add Refresh Messages button to re-fetch edited Discord messages

Instructors can now click "Refresh Messages" on the Students page to
re-fetch all #attendance and #eod messages from Discord since the
cohort start date, updating any edited messages via the existing upsert.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dsshimel

attendabot/backend/src/api/routes/students.ts

@@ -17,7 +17,10 @@ import {
   getStudentImage,
   updateStudentImage,
   deleteStudentImage,
+  logMessage,
 } from "../../services/db";
+import { fetchTextChannel, fetchMessagesSince } from "../../services/discord";
+import { MONITORED_CHANNEL_IDS } from "../../bot/constants";
 
 /** Router for student endpoints. */
 export const studentsRouter = Router();
@@ -316,3 +319,54 @@ studentsRouter.delete("/:id/image", (req: AuthRequest, res: Response) => {
     res.status(500).json({ error: "Failed to delete student image" });
   }
 });
+
+/** POST /api/cohorts/:cohortId/refresh-messages - Re-fetch Discord messages since cohort start date. */
+cohortsRouter.post("/:cohortId/refresh-messages", async (req: AuthRequest, res: Response) => {
+  try {
+    const cohortId = parseInt(req.params.cohortId, 10);
+    if (isNaN(cohortId)) {
+      res.status(400).json({ error: "Invalid cohort ID" });
+      return;
+    }
+
+    const cohorts = getCohorts();
+    const cohort = cohorts.find((c) => c.id === cohortId);
+    if (!cohort) {
+      res.status(404).json({ error: "Cohort not found" });
+      return;
+    }
+
+    if (!cohort.start_date) {
+      res.status(400).json({ error: "Cohort has no start date" });
+      return;
+    }
+
+    const since = new Date(cohort.start_date);
+    let messagesProcessed = 0;
+
+    for (const channelId of MONITORED_CHANNEL_IDS) {
+      const channel = await fetchTextChannel(channelId);
+      const messages = await fetchMessagesSince(channel, since);
+
+      for (const message of messages) {
+        logMessage({
+          discord_message_id: message.id,
+          channel_id: message.channelId,
+          channel_name: channel.name,
+          author_id: message.author.id,
+          display_name: message.member?.displayName || null,
+          username: message.author.username,
+          content: message.content,
+          created_at: message.createdAt.toISOString(),
+        });
+        messagesProcessed++;
+      }
+    }
+
+    console.log(`Refreshed ${messagesProcessed} messages for cohort ${cohort.name}`);
+    res.json({ success: true, messagesProcessed });
+  } catch (error) {
+    console.error("Error refreshing messages:", error);
+    res.status(500).json({ error: "Failed to refresh messages" });
+  }
+});

attendabot/backend/src/test/api/students.test.ts

@@ -546,3 +546,135 @@ describe("Cohort API - Database Operations", () => {
     });
   });
 });
+
+describe("Refresh Messages - Validation Logic", () => {
+  let db: Database.Database;
+
+  beforeEach(() => {
+    db = createTestDatabase();
+  });
+
+  afterEach(() => {
+    db.close();
+  });
+
+  describe("cohortId parameter validation", () => {
+    it("rejects non-numeric cohort ID", () => {
+      const parsed = parseInt("abc", 10);
+      expect(isNaN(parsed)).toBe(true);
+    });
+
+    it("accepts valid numeric cohort ID", () => {
+      const parsed = parseInt("5", 10);
+      expect(isNaN(parsed)).toBe(false);
+      expect(parsed).toBe(5);
+    });
+  });
+
+  describe("cohort lookup", () => {
+    it("returns undefined for non-existent cohort", () => {
+      const stmt = db.prepare("SELECT * FROM cohorts WHERE id = ?");
+      const cohort = stmt.get(9999);
+      expect(cohort).toBeUndefined();
+    });
+
+    it("finds existing cohort by ID", () => {
+      const created = createTestCohort(db, "Sp2026");
+
+      const stmt = db.prepare("SELECT * FROM cohorts WHERE id = ?");
+      const cohort = stmt.get(created.id) as { id: number; name: string };
+
+      expect(cohort).toBeDefined();
+      expect(cohort.name).toBe("Sp2026");
+    });
+  });
+
+  describe("start_date validation", () => {
+    it("rejects cohort with no start_date", () => {
+      const cohort = createTestCohort(db, "NoDate");
+
+      const stmt = db.prepare("SELECT start_date FROM cohorts WHERE id = ?");
+      const row = stmt.get(cohort.id) as { start_date: string | null };
+
+      expect(row.start_date).toBeNull();
+    });
+
+    it("accepts cohort with start_date", () => {
+      const cohort = createTestCohort(db, "HasDate");
+      db.prepare("UPDATE cohorts SET start_date = ? WHERE id = ?")
+        .run("2026-02-02", cohort.id);
+
+      const stmt = db.prepare("SELECT start_date FROM cohorts WHERE id = ?");
+      const row = stmt.get(cohort.id) as { start_date: string };
+
+      expect(row.start_date).toBe("2026-02-02");
+    });
+
+    it("parses start_date into a valid Date", () => {
+      const since = new Date("2026-02-02");
+      expect(since.getTime()).not.toBeNaN();
+      expect(since.toISOString()).toBe("2026-02-02T00:00:00.000Z");
+    });
+  });
+
+  describe("message upsert on refresh", () => {
+    it("inserts new messages into the database", () => {
+      const channel = createTestChannel(db, "ch-1", "eod");
+      const user = createTestUser(db, "user-1", "testuser");
+
+      db.prepare(`
+        INSERT INTO messages (discord_message_id, channel_id, author_id, content, created_at)
+        VALUES (?, ?, ?, ?, ?)
+      `).run("msg-1", channel.channel_id, user.author_id, "Original EOD", "2026-02-06T18:00:00.000Z");
+
+      const stmt = db.prepare("SELECT content FROM messages WHERE discord_message_id = ?");
+      const row = stmt.get("msg-1") as { content: string };
+      expect(row.content).toBe("Original EOD");
+    });
+
+    it("upserts edited messages to update content", () => {
+      const channel = createTestChannel(db, "ch-1", "eod");
+      const user = createTestUser(db, "user-1", "testuser");
+
+      // Insert original
+      db.prepare(`
+        INSERT INTO messages (discord_message_id, channel_id, author_id, content, created_at)
+        VALUES (?, ?, ?, ?, ?)
+      `).run("msg-1", channel.channel_id, user.author_id, "Original EOD", "2026-02-06T18:00:00.000Z");
+
+      // Upsert with updated content (same discord_message_id)
+      db.prepare(`
+        INSERT INTO messages (discord_message_id, channel_id, author_id, content, created_at)
+        VALUES (?, ?, ?, ?, ?)
+        ON CONFLICT(discord_message_id) DO UPDATE SET content = excluded.content
+      `).run("msg-1", channel.channel_id, user.author_id, "Updated EOD with 9 PRs", "2026-02-06T18:00:00.000Z");
+
+      const stmt = db.prepare("SELECT content FROM messages WHERE discord_message_id = ?");
+      const row = stmt.get("msg-1") as { content: string };
+      expect(row.content).toBe("Updated EOD with 9 PRs");
+    });
+
+    it("does not create duplicate rows on upsert", () => {
+      const channel = createTestChannel(db, "ch-1", "eod");
+      const user = createTestUser(db, "user-1", "testuser");
+
+      const insertStmt = db.prepare(`
+        INSERT INTO messages (discord_message_id, channel_id, author_id, content, created_at)
+        VALUES (?, ?, ?, ?, ?)
+        ON CONFLICT(discord_message_id) DO UPDATE SET content = excluded.content
+      `);
+
+      insertStmt.run("msg-1", channel.channel_id, user.author_id, "Version 1", "2026-02-06T18:00:00.000Z");
+      insertStmt.run("msg-1", channel.channel_id, user.author_id, "Version 2", "2026-02-06T18:00:00.000Z");
+      insertStmt.run("msg-1", channel.channel_id, user.author_id, "Version 3", "2026-02-06T18:00:00.000Z");
+
+      const count = db.prepare("SELECT COUNT(*) as count FROM messages WHERE discord_message_id = ?")
+        .get("msg-1") as { count: number };
+      expect(count.count).toBe(1);
+
+      const row = db.prepare("SELECT content FROM messages WHERE discord_message_id = ?")
+        .get("msg-1") as { content: string };
+      expect(row.content).toBe("Version 3");
+    });
+  });
+});

attendabot/frontend/src/api/client.ts

@@ -848,6 +848,27 @@ export async function getObservers(): Promise<Observer[]> {
   }
 }
 
+/** Re-fetches Discord messages since cohort start date and upserts them into the database. */
+export async function refreshMessages(cohortId: number): Promise<{
+  success: boolean;
+  messagesProcessed?: number;
+  error?: string;
+}> {
+  try {
+    const res = await fetchWithAuth(`${API_BASE}/cohorts/${cohortId}/refresh-messages`, {
+      method: "POST",
+    });
+    const data = await res.json();
+    if (!res.ok) {
+      return { success: false, error: data.error || "Refresh failed" };
+    }
+    return { success: true, messagesProcessed: data.messagesProcessed };
+  } catch (error) {
+    console.error(error);
+    return { success: false, error: "Network error" };
+  }
+}
+
 /** Syncs observers from the Discord @instructors role. */
 export async function syncObservers(): Promise<Observer[]> {
   try {

attendabot/frontend/src/components/StudentCohortPanel.tsx

@@ -12,6 +12,7 @@ import {
   deleteStudent,
   updateStudent,
   getObservers,
+  refreshMessages,
 } from "../api/client";
 import { StudentTable } from "./StudentTable";
 import { StudentDetail } from "./StudentDetail";
@@ -29,6 +30,8 @@ export function StudentCohortPanel() {
   const [sidebarOpen, setSidebarOpen] = useState(false);
   const [modalOpen, setModalOpen] = useState(false);
   const [loading, setLoading] = useState(true);
+  const [refreshing, setRefreshing] = useState(false);
+  const [refreshStatus, setRefreshStatus] = useState<string | null>(null);
 
   // Load cohorts and observers on mount
   useEffect(() => {
@@ -108,6 +111,21 @@ export function StudentCohortPanel() {
     }
   };
 
+  const handleRefreshMessages = async () => {
+    if (selectedCohortId === null || refreshing) return;
+    setRefreshing(true);
+    setRefreshStatus(null);
+    const result = await refreshMessages(selectedCohortId);
+    if (result.success) {
+      setRefreshStatus(`Refreshed ${result.messagesProcessed} messages`);
+      loadStudents();
+    } else {
+      setRefreshStatus(`Error: ${result.error}`);
+    }
+    setRefreshing(false);
+    setTimeout(() => setRefreshStatus(null), 5000);
+  };
+
   const handleStudentNameChange = async (newName: string) => {
     if (!selectedStudent) return;
     const updated = await updateStudent(selectedStudent.id, { name: newName });
@@ -139,6 +157,13 @@ export function StudentCohortPanel() {
         >
           Add Student
         </button>
+        <button
+          onClick={handleRefreshMessages}
+          disabled={selectedCohortId === null || refreshing}
+        >
+          {refreshing ? "Refreshing..." : "Refresh Messages"}
+        </button>
+        {refreshStatus && <span className="refresh-status">{refreshStatus}</span>}
       </div>
 
       {loading ? (