Charge tuition automatically from attendance

Adds a per-student daily rate (students.daily_tuition_cents) and a trigger
that writes a tuition charge when a student is marked present or late.

Idempotency is the crux. The attendance UI upserts on (student_id, date)
and teachers toggle a status freely — present, absent, present again. A
naive "insert a charge on attendance" trigger bills the family once per
click. So each auto-charge is bound to the attendance row that caused it
via ledger_entries.attendance_id (UNIQUE), which turns the write into an
upsert, lets a change back to absent delete the charge, and cascades the
charge away if the attendance record is deleted.

Manual entries keep attendance_id NULL — Postgres allows unlimited NULLs
in a unique index — so hand-entered charges are untouched and the UI can
tell auto from manual.

A NULL rate (the default) means never auto-charge, so nothing begins
billing until a rate is deliberately set on a student. Existing
attendance is not backfilled: retroactively generating charges against
families' balances should be an explicit decision, not a side effect of
deploying a migration.

The trigger is SECURITY DEFINER because the writer is a teacher marking
attendance while ledger_entries is admin-write under RLS; teachers gain
no general ledger access, only this fixed attendance-derived write.

Verified against the live schema across all eight paths: charge on
present, reversal on absent, no duplicate on re-mark, late billable,
excused free, no rate means no charge, rate change on re-save, and
cascade on attendance delete.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/integrations/supabase/types.ts

@@ -480,6 +480,7 @@ export type Database = {
       ledger_entries: {
         Row: {
           amount_cents: number
+          attendance_id: string | null
           category: Database["public"]["Enums"]["ledger_category"]
           created_at: string
           created_by: string | null
@@ -491,6 +492,7 @@ export type Database = {
         }
         Insert: {
           amount_cents: number
+          attendance_id?: string | null
           category?: Database["public"]["Enums"]["ledger_category"]
           created_at?: string
           created_by?: string | null
@@ -502,6 +504,7 @@ export type Database = {
         }
         Update: {
           amount_cents?: number
+          attendance_id?: string | null
           category?: Database["public"]["Enums"]["ledger_category"]
           created_at?: string
           created_by?: string | null
@@ -512,6 +515,13 @@ export type Database = {
           student_id?: string
         }
         Relationships: [
+          {
+            foreignKeyName: "ledger_entries_attendance_id_fkey"
+            columns: ["attendance_id"]
+            isOneToOne: true
+            referencedRelation: "attendance"
+            referencedColumns: ["id"]
+          },
           {
             foreignKeyName: "ledger_entries_student_id_fkey"
             columns: ["student_id"]
@@ -1159,6 +1169,7 @@ export type Database = {
           class_id: string | null
           created_at: string
           custody_agreement: string | null
+          daily_tuition_cents: number | null
           disciplinary_history: string | null
           dismissal_methods: string[]
           dismissal_other: string | null
@@ -1192,6 +1203,7 @@ export type Database = {
           class_id?: string | null
           created_at?: string
           custody_agreement?: string | null
+          daily_tuition_cents?: number | null
           disciplinary_history?: string | null
           dismissal_methods?: string[]
           dismissal_other?: string | null
@@ -1225,6 +1237,7 @@ export type Database = {
           class_id?: string | null
           created_at?: string
           custody_agreement?: string | null
+          daily_tuition_cents?: number | null
           disciplinary_history?: string | null
           dismissal_methods?: string[]
           dismissal_other?: string | null

src/routes/_authenticated/students.$id.tsx

@@ -18,6 +18,7 @@ import { createIntakeToken } from "@/lib/intake.functions";
 import { genTempPassword } from "@/lib/temp-password";
 import { StudentGradeReport } from "@/components/gradebook";
 import { StudentPlansTab } from "@/components/plans";
+import { money } from "@/lib/reports";
 
 export const Route = createFileRoute("/_authenticated/students/$id")({
   head: () => ({ meta: [{ title: "Student — School Portal" }] }),
@@ -167,7 +168,16 @@ function ProfileTab({ studentId, canEdit, isAdmin }: { studentId: string; canEdi
   // background refetch can never clobber in-progress input. Functional updates
   // avoid stale-closure races.
   const [form, setForm] = useState<Record<string, unknown>>({});
-  const startEdit = () => { setForm({ ...(s as Record<string, unknown>) }); setEditing(true); };
+  // daily_tuition_cents is stored in cents but edited in dollars, so it gets its
+  // own form key and is converted on save rather than going through the string
+  // field helpers below.
+  const startEdit = () => {
+    setForm({
+      ...(s as Record<string, unknown>),
+      tuition_rate_input: s?.daily_tuition_cents != null ? (s.daily_tuition_cents / 100).toFixed(2) : "",
+    });
+    setEditing(true);
+  };
   const c = (editing ? form : s) as Record<string, unknown> | null;
   const upd = (k: string, v: unknown) => setForm((f) => ({ ...f, [k]: v }));
   // Read date inputs straight from the DOM at save time (Safari doesn't reliably
@@ -193,6 +203,13 @@ function ProfileTab({ studentId, canEdit, isAdmin }: { studentId: string; canEdi
         const el = dateRefs.current[k];
         if (el) payload[k] = el.value || null;
       }
+      // Dollars -> cents. Blank clears the rate, which stops auto-charging.
+      const rate = String(c.tuition_rate_input ?? "").trim();
+      const rateNum = Number(rate);
+      if (rate !== "" && (!Number.isFinite(rateNum) || rateNum < 0)) {
+        throw new Error("Daily tuition rate must be a positive amount");
+      }
+      payload.daily_tuition_cents = rate === "" ? null : Math.round(rateNum * 100);
       const { error } = await supabase.from("students").update(payload as never).eq("id", studentId);
       if (error) throw error;
     },
@@ -235,6 +252,18 @@ function ProfileTab({ studentId, canEdit, isAdmin }: { studentId: string; canEdi
           <ViewRow label="Photo release" value={c.photo_release ? "Granted" : "Not granted"} />
           {isAdmin && <ViewRow label="Internal notes" value={val("notes")} />}
         </Section>
+        {isAdmin && (
+          <Section title="Tuition">
+            <ViewRow
+              label="Daily rate"
+              value={
+                c.daily_tuition_cents != null
+                  ? `${money(c.daily_tuition_cents as number)} — charged automatically when marked present or late`
+                  : "Not set — attendance does not create charges"
+              }
+            />
+          </Section>
+        )}
         <Section title="Agreement">
           <ViewRow label="Signed by" value={val("agreement_signed_by")} />
           <ViewRow label="Date" value={val("agreement_signed_date")} />
@@ -293,6 +322,23 @@ function ProfileTab({ studentId, canEdit, isAdmin }: { studentId: string; canEdi
         <div className="flex items-center justify-between max-w-sm"><Label className="text-xs">Photo release granted</Label><Switch checked={!!c.photo_release} onCheckedChange={(v) => upd("photo_release", v)} /></div>
         {isAdmin && A("notes", "Internal notes (staff only)")}
       </Section>
+      {isAdmin && (
+        <Section title="Tuition">
+          <Field label="Daily rate in dollars — leave blank for no automatic charging">
+            <Input
+              inputMode="decimal"
+              placeholder="e.g. 45.00"
+              value={(c.tuition_rate_input as string) ?? ""}
+              onChange={(e) => upd("tuition_rate_input", e.target.value)}
+            />
+          </Field>
+          <p className="text-xs text-muted-foreground">
+            When set, marking this student present or late adds a tuition charge for that day. Changing
+            a status to absent or excused removes the charge again. Existing attendance is not billed
+            retroactively.
+          </p>
+        </Section>
+      )}
       <Section title="Agreement">
         <div className="grid grid-cols-2 gap-3">{T("agreement_signed_by", "Signed by")}{D("agreement_signed_date", "Date")}</div>
       </Section>

supabase/migrations/20260726120000_attendance_tuition_autocharge.sql

@@ -0,0 +1,66 @@
+-- Auto-charge tuition when a student is marked present or late.
+--
+-- Idempotency is the whole problem here. The attendance UI upserts on
+-- (student_id, date) and teachers freely toggle a status — present, then absent,
+-- then present again. A naive "insert a charge on attendance" trigger bills the
+-- family once per click. So each auto-charge is bound to the attendance row that
+-- caused it via ledger_entries.attendance_id (UNIQUE), which makes the write an
+-- upsert and lets a status change back to absent *remove* the charge.
+--
+-- Manual ledger entries keep attendance_id NULL. Postgres allows unlimited NULLs
+-- in a unique index, so hand-entered charges are unaffected, and the UI can tell
+-- auto from manual by whether attendance_id is set.
+
+-- Per-student daily rate. NULL (the default) means "never auto-charge", so
+-- nothing starts billing until a rate is deliberately set on a student.
+ALTER TABLE public.students
+  ADD COLUMN IF NOT EXISTS daily_tuition_cents INTEGER;
+
+ALTER TABLE public.ledger_entries
+  ADD COLUMN IF NOT EXISTS attendance_id UUID REFERENCES public.attendance(id) ON DELETE CASCADE;
+
+-- One auto-charge per attendance record, and deleting the attendance record
+-- takes its charge with it (ON DELETE CASCADE above).
+DO $$ BEGIN
+  ALTER TABLE public.ledger_entries ADD CONSTRAINT ledger_entries_attendance_id_key UNIQUE (attendance_id);
+EXCEPTION WHEN duplicate_table OR duplicate_object THEN NULL; END $$;
+
+-- SECURITY DEFINER because the writer is a *teacher* marking attendance, and
+-- ledger_entries is admin-write under RLS. The teacher never gains general
+-- ledger access — only this function's fixed, attendance-derived write.
+CREATE OR REPLACE FUNCTION public.sync_attendance_tuition()
+RETURNS TRIGGER LANGUAGE plpgsql SECURITY DEFINER SET search_path = public AS $$
+DECLARE
+  rate INTEGER;
+BEGIN
+  SELECT daily_tuition_cents INTO rate FROM public.students WHERE id = NEW.student_id;
+
+  -- 'present' and 'late' are billable: the student attended either way.
+  -- 'absent' and 'excused' are not.
+  IF NEW.status IN ('present', 'late') AND rate IS NOT NULL AND rate > 0 THEN
+    INSERT INTO public.ledger_entries
+      (student_id, date, kind, category, amount_cents, note, created_by, attendance_id)
+    VALUES
+      (NEW.student_id, NEW.date, 'charge', 'tuition', rate,
+       'Auto-charged from attendance (' || NEW.status || ')', NEW.recorded_by, NEW.id)
+    ON CONFLICT (attendance_id) DO UPDATE
+      SET amount_cents = EXCLUDED.amount_cents,
+          date         = EXCLUDED.date,
+          note         = EXCLUDED.note;
+  ELSE
+    -- Status moved to absent/excused, or the rate was cleared: undo the charge.
+    DELETE FROM public.ledger_entries WHERE attendance_id = NEW.id;
+  END IF;
+
+  RETURN NEW;
+END $$;
+
+DROP TRIGGER IF EXISTS trg_attendance_tuition ON public.attendance;
+CREATE TRIGGER trg_attendance_tuition
+AFTER INSERT OR UPDATE ON public.attendance
+FOR EACH ROW EXECUTE FUNCTION public.sync_attendance_tuition();
+
+-- Deliberately NOT backfilled. Existing attendance records stay unbilled —
+-- retroactively generating charges against families' balances should be an
+-- explicit decision, not a side effect of deploying this migration. Re-saving an
+-- attendance record re-fires the trigger and bills that day at the current rate.