Fix silent deletes: 204 handling, batch-delete guard, mutation feedback

backend/app/routers/batches.py

@@ -5,7 +5,7 @@
 
 from ..database import get_db
 from ..deps import require_staff
-from ..models import Batch, BatchEnrollment, Student
+from ..models import Batch, BatchEnrollment, Payment, Session, Student
 from ..schemas import BatchCreate, BatchOut, NameRef, StudentOut
 
 router = APIRouter(prefix="/batches", tags=["batches"])
@@ -70,6 +70,28 @@ def update_batch(
 @router.delete("/{batch_id}", status_code=204)
 def delete_batch(batch_id: int, db: Session = Depends(get_db), _=Depends(require_staff)):
     batch = _get(db, batch_id)
+    # Block deletes that would orphan real data (FK has no cascade, so the commit
+    # would otherwise 500). Only *active* enrollments count as "in use" — unenroll
+    # is a soft delete, so removed students leave an inactive row behind that we
+    # clean up below rather than block on.
+    blockers = []
+    n = db.query(BatchEnrollment).filter_by(batch_id=batch_id, is_active=True).count()
+    if n:
+        blockers.append(f"{n} enrolled student(s)")
+    n = db.query(Session).filter_by(batch_id=batch_id).count()
+    if n:
+        blockers.append(f"{n} session(s)")
+    n = db.query(Payment).filter_by(batch_id=batch_id).count()
+    if n:
+        blockers.append(f"{n} payment(s)")
+    if blockers:
+        raise HTTPException(
+            status_code=409,
+            detail="Can't delete: batch still has " + ", ".join(blockers) + ". Remove them first.",
+        )
+    # Drop the dead join rows left by unenroll — they only hold the FK and have no
+    # meaning once the batch is gone.
+    db.query(BatchEnrollment).filter_by(batch_id=batch_id).delete()
     db.delete(batch)
     db.commit()
 

frontend/src/api.js

@@ -32,6 +32,7 @@ async function request(path, { method = "GET", body, form } = {}) {
     const detail = await res.json().catch(() => ({}));
     throw new Error(detail.detail || `Request failed (${res.status})`);
   }
+  if (res.status === 204) return null; // No Content (e.g. DELETE) — nothing to parse
   const ct = res.headers.get("content-type") || "";
   return ct.includes("application/json") ? res.json() : res.text();
 }

frontend/src/pages/Batches.jsx

@@ -1,26 +1,43 @@
 import { useState } from "react";
 import { api } from "../api";
 import { Page, Card, EmptyState, Stagger, inr, useApi } from "../ui";
+import { useToast } from "../components/Toast";
 
 function BatchCard({ batch, allStudents, onEdit, onChanged }) {
   // Roster comes from the /batches list response (no per-card fetch); onChanged
   // reloads the list, which refreshes this batch's students.
   const roster = batch.students || [];
+  const toast = useToast();
 
   async function add(e) {
     const sid = Number(e.target.value);
     if (!sid) return;
-    await api.post("/students/enroll", { student_id: sid, batch_id: batch.id });
-    onChanged();
+    try {
+      await api.post("/students/enroll", { student_id: sid, batch_id: batch.id });
+      toast.success("Student added.");
+      onChanged();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
   async function remove(sid) {
-    await api.post("/students/unenroll", { student_id: sid, batch_id: batch.id });
-    onChanged();
+    try {
+      await api.post("/students/unenroll", { student_id: sid, batch_id: batch.id });
+      toast.success("Student removed.");
+      onChanged();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
   async function del() {
     if (!confirm(`Delete batch "${batch.name}"?`)) return;
-    await api.del(`/batches/${batch.id}`);
-    onChanged();
+    try {
+      await api.del(`/batches/${batch.id}`);
+      toast.success("Batch deleted.");
+      onChanged();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
 
   const enrolledIds = new Set(roster.map((s) => s.id));

frontend/src/pages/StudentDetail.jsx

@@ -2,6 +2,7 @@ import { useState } from "react";
 import { Link, useParams } from "react-router-dom";
 import { api } from "../api";
 import { Page, Table, Loading, useApi } from "../ui";
+import { useToast } from "../components/Toast";
 
 const MARK = {
   present: { icon: "✓", word: "", cls: "text-sage" },
@@ -87,6 +88,7 @@ export default function StudentDetail() {
   const calendar = useApi(() => api.get(`/students/${id}/attendance-calendar`), [id]);
   const [batchId, setBatchId] = useState("");
   const [form, setForm] = useState(null); // edit student details
+  const toast = useToast();
 
   async function save(e) {
     e.preventDefault();
@@ -103,13 +105,23 @@ export default function StudentDetail() {
 
   async function enroll() {
     if (!batchId) return;
-    await api.post("/students/enroll", { student_id: Number(id), batch_id: Number(batchId) });
-    setBatchId("");
-    enrolled.reload();
+    try {
+      await api.post("/students/enroll", { student_id: Number(id), batch_id: Number(batchId) });
+      setBatchId("");
+      toast.success("Enrolled.");
+      enrolled.reload();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
   async function unenroll(bid) {
-    await api.post("/students/unenroll", { student_id: Number(id), batch_id: bid });
-    enrolled.reload();
+    try {
+      await api.post("/students/unenroll", { student_id: Number(id), batch_id: bid });
+      toast.success("Unenrolled.");
+      enrolled.reload();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
 
   if (!student.data) return <Page title="Student">{student.error || "Loading…"}</Page>;

frontend/src/pages/Tutors.jsx

@@ -1,10 +1,12 @@
 import { useState } from "react";
 import { api } from "../api";
 import { Page, EntityCard, EmptyState, Stagger, inr, useApi } from "../ui";
+import { useToast } from "../components/Toast";
 
 export default function Tutors() {
   const list = useApi(() => api.get("/tutors"));
   const [form, setForm] = useState(null);
+  const toast = useToast();
 
   async function save(e) {
     e.preventDefault();
@@ -22,8 +24,13 @@ export default function Tutors() {
   }
 
   async function deactivate(t) {
-    await api.post(`/tutors/${t.id}/deactivate`);
-    list.reload();
+    try {
+      await api.post(`/tutors/${t.id}/deactivate`);
+      toast.success("Tutor deactivated.");
+      list.reload();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
 
   return (

frontend/src/pages/Users.jsx

@@ -1,12 +1,14 @@
 import { useState } from "react";
 import { api } from "../api";
 import { Page, Table, useApi } from "../ui";
+import { useToast } from "../components/Toast";
 
 export default function Users() {
   const list = useApi(() => api.get("/users"));
   const students = useApi(() => api.get("/students"));
   const tutors = useApi(() => api.get("/tutors"));
   const [form, setForm] = useState(null);
+  const toast = useToast();
 
   async function create(e) {
     e.preventDefault();
@@ -22,8 +24,13 @@ export default function Users() {
   }
 
   async function toggle(u) {
-    await api.post(`/users/${u.id}/${u.is_active ? "disable" : "enable"}`);
-    list.reload();
+    try {
+      await api.post(`/users/${u.id}/${u.is_active ? "disable" : "enable"}`);
+      toast.success(u.is_active ? "User disabled." : "User enabled.");
+      list.reload();
+    } catch (err) {
+      toast.error(err.message);
+    }
   }
 
   return (