From f7c9a4d32e18d485f0cfcca978edce35f73f700e Mon Sep 17 00:00:00 2001
From: Lakshya Gupta <lakshyagupta2440@gmail.com>
Date: Sun, 25 Oct 2026 05:21:35 +0530
Subject: [PATCH 1/4] feat(attendance): session attendance tracking and student
 participation register

---
 public/activity-detail.html | 300 ++++++++++++++++++++++++-
 public/dashboard.html       |  25 ++-
 schema.sql                  |   3 +-
 src/worker.py               | 301 ++++++++++++++++++++++---
 tests/test_attendance.py    | 435 ++++++++++++++++++++++++++++++++++++
 5 files changed, 1031 insertions(+), 33 deletions(-)
 create mode 100644 tests/test_attendance.py

diff --git a/public/activity-detail.html b/public/activity-detail.html
index 2dec498..425e190 100644
--- a/public/activity-detail.html
+++ b/public/activity-detail.html
@@ -180,7 +180,64 @@ <h2 class="text-xl font-bold mb-2">Prerequisites</h2>
         </div>
       </div>
     </div>
-  </section>
+  <!-- ===== SESSION ATTENDANCE MODAL (Host / Instructor) ===== -->
+  <div id="attendance-modal" class="hidden fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-sm" role="dialog" aria-modal="true" aria-labelledby="att-modal-title">
+    <div class="bg-white dark:bg-gray-800 rounded-2xl shadow-2xl border border-gray-200 dark:border-gray-700 w-full max-w-2xl max-h-[90vh] flex flex-col overflow-hidden">
+      
+      <!-- Modal Header -->
+      <div class="px-6 py-5 border-b border-gray-200 dark:border-gray-700 bg-gradient-to-r from-teal-500/10 via-cyan-500/10 to-transparent flex items-center justify-between">
+        <div class="flex items-center gap-3">
+          <div class="w-10 h-10 rounded-xl bg-teal-500 text-white flex items-center justify-center shadow-md">
+            <i class="fas fa-clipboard-user text-lg"></i>
+          </div>
+          <div>
+            <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white leading-tight">Session Attendance Register</h2>
+            <p id="att-modal-subtitle" class="text-xs text-gray-500 dark:text-gray-400 mt-0.5">Mark and track student participation</p>
+          </div>
+        </div>
+        <button type="button" onclick="closeAttendanceModal()" class="w-9 h-9 rounded-lg text-gray-400 hover:text-gray-600 dark:hover:text-gray-200 hover:bg-gray-100 dark:hover:bg-gray-700 flex items-center justify-center transition" aria-label="Close modal">
+          <i class="fas fa-times text-base"></i>
+        </button>
+      </div>
+
+      <!-- Quick Action / Stats Bar -->
+      <div class="px-6 py-3 bg-gray-50 dark:bg-gray-900/40 border-b border-gray-200 dark:border-gray-700 flex flex-wrap items-center justify-between gap-3 text-xs">
+        <div id="att-summary-counts" class="flex flex-wrap items-center gap-3 font-medium text-gray-600 dark:text-gray-300">
+          <span>Loading student register...</span>
+        </div>
+        <div class="flex items-center gap-2">
+          <button type="button" onclick="bulkSetAttendance('attended')" class="px-2.5 py-1 rounded-lg bg-emerald-50 dark:bg-emerald-950/40 text-emerald-700 dark:text-emerald-300 hover:bg-emerald-100 dark:hover:bg-emerald-900/50 font-semibold border border-emerald-200 dark:border-emerald-800 transition">
+            <i class="fas fa-check mr-1"></i>All Attended
+          </button>
+          <button type="button" onclick="bulkSetAttendance('missed')" class="px-2.5 py-1 rounded-lg bg-rose-50 dark:bg-rose-950/40 text-rose-700 dark:text-rose-300 hover:bg-rose-100 dark:hover:bg-rose-900/50 font-semibold border border-rose-200 dark:border-rose-800 transition">
+            <i class="fas fa-times mr-1"></i>All Missed
+          </button>
+        </div>
+      </div>
+
+      <!-- Student Register Body -->
+      <div id="att-students-list" class="flex-1 overflow-y-auto px-6 py-4 divide-y divide-gray-100 dark:divide-gray-700/60 space-y-2">
+        <div class="py-8 text-center text-sm text-gray-500 dark:text-gray-400 flex flex-col items-center gap-2">
+          <i class="fas fa-spinner fa-spin text-2xl text-teal-500"></i>
+          <span>Loading participant records...</span>
+        </div>
+      </div>
+
+      <!-- Modal Footer -->
+      <div class="px-6 py-4 border-t border-gray-200 dark:border-gray-700 bg-gray-50 dark:bg-gray-900/60 flex items-center justify-between gap-4">
+        <div id="att-status-msg" class="text-xs font-medium"></div>
+        <div class="flex items-center gap-3">
+          <button type="button" onclick="closeAttendanceModal()" class="px-4 py-2 rounded-xl border border-gray-300 dark:border-gray-600 text-gray-700 dark:text-gray-300 font-semibold text-sm hover:bg-gray-100 dark:hover:bg-gray-700 transition">
+            Close
+          </button>
+          <button id="btn-save-attendance" type="button" onclick="saveAttendance()" class="px-5 py-2 rounded-xl bg-teal-600 hover:bg-teal-700 text-white font-bold text-sm shadow-md hover:shadow-lg transition flex items-center gap-2">
+            <i class="fas fa-save"></i>Save Attendance
+          </button>
+        </div>
+      </div>
+
+    </div>
+  </div>
 </main>
 <script>
   const API = '';
@@ -434,16 +491,40 @@ <h2 class="text-xl font-bold mb-2">Prerequisites</h2>
         locked ? '' : (s.location || '')
       ) : '';
 
+      let attendanceBadge = '';
+      if (data.is_enrolled) {
+        if (s.my_attendance === 'attended') {
+          attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-emerald-100 text-emerald-800 dark:bg-emerald-900/40 dark:text-emerald-300"><i class="fas fa-check-circle text-emerald-600 dark:text-emerald-400"></i>Attended</span>';
+        } else if (s.my_attendance === 'missed') {
+          attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-rose-100 text-rose-800 dark:bg-rose-900/40 dark:text-rose-300"><i class="fas fa-times-circle text-rose-600 dark:text-rose-400"></i>Missed</span>';
+        } else if (s.my_attendance === 'excused') {
+          attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-amber-100 text-amber-800 dark:bg-amber-900/40 dark:text-amber-300"><i class="fas fa-info-circle text-amber-600 dark:text-amber-400"></i>Excused</span>';
+        } else {
+          attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs text-gray-500 dark:text-gray-400 bg-gray-100 dark:bg-gray-800 rounded"><i class="fas fa-clock"></i>Registered</span>';
+        }
+      }
+
+      let hostActionBtn = '';
+      if (data.is_host) {
+        hostActionBtn = '<button type="button" onclick="openAttendanceModal(\'' + esc(s.id) + '\', \'' + esc(s.title || 'Session') + '\')" class="shrink-0 inline-flex items-center gap-1 px-2.5 py-1 text-xs font-semibold rounded-lg bg-teal-600 hover:bg-teal-700 text-white shadow-sm transition" title="Mark student attendance"><i class="fas fa-clipboard-user"></i><span>Attendance</span></button>';
+      }
+
       return '<li class="px-6 py-4 hover:bg-gray-50 dark:hover:bg-gray-700/50 transition">' +
         '<div class="flex items-start justify-between gap-3">' +
           '<div class="min-w-0 flex-1">' +
-            '<p class="font-semibold text-gray-800 dark:text-gray-200 text-sm">' + esc(s.title || 'Session') + '</p>' +
+            '<div class="flex items-center gap-2 flex-wrap">' +
+              '<p class="font-semibold text-gray-800 dark:text-gray-200 text-sm">' + esc(s.title || 'Session') + '</p>' +
+              attendanceBadge +
+            '</div>' +
             (s.start_time ? '<p class="text-xs text-gray-500 dark:text-gray-400 mt-1.5 flex items-center gap-1.5"><i class="fas fa-clock text-teal-500"></i>' + esc(s.start_time) + (s.end_time ? ' - ' + esc(s.end_time) : '') + '</p>' : '') +
             (locked ? '<p class="text-xs text-gray-400 dark:text-gray-500 mt-1.5">🔒 Join to see location and details</p>' :
               (s.location ? '<p class="text-xs text-teal-600 dark:text-teal-400 mt-1.5 flex items-center gap-1.5"><i class="fas fa-location-dot"></i>' + esc(s.location) + '</p>' : '') +
               (s.description ? '<p class="text-xs text-gray-500 dark:text-gray-400 mt-1.5">' + esc(s.description) + '</p>' : '')) +
           '</div>' +
-          (sessionGcalUrl ? '<a href="' + esc(sessionGcalUrl) + '" target="_blank" rel="noopener noreferrer" class="shrink-0 inline-flex items-center gap-1 px-2.5 py-1 text-[11px] font-medium rounded border border-gray-200 dark:border-gray-600 hover:border-teal-500 text-gray-600 dark:text-gray-300 hover:text-teal-600 dark:hover:text-teal-400 transition" title="Add this session to Google Calendar"><i class="fab fa-google text-xs"></i><span>Add</span></a>' : '') +
+          '<div class="flex items-center gap-1.5 shrink-0">' +
+            hostActionBtn +
+            (sessionGcalUrl ? '<a href="' + esc(sessionGcalUrl) + '" target="_blank" rel="noopener noreferrer" class="shrink-0 inline-flex items-center gap-1 px-2.5 py-1 text-[11px] font-medium rounded border border-gray-200 dark:border-gray-600 hover:border-teal-500 text-gray-600 dark:text-gray-300 hover:text-teal-600 dark:hover:text-teal-400 transition" title="Add this session to Google Calendar"><i class="fab fa-google text-xs"></i><span>Add</span></a>' : '') +
+          '</div>' +
         '</div>' +
         '</li>';
     }).join('');
@@ -561,8 +642,20 @@ <h2 class="text-xl font-bold mb-2">Prerequisites</h2>
       currentEnrollment = data.enrollment || null;
       renderCertificateSection(data);
       document.getElementById('member-card').classList.remove('hidden');
-      const enr = data.enrollment || {};
-      document.getElementById('enr-details').innerHTML = '<span class="badge bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-300">' + esc(enr.status || 'active') + '</span><span class="text-green-700 dark:text-green-300">✅ You have full access to session details.</span>';
+      let attHtml = '';
+      if (data.attendance && data.attendance.total_sessions > 0) {
+        const pct = data.attendance.percentage !== null ? data.attendance.percentage : 0;
+        attHtml = '<div class="w-full mt-3 pt-3 border-t border-green-200 dark:border-green-800">' +
+          '<div class="flex items-center justify-between text-xs text-green-900 dark:text-green-200 mb-1">' +
+            '<span class="font-semibold flex items-center"><i class="fas fa-clipboard-check mr-1.5 text-green-600 dark:text-green-400"></i>Attendance Rate:</span>' +
+            '<span class="font-bold">' + pct + '% (' + data.attendance.attended + '/' + data.attendance.total_sessions + ' sessions attended)</span>' +
+          '</div>' +
+          '<div class="w-full bg-green-200/60 dark:bg-green-950 rounded-full h-2 overflow-hidden">' +
+            '<div class="bg-gradient-to-r from-teal-500 to-green-500 h-2 rounded-full transition-all duration-500" style="width: ' + Math.min(100, Math.max(0, pct)) + '%"></div>' +
+          '</div>' +
+        '</div>';
+      }
+      document.getElementById('enr-details').innerHTML = '<span class="badge bg-emerald-100 text-emerald-700 dark:bg-emerald-900/30 dark:text-emerald-300">' + esc(enr.status || 'active') + '</span><span class="text-green-700 dark:text-green-300">✅ You have full access to session details.</span>' + attHtml;
       action.innerHTML = '<div class="flex flex-wrap items-center gap-3"><span class="inline-flex items-center gap-2 text-teal-700 dark:text-teal-200 text-sm font-semibold">✅ Joined</span>' + (data.is_completed ? '<span class="inline-flex items-center gap-2 text-blue-600 dark:text-blue-300 text-sm font-semibold">Completed</span>' : '<button onclick="markComplete()" class="inline-flex items-center gap-2 bg-teal-600 hover:bg-teal-700 text-white font-bold px-5 py-3 rounded-xl shadow-lg min-h-11"><i class="fas fa-check"></i>Mark complete</button>') + '</div>';
       welcome.textContent = 'You are participating in this activity. Session locations and details are visible above.';
       return;
@@ -743,6 +836,203 @@ <h2 class="text-xl font-bold mb-2">Prerequisites</h2>
     } catch (err) {
       card.classList.add('hidden');
     }
+  // --- Session Attendance Register (Host) & Viewer (Student) ---
+  let activeAttendanceSessionId = null;
+  let attendanceRegisterState = []; // [{ user_id, name, username, status }]
+
+  async function openAttendanceModal(sessionId, sessionTitle) {
+    activeAttendanceSessionId = sessionId;
+    const modal = document.getElementById('attendance-modal');
+    const title = document.getElementById('att-modal-title');
+    const subtitle = document.getElementById('att-modal-subtitle');
+    const list = document.getElementById('att-students-list');
+    const statusMsg = document.getElementById('att-status-msg');
+    const saveBtn = document.getElementById('btn-save-attendance');
+
+    if (!modal) return;
+    modal.classList.remove('hidden');
+    if (title) title.textContent = 'Attendance: ' + (sessionTitle || 'Session');
+    if (subtitle) subtitle.textContent = (currentActivity && currentActivity.title ? currentActivity.title : 'Activity') + ' · Mark Student Participation';
+    if (statusMsg) {
+      statusMsg.className = 'text-xs font-medium';
+      statusMsg.textContent = '';
+    }
+    if (saveBtn) saveBtn.disabled = false;
+
+    if (list) {
+      list.innerHTML = `
+        <div class="py-8 text-center text-sm text-gray-500 dark:text-gray-400 flex flex-col items-center gap-2">
+          <i class="fas fa-spinner fa-spin text-2xl text-teal-500"></i>
+          <span>Loading participant records...</span>
+        </div>
+      `;
+    }
+
+    try {
+      const res = await fetch('/api/sessions/' + encodeURIComponent(sessionId) + '/attendance', {
+        headers: { Authorization: 'Bearer ' + token }
+      });
+      const data = await res.json();
+      if (!res.ok) throw new Error(data.error || 'Failed to load attendance');
+
+      attendanceRegisterState = (data.attendance || []).map(r => ({
+        user_id: r.user_id,
+        name: r.name || r.username || 'Student',
+        username: r.username || '',
+        status: (r.status === 'attended' || r.status === 'missed' || r.status === 'excused') ? r.status : 'registered'
+      }));
+
+      renderAttendanceRegister();
+    } catch (err) {
+      if (list) {
+        list.innerHTML = `
+          <div class="py-8 text-center text-red-500 text-sm">
+            <i class="fas fa-exclamation-circle text-2xl mb-2"></i>
+            <p>${esc(err.message || 'Error loading attendance')}</p>
+          </div>
+        `;
+      }
+    }
+  }
+
+  function closeAttendanceModal() {
+    const modal = document.getElementById('attendance-modal');
+    if (modal) modal.classList.add('hidden');
+    activeAttendanceSessionId = null;
+    attendanceRegisterState = [];
+  }
+
+  function renderAttendanceRegister() {
+    const list = document.getElementById('att-students-list');
+    if (!list) return;
+
+    if (!attendanceRegisterState.length) {
+      list.innerHTML = `
+        <div class="py-12 text-center text-gray-500 dark:text-gray-400">
+          <i class="fas fa-user-graduate text-3xl mb-3 text-gray-400 block"></i>
+          <p class="font-semibold text-base">No active students enrolled yet.</p>
+          <p class="text-xs mt-1 text-gray-400">Students who join this activity will automatically appear in this register.</p>
+        </div>
+      `;
+      updateAttendanceSummary();
+      return;
+    }
+
+    list.innerHTML = attendanceRegisterState.map(st => {
+      const isAttended = st.status === 'attended';
+      const isMissed = st.status === 'missed';
+      const isExcused = st.status === 'excused';
+
+      return `
+        <div class="py-3 flex flex-col sm:flex-row sm:items-center justify-between gap-3">
+          <div class="flex items-center gap-3 min-w-0">
+            <div class="w-9 h-9 rounded-full bg-teal-100 dark:bg-teal-900/40 border border-teal-300 dark:border-teal-700 flex items-center justify-center text-teal-800 dark:text-teal-200 font-bold text-xs shrink-0">
+              ${esc((st.name || 'S').trim().slice(0, 1).toUpperCase())}
+            </div>
+            <div class="min-w-0">
+              <p class="font-bold text-sm text-gray-900 dark:text-gray-100 truncate">${esc(st.name)}</p>
+              ${st.username ? `<p class="text-xs text-gray-500 dark:text-gray-400 truncate">@${esc(st.username)}</p>` : ''}
+            </div>
+          </div>
+          <div class="flex items-center gap-1.5 shrink-0 self-end sm:self-auto" role="radiogroup" aria-label="Attendance status for ${esc(st.name)}">
+            <button type="button" onclick="setStudentStatus('${esc(st.user_id)}', 'attended')" class="px-3 py-1.5 text-xs font-semibold rounded-lg transition-all flex items-center gap-1 ${isAttended ? 'bg-emerald-600 text-white shadow-sm ring-2 ring-emerald-400/50' : 'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-emerald-50 dark:hover:bg-emerald-950/30'}">
+              <i class="fas fa-check text-[10px]"></i><span>Attended</span>
+            </button>
+            <button type="button" onclick="setStudentStatus('${esc(st.user_id)}', 'missed')" class="px-3 py-1.5 text-xs font-semibold rounded-lg transition-all flex items-center gap-1 ${isMissed ? 'bg-rose-600 text-white shadow-sm ring-2 ring-rose-400/50' : 'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-rose-50 dark:hover:bg-rose-950/30'}">
+              <i class="fas fa-times text-[10px]"></i><span>Missed</span>
+            </button>
+            <button type="button" onclick="setStudentStatus('${esc(st.user_id)}', 'excused')" class="px-3 py-1.5 text-xs font-semibold rounded-lg transition-all flex items-center gap-1 ${isExcused ? 'bg-amber-500 text-white shadow-sm ring-2 ring-amber-400/50' : 'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-amber-50 dark:hover:bg-amber-950/30'}">
+              <i class="fas fa-info-circle text-[10px]"></i><span>Excused</span>
+            </button>
+          </div>
+        </div>
+      `;
+    }).join('');
+
+    updateAttendanceSummary();
+  }
+
+  function setStudentStatus(userId, status) {
+    const item = attendanceRegisterState.find(s => s.user_id === userId);
+    if (!item) return;
+    item.status = (item.status === status) ? 'registered' : status;
+    renderAttendanceRegister();
+  }
+
+  function bulkSetAttendance(status) {
+    attendanceRegisterState.forEach(s => {
+      s.status = status;
+    });
+    renderAttendanceRegister();
+  }
+
+  function updateAttendanceSummary() {
+    const container = document.getElementById('att-summary-counts');
+    if (!container) return;
+    const total = attendanceRegisterState.length;
+    const attended = attendanceRegisterState.filter(s => s.status === 'attended').length;
+    const missed = attendanceRegisterState.filter(s => s.status === 'missed').length;
+    const excused = attendanceRegisterState.filter(s => s.status === 'excused').length;
+    const rate = total > 0 ? Math.round((attended / total) * 100) : 0;
+
+    container.innerHTML = `
+      <span class="inline-flex items-center gap-1 text-gray-600 dark:text-gray-300 font-semibold"><i class="fas fa-users text-teal-500"></i>Total: ${total}</span>
+      <span class="inline-flex items-center gap-1 text-emerald-600 dark:text-emerald-400 font-bold"><i class="fas fa-check-circle"></i>${attended} Attended</span>
+      <span class="inline-flex items-center gap-1 text-rose-600 dark:text-rose-400 font-bold"><i class="fas fa-times-circle"></i>${missed} Missed</span>
+      <span class="inline-flex items-center gap-1 text-amber-600 dark:text-amber-400 font-bold"><i class="fas fa-info-circle"></i>${excused} Excused</span>
+      <span class="inline-flex items-center gap-1 bg-teal-100 dark:bg-teal-900/40 text-teal-800 dark:text-teal-200 px-2 py-0.5 rounded-full font-bold ml-auto">${rate}% Rate</span>
+    `;
+  }
+
+  async function saveAttendance() {
+    if (!activeAttendanceSessionId || !token) return;
+    const statusMsg = document.getElementById('att-status-msg');
+    const saveBtn = document.getElementById('btn-save-attendance');
+
+    const payload = attendanceRegisterState
+      .filter(s => s.status === 'attended' || s.status === 'missed' || s.status === 'excused')
+      .map(s => ({ user_id: s.user_id, status: s.status }));
+
+    if (saveBtn) {
+      saveBtn.disabled = true;
+      saveBtn.innerHTML = '<i class="fas fa-spinner fa-spin"></i>Saving...';
+    }
+    if (statusMsg) {
+      statusMsg.className = 'text-xs text-gray-500 dark:text-gray-400';
+      statusMsg.textContent = 'Saving attendance...';
+    }
+
+    try {
+      const res = await fetch('/api/sessions/' + encodeURIComponent(activeAttendanceSessionId) + '/attendance', {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          Authorization: 'Bearer ' + token
+        },
+        body: JSON.stringify(payload)
+      });
+      const data = await res.json();
+      if (!res.ok) throw new Error(data.error || 'Failed to record attendance');
+
+      if (statusMsg) {
+        statusMsg.className = 'text-xs text-emerald-600 dark:text-emerald-400 font-semibold';
+        statusMsg.textContent = '✅ ' + (data.message || 'Attendance saved successfully!');
+      }
+
+      setTimeout(() => {
+        closeAttendanceModal();
+      }, 1200);
+    } catch (err) {
+      if (statusMsg) {
+        statusMsg.className = 'text-xs text-rose-600 dark:text-rose-400 font-semibold';
+        statusMsg.textContent = '❌ ' + (err.message || 'Error saving attendance');
+      }
+    } finally {
+      if (saveBtn) {
+        saveBtn.disabled = false;
+        saveBtn.innerHTML = '<i class="fas fa-save"></i>Save Attendance';
+      }
+    }
   }
 
   async function loadActivityDetail() {
diff --git a/public/dashboard.html b/public/dashboard.html
index 40da9ce..b68c5bd 100644
--- a/public/dashboard.html
+++ b/public/dashboard.html
@@ -109,7 +109,7 @@ <h1 id="header-welcome" class="text-3xl md:text-4xl lg:text-5xl font-extrabold t
     <div class="max-w-[90rem] mx-auto px-4 md:px-6 py-12">
 
       <!-- STAT CARDS -->
-      <div class="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-6 mb-10">
+      <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-5 gap-6 mb-10">
         <div id="stat-cards" class="contents"></div>
       </div>
 
@@ -274,13 +274,19 @@ <h1 id="header-welcome" class="text-3xl md:text-4xl lg:text-5xl font-extrabold t
     // Calculate stats
     const totalParticipants = hosted.reduce((sum, a) => sum + (a.participant_count || 0), 0);
     const totalSessions = hosted.reduce((sum, a) => sum + (a.session_count || 0), 0);
+    const attRateDisplay = (data.attendance_percentage !== null && data.attendance_percentage !== undefined)
+        ? `${data.attendance_percentage}%`
+        : (data.attendance_summary && data.attendance_summary.total_sessions > 0
+            ? `${data.attendance_summary.attendance_percentage || 0}%`
+            : (joined.length ? '100%' : 'N/A'));
 
     // Render stat cards
     document.getElementById('stat-cards').innerHTML =
         statCard(hosted.length, 'Hosted Activities', 'fa-broadcast-tower', 'text-teal-600 dark:text-teal-400') +
         statCard(totalParticipants, 'Total Participants', 'fa-users', 'text-purple-600 dark:text-purple-400') +
         statCard(joined.length, 'Joined Activities', 'fa-heart', 'text-pink-600 dark:text-pink-400') +
-        statCard(totalSessions, 'Total Sessions', 'fa-calendar', 'text-cyan-600 dark:text-cyan-400');
+        statCard(totalSessions, 'Total Sessions', 'fa-calendar', 'text-cyan-600 dark:text-cyan-400') +
+        statCard(attRateDisplay, 'Attendance Rate', 'fa-clipboard-check', 'text-emerald-600 dark:text-emerald-400');
 
     // Quick actions
     document.getElementById('quick-actions').innerHTML = `
@@ -420,7 +426,22 @@ <h3 class="font-bold text-gray-800 dark:text-gray-200 text-base">
                                 <span class="inline-block px-2 py-1 rounded bg-gray-100 dark:bg-gray-700">
                                     <i class="fas fa-signal mr-1"></i>${fmtLabel[a.format] || a.format}
                                 </span>
+                                ${a.attendance_percentage !== null && a.attendance_percentage !== undefined ? `
+                                <span class="inline-block px-2.5 py-1 rounded-full text-xs font-semibold bg-emerald-50 dark:bg-emerald-900/30 text-emerald-700 dark:text-emerald-300">
+                                    <i class="fas fa-clipboard-check mr-1"></i>${a.attendance_percentage}% Attendance (${a.attended_sessions || 0}/${a.session_count || 0})
+                                </span>
+                                ` : (a.session_count > 0 ? `
+                                <span class="inline-block px-2 py-1 rounded bg-gray-100 dark:bg-gray-700">
+                                    <i class="fas fa-calendar mr-1"></i>${a.session_count} sessions
+                                </span>
+                                ` : '')}
+                            </div>
+                            
+                            ${a.attendance_percentage !== null && a.attendance_percentage !== undefined ? `
+                            <div class="w-full bg-gray-100 dark:bg-gray-700 rounded-full h-1.5 overflow-hidden" title="Attendance: ${a.attendance_percentage}%">
+                                <div class="bg-gradient-to-r from-teal-500 to-emerald-500 h-1.5 rounded-full" style="width: ${Math.min(100, Math.max(0, a.attendance_percentage))}%"></div>
                             </div>
+                            ` : ''}
                             
                             ${tagsList ? `<div class="flex flex-wrap gap-1.5">${tagsList}</div>` : ''}
                             
diff --git a/schema.sql b/schema.sql
index 95ff25d..322d3b4 100644
--- a/schema.sql
+++ b/schema.sql
@@ -72,8 +72,9 @@ CREATE TABLE IF NOT EXISTS session_attendance (
     id         TEXT PRIMARY KEY,
     session_id TEXT NOT NULL,
     user_id    TEXT NOT NULL,
-    status     TEXT NOT NULL DEFAULT 'registered', -- registered | attended | missed
+    status     TEXT NOT NULL DEFAULT 'registered', -- registered | attended | missed | excused
     created_at TEXT NOT NULL DEFAULT (datetime('now')),
+    updated_at TEXT,
     UNIQUE (session_id, user_id),
     FOREIGN KEY (session_id) REFERENCES sessions(id),
     FOREIGN KEY (user_id)    REFERENCES users(id)
diff --git a/src/worker.py b/src/worker.py
index f66a112..a004dc0 100644
--- a/src/worker.py
+++ b/src/worker.py
@@ -14,6 +14,8 @@
   POST /api/join              – join an activity
   GET  /api/dashboard         – personal dashboard
   POST /api/sessions          – add a session to activity    [host]
+  GET  /api/sessions/:id/attendance – get session attendance register [host]
+  POST /api/sessions/:id/attendance – mark session attendance         [host]
   GET  /api/tags              – list all tags
   POST /api/activity-tags     – add tags to an activity      [host]
 
@@ -1029,6 +1031,7 @@ async def send_password_change_email(to_email: str, username: str, token: str, e
         user_id    TEXT NOT NULL,
         status     TEXT NOT NULL DEFAULT 'registered',
         created_at TEXT NOT NULL DEFAULT (datetime('now')),
+        updated_at TEXT,
         UNIQUE (session_id, user_id),
         FOREIGN KEY (session_id) REFERENCES sessions(id),
         FOREIGN KEY (user_id)    REFERENCES users(id)
@@ -2403,6 +2406,23 @@ async def api_get_activity(activity_ref: str, req, env):
 
     is_host = bool(user and act.host_uid == user["id"])
 
+    user_attendance = {}
+    if user and user.get("id"):
+        try:
+            att_res = await env.DB.prepare(
+                "SELECT sa.session_id, sa.status, sa.created_at, sa.updated_at"
+                " FROM session_attendance sa"
+                " JOIN sessions s ON s.id = sa.session_id"
+                " WHERE s.activity_id = ? AND sa.user_id = ?"
+            ).bind(act_id, user["id"]).all()
+            for ar in (att_res.results or []):
+                user_attendance[ar.session_id] = {
+                    "status": ar.status,
+                    "marked_at": getattr(ar, "updated_at", None) or getattr(ar, "created_at", None),
+                }
+        except Exception:
+            user_attendance = {}
+
     ses_res = await env.DB.prepare(
         "SELECT id,title,description,start_time,end_time,location,created_at"
         " FROM sessions WHERE activity_id=? ORDER BY start_time"
@@ -2410,13 +2430,15 @@ async def api_get_activity(activity_ref: str, req, env):
 
     sessions = []
     for s in ses_res.results or []:
+        att_info = user_attendance.get(s.id)
         sessions.append({
-            "id":          s.id,
-            "title":       s.title,
-            "description": await decrypt_aes(s.description or "", enc) if (is_enrolled or is_host) else None,
-            "start_time":  s.start_time,
-            "end_time":    s.end_time,
-            "location":    await decrypt_aes(s.location or "", enc) if (is_enrolled or is_host) else None,
+            "id":            s.id,
+            "title":         s.title,
+            "description":   await decrypt_aes(s.description or "", enc) if (is_enrolled or is_host) else None,
+            "start_time":    s.start_time,
+            "end_time":      s.end_time,
+            "location":      await decrypt_aes(s.location or "", enc) if (is_enrolled or is_host) else None,
+            "my_attendance": att_info.get("status") if att_info else None,
         })
 
     t_res = await env.DB.prepare(
@@ -2488,6 +2510,17 @@ async def api_get_activity(activity_ref: str, req, env):
             "status": enrollment.status,
             "id":     enrollment.id,
         } if enrollment else None,
+        "attendance": {
+            "total_sessions": len(sessions),
+            "attended": sum(1 for s in sessions if s.get("my_attendance") == "attended"),
+            "missed": sum(1 for s in sessions if s.get("my_attendance") == "missed"),
+            "excused": sum(1 for s in sessions if s.get("my_attendance") == "excused"),
+            "percentage": (
+                round((sum(1 for s in sessions if s.get("my_attendance") == "attended") / len(sessions)) * 100, 1)
+                if len(sessions) > 0
+                else None
+            ),
+        } if is_enrolled else None,
     })
 
 
@@ -3133,7 +3166,7 @@ async def api_dashboard(req, env):
 
     hosted = []
     for r in res.results or []:
-        desc = await decrypt_aes(r.description or "", enc)
+        desc = await decrypt_aes(getattr(r, "description", "") or "", enc)
         t_res = await env.DB.prepare(
             "SELECT t.name FROM tags t JOIN activity_tags at2 ON at2.tag_id=t.id"
             " WHERE at2.activity_id=?"
@@ -3146,16 +3179,19 @@ async def api_dashboard(req, env):
             "type":              r.type,
             "format":            r.format,
             "schedule_type":     r.schedule_type,
-            "participant_count": r.participant_count,
-            "session_count":     r.session_count,
+            "participant_count": getattr(r, "participant_count", 0) or 0,
+            "session_count":     getattr(r, "session_count", 0) or 0,
             "tags":              [t.name for t in (t_res.results or [])],
-            "created_at":        r.created_at,
+            "created_at":        getattr(r, "created_at", "") or "",
         })
 
     res2 = await env.DB.prepare(
         "SELECT a.id,a.title,a.description,a.slug,a.type,a.format,a.schedule_type,"
         "e.role AS enr_role,e.status AS enr_status,e.created_at AS joined_at,"
-        "u.name AS host_name_enc"
+        "u.name AS host_name_enc,"
+        "(SELECT COUNT(*) FROM sessions WHERE activity_id=a.id) AS session_count,"
+        "(SELECT COUNT(*) FROM session_attendance sa JOIN sessions s ON s.id=sa.session_id"
+        " WHERE s.activity_id=a.id AND sa.user_id=e.user_id AND sa.status='attended') AS attended_count"
         " FROM enrollments e"
         " JOIN activities a ON e.activity_id=a.id"
         " JOIN users u ON a.host_id=u.id"
@@ -3164,27 +3200,56 @@ async def api_dashboard(req, env):
 
     joined = []
     for r in res2.results or []:
-        desc = await decrypt_aes(r.description or "", enc)
+        desc = await decrypt_aes(getattr(r, "description", "") or "", enc)
         t_res = await env.DB.prepare(
             "SELECT t.name FROM tags t JOIN activity_tags at2 ON at2.tag_id=t.id"
             " WHERE at2.activity_id=?"
         ).bind(r.id).all()
+        session_count = int(getattr(r, "session_count", 0) or 0)
+        attended_count = int(getattr(r, "attended_count", 0) or 0)
+        act_attendance_pct = (
+            round((attended_count / session_count) * 100, 1)
+            if session_count > 0
+            else None
+        )
         joined.append({
-            "id":            r.id,
-            "slug":          getattr(r, "slug", "") or "",
-            "title":         r.title,
-            "description":   desc,
-            "type":          r.type,
-            "format":        r.format,
-            "schedule_type": r.schedule_type,
-            "enr_role":      r.enr_role,
-            "enr_status":    r.enr_status,
-            "host_name":     await decrypt_aes(r.host_name_enc or "", enc),
-            "tags":          [t.name for t in (t_res.results or [])],
-            "joined_at":     r.joined_at,
+            "id":                    r.id,
+            "slug":                  getattr(r, "slug", "") or "",
+            "title":                 r.title,
+            "description":           desc,
+            "type":                  r.type,
+            "format":                r.format,
+            "schedule_type":         r.schedule_type,
+            "enr_role":              getattr(r, "enr_role", "participant") or "participant",
+            "enr_status":            getattr(r, "enr_status", "active") or "active",
+            "host_name":             await decrypt_aes(getattr(r, "host_name_enc", "") or "", enc),
+            "tags":                  [t.name for t in (t_res.results or [])],
+            "joined_at":             getattr(r, "joined_at", "") or "",
+            "session_count":         session_count,
+            "total_sessions":        session_count,
+            "attended_sessions":     attended_count,
+            "attendance_percentage": act_attendance_pct,
         })
 
-    return json_resp({"user": user, "hosted_activities": hosted, "joined_activities": joined})
+    total_joined_sessions = sum(a["session_count"] for a in joined)
+    total_attended_sessions = sum(a["attended_sessions"] for a in joined)
+    overall_attendance_pct = (
+        round((total_attended_sessions / total_joined_sessions) * 100, 1)
+        if total_joined_sessions > 0
+        else None
+    )
+
+    return json_resp({
+        "user": user,
+        "hosted_activities": hosted,
+        "joined_activities": joined,
+        "attendance_percentage": overall_attendance_pct,
+        "attendance_summary": {
+            "total_sessions": total_joined_sessions,
+            "attended_sessions": total_attended_sessions,
+            "attendance_percentage": overall_attendance_pct,
+        }
+    })
 
 
 async def api_profile(req, env):
@@ -3642,6 +3707,186 @@ async def api_create_session(req, env):
     return ok({"id": sid}, "Session created")
 
 
+async def api_get_session_attendance(req, env, session_id: str):
+    user = verify_token(req.headers.get("Authorization"), env.JWT_SECRET)
+    if not user:
+        return err("Authentication required", 401)
+
+    session = await env.DB.prepare(
+        "SELECT s.id, s.activity_id, s.title, a.host_id, a.title AS activity_title"
+        " FROM sessions s"
+        " JOIN activities a ON a.id = s.activity_id"
+        " WHERE s.id = ?"
+    ).bind(session_id).first()
+
+    if not session:
+        return err("Session not found", 404)
+
+    if session.host_id != user["id"] and user.get("role") != "admin":
+        return err("Host access required", 403)
+
+    enc = env.ENCRYPTION_KEY
+
+    # 1. Fetch active enrollments for this activity with attendance status for this session
+    enr_res = await env.DB.prepare(
+        "SELECT e.user_id, e.role AS enr_role, e.status AS enr_status,"
+        " u.name, u.username, u.email,"
+        " sa.id AS attendance_id, sa.status AS attendance_status, sa.created_at AS marked_at, sa.updated_at"
+        " FROM enrollments e"
+        " JOIN users u ON e.user_id = u.id"
+        " LEFT JOIN session_attendance sa ON sa.session_id = ? AND sa.user_id = e.user_id"
+        " WHERE e.activity_id = ? AND e.status = 'active'"
+        " ORDER BY e.created_at ASC"
+    ).bind(session_id, session.activity_id).all()
+
+    records = []
+    seen_user_ids = set()
+    attended_cnt = 0
+    missed_cnt = 0
+    excused_cnt = 0
+
+    for r in (enr_res.results or []):
+        seen_user_ids.add(r.user_id)
+        name = await decrypt_aes(getattr(r, "name", "") or "", enc)
+        username = await decrypt_aes(getattr(r, "username", "") or "", enc)
+        st = getattr(r, "attendance_status", None) or "registered"
+        if st == "attended":
+            attended_cnt += 1
+        elif st == "missed":
+            missed_cnt += 1
+        elif st == "excused":
+            excused_cnt += 1
+
+        records.append({
+            "user_id": r.user_id,
+            "name": name or username or "Participant",
+            "username": username or "",
+            "status": st,
+            "marked_at": getattr(r, "updated_at", None) or getattr(r, "marked_at", None),
+        })
+
+    # 2. Check any additional attendance rows for this session not covered by active enrollments
+    extra_att = await env.DB.prepare(
+        "SELECT sa.user_id, sa.status, sa.created_at, sa.updated_at, u.name, u.username"
+        " FROM session_attendance sa"
+        " JOIN users u ON u.id = sa.user_id"
+        " WHERE sa.session_id = ?"
+    ).bind(session_id).all()
+
+    for r in (extra_att.results or []):
+        if r.user_id not in seen_user_ids:
+            seen_user_ids.add(r.user_id)
+            name = await decrypt_aes(getattr(r, "name", "") or "", enc)
+            username = await decrypt_aes(getattr(r, "username", "") or "", enc)
+            st = getattr(r, "status", None) or "registered"
+            if st == "attended":
+                attended_cnt += 1
+            elif st == "missed":
+                missed_cnt += 1
+            elif st == "excused":
+                excused_cnt += 1
+            records.append({
+                "user_id": r.user_id,
+                "name": name or username or "Participant",
+                "username": username or "",
+                "status": st,
+                "marked_at": getattr(r, "updated_at", None) or getattr(r, "created_at", None),
+            })
+
+    total = len(records)
+    registered_cnt = total - (attended_cnt + missed_cnt + excused_cnt)
+    attendance_rate = round((attended_cnt / total) * 100, 1) if total > 0 else 0.0
+
+    return json_resp({
+        "success": True,
+        "session_id": session_id,
+        "session_title": getattr(session, "title", "") or "",
+        "activity_id": session.activity_id,
+        "activity_title": getattr(session, "activity_title", "") or "",
+        "attendance": records,
+        "summary": {
+            "total": total,
+            "attended": attended_cnt,
+            "missed": missed_cnt,
+            "excused": excused_cnt,
+            "registered": registered_cnt,
+            "attendance_rate": attendance_rate,
+        }
+    })
+
+
+async def api_record_session_attendance(req, env, session_id: str):
+    user = verify_token(req.headers.get("Authorization"), env.JWT_SECRET)
+    if not user:
+        return err("Authentication required", 401)
+
+    session = await env.DB.prepare(
+        "SELECT s.id, s.activity_id, s.title, a.host_id"
+        " FROM sessions s"
+        " JOIN activities a ON a.id = s.activity_id"
+        " WHERE s.id = ?"
+    ).bind(session_id).first()
+
+    if not session:
+        return err("Session not found", 404)
+
+    if session.host_id != user["id"] and user.get("role") != "admin":
+        return err("Host access required", 403)
+
+    try:
+        text = await req.text()
+        body = json.loads(text) if text else None
+    except Exception:
+        return err("Invalid JSON body", 400)
+
+    if isinstance(body, list):
+        records = body
+    elif isinstance(body, dict):
+        records = body.get("attendance")
+        if records is None:
+            records = body.get("records")
+        if records is None:
+            return err("Payload must be a list of attendance records or an object with 'attendance' list", 400)
+    else:
+        return err("Payload must be a list or an object containing an 'attendance' array", 400)
+
+    if not isinstance(records, list):
+        return err("Attendance records must be a list", 400)
+
+    valid_statuses = {"attended", "missed", "excused"}
+    records_to_save = []
+    for item in records:
+        if not isinstance(item, dict):
+            return err("Each attendance record must be an object", 400)
+        uid = str(item.get("user_id") or "").strip()
+        raw_status = str(item.get("status") or "").strip().lower()
+        if not uid:
+            return err("user_id is required for each attendance record", 400)
+        if raw_status not in valid_statuses:
+            return err(f"Invalid status '{item.get('status')}'. Must be one of: attended, missed, excused", 400)
+        records_to_save.append((uid, raw_status))
+
+    saved_count = 0
+    for uid, status in records_to_save:
+        att_id = new_id()
+        await env.DB.prepare(
+            "INSERT INTO session_attendance (id, session_id, user_id, status, created_at, updated_at)"
+            " VALUES (?, ?, ?, ?, datetime('now'), datetime('now'))"
+            " ON CONFLICT(session_id, user_id) DO UPDATE SET"
+            "   status = excluded.status,"
+            "   updated_at = datetime('now')"
+        ).bind(att_id, session_id, uid, status).run()
+        saved_count += 1
+
+    return json_resp({
+        "success": True,
+        "message": "Attendance recorded successfully",
+        "session_id": session_id,
+        "updated": saved_count,
+        "records": [{"user_id": u, "status": s} for u, s in records_to_save],
+    })
+
+
 async def api_list_tags(_req, env):
     res  = await env.DB.prepare("SELECT id,name FROM tags ORDER BY name").all()
     tags = [{"id": r.id, "name": r.name} for r in (res.results or [])]
@@ -8157,6 +8402,12 @@ async def _dispatch(request, env):
         if path == "/api/sessions" and method == "POST":
             return await api_create_session(request, env)
 
+        m_session_attendance = re.fullmatch(r"/api/sessions/([A-Za-z0-9_-]+)/attendance", path)
+        if m_session_attendance and method == "GET":
+            return await api_get_session_attendance(request, env, m_session_attendance.group(1))
+        if m_session_attendance and method == "POST":
+            return await api_record_session_attendance(request, env, m_session_attendance.group(1))
+
         if path == "/api/subjects" and method == "GET":
             return await api_list_subjects(request, env)
 
diff --git a/tests/test_attendance.py b/tests/test_attendance.py
new file mode 100644
index 0000000..701ac1b
--- /dev/null
+++ b/tests/test_attendance.py
@@ -0,0 +1,435 @@
+"""
+Tests for session attendance tracking and student participation register.
+Covers:
+- POST /api/sessions/:id/attendance (host authorization, validation, saving records)
+- GET  /api/sessions/:id/attendance (host restriction, student participation register retrieval)
+- Attendance percentage calculations in student dashboard (api_dashboard) and activity detail (api_get_activity)
+- Non-host permission denial (403) and unauthenticated rejection (401)
+- Dispatcher routing for attendance endpoints
+"""
+
+import base64
+import json
+import pytest
+from tests.helpers import (
+    load_worker,
+    MockRequest,
+    MockRow,
+    MockDB,
+    make_env,
+    make_stmt,
+    json_request,
+)
+
+worker = load_worker()
+
+JWT_SECRET = "test-jwt-secret"
+ENC_KEY = "test-encryption-key"
+
+
+def _parse(resp):
+    return json.loads(resp.body)
+
+
+def _token(uid="host-1", username="instructor", role="host"):
+    return worker.create_token(uid, username, role, JWT_SECRET)
+
+
+def _auth(token):
+    return {"Authorization": f"Bearer {token}"} if token else {}
+
+
+def _enc(val: str) -> str:
+    """Compute mock-AES ciphertext synchronously (IV = 12 zero bytes, ct = plaintext)."""
+    iv = b"\x00" * 12
+    return "v1:" + base64.b64encode(iv + val.encode("utf-8")).decode("ascii")
+
+
+# ---------------------------------------------------------------------------
+# POST /api/sessions/:id/attendance
+# ---------------------------------------------------------------------------
+
+class TestPostSessionAttendance:
+    def _req(self, sid, payload, token=None):
+        headers = _auth(token) if token else {}
+        return json_request(f"/api/sessions/{sid}/attendance", payload, headers=headers)
+
+    async def test_no_auth_returns_401(self):
+        req = self._req("s-1", [{"user_id": "u-1", "status": "attended"}])
+        r = await worker.api_record_session_attendance(req, make_env(), "s-1")
+        assert r.status == 401
+        data = _parse(r)
+        assert "Authentication required" in data.get("error", "")
+
+    async def test_session_not_found_returns_404(self):
+        tok = _token(uid="host-1")
+        env = make_env(db=MockDB([make_stmt(first=None)]))
+        req = self._req("nonexistent", [{"user_id": "u-1", "status": "attended"}], token=tok)
+        r = await worker.api_record_session_attendance(req, env, "nonexistent")
+        assert r.status == 404
+        assert "Session not found" in _parse(r).get("error", "")
+
+    async def test_non_host_permission_denial_returns_403(self):
+        tok = _token(uid="student-1", role="member")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        req = self._req("s-1", [{"user_id": "u-1", "status": "attended"}], token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 403
+        assert "Host access required" in _parse(r).get("error", "")
+
+    async def test_invalid_json_body_returns_400(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        req = MockRequest(
+            method="POST",
+            url="http://localhost/api/sessions/s-1/attendance",
+            headers=_auth(tok),
+            body="invalid-json{",
+        )
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 400
+        assert "Invalid JSON body" in _parse(r).get("error", "")
+
+    async def test_invalid_payload_type_returns_400(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        req = self._req("s-1", {"invalid_key": "not-attendance"}, token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 400
+
+    async def test_missing_user_id_returns_400(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        req = self._req("s-1", [{"status": "attended"}], token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 400
+        assert "user_id is required" in _parse(r).get("error", "")
+
+    async def test_invalid_status_returns_400(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        req = self._req("s-1", [{"user_id": "u-1", "status": "present"}], token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 400
+        assert "Must be one of: attended, missed, excused" in _parse(r).get("error", "")
+
+    async def test_host_successfully_marks_attendance_direct_list(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([
+            make_stmt(first=session_row),  # session check
+            make_stmt(),                   # upsert u-1
+            make_stmt(),                   # upsert u-2
+            make_stmt(),                   # upsert u-3
+        ]))
+        payload = [
+            {"user_id": "u-1", "status": "attended"},
+            {"user_id": "u-2", "status": "missed"},
+            {"user_id": "u-3", "status": "excused"},
+        ]
+        req = self._req("s-1", payload, token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 200
+        data = _parse(r)
+        assert data["success"] is True
+        assert data["updated"] == 3
+        assert len(data["records"]) == 3
+        assert data["records"][0] == {"user_id": "u-1", "status": "attended"}
+        assert data["records"][1] == {"user_id": "u-2", "status": "missed"}
+        assert data["records"][2] == {"user_id": "u-3", "status": "excused"}
+
+    async def test_host_successfully_marks_attendance_object_wrapper(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([
+            make_stmt(first=session_row),
+            make_stmt(),
+        ]))
+        payload = {
+            "attendance": [
+                {"user_id": "u-1", "status": "attended"}
+            ]
+        }
+        req = self._req("s-1", payload, token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 200
+        data = _parse(r)
+        assert data["success"] is True
+        assert data["updated"] == 1
+
+
+# ---------------------------------------------------------------------------
+# GET /api/sessions/:id/attendance
+# ---------------------------------------------------------------------------
+
+class TestGetSessionAttendance:
+    def _req(self, sid, token=None):
+        headers = _auth(token) if token else {}
+        return MockRequest(method="GET", url=f"http://localhost/api/sessions/{sid}/attendance", headers=headers)
+
+    async def test_no_auth_returns_401(self):
+        req = self._req("s-1")
+        r = await worker.api_get_session_attendance(req, make_env(), "s-1")
+        assert r.status == 401
+
+    async def test_session_not_found_returns_404(self):
+        tok = _token(uid="host-1")
+        env = make_env(db=MockDB([make_stmt(first=None)]))
+        r = await worker.api_get_session_attendance(self._req("s-999", tok), env, "s-999")
+        assert r.status == 404
+
+    async def test_non_host_permission_denial_returns_403(self):
+        tok = _token(uid="student-1", role="member")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1", activity_title="Course 101")
+        env = make_env(db=MockDB([make_stmt(first=session_row)]))
+        r = await worker.api_get_session_attendance(self._req("s-1", tok), env, "s-1")
+        assert r.status == 403
+        assert "Host access required" in _parse(r).get("error", "")
+
+    async def test_host_retrieves_attendance_register_with_summary(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1", activity_title="Intro to Python")
+        
+        # Enrolled students with attendance statuses
+        student1 = MockRow(
+            user_id="u-1", enr_role="participant", enr_status="active",
+            name=_enc("Alice Bob"), username=_enc("alice"), email=_enc("alice@example.com"),
+            attendance_id="att-1", attendance_status="attended", marked_at="2026-10-25 10:00:00", updated_at="2026-10-25 10:00:00"
+        )
+        student2 = MockRow(
+            user_id="u-2", enr_role="participant", enr_status="active",
+            name=_enc("Charlie Dan"), username=_enc("charlie"), email=_enc("charlie@example.com"),
+            attendance_id="att-2", attendance_status="missed", marked_at="2026-10-25 10:00:00", updated_at="2026-10-25 10:00:00"
+        )
+        student3 = MockRow(
+            user_id="u-3", enr_role="participant", enr_status="active",
+            name=_enc("Eve Frank"), username=_enc("eve"), email=_enc("eve@example.com"),
+            attendance_id=None, attendance_status=None, marked_at=None, updated_at=None
+        )
+
+        env = make_env(
+            db=MockDB([
+                make_stmt(first=session_row),                           # session lookup
+                make_stmt(all_results=[student1, student2, student3]),  # enrollments query
+                make_stmt(all_results=[]),                              # extra attendance query
+            ]),
+            enc_key=ENC_KEY,
+        )
+
+        r = await worker.api_get_session_attendance(self._req("s-1", tok), env, "s-1")
+        assert r.status == 200
+        data = _parse(r)
+        assert data["success"] is True
+        assert data["session_id"] == "s-1"
+        assert data["session_title"] == "Week 1"
+        assert len(data["attendance"]) == 3
+
+        att = data["attendance"]
+        assert att[0]["user_id"] == "u-1"
+        assert att[0]["name"] == "Alice Bob"
+        assert att[0]["status"] == "attended"
+
+        assert att[1]["user_id"] == "u-2"
+        assert att[1]["name"] == "Charlie Dan"
+        assert att[1]["status"] == "missed"
+
+        assert att[2]["user_id"] == "u-3"
+        assert att[2]["status"] == "registered"
+
+        summary = data["summary"]
+        assert summary["total"] == 3
+        assert summary["attended"] == 1
+        assert summary["missed"] == 1
+        assert summary["excused"] == 0
+        assert summary["registered"] == 1
+        assert summary["attendance_rate"] == 33.3
+
+
+# ---------------------------------------------------------------------------
+# Attendance Percentage Calculations in Dashboard & Activity Detail
+# ---------------------------------------------------------------------------
+
+class TestAttendancePercentageCalculation:
+    async def test_dashboard_attendance_percentage_calculation(self):
+        tok = _token(uid="student-1", username="student", role="member")
+        
+        # Student enrolled in two activities:
+        # act-1: 4 sessions, 3 attended -> 75.0%
+        # act-2: 2 sessions, 2 attended -> 100.0%
+        # Overall: 5 attended out of 6 sessions -> 83.3%
+        act1_row = MockRow(
+            id="act-1", title="Python 101", description="", slug="python-101",
+            type="course", format="self_paced", schedule_type="multi_session",
+            enr_role="participant", enr_status="active", joined_at="2026-01-01",
+            host_name_enc=_enc("Professor X"),
+            session_count=4, attended_count=3,
+        )
+        act2_row = MockRow(
+            id="act-2", title="Web Dev 101", description="", slug="web-dev-101",
+            type="course", format="live", schedule_type="multi_session",
+            enr_role="participant", enr_status="active", joined_at="2026-01-02",
+            host_name_enc=_enc("Professor Y"),
+            session_count=2, attended_count=2,
+        )
+
+        env = make_env(
+            db=MockDB([
+                make_stmt(all_results=[]),                    # hosted activities (empty)
+                make_stmt(all_results=[act1_row, act2_row]),  # joined activities
+                make_stmt(all_results=[]),                    # tags for act-1
+                make_stmt(all_results=[]),                    # tags for act-2
+            ]),
+            enc_key=ENC_KEY,
+        )
+
+        req = MockRequest(method="GET", url="http://localhost/api/dashboard", headers=_auth(tok))
+        r = await worker.api_dashboard(req, env)
+        assert r.status == 200
+        data = _parse(r)
+
+        joined = data["joined_activities"]
+        assert len(joined) == 2
+        assert joined[0]["title"] == "Python 101"
+        assert joined[0]["session_count"] == 4
+        assert joined[0]["attended_sessions"] == 3
+        assert joined[0]["attendance_percentage"] == 75.0
+
+        assert joined[1]["title"] == "Web Dev 101"
+        assert joined[1]["session_count"] == 2
+        assert joined[1]["attended_sessions"] == 2
+        assert joined[1]["attendance_percentage"] == 100.0
+
+        assert data["attendance_percentage"] == 83.3
+        summary = data["attendance_summary"]
+        assert summary["total_sessions"] == 6
+        assert summary["attended_sessions"] == 5
+        assert summary["attendance_percentage"] == 83.3
+
+    async def test_dashboard_zero_sessions_safe(self):
+        tok = _token(uid="student-1", role="member")
+        act_row = MockRow(
+            id="act-1", title="Self Paced Course", description="", slug="self-paced",
+            type="course", format="self_paced", schedule_type="ongoing",
+            enr_role="participant", enr_status="active", joined_at="2026-01-01",
+            host_name_enc=_enc("Prof"),
+            session_count=0, attended_count=0,
+        )
+
+        env = make_env(
+            db=MockDB([
+                make_stmt(all_results=[]),
+                make_stmt(all_results=[act_row]),
+                make_stmt(all_results=[]),
+            ]),
+            enc_key=ENC_KEY,
+        )
+
+        req = MockRequest(method="GET", url="http://localhost/api/dashboard", headers=_auth(tok))
+        r = await worker.api_dashboard(req, env)
+        assert r.status == 200
+        data = _parse(r)
+        assert data["joined_activities"][0]["attendance_percentage"] is None
+        assert data["attendance_percentage"] is None
+        assert data["attendance_summary"]["total_sessions"] == 0
+
+    async def test_activity_detail_attendance_percentage_for_enrolled_student(self):
+        tok = _token(uid="student-1", role="member")
+
+        act_row = MockRow(
+            id="act-1", title="Data Science", description="", type="course",
+            format="live", schedule_type="multi_session", host_id="host-1",
+            host_uid="host-1", host_name_enc=_enc("Host User"), created_at="2026-01-01",
+            status="published", slug="data-science",
+        )
+        enr_row = MockRow(id="enr-1", role="participant", status="active", user_id="student-1", activity_id="act-1")
+        
+        # 3 sessions: session 1 attended, session 2 missed, session 3 unrecorded
+        s1 = MockRow(id="s-1", title="Session 1", description="", start_time="10:00", end_time="11:00", location="")
+        s2 = MockRow(id="s-2", title="Session 2", description="", start_time="10:00", end_time="11:00", location="")
+        s3 = MockRow(id="s-3", title="Session 3", description="", start_time="10:00", end_time="11:00", location="")
+
+        # User attendance records
+        att1 = MockRow(session_id="s-1", status="attended", created_at="2026-10-25", updated_at="2026-10-25")
+        att2 = MockRow(session_id="s-2", status="missed", created_at="2026-10-25", updated_at="2026-10-25")
+
+        env = make_env(
+            db=MockDB([
+                make_stmt(first=act_row),                  # find activity
+                make_stmt(first=enr_row),                  # check enrollment
+                make_stmt(first=None),                     # completion check
+                make_stmt(first=None),                     # interest check
+                make_stmt(all_results=[att1, att2]),       # user attendance rows
+                make_stmt(all_results=[s1, s2, s3]),       # sessions
+                make_stmt(all_results=[]),                 # tags
+                make_stmt(first=MockRow(cnt=1)),           # enrollment count
+                make_stmt(first=MockRow(cnt=0)),           # interest count
+            ]),
+            enc_key=ENC_KEY,
+        )
+
+        req = MockRequest(method="GET", url="http://localhost/api/activities/act-1", headers=_auth(tok))
+        r = await worker.api_get_activity("act-1", req, env)
+        assert r.status == 200
+        data = _parse(r)
+        
+        assert data["is_enrolled"] is True
+        sessions = data["sessions"]
+        assert len(sessions) == 3
+        assert sessions[0]["my_attendance"] == "attended"
+        assert sessions[1]["my_attendance"] == "missed"
+        assert sessions[2]["my_attendance"] is None
+
+        att = data["attendance"]
+        assert att["total_sessions"] == 3
+        assert att["attended"] == 1
+        assert att["missed"] == 1
+        assert att["percentage"] == 33.3
+
+
+# ---------------------------------------------------------------------------
+# Dispatcher End-to-End Route Matching
+# ---------------------------------------------------------------------------
+
+class TestAttendanceDispatcher:
+    async def test_dispatch_get_session_attendance(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-100", activity_id="act-1", title="Class 1", host_id="host-1", activity_title="Math")
+        env = make_env(
+            db=MockDB([
+                make_stmt(first=session_row),
+                make_stmt(all_results=[]),
+                make_stmt(all_results=[]),
+            ]),
+            enc_key=ENC_KEY,
+        )
+        req = MockRequest(method="GET", url="http://localhost/api/sessions/s-100/attendance", headers=_auth(tok))
+        r = await worker._dispatch(req, env)
+        assert r.status == 200
+        data = _parse(r)
+        assert data["session_id"] == "s-100"
+
+    async def test_dispatch_post_session_attendance(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-100", activity_id="act-1", title="Class 1", host_id="host-1")
+        env = make_env(
+            db=MockDB([
+                make_stmt(first=session_row),
+                make_stmt(),
+            ]),
+            enc_key=ENC_KEY,
+        )
+        req = json_request(
+            "/api/sessions/s-100/attendance",
+            [{"user_id": "u-1", "status": "attended"}],
+            headers=_auth(tok),
+        )
+        r = await worker._dispatch(req, env)
+        assert r.status == 200
+        data = _parse(r)
+        assert data["success"] is True
+        assert data["updated"] == 1

From d89212da7e95f3d9324889b1c139fb6cf00bfc4b Mon Sep 17 00:00:00 2001
From: Lakshya Gupta <lakshyagupta2440@gmail.com>
Date: Sun, 25 Oct 2026 14:04:55 +0530
Subject: [PATCH 2/4] fix(attendance): fix unclosed function in activity-detail
 script

---
 public/activity-detail.html | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/public/activity-detail.html b/public/activity-detail.html
index 425e190..2c6401b 100644
--- a/public/activity-detail.html
+++ b/public/activity-detail.html
@@ -466,7 +466,12 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     }
     sessCard.classList.remove('hidden');
 
-    const icsUrl = `/api/activities/${encodeURIComponent(data.slug || data.id)}/calendar.ics` + (token ? `?token=${encodeURIComponent(token)}` : '');
+    const act = data.activity || {};
+    const actRef = act.slug || act.id || data.slug || data.id || '';
+    const actTitle = act.title || data.title || 'Activity';
+    const actDesc = act.description || data.description || '';
+
+    const icsUrl = `/api/activities/${encodeURIComponent(actRef)}/calendar.ics` + (token ? `?token=${encodeURIComponent(token)}` : '');
     const icsBtn = document.getElementById('btn-export-ics');
     if (icsBtn) {
       icsBtn.href = icsUrl;
@@ -475,8 +480,8 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     const firstSession = data.sessions[0];
     const gcalBtn = document.getElementById('btn-google-calendar');
     if (gcalBtn && firstSession) {
-      const gcalTitle = `${data.title || 'Activity'} - ${firstSession.title || 'Session'}`;
-      const gcalDetails = `${data.description ? data.description.slice(0, 300) : ''}\n\nView on Alpha One Labs: ${window.location.origin}/activity/${encodeURIComponent(data.slug || data.id)}`;
+      const gcalTitle = `${actTitle} - ${firstSession.title || 'Session'}`;
+      const gcalDetails = `${actDesc ? actDesc.slice(0, 300) : ''}\n\nView on Alpha One Labs: ${window.location.origin}/activity/${encodeURIComponent(actRef)}`;
       const gcalLoc = firstSession.location || 'Alpha One Labs';
       gcalBtn.href = formatGoogleCalendarUrl(gcalTitle, firstSession.start_time, firstSession.end_time, gcalDetails, gcalLoc);
     }
@@ -484,10 +489,10 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     ul.innerHTML = data.sessions.map(s => {
       const locked = !data.is_enrolled && !data.is_host;
       const sessionGcalUrl = s.start_time ? formatGoogleCalendarUrl(
-        `${data.title || 'Activity'} - ${s.title || 'Session'}`,
+        `${actTitle} - ${s.title || 'Session'}`,
         s.start_time,
         s.end_time,
-        `${s.description || (data.description ? data.description.slice(0, 200) : '')}\n\n${window.location.origin}/activity/${encodeURIComponent(data.slug || data.id)}`,
+        `${s.description || (actDesc ? actDesc.slice(0, 200) : '')}\n\n${window.location.origin}/activity/${encodeURIComponent(actRef)}`,
         locked ? '' : (s.location || '')
       ) : '';
 
@@ -836,6 +841,8 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     } catch (err) {
       card.classList.add('hidden');
     }
+  }
+
   // --- Session Attendance Register (Host) & Viewer (Student) ---
   let activeAttendanceSessionId = null;
   let attendanceRegisterState = []; // [{ user_id, name, username, status }]

From 9aed900c876b045e9ca9042dc41d9b7f7f79e7a9 Mon Sep 17 00:00:00 2001
From: Lakshya Gupta <lakshyagupta2440@gmail.com>
Date: Sun, 25 Oct 2026 14:15:14 +0530
Subject: [PATCH 3/4] fix(attendance): support undoing attendance marks and
 refresh UI on save

---
 public/activity-detail.html | 18 ++++++++++++------
 src/worker.py               | 26 ++++++++++++++++----------
 tests/test_attendance.py    | 22 ++++++++++++++++++++++
 3 files changed, 50 insertions(+), 16 deletions(-)

diff --git a/public/activity-detail.html b/public/activity-detail.html
index 2c6401b..91ec130 100644
--- a/public/activity-detail.html
+++ b/public/activity-detail.html
@@ -212,6 +212,9 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
           <button type="button" onclick="bulkSetAttendance('missed')" class="px-2.5 py-1 rounded-lg bg-rose-50 dark:bg-rose-950/40 text-rose-700 dark:text-rose-300 hover:bg-rose-100 dark:hover:bg-rose-900/50 font-semibold border border-rose-200 dark:border-rose-800 transition">
             <i class="fas fa-times mr-1"></i>All Missed
           </button>
+          <button type="button" onclick="bulkSetAttendance('registered')" class="px-2.5 py-1 rounded-lg bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-gray-200 dark:hover:bg-gray-600 font-semibold border border-gray-300 dark:border-gray-600 transition" title="Reset all attendance marks">
+            <i class="fas fa-rotate-left mr-1"></i>Reset All
+          </button>
         </div>
       </div>
 
@@ -644,7 +647,8 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
       return;
     }
     if (data.is_enrolled) {
-      currentEnrollment = data.enrollment || null;
+      const enr = data.enrollment || {};
+      currentEnrollment = enr;
       renderCertificateSection(data);
       document.getElementById('member-card').classList.remove('hidden');
       let attHtml = '';
@@ -996,9 +1000,10 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     const statusMsg = document.getElementById('att-status-msg');
     const saveBtn = document.getElementById('btn-save-attendance');
 
-    const payload = attendanceRegisterState
-      .filter(s => s.status === 'attended' || s.status === 'missed' || s.status === 'excused')
-      .map(s => ({ user_id: s.user_id, status: s.status }));
+    const payload = attendanceRegisterState.map(s => ({
+      user_id: s.user_id,
+      status: (s.status === 'attended' || s.status === 'missed' || s.status === 'excused') ? s.status : 'registered'
+    }));
 
     if (saveBtn) {
       saveBtn.disabled = true;
@@ -1026,9 +1031,10 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
         statusMsg.textContent = '✅ ' + (data.message || 'Attendance saved successfully!');
       }
 
-      setTimeout(() => {
+      setTimeout(async () => {
         closeAttendanceModal();
-      }, 1200);
+        await loadActivityDetail();
+      }, 700);
     } catch (err) {
       if (statusMsg) {
         statusMsg.className = 'text-xs text-rose-600 dark:text-rose-400 font-semibold';
diff --git a/src/worker.py b/src/worker.py
index a004dc0..08f6d86 100644
--- a/src/worker.py
+++ b/src/worker.py
@@ -3853,7 +3853,7 @@ async def api_record_session_attendance(req, env, session_id: str):
     if not isinstance(records, list):
         return err("Attendance records must be a list", 400)
 
-    valid_statuses = {"attended", "missed", "excused"}
+    valid_statuses = {"attended", "missed", "excused", "registered", "unmarked"}
     records_to_save = []
     for item in records:
         if not isinstance(item, dict):
@@ -3863,19 +3863,25 @@ async def api_record_session_attendance(req, env, session_id: str):
         if not uid:
             return err("user_id is required for each attendance record", 400)
         if raw_status not in valid_statuses:
-            return err(f"Invalid status '{item.get('status')}'. Must be one of: attended, missed, excused", 400)
+            return err(f"Invalid status '{item.get('status')}'. Must be one of: attended, missed, excused, registered", 400)
         records_to_save.append((uid, raw_status))
 
     saved_count = 0
     for uid, status in records_to_save:
-        att_id = new_id()
-        await env.DB.prepare(
-            "INSERT INTO session_attendance (id, session_id, user_id, status, created_at, updated_at)"
-            " VALUES (?, ?, ?, ?, datetime('now'), datetime('now'))"
-            " ON CONFLICT(session_id, user_id) DO UPDATE SET"
-            "   status = excluded.status,"
-            "   updated_at = datetime('now')"
-        ).bind(att_id, session_id, uid, status).run()
+        if status in ("registered", "unmarked"):
+            # Undo / reset attendance mark
+            await env.DB.prepare(
+                "DELETE FROM session_attendance WHERE session_id = ? AND user_id = ?"
+            ).bind(session_id, uid).run()
+        else:
+            att_id = new_id()
+            await env.DB.prepare(
+                "INSERT INTO session_attendance (id, session_id, user_id, status, created_at, updated_at)"
+                " VALUES (?, ?, ?, ?, datetime('now'), datetime('now'))"
+                " ON CONFLICT(session_id, user_id) DO UPDATE SET"
+                "   status = excluded.status,"
+                "   updated_at = datetime('now')"
+            ).bind(att_id, session_id, uid, status).run()
         saved_count += 1
 
     return json_resp({
diff --git a/tests/test_attendance.py b/tests/test_attendance.py
index 701ac1b..e010380 100644
--- a/tests/test_attendance.py
+++ b/tests/test_attendance.py
@@ -162,6 +162,28 @@ async def test_host_successfully_marks_attendance_object_wrapper(self):
         assert data["success"] is True
         assert data["updated"] == 1
 
+    async def test_host_successfully_undos_attendance_with_registered_status(self):
+        tok = _token(uid="host-1")
+        session_row = MockRow(id="s-1", activity_id="act-1", title="Week 1", host_id="host-1")
+        env = make_env(db=MockDB([
+            make_stmt(first=session_row),  # session check
+            make_stmt(),                   # delete u-1 from session_attendance
+            make_stmt(),                   # delete u-2 from session_attendance
+        ]))
+        payload = [
+            {"user_id": "u-1", "status": "registered"},
+            {"user_id": "u-2", "status": "unmarked"},
+        ]
+        req = self._req("s-1", payload, token=tok)
+        r = await worker.api_record_session_attendance(req, env, "s-1")
+        assert r.status == 200
+        data = _parse(r)
+        assert data["success"] is True
+        assert data["updated"] == 2
+        assert len(data["records"]) == 2
+        assert data["records"][0] == {"user_id": "u-1", "status": "registered"}
+        assert data["records"][1] == {"user_id": "u-2", "status": "unmarked"}
+
 
 # ---------------------------------------------------------------------------
 # GET /api/sessions/:id/attendance

From 1d7f399d0b3d43eaf309e9f87ed5d3451c942c80 Mon Sep 17 00:00:00 2001
From: Lakshya Gupta <lakshyagupta2440@gmail.com>
Date: Sun, 25 Oct 2026 14:32:04 +0530
Subject: [PATCH 4/4] feat(attendance): remove excused attendance status and
 simplify to attended/missed

---
 public/activity-detail.html | 12 ++----------
 schema.sql                  |  2 +-
 src/worker.py               | 13 +++----------
 tests/test_attendance.py    |  7 +++----
 4 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/public/activity-detail.html b/public/activity-detail.html
index 91ec130..7d99529 100644
--- a/public/activity-detail.html
+++ b/public/activity-detail.html
@@ -505,8 +505,6 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
           attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-emerald-100 text-emerald-800 dark:bg-emerald-900/40 dark:text-emerald-300"><i class="fas fa-check-circle text-emerald-600 dark:text-emerald-400"></i>Attended</span>';
         } else if (s.my_attendance === 'missed') {
           attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-rose-100 text-rose-800 dark:bg-rose-900/40 dark:text-rose-300"><i class="fas fa-times-circle text-rose-600 dark:text-rose-400"></i>Missed</span>';
-        } else if (s.my_attendance === 'excused') {
-          attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs font-semibold rounded-full bg-amber-100 text-amber-800 dark:bg-amber-900/40 dark:text-amber-300"><i class="fas fa-info-circle text-amber-600 dark:text-amber-400"></i>Excused</span>';
         } else {
           attendanceBadge = '<span class="inline-flex items-center gap-1 px-2 py-0.5 text-xs text-gray-500 dark:text-gray-400 bg-gray-100 dark:bg-gray-800 rounded"><i class="fas fa-clock"></i>Registered</span>';
         }
@@ -890,7 +888,7 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
         user_id: r.user_id,
         name: r.name || r.username || 'Student',
         username: r.username || '',
-        status: (r.status === 'attended' || r.status === 'missed' || r.status === 'excused') ? r.status : 'registered'
+        status: (r.status === 'attended' || r.status === 'missed') ? r.status : 'registered'
       }));
 
       renderAttendanceRegister();
@@ -932,7 +930,6 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     list.innerHTML = attendanceRegisterState.map(st => {
       const isAttended = st.status === 'attended';
       const isMissed = st.status === 'missed';
-      const isExcused = st.status === 'excused';
 
       return `
         <div class="py-3 flex flex-col sm:flex-row sm:items-center justify-between gap-3">
@@ -952,9 +949,6 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
             <button type="button" onclick="setStudentStatus('${esc(st.user_id)}', 'missed')" class="px-3 py-1.5 text-xs font-semibold rounded-lg transition-all flex items-center gap-1 ${isMissed ? 'bg-rose-600 text-white shadow-sm ring-2 ring-rose-400/50' : 'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-rose-50 dark:hover:bg-rose-950/30'}">
               <i class="fas fa-times text-[10px]"></i><span>Missed</span>
             </button>
-            <button type="button" onclick="setStudentStatus('${esc(st.user_id)}', 'excused')" class="px-3 py-1.5 text-xs font-semibold rounded-lg transition-all flex items-center gap-1 ${isExcused ? 'bg-amber-500 text-white shadow-sm ring-2 ring-amber-400/50' : 'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-300 hover:bg-amber-50 dark:hover:bg-amber-950/30'}">
-              <i class="fas fa-info-circle text-[10px]"></i><span>Excused</span>
-            </button>
           </div>
         </div>
       `;
@@ -983,14 +977,12 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
     const total = attendanceRegisterState.length;
     const attended = attendanceRegisterState.filter(s => s.status === 'attended').length;
     const missed = attendanceRegisterState.filter(s => s.status === 'missed').length;
-    const excused = attendanceRegisterState.filter(s => s.status === 'excused').length;
     const rate = total > 0 ? Math.round((attended / total) * 100) : 0;
 
     container.innerHTML = `
       <span class="inline-flex items-center gap-1 text-gray-600 dark:text-gray-300 font-semibold"><i class="fas fa-users text-teal-500"></i>Total: ${total}</span>
       <span class="inline-flex items-center gap-1 text-emerald-600 dark:text-emerald-400 font-bold"><i class="fas fa-check-circle"></i>${attended} Attended</span>
       <span class="inline-flex items-center gap-1 text-rose-600 dark:text-rose-400 font-bold"><i class="fas fa-times-circle"></i>${missed} Missed</span>
-      <span class="inline-flex items-center gap-1 text-amber-600 dark:text-amber-400 font-bold"><i class="fas fa-info-circle"></i>${excused} Excused</span>
       <span class="inline-flex items-center gap-1 bg-teal-100 dark:bg-teal-900/40 text-teal-800 dark:text-teal-200 px-2 py-0.5 rounded-full font-bold ml-auto">${rate}% Rate</span>
     `;
   }
@@ -1002,7 +994,7 @@ <h2 id="att-modal-title" class="text-lg font-bold text-gray-900 dark:text-white
 
     const payload = attendanceRegisterState.map(s => ({
       user_id: s.user_id,
-      status: (s.status === 'attended' || s.status === 'missed' || s.status === 'excused') ? s.status : 'registered'
+      status: (s.status === 'attended' || s.status === 'missed') ? s.status : 'registered'
     }));
 
     if (saveBtn) {
diff --git a/schema.sql b/schema.sql
index 322d3b4..acaaf04 100644
--- a/schema.sql
+++ b/schema.sql
@@ -72,7 +72,7 @@ CREATE TABLE IF NOT EXISTS session_attendance (
     id         TEXT PRIMARY KEY,
     session_id TEXT NOT NULL,
     user_id    TEXT NOT NULL,
-    status     TEXT NOT NULL DEFAULT 'registered', -- registered | attended | missed | excused
+    status     TEXT NOT NULL DEFAULT 'registered', -- registered | attended | missed
     created_at TEXT NOT NULL DEFAULT (datetime('now')),
     updated_at TEXT,
     UNIQUE (session_id, user_id),
diff --git a/src/worker.py b/src/worker.py
index 08f6d86..b48700e 100644
--- a/src/worker.py
+++ b/src/worker.py
@@ -2514,7 +2514,6 @@ async def api_get_activity(activity_ref: str, req, env):
             "total_sessions": len(sessions),
             "attended": sum(1 for s in sessions if s.get("my_attendance") == "attended"),
             "missed": sum(1 for s in sessions if s.get("my_attendance") == "missed"),
-            "excused": sum(1 for s in sessions if s.get("my_attendance") == "excused"),
             "percentage": (
                 round((sum(1 for s in sessions if s.get("my_attendance") == "attended") / len(sessions)) * 100, 1)
                 if len(sessions) > 0
@@ -3743,7 +3742,6 @@ async def api_get_session_attendance(req, env, session_id: str):
     seen_user_ids = set()
     attended_cnt = 0
     missed_cnt = 0
-    excused_cnt = 0
 
     for r in (enr_res.results or []):
         seen_user_ids.add(r.user_id)
@@ -3754,8 +3752,6 @@ async def api_get_session_attendance(req, env, session_id: str):
             attended_cnt += 1
         elif st == "missed":
             missed_cnt += 1
-        elif st == "excused":
-            excused_cnt += 1
 
         records.append({
             "user_id": r.user_id,
@@ -3783,8 +3779,6 @@ async def api_get_session_attendance(req, env, session_id: str):
                 attended_cnt += 1
             elif st == "missed":
                 missed_cnt += 1
-            elif st == "excused":
-                excused_cnt += 1
             records.append({
                 "user_id": r.user_id,
                 "name": name or username or "Participant",
@@ -3794,7 +3788,7 @@ async def api_get_session_attendance(req, env, session_id: str):
             })
 
     total = len(records)
-    registered_cnt = total - (attended_cnt + missed_cnt + excused_cnt)
+    registered_cnt = total - (attended_cnt + missed_cnt)
     attendance_rate = round((attended_cnt / total) * 100, 1) if total > 0 else 0.0
 
     return json_resp({
@@ -3808,7 +3802,6 @@ async def api_get_session_attendance(req, env, session_id: str):
             "total": total,
             "attended": attended_cnt,
             "missed": missed_cnt,
-            "excused": excused_cnt,
             "registered": registered_cnt,
             "attendance_rate": attendance_rate,
         }
@@ -3853,7 +3846,7 @@ async def api_record_session_attendance(req, env, session_id: str):
     if not isinstance(records, list):
         return err("Attendance records must be a list", 400)
 
-    valid_statuses = {"attended", "missed", "excused", "registered", "unmarked"}
+    valid_statuses = {"attended", "missed", "registered", "unmarked"}
     records_to_save = []
     for item in records:
         if not isinstance(item, dict):
@@ -3863,7 +3856,7 @@ async def api_record_session_attendance(req, env, session_id: str):
         if not uid:
             return err("user_id is required for each attendance record", 400)
         if raw_status not in valid_statuses:
-            return err(f"Invalid status '{item.get('status')}'. Must be one of: attended, missed, excused, registered", 400)
+            return err(f"Invalid status '{item.get('status')}'. Must be one of: attended, missed, registered", 400)
         records_to_save.append((uid, raw_status))
 
     saved_count = 0
diff --git a/tests/test_attendance.py b/tests/test_attendance.py
index e010380..80dbc60 100644
--- a/tests/test_attendance.py
+++ b/tests/test_attendance.py
@@ -116,7 +116,7 @@ async def test_invalid_status_returns_400(self):
         req = self._req("s-1", [{"user_id": "u-1", "status": "present"}], token=tok)
         r = await worker.api_record_session_attendance(req, env, "s-1")
         assert r.status == 400
-        assert "Must be one of: attended, missed, excused" in _parse(r).get("error", "")
+        assert "Must be one of: attended, missed, registered" in _parse(r).get("error", "")
 
     async def test_host_successfully_marks_attendance_direct_list(self):
         tok = _token(uid="host-1")
@@ -130,7 +130,7 @@ async def test_host_successfully_marks_attendance_direct_list(self):
         payload = [
             {"user_id": "u-1", "status": "attended"},
             {"user_id": "u-2", "status": "missed"},
-            {"user_id": "u-3", "status": "excused"},
+            {"user_id": "u-3", "status": "attended"},
         ]
         req = self._req("s-1", payload, token=tok)
         r = await worker.api_record_session_attendance(req, env, "s-1")
@@ -141,7 +141,7 @@ async def test_host_successfully_marks_attendance_direct_list(self):
         assert len(data["records"]) == 3
         assert data["records"][0] == {"user_id": "u-1", "status": "attended"}
         assert data["records"][1] == {"user_id": "u-2", "status": "missed"}
-        assert data["records"][2] == {"user_id": "u-3", "status": "excused"}
+        assert data["records"][2] == {"user_id": "u-3", "status": "attended"}
 
     async def test_host_successfully_marks_attendance_object_wrapper(self):
         tok = _token(uid="host-1")
@@ -267,7 +267,6 @@ async def test_host_retrieves_attendance_register_with_summary(self):
         assert summary["total"] == 3
         assert summary["attended"] == 1
         assert summary["missed"] == 1
-        assert summary["excused"] == 0
         assert summary["registered"] == 1
         assert summary["attendance_rate"] == 33.3