tier").annotate(latest_period_end=latest_period_end).order_by("club__name")
+    subscriptions = Subscription.objects.filter(auto_renew=True, club__archived_at__isnull=True).select_related("club", "plan").annotate(latest_period_end=latest_period_end).order_by("club__name")
 
-    return [subscription for subscription in subscriptions if subscription.latest_period_end is None or subscription.latest_period_end <= horizon]
+    def is_due(subscription) -> bool:
+        if subscription.latest_period_end is None:
+            return True
+        lead = subscription.plan.renewal_lead_days if lead_days is None else lead_days
+
+        return subscription.latest_period_end <= today + timedelta(days=lead)
+
+    return [subscription for subscription in subscriptions if is_due(subscription)]
 
 
 def renew(subscription: Subscription) -> Due:

billing/services/invoices.py

@@ -1,6 +1,6 @@
 """Invoice PDFs.
 
-The PDF is rendered on demand from the Due's frozen snapshot (tier, amount, dates), so it
+The PDF is rendered on demand from the Due's frozen snapshot (plan, amount, dates), so it
 carries no state of its own beyond the number. Only the number is stored — an accountant
 reconciles against it, so it is allocated once, never recomputed.
 """

billing/services/notices.py

@@ -0,0 +1,77 @@
+"""What a club's own admins are told about money they owe the platform.
+
+Separate from dues.py because the audience is different: everything in dues.py is read by
+platform staff in the control panel, and this is the one piece of billing a *club* sees. It
+returns data, never rendered text — the wording lives in the template so it can be translated,
+and the same notice feeds both the on-screen banner and the reminder email.
+"""
+
+from dataclasses import dataclass
+from datetime import date
+from decimal import Decimal
+
+from django.utils import timezone
+
+from billing.models import Due
+
+#: Inside this many days of being archived, the notice stops being a warning and becomes a
+#: final one — which is also the point at which it follows the admin onto every page.
+URGENT_DAYS = 7
+
+INFO = "info"
+WARNING = "warning"
+ERROR = "error"
+
+
+@dataclass(frozen=True)
+class BillingNotice:
+    """The single most pressing thing a club owes, and how alarmed to be about it."""
+
+    level: str
+    due: Due
+    amount_outstanding: Decimal
+    period_start: date
+    grace_until: date
+    days_until_archive: int
+    #: False when the subscription has auto_archive off. Money is still owed and still worth
+    #: saying so, but the countdown must not claim an archiving that will never happen.
+    will_archive: bool
+
+    @property
+    def is_urgent(self) -> bool:
+        return self.level == ERROR
+
+
+def club_billing_notice(club, today: date | None = None) -> BillingNotice | None:
+    """The notice for ``club``, or None when it owes nothing.
+
+    Picks the due with the earliest ``grace_until`` when several are owing: that is the one
+    that will archive the club first, so it is the one worth shouting about.
+    """
+    today = today or timezone.localdate()
+
+    due = club.dues.filter(status__in=Due.OWING).select_related("plan").order_by("grace_until").first()
+    if due is None:
+        return None
+
+    subscription = getattr(club, "subscription", None)
+    will_archive = subscription.auto_archive if subscription is not None else False
+    days_left = due.days_until_archive(today)
+
+    if due.is_overdue(today):
+        level = ERROR
+    elif due.is_in_grace(today):
+        level = ERROR if days_left <= URGENT_DAYS else WARNING
+    else:
+        # Issued during the plan's renewal lead window: billed, but nothing is late yet.
+        level = INFO
+
+    return BillingNotice(
+        level=level,
+        due=due,
+        amount_outstanding=due.balance,
+        period_start=due.period_start,
+        grace_until=due.grace_until,
+        days_until_archive=days_left,
+        will_archive=will_archive,
+    )

billing/services/reminders.py

@@ -0,0 +1,98 @@
+"""Emailing a club's admins about money it owes the platform.
+
+Built on the same BillingNotice the on-screen banner uses (notices.py), so the email and the
+banner can never disagree about how much is owed or how long is left.
+
+**Sent once per escalation level, not once per run.** The command is on a daily cron; a club
+that owes money for a month must not receive thirty identical emails. ``Due.last_reminder_level``
+records the level last mailed, so an escalation (info -> warning -> error) always gets through
+and a repeat of the same level never does.
+"""
+
+from dataclasses import dataclass
+
+from django.conf import settings
+from django.core.mail import EmailMultiAlternatives
+from django.template.loader import render_to_string
+from django.utils import timezone
+from django.utils.translation import gettext as _
+
+from billing.services.notices import BillingNotice, club_billing_notice
+from club.models import ClubRole
+
+
+@dataclass(frozen=True)
+class ReminderResult:
+    club: object
+    notice: BillingNotice
+    recipients: list[str]
+    sent: bool
+    skipped_reason: str = ""
+
+
+def admin_emails(club) -> list[str]:
+    """Every club admin we can actually reach, de-duplicated and order-stable.
+
+    A club with admins but no email addresses returns empty — the caller reports that rather
+    than silently counting it as reminded.
+    """
+    roles = ClubRole.objects.filter(club=club, role=ClubRole.Roles.ADMIN).select_related("member", "member__user").order_by("member__last_name", "member__first_name")
+
+    seen, emails = set(), []
+    for role in roles:
+        email = role.member.contact_email
+        if email and email not in seen:
+            seen.add(email)
+            emails.append(email)
+
+    return emails
+
+
+def needs_reminder(due, notice: BillingNotice) -> bool:
+    """True when this due has not yet been mailed at its current level."""
+    return due.last_reminder_level != notice.level
+
+
+def send_reminder(club, notice: BillingNotice, *, recipients: list[str]) -> None:
+    """Render and send one reminder, then record the level so it is not repeated."""
+    context = {
+        "club": club,
+        "notice": notice,
+        "due": notice.due,
+        "billing_contact": settings.BILLING_CONTACT_EMAIL,
+    }
+    subject = render_to_string("billing/email/reminder_subject.txt", context).strip()
+    text_body = render_to_string("billing/email/reminder.txt", context)
+
+    message = EmailMultiAlternatives(subject=subject, body=text_body, from_email=settings.DEFAULT_FROM_EMAIL, to=recipients)
+    message.send(fail_silently=False)
+
+    notice.due.last_reminder_level = notice.level
+    notice.due.last_reminder_sent_at = timezone.now()
+    notice.due.save(update_fields=["last_reminder_level", "last_reminder_sent_at", "modified"])
+
+
+def reminders_to_send(clubs, today=None, *, force: bool = False) -> list[ReminderResult]:
+    """Work out who would be reminded, without sending anything.
+
+    Returned whether or not each one is actually sendable, so the command can report a club
+    with no reachable admin instead of skipping it in silence — an unreachable club is exactly
+    the one that gets archived without ever having been told.
+    """
+    results = []
+    for club in clubs:
+        notice = club_billing_notice(club, today)
+        if notice is None:
+            continue
+
+        recipients = admin_emails(club)
+        if not recipients:
+            results.append(ReminderResult(club=club, notice=notice, recipients=[], sent=False, skipped_reason=_("no club admin with an email address")))
+            continue
+        if not force and not needs_reminder(notice.due, notice):
+            results.append(ReminderResult(club=club, notice=notice, recipients=recipients, sent=False, skipped_reason=_("already reminded at this level")))
+            continue
+
+        results.append(ReminderResult(club=club, notice=notice, recipients=recipients, sent=True))
+
+    return results

billing/templates/billing/email/reminder.txt

@@ -0,0 +1,14 @@
+{% load i18n %}{% blocktrans with club=club.name %}Hello,
+
+This is a reminder about the RosterChief platform fees for {{ club }}.{% endblocktrans %}
+
+{% blocktrans with amount=notice.amount_outstanding %}Outstanding: EUR {{ amount }}{% endblocktrans %}
+{% blocktrans with start=due.period_start|date:"j M Y" end=due.period_end|date:"j M Y" %}Period:      {{ start }} to {{ end }}{% endblocktrans %}
+{% if due.invoice %}{% blocktrans with number=due.invoice.number %}Invoice:     {{ number }}{% endblocktrans %}
+{% endif %}
+{% if notice.will_archive %}{% if notice.days_until_archive < 0 %}{% trans "This club is now past its payment deadline and is due to be archived. While archived, nobody can sign in and the club's site stops resolving. No data is deleted, and access is restored as soon as payment is received." %}{% else %}{% blocktrans count days=notice.days_until_archive %}If we do not receive payment within {{ days }} day, this club will be archived. While archived, nobody can sign in and the club's site stops resolving. No data is deleted.{% plural %}If we do not receive payment within {{ days }} days, this club will be archived. While archived, nobody can sign in and the club's site stops resolving. No data is deleted.{% endblocktrans %}{% endif %}{% else %}{% trans "Please settle this to keep your account in good standing." %}{% endif %}
+
+{% blocktrans with contact=billing_contact %}If you have already paid, or you think this is a mistake, reply to {{ contact }} and we will sort it out.{% endblocktrans %}
+
+{% trans "Thank you," %}
+{% trans "RosterChief" %}

billing/templates/billing/email/reminder_subject.txt

@@ -0,0 +1 @@
+{% load i18n %}{% if notice.level == 'error' %}{% blocktrans with club=club.name %}Action required: {{ club }} is about to be archived{% endblocktrans %}{% else %}{% blocktrans with club=club.name %}Platform fees are due for {{ club }}{% endblocktrans %}{% endif %}

billing/templates/billing/invoice.html

@@ -72,7 +72,7 @@
             <tbody>
                 <tr>
                     <td>
-                        <strong>{{ due.tier.name }}</strong> — platform subscription
+                        <strong>{{ due.plan.name }}</strong> — platform subscription
                         <div class="muted">{{ due.period_start|date:"j M Y" }} to {{ due.period_end|date:"j M Y" }}</div>
                     </td>
                     <td class="right">€{{ due.amount|floatformat:2 }}</td>

billing/tests.py

@@ -4,64 +4,78 @@ from decimal import Decimal
 from io import StringIO
 from unittest import mock
 
+from django.core import mail
+from django.core.exceptions import ValidationError
 from django.core.management import call_command
 from django.core.management.base import CommandError
+from django.db.utils import IntegrityError
 from django.test import TestCase
 from django.utils import timezone
 
-from club.models import Club
+from authentication.models import User
+from club.models import Club, ClubRole
+from members.models import Member
 
-from .models import GRACE_DAYS, Due, Invoice, Subscription, Tier, TierPrice, add_one_year
+from .models import DEFAULT_DURATION_MONTHS, DEFAULT_GRACE_DAYS, DEFAULT_RENEWAL_LEAD_DAYS, Due, Invoice, Plan, PlanPrice, Subscription, add_months
 from .services import BillingError
 from .services.dues import archivable_clubs, dues_in_grace, dues_overdue, next_period_start, open_period, reactivate, record_payment, remove_payment, renew, start_trial, subscribe, subscriptions_due_for_renewal, waive
 from .services.invoices import invoice_pdf, issue_invoice, render_pdf
+from .services.notices import club_billing_notice
+from .services.reminders import admin_emails, reminders_to_send, send_reminder
 
 
 class BillingTestBase(TestCase):
     def setUp(self):
         self.today = timezone.localdate()
         self.club = Club.objects.create(name="Ajax United")
-        self.tier = Tier.objects.create(name="Standard")
+        self.plan = Plan.objects.create(name="Standard")
         # Priced well back, so a backdated (lapsed) period still has a price in force —
         # opening one before any price existed is refused, and rightly so.
-        TierPrice.objects.create(tier=self.tier, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("500.00"))
+        PlanPrice.objects.create(plan=self.plan, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("500.00"))
 
     def bill(self, start=None, club=None):
-        return open_period(club or self.club, start=start, tier=self.tier)
+        return open_period(club or self.club, start=start, plan=self.plan)
 
 
-class TierPriceTests(BillingTestBase):
+class PlanPriceTests(BillingTestBase):
     def test_the_price_in_force_is_the_latest_one_that_has_started(self):
-        TierPrice.objects.create(tier=self.tier, active_from=self.today, amount=Decimal("600.00"))
+        PlanPrice.objects.create(plan=self.plan, active_from=self.today, amount=Decimal("600.00"))
 
-        self.assertEqual(self.tier.price_on(self.today - datetime.timedelta(days=1)), Decimal("500.00"))
-        self.assertEqual(self.tier.price_on(self.today), Decimal("600.00"))
+        self.assertEqual(self.plan.price_on(self.today - datetime.timedelta(days=1)), Decimal("500.00"))
+        self.assertEqual(self.plan.price_on(self.today), Decimal("600.00"))
 
     def test_a_future_price_does_not_apply_yet(self):
-        TierPrice.objects.create(tier=self.tier, active_from=self.today + datetime.timedelta(days=30), amount=Decimal("600.00"))
+        PlanPrice.objects.create(plan=self.plan, active_from=self.today + datetime.timedelta(days=30), amount=Decimal("600.00"))
 
-        self.assertEqual(self.tier.price_on(self.today), Decimal("500.00"))
+        self.assertEqual(self.plan.price_on(self.today), Decimal("500.00"))
 
-    def test_a_tier_with_no_price_yet_cannot_be_billed(self):
+    def test_a_plan_with_no_price_yet_cannot_be_billed(self):
         # None must never be read as free.
-        empty = Tier.objects.create(name="Enterprise")
+        empty = Plan.objects.create(name="Enterprise")
 
         self.assertIsNone(empty.price_on(self.today))
 
         with self.assertRaises(BillingError):
-            open_period(self.club, tier=empty)
+            open_period(self.club, plan=empty)
 
 
 class PeriodTests(BillingTestBase):
-    def test_a_period_runs_a_rolling_year_with_a_grace_tail(self):
+    def test_a_period_runs_for_the_plans_duration(self):
         due = self.bill(start=datetime.date(2026, 3, 1))
 
         self.assertEqual(due.period_end, datetime.date(2027, 2, 28))
-        self.assertEqual(due.grace_until, due.period_end + datetime.timedelta(days=GRACE_DAYS))
+
+    def test_grace_is_measured_from_the_period_start_not_its_end(self):
+        # The whole point of the redesign: measured from the end, an annual club would get
+        # ~410 days of unpaid use before anything switched it off.
+        due = self.bill(start=datetime.date(2026, 3, 1))
+
+        self.assertEqual(due.grace_until, datetime.date(2026, 3, 1) + datetime.timedelta(days=DEFAULT_GRACE_DAYS))
+        self.assertLess(due.grace_until, due.period_end)
 
     def test_a_leap_day_period_does_not_explode(self):
         # 29 February has no counterpart in a common year.
-        self.assertEqual(add_one_year(datetime.date(2028, 2, 29)), datetime.date(2029, 2, 28))
+        self.assertEqual(add_months(datetime.date(2028, 2, 29), 12), datetime.date(2029, 2, 28))
 
     def test_the_next_period_continues_from_the_last_one(self):
         # Not from today: a club that pays two months late has still used those two months,
@@ -75,7 +89,7 @@ class PeriodTests(BillingTestBase):
 
     def test_the_amount_is_snapshotted_at_the_price_of_the_day(self):
         due = self.bill()
-        TierPrice.objects.create(tier=self.tier, active_from=self.today + datetime.timedelta(days=1), amount=Decimal("900.00"))
+        PlanPrice.objects.create(plan=self.plan, active_from=self.today + datetime.timedelta(days=1), amount=Decimal("900.00"))
         due.refresh_from_db()
 
         # Raising the rate must not rewrite what was already billed.
@@ -87,16 +101,16 @@ class PeriodTests(BillingTestBase):
         with self.assertRaises(BillingError):
             self.bill(start=self.today)
 
-    def test_a_club_with_no_tier_cannot_be_billed(self):
+    def test_a_club_with_no_plan_cannot_be_billed(self):
         with self.assertRaises(BillingError):
             open_period(Club.objects.create(name="Feyenoord"))
 
-    def test_subscribing_puts_a_club_on_a_tier_and_opens_a_period(self):
+    def test_subscribing_puts_a_club_on_a_plan_and_opens_a_period(self):
         club = Club.objects.create(name="Feyenoord")
 
-        subscribe(club, self.tier)
+        subscribe(club, self.plan)
 
-        self.assertEqual(Subscription.objects.get(club=club).tier, self.tier)
+        self.assertEqual(Subscription.objects.get(club=club).plan, self.plan)
         self.assertEqual(club.dues.count(), 1)
 
 
@@ -175,15 +189,24 @@ class PaymentTests(BillingTestBase):
 
 
 class GraceAndArchiveTests(BillingTestBase):
-    LAPSED = 365 + GRACE_DAYS + 10
+    LAPSED = DEFAULT_GRACE_DAYS + 10
 
-    def test_a_period_past_its_end_but_inside_grace_is_in_grace(self):
-        due = self.bill(start=self.today - datetime.timedelta(days=370))
+    def test_a_started_but_unpaid_period_inside_grace_is_in_grace(self):
+        # Grace runs from the period START now, so this is a period that began a few days
+        # ago and has not been paid -- not one that has already run its full length.
+        due = self.bill(start=self.today - datetime.timedelta(days=5))
 
         self.assertTrue(due.is_in_grace(self.today))
         self.assertFalse(due.is_overdue(self.today))
         self.assertIn(due, dues_in_grace(self.today))
 
+    def test_a_period_issued_ahead_of_its_start_is_not_yet_in_grace(self):
+        due = self.bill(start=self.today + datetime.timedelta(days=10))
+
+        self.assertTrue(due.is_issued_ahead(self.today))
+        self.assertFalse(due.is_in_grace(self.today))
+        self.assertFalse(due.is_overdue(self.today))
+
     def test_a_period_past_grace_is_overdue(self):
         due = self.bill(start=self.today - datetime.timedelta(days=self.LAPSED))
 
@@ -200,19 +223,19 @@ class GraceAndArchiveTests(BillingTestBase):
         self.assertNotIn(due, dues_overdue(self.today))
 
     def test_an_overdue_club_is_archivable(self):
-        subscribe(self.club, self.tier, start=self.today - datetime.timedelta(days=self.LAPSED))
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=self.LAPSED))
 
         self.assertEqual(archivable_clubs(self.today).count(), 1)
 
     def test_a_club_that_opted_out_is_never_archived(self):
         # auto_archive off is how you stop a club you are negotiating with from being
         # switched off overnight.
-        subscribe(self.club, self.tier, start=self.today - datetime.timedelta(days=self.LAPSED), auto_archive=False)
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=self.LAPSED), auto_archive=False)
 
         self.assertEqual(archivable_clubs(self.today).count(), 0)
 
     def test_an_already_archived_club_is_not_archived_again(self):
-        subscribe(self.club, self.tier, start=self.today - datetime.timedelta(days=self.LAPSED))
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=self.LAPSED))
         self.club.archive()
 
         self.assertEqual(archivable_clubs(self.today).count(), 0)
@@ -221,7 +244,7 @@ class GraceAndArchiveTests(BillingTestBase):
 class ArchiveCommandTests(BillingTestBase):
     def setUp(self):
         super().setUp()
-        subscribe(self.club, self.tier, start=self.today - datetime.timedelta(days=365 + GRACE_DAYS + 10))
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=DEFAULT_GRACE_DAYS + 10))
 
     def run_command(self, *args):
         out = StringIO()
@@ -253,9 +276,9 @@ class ArchiveCommandTests(BillingTestBase):
 class ReactivationTests(BillingTestBase):
     def setUp(self):
         super().setUp()
-        # Through subscribe(), not open_period(): reactivating reads the club's tier off its
+        # Through subscribe(), not open_period(): reactivating reads the club's plan off its
         # subscription, and a club billed without one cannot be re-billed later.
-        subscribe(self.club, self.tier, start=self.today - datetime.timedelta(days=400))
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=400))
         self.first = self.club.dues.first()
         self.club.archive()
 
@@ -282,7 +305,7 @@ class InvoiceTests(BillingTestBase):
         # Unlike the shop's per-club order numbers: these are OUR invoices, and one sequence
         # covers every club we bill.
         first = self.bill(start=self.today).invoice
-        second = open_period(Club.objects.create(name="Feyenoord"), tier=self.tier).invoice
+        second = open_period(Club.objects.create(name="Feyenoord"), plan=self.plan).invoice
 
         year = timezone.now().year
         self.assertEqual(first.number, f"INV-{year}-00001")
@@ -330,12 +353,12 @@ class ModelStringTests(BillingTestBase):
         due = self.bill()
         payment = record_payment(due, Decimal("10.00"))
 
-        self.assertEqual(str(self.tier), "Standard")
-        self.assertIn("500.00", str(self.tier.prices.first()))
+        self.assertEqual(str(self.plan), "Standard")
+        self.assertIn("500.00", str(self.plan.prices.first()))
         self.assertIn("Ajax United", str(due))
         self.assertIn("10.00", str(payment))
         self.assertIn("INV-", str(due.invoice))
-        self.assertIn("Standard", str(subscribe(Club.objects.create(name="PSV"), self.tier)))
+        self.assertIn("Standard", str(subscribe(Club.objects.create(name="PSV"), self.plan)))
 
 
 class RenewalTests(BillingTestBase):
@@ -346,7 +369,7 @@ class RenewalTests(BillingTestBase):
     def ending_in(self, days, **kwargs):
         """A club whose current period ends `days` from now."""
         club = Club.objects.create(name=f"Club {days}")
-        subscribe(club, self.tier, start=self.today - datetime.timedelta(days=365 - days), **kwargs)
+        subscribe(club, self.plan, start=self.today - datetime.timedelta(days=365 - days), **kwargs)
         return club
 
     def test_a_club_nearing_its_end_date_is_picked_up(self):
@@ -395,7 +418,7 @@ class RenewalTests(BillingTestBase):
 
     def test_the_new_period_is_billed_at_the_price_in_force_then(self):
         club = self.ending_in(20)
-        TierPrice.objects.create(tier=self.tier, active_from=self.today, amount=Decimal("900.00"))
+        PlanPrice.objects.create(plan=self.plan, active_from=self.today, amount=Decimal("900.00"))
 
         due = renew(club.subscription)
 
@@ -427,15 +450,15 @@ class RenewalTests(BillingTestBase):
 
         self.assertEqual(club.dues.count(), 2)
 
-    def test_an_unpriced_tier_fails_loudly_without_stopping_the_others(self):
+    def test_an_unpriced_plan_fails_loudly_without_stopping_the_others(self):
         priced = self.ending_in(20)
         broken = Club.objects.create(name="Unpriced FC")
-        subscribe(broken, self.tier, start=self.today - datetime.timedelta(days=350))
+        subscribe(broken, self.plan, start=self.today - datetime.timedelta(days=350))
         # Its next period starts beyond the last price... by removing every price, it cannot bill.
-        TierPrice.objects.all().delete()
-        cheap = Tier.objects.create(name="Cheap")
-        TierPrice.objects.create(tier=cheap, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("100.00"))
-        priced.subscription.tier = cheap
+        PlanPrice.objects.all().delete()
+        cheap = Plan.objects.create(name="Cheap")
+        PlanPrice.objects.create(plan=cheap, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("100.00"))
+        priced.subscription.plan = cheap
         priced.subscription.save()
 
         with self.assertRaises(CommandError):
@@ -446,7 +469,7 @@ class RenewalTests(BillingTestBase):
 
     def test_a_subscription_with_no_period_at_all_is_renewed(self):
         club = Club.objects.create(name="Orphan FC")
-        Subscription.objects.create(club=club, tier=self.tier)
+        Subscription.objects.create(club=club, plan=self.plan)
 
         self.assertIn(club, [s.club for s in subscriptions_due_for_renewal()])
 
@@ -469,7 +492,7 @@ class RenewedButUnpaidTests(BillingTestBase):
         """A club on its first, PAID period — far enough back that a renewal from its end is
         itself already past grace, so only the renewal's payment state decides the outcome."""
         club = Club.objects.create(name="Renewed FC")
-        subscribe(club, self.tier, start=self.today - datetime.timedelta(days=800))
+        subscribe(club, self.plan, start=self.today - datetime.timedelta(days=800))
         first = club.dues.first()
         record_payment(first, first.amount)  # the FIRST period is settled; only the renewal is in question
         return club
@@ -498,66 +521,281 @@ class TrialTests(BillingTestBase):
 
     def setUp(self):
         super().setUp()
-        self.trial_tier = Tier.objects.create(name="Trial")
-        TierPrice.objects.create(tier=self.trial_tier, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("50.00"))
+        # A trial is a plan whose own duration_months IS the trial length -- there is no
+        # trial_months argument any more.
+        self.trial_plan = Plan.objects.create(name="Trial", duration_months=2, is_trial=True, grace_days=14, renewal_lead_days=7)
+        PlanPrice.objects.create(plan=self.trial_plan, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("50.00"))
 
     def test_start_trial_creates_a_short_trial_period(self):
-        due = start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=2)
+        due = start_trial(self.club, self.trial_plan, post_trial_plan=self.plan)
 
         subscription = self.club.subscription
-        self.assertEqual(subscription.tier, self.trial_tier)
-        self.assertEqual(subscription.post_trial_tier, self.tier)
+        self.assertEqual(subscription.plan, self.trial_plan)
+        self.assertEqual(subscription.post_trial_plan, self.plan)
         self.assertEqual(subscription.trial_ends_at, due.period_end)
         self.assertTrue(due.is_trial)
         # Roughly 2 months, nowhere near the standard ~1-year period.
         self.assertLess((due.period_end - due.period_start).days, 65)
 
     def test_start_trial_refuses_if_already_subscribed(self):
-        subscribe(self.club, self.tier)
+        subscribe(self.club, self.plan)
 
         with self.assertRaises(BillingError):
-            start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=2)
+            start_trial(self.club, self.trial_plan, post_trial_plan=self.plan)
 
-    def test_start_trial_refuses_a_non_positive_length(self):
-        with self.assertRaises(BillingError):
-            start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=0)
+    def test_the_trials_length_comes_from_its_plan(self):
+        due = start_trial(self.club, self.trial_plan, post_trial_plan=self.plan)
 
-    def test_renewing_after_the_trial_switches_to_the_post_trial_tier(self):
-        start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=2)
+        self.assertEqual(due.period_end, add_months(due.period_start, 2) - datetime.timedelta(days=1))
+
+    def test_renewing_after_the_trial_switches_to_the_post_trial_plan(self):
+        start_trial(self.club, self.trial_plan, post_trial_plan=self.plan)
 
         due = renew(self.club.subscription)
 
         self.club.refresh_from_db()
-        self.assertEqual(self.club.subscription.tier, self.tier)
+        self.assertEqual(self.club.subscription.plan, self.plan)
         self.assertIsNone(self.club.subscription.trial_ends_at)
-        self.assertIsNone(self.club.subscription.post_trial_tier)
-        self.assertEqual(due.tier, self.tier)
+        self.assertIsNone(self.club.subscription.post_trial_plan)
+        self.assertEqual(due.plan, self.plan)
         self.assertFalse(due.is_trial)
         self.assertEqual(due.amount, Decimal("500.00"))
 
-    def test_manually_opening_the_next_period_also_switches_tier(self):
+    def test_manually_opening_the_next_period_also_switches_plan(self):
         # Same conversion must fire via the control panel's "Open period" button, which
         # calls open_period() directly rather than renew().
-        start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=2)
+        start_trial(self.club, self.trial_plan, post_trial_plan=self.plan)
 
         open_period(self.club)
 
         self.club.refresh_from_db()
-        self.assertEqual(self.club.subscription.tier, self.tier)
+        self.assertEqual(self.club.subscription.plan, self.plan)
 
     def test_a_trial_nearing_its_end_is_picked_up_for_renewal(self):
-        start_trial(self.club, self.trial_tier, post_trial_tier=self.tier, trial_months=2, start=self.today - datetime.timedelta(days=50))
+        # Inside the TRIAL PLAN's own 7-day lead, not the 30-day one an annual plan uses:
+        # a 2-month trial renewed a month early would be renewed before it had begun.
+        start_trial(self.club, self.trial_plan, post_trial_plan=self.plan, start=self.today - datetime.timedelta(days=57))
 
         self.assertIn(self.club, [s.club for s in subscriptions_due_for_renewal()])
 
-    def test_a_zero_amount_trial_is_created_already_paid(self):
-        free_tier = Tier.objects.create(name="Free Trial")
-        TierPrice.objects.create(tier=free_tier, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("0.00"))
+    def test_a_trial_outside_its_own_lead_window_is_not_yet_renewed(self):
+        # Same trial 7 days earlier in its life: an annual plan's 30-day lead would have
+        # picked this up, and the per-plan lead is exactly what stops that.
+        start_trial(self.club, self.trial_plan, post_trial_plan=self.plan, start=self.today - datetime.timedelta(days=40))
 
-        due = start_trial(self.club, free_tier, post_trial_tier=self.tier, trial_months=2)
+        self.assertNotIn(self.club, [s.club for s in subscriptions_due_for_renewal()])
+
+    def test_a_zero_amount_trial_is_created_already_paid(self):
+        free_plan = Plan.objects.create(name="Free Trial")
+        PlanPrice.objects.create(plan=free_plan, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("0.00"))
+
+        due = start_trial(self.club, free_plan, post_trial_plan=self.plan)
 
         self.assertEqual(due.status, Due.Status.PAID)
         self.assertIsNotNone(due.paid_at)
         far_future = due.grace_until + datetime.timedelta(days=100)
         self.assertNotIn(due, dues_overdue(far_future))
         self.assertNotIn(self.club, [d.club for d in archivable_clubs(far_future)])
+
+
+class PlanClockTests(BillingTestBase):
+    """The three per-plan clocks, and the constraints that keep them sane -- see BILLING.md §3."""
+
+    def make_plan(self, **kwargs):
+        # A short plan cannot keep the annual defaults -- 30 days' lead on a 1-month period is
+        # exactly what the constraints forbid, so scale them down with the duration.
+        months = kwargs.get("duration_months", DEFAULT_DURATION_MONTHS)
+        defaults = {"name": f"Plan {Plan.objects.count()}", "renewal_lead_days": min(DEFAULT_RENEWAL_LEAD_DAYS, months * 7), "grace_days": min(DEFAULT_GRACE_DAYS, months * 14)}
+        plan = Plan.objects.create(**defaults | kwargs)
+        PlanPrice.objects.create(plan=plan, active_from=self.today - datetime.timedelta(days=1200), amount=Decimal("10.00"))
+        return plan
+
+    def test_a_monthly_plan_gets_a_one_month_period(self):
+        plan = self.make_plan(duration_months=1)
+
+        due = open_period(self.club, plan=plan, start=datetime.date(2026, 3, 1))
+
+        self.assertEqual(due.period_end, datetime.date(2026, 3, 31))
+
+    def test_a_quarterly_plan_gets_a_three_month_period(self):
+        plan = self.make_plan(duration_months=3)
+
+        due = open_period(self.club, plan=plan, start=datetime.date(2026, 3, 1))
+
+        self.assertEqual(due.period_end, datetime.date(2026, 5, 31))
+
+    def test_grace_days_are_per_plan(self):
+        plan = self.make_plan(duration_months=1, grace_days=14)
+
+        due = open_period(self.club, plan=plan, start=datetime.date(2026, 3, 1))
+
+        self.assertEqual(due.grace_until, datetime.date(2026, 3, 15))
+
+    def test_editing_a_plans_grace_does_not_move_an_open_period(self):
+        # grace_until is a stored snapshot for the same reason `amount` is: repricing the
+        # plan must not silently re-date an archiving already in flight.
+        plan = self.make_plan(grace_days=30)
+        due = open_period(self.club, plan=plan, start=self.today)
+        original = due.grace_until
+
+        plan.grace_days = 1
+        plan.save(update_fields=["grace_days"])
+        due.refresh_from_db()
+
+        self.assertEqual(due.grace_until, original)
+
+    def test_a_lead_longer_than_the_period_is_rejected(self):
+        with self.assertRaises(IntegrityError):
+            Plan.objects.create(name="Runaway", duration_months=1, renewal_lead_days=90)
+
+    def test_grace_longer_than_the_period_is_rejected(self):
+        with self.assertRaises(IntegrityError):
+            Plan.objects.create(name="Never archives", duration_months=1, grace_days=90)
+
+    def test_full_clean_reports_an_impossible_lead_as_a_form_error(self):
+        # Not an IntegrityError/500: a platform admin typing this into the plan form should
+        # be told which field is wrong.
+        plan = Plan(name="Runaway", duration_months=1, renewal_lead_days=90, grace_days=14)
+
+        with self.assertRaises(ValidationError) as caught:
+            plan.full_clean()
+
+        self.assertIn("renewal_lead_days", caught.exception.error_dict)
+
+    def test_renewal_lead_is_read_from_each_plan(self):
+        monthly = self.make_plan(duration_months=1, renewal_lead_days=7, grace_days=14)
+        club = Club.objects.create(name="Monthly FC")
+        # Period ends in 3 days: inside a 7-day lead, well outside an annual plan's 30.
+        subscribe(club, monthly, start=self.today - datetime.timedelta(days=27))
+
+        self.assertIn(club, [s.club for s in subscriptions_due_for_renewal()])
+
+    def test_an_explicit_lead_days_overrides_every_plan(self):
+        monthly = self.make_plan(duration_months=1, renewal_lead_days=1, grace_days=14)
+        club = Club.objects.create(name="Override FC")
+        subscribe(club, monthly, start=self.today - datetime.timedelta(days=20))
+
+        self.assertNotIn(club, [s.club for s in subscriptions_due_for_renewal()])
+        self.assertIn(club, [s.club for s in subscriptions_due_for_renewal(lead_days=30)])
+
+
+class BillingNoticeTests(BillingTestBase):
+    """What a club's own admins are told -- see billing/services/notices.py."""
+
+    def test_no_notice_when_nothing_is_owed(self):
+        due = self.bill()
+        record_payment(due, Decimal("500.00"))
+
+        self.assertIsNone(club_billing_notice(self.club, self.today))
+
+    def test_no_notice_for_a_club_that_was_never_billed(self):
+        self.assertIsNone(club_billing_notice(self.club, self.today))
+
+    def test_a_period_issued_ahead_of_its_start_is_only_informational(self):
+        self.bill(start=self.today + datetime.timedelta(days=10))
+
+        self.assertEqual(club_billing_notice(self.club, self.today).level, "info")
+
+    def test_an_unpaid_started_period_warns(self):
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=1))
+
+        notice = club_billing_notice(self.club, self.today)
+
+        self.assertEqual(notice.level, "warning")
+        self.assertEqual(notice.amount_outstanding, Decimal("500.00"))
+        self.assertFalse(notice.is_urgent)
+
+    def test_the_last_week_before_archiving_is_urgent(self):
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=DEFAULT_GRACE_DAYS - 2))
+
+        notice = club_billing_notice(self.club, self.today)
+
+        self.assertEqual(notice.level, "error")
+        self.assertTrue(notice.is_urgent)
+        self.assertEqual(notice.days_until_archive, 2)
+
+    def test_an_overdue_period_is_urgent_with_a_negative_countdown(self):
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=DEFAULT_GRACE_DAYS + 5))
+
+        notice = club_billing_notice(self.club, self.today)
+
+        self.assertEqual(notice.level, "error")
+        self.assertLess(notice.days_until_archive, 0)
+
+    def test_auto_archive_off_still_reports_the_debt_but_promises_no_archiving(self):
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=1), auto_archive=False)
+
+        notice = club_billing_notice(self.club, self.today)
+
+        self.assertEqual(notice.amount_outstanding, Decimal("500.00"))
+        self.assertFalse(notice.will_archive)
+
+    def test_the_soonest_archiving_due_is_the_one_reported(self):
+        self.bill(start=self.today - datetime.timedelta(days=1))
+        later = self.bill(start=self.today + datetime.timedelta(days=400))
+
+        self.assertNotEqual(club_billing_notice(self.club, self.today).due, later)
+
+
+class BillingReminderTests(BillingTestBase):
+    """Reminder emails -- see billing/services/reminders.py. Sent once per escalation
+    level, because the command is on a daily cron."""
+
+    def setUp(self):
+        super().setUp()
+        user = User.objects.create_user(email="admin@ajax.example", password="pw-secret-123")
+        member = Member.objects.create(user=user, first_name="Ada", last_name="Admin")
+        ClubRole.objects.create(club=self.club, member=member, role=ClubRole.Roles.ADMIN)
+        subscribe(self.club, self.plan, start=self.today - datetime.timedelta(days=1))
+        self.due = self.club.dues.first()
+
+    def test_a_reminder_goes_to_the_club_admins(self):
+        self.assertEqual(admin_emails(self.club), ["admin@ajax.example"])
+
+    def test_sending_records_the_level_and_fills_the_outbox(self):
+        notice = club_billing_notice(self.club, self.today)
+        send_reminder(self.club, notice, recipients=["admin@ajax.example"])
+
+        self.due.refresh_from_db()
+        self.assertEqual(len(mail.outbox), 1)
+        self.assertEqual(self.due.last_reminder_level, notice.level)
+        self.assertIsNotNone(self.due.last_reminder_sent_at)
+
+    def test_a_second_run_at_the_same_level_sends_nothing(self):
+        notice = club_billing_notice(self.club, self.today)
+        send_reminder(self.club, notice, recipients=["admin@ajax.example"])
+        self.due.refresh_from_db()
+
+        results = reminders_to_send([self.club], self.today)
+
+        self.assertFalse(results[0].sent)
+        self.assertIn("already reminded", results[0].skipped_reason)
+
+    def test_an_escalation_gets_through(self):
+        send_reminder(self.club, club_billing_notice(self.club, self.today), recipients=["admin@ajax.example"])
+
+        # Far enough on that the same due is now urgent rather than merely a warning.
+        later = self.today + datetime.timedelta(days=DEFAULT_GRACE_DAYS)
+        results = reminders_to_send([self.club], later)
+
+        self.assertTrue(results[0].sent)
+        self.assertEqual(results[0].notice.level, "error")
+
+    def test_force_resends_at_the_same_level(self):
+        send_reminder(self.club, club_billing_notice(self.club, self.today), recipients=["admin@ajax.example"])
+        self.due.refresh_from_db()
+
+        self.assertTrue(reminders_to_send([self.club], self.today, force=True)[0].sent)
+
+    def test_a_club_with_no_reachable_admin_is_reported_not_skipped_silently(self):
+        ClubRole.objects.all().delete()
+
+        results = reminders_to_send([self.club], self.today)
+
+        self.assertFalse(results[0].sent)
+        self.assertIn("no club admin", results[0].skipped_reason)
+
+    def test_a_settled_club_produces_no_reminder(self):
+        record_payment(self.due, Decimal("500.00"))
+
+        self.assertEqual(reminders_to_send([self.club], self.today), [])