Add cancel RSVP feature (backend DELETE endpoint + frontend UI)

Allows guests to cancel their RSVP via a DELETE endpoint using their
guestToken. Frontend shows cancel button in RsvpBar and clears local
storage on success. Includes unit tests, integration tests, and E2E spec.

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

frontend/src/components/EventList.vue

@@ -28,7 +28,7 @@
     <ConfirmDialog
       :open="!!pendingDeleteToken"
       title="Remove event?"
-      message="This event will be removed from your list."
+      :message="deleteDialogMessage"
       confirm-label="Remove"
       cancel-label="Cancel"
       @confirm="confirmDelete"
@@ -42,24 +42,62 @@ import { computed, ref } from 'vue'
 import { useEventStorage, isValidStoredEvent } from '../composables/useEventStorage'
 import { useEventGrouping } from '../composables/useEventGrouping'
 import { formatRelativeTime } from '../composables/useRelativeTime'
+import { api } from '../api/client'
 import EventCard from './EventCard.vue'
 import SectionHeader from './SectionHeader.vue'
 import DateSubheader from './DateSubheader.vue'
 import ConfirmDialog from './ConfirmDialog.vue'
 import type { StoredEvent } from '../composables/useEventStorage'
 
-const { getStoredEvents, removeEvent } = useEventStorage()
+const { getStoredEvents, getRsvp, removeEvent } = useEventStorage()
 
 const pendingDeleteToken = ref<string | null>(null)
+const deleteError = ref('')
+
+const deleteDialogMessage = computed(() => {
+  if (!pendingDeleteToken.value) return ''
+  const rsvp = getRsvp(pendingDeleteToken.value)
+  if (rsvp) {
+    return 'This event will be removed from your list and your attendance will be cancelled.'
+  }
+  return 'This event will be removed from your list.'
+})
 
 function requestDelete(eventToken: string) {
+  deleteError.value = ''
   pendingDeleteToken.value = eventToken
 }
 
-function confirmDelete() {
-  if (pendingDeleteToken.value) {
-    removeEvent(pendingDeleteToken.value)
+async function confirmDelete() {
+  if (!pendingDeleteToken.value) return
+
+  const eventToken = pendingDeleteToken.value
+  const rsvp = getRsvp(eventToken)
+
+  if (rsvp) {
+    try {
+      const { response } = await api.DELETE('/events/{token}/rsvps/{rsvpToken}', {
+        params: {
+          path: {
+            token: eventToken,
+            rsvpToken: rsvp.rsvpToken,
+          },
+        },
+      })
+
+      if (response.status !== 204 && response.status !== 404) {
+        deleteError.value = 'Could not cancel attendance. Please try again.'
+        pendingDeleteToken.value = null
+        return
+      }
+    } catch {
+      deleteError.value = 'Could not cancel attendance. Please try again.'
+      pendingDeleteToken.value = null
+      return
+    }
   }
+
+  removeEvent(eventToken)
   pendingDeleteToken.value = null
 }
 

frontend/src/components/RsvpBar.vue

@@ -2,9 +2,32 @@
   <div class="rsvp-bar">
     <div class="rsvp-bar__inner">
       <!-- Status state: already RSVPed -->
-      <div v-if="hasRsvp" class="rsvp-bar__status">
-        <span class="rsvp-bar__check" aria-hidden="true">✓</span>
-        <span class="rsvp-bar__text">You're attending!</span>
+      <div v-if="hasRsvp" class="rsvp-bar__status-wrapper">
+        <div
+          class="rsvp-bar__status"
+          role="button"
+          tabindex="0"
+          :aria-expanded="expanded"
+          aria-label="You're attending. Tap to show cancel option."
+          @click="expanded = !expanded"
+          @keydown.enter.prevent="expanded = !expanded"
+          @keydown.space.prevent="expanded = !expanded"
+          @keydown.escape="expanded = false"
+        >
+          <span class="rsvp-bar__check" aria-hidden="true">✓</span>
+          <span class="rsvp-bar__text">You're attending!</span>
+          <span class="rsvp-bar__chevron" :class="{ 'rsvp-bar__chevron--open': expanded }" aria-hidden="true">›</span>
+        </div>
+        <Transition name="rsvp-bar-cancel">
+          <button
+            v-if="expanded"
+            class="rsvp-bar__cancel"
+            type="button"
+            @click="$emit('cancel')"
+          >
+            Cancel attendance
+          </button>
+        </Transition>
       </div>
 
       <!-- CTA state: no RSVP yet -->
@@ -18,13 +41,37 @@
 </template>
 
 <script setup lang="ts">
-defineProps<{
+import { ref, watch } from 'vue'
+
+const props = defineProps<{
   hasRsvp?: boolean
 }>()
 
 defineEmits<{
   open: []
+  cancel: []
 }>()
+
+const expanded = ref(false)
+
+watch(() => props.hasRsvp, () => {
+  expanded.value = false
+})
+
+function onClickOutside(e: MouseEvent) {
+  const target = e.target as HTMLElement
+  if (!target.closest('.rsvp-bar__status-wrapper')) {
+    expanded.value = false
+  }
+}
+
+watch(expanded, (isExpanded) => {
+  if (isExpanded) {
+    document.addEventListener('click', onClickOutside, { capture: true })
+  } else {
+    document.removeEventListener('click', onClickOutside, { capture: true })
+  }
+})
 </script>
 
 <style scoped>
@@ -73,6 +120,12 @@ defineEmits<{
   cursor: pointer;
 }
 
+.rsvp-bar__status-wrapper {
+  display: flex;
+  flex-direction: column;
+  gap: var(--spacing-xs);
+}
+
 .rsvp-bar__status {
   display: flex;
   align-items: center;
@@ -88,6 +141,13 @@ defineEmits<{
   font-weight: 600;
   font-size: 0.95rem;
   color: var(--color-text-on-gradient);
+  cursor: pointer;
+  user-select: none;
+  -webkit-user-select: none;
+}
+
+.rsvp-bar__status:hover {
+  background: linear-gradient(135deg, var(--color-glass-hover) 0%, var(--color-glass-strong) 100%);
 }
 
 .rsvp-bar__check {
@@ -101,4 +161,49 @@ defineEmits<{
   text-overflow: ellipsis;
   white-space: nowrap;
 }
+
+.rsvp-bar__chevron {
+  font-size: 1.2rem;
+  font-weight: 700;
+  transition: transform 0.2s ease;
+  transform: rotate(0deg);
+  margin-left: auto;
+}
+
+.rsvp-bar__chevron--open {
+  transform: rotate(90deg);
+}
+
+.rsvp-bar__cancel {
+  display: block;
+  width: 100%;
+  padding: var(--spacing-sm) var(--spacing-lg);
+  border-radius: var(--radius-card);
+  font-family: inherit;
+  font-size: 0.9rem;
+  font-weight: 600;
+  color: #ef5350;
+  background: linear-gradient(135deg, var(--color-glass-strong) 0%, var(--color-glass-subtle) 100%);
+  border: 1px solid var(--color-glass-border);
+  backdrop-filter: blur(16px);
+  -webkit-backdrop-filter: blur(16px);
+  cursor: pointer;
+  text-align: center;
+  transition: background 0.15s ease;
+}
+
+.rsvp-bar__cancel:hover {
+  background: linear-gradient(135deg, var(--color-glass-hover) 0%, var(--color-glass-strong) 100%);
+}
+
+.rsvp-bar-cancel-enter-active,
+.rsvp-bar-cancel-leave-active {
+  transition: opacity 0.15s ease, transform 0.15s ease;
+}
+
+.rsvp-bar-cancel-enter-from,
+.rsvp-bar-cancel-leave-to {
+  opacity: 0;
+  transform: translateY(-4px);
+}
 </style>

frontend/src/composables/useEventStorage.ts

@@ -78,10 +78,20 @@ export function useEventStorage() {
     return undefined
   }
 
+  function removeRsvp(eventToken: string): void {
+    const events = readEvents()
+    const event = events.find((e) => e.eventToken === eventToken)
+    if (event) {
+      delete event.rsvpToken
+      delete event.rsvpName
+      writeEvents(events)
+    }
+  }
+
   function removeEvent(eventToken: string): void {
     const events = readEvents().filter((e) => e.eventToken !== eventToken)
     writeEvents(events)
   }
 
-  return { saveCreatedEvent, getStoredEvents, getOrganizerToken, saveRsvp, getRsvp, removeEvent }
+  return { saveCreatedEvent, getStoredEvents, getOrganizerToken, saveRsvp, getRsvp, removeRsvp, removeEvent }
 }

frontend/src/views/EventDetailView.vue

@@ -70,11 +70,28 @@
       </div>
     </div>
 
+    <!-- Cancel error message -->
+    <div v-if="cancelError" class="detail__cancel-error" role="alert">
+      <p>{{ cancelError }}</p>
+    </div>
+
     <!-- RSVP bar -->
     <RsvpBar
       v-if="state === 'loaded' && event && !isOrganizer"
       :has-rsvp="!!rsvpName"
       @open="sheetOpen = true"
+      @cancel="confirmCancelOpen = true"
+    />
+
+    <!-- Cancel confirmation dialog -->
+    <ConfirmDialog
+      :open="confirmCancelOpen"
+      title="Cancel attendance?"
+      message="Your attendance will be permanently cancelled."
+      confirm-label="Cancel attendance"
+      cancel-label="Keep"
+      @confirm="handleCancelRsvp"
+      @cancel="confirmCancelOpen = false"
     />
 
     <!-- RSVP bottom sheet -->
@@ -113,6 +130,7 @@ import { api } from '@/api/client'
 import { useEventStorage } from '@/composables/useEventStorage'
 import AttendeeList from '@/components/AttendeeList.vue'
 import BottomSheet from '@/components/BottomSheet.vue'
+import ConfirmDialog from '@/components/ConfirmDialog.vue'
 import RsvpBar from '@/components/RsvpBar.vue'
 import type { components } from '@/api/schema'
 
@@ -120,7 +138,7 @@ type GetEventResponse = components['schemas']['GetEventResponse']
 type State = 'loading' | 'loaded' | 'not-found' | 'error'
 
 const route = useRoute()
-const { saveRsvp, getRsvp, getOrganizerToken } = useEventStorage()
+const { saveRsvp, getRsvp, removeRsvp, getOrganizerToken } = useEventStorage()
 
 const state = ref<State>('loading')
 const event = ref<GetEventResponse | null>(null)
@@ -132,6 +150,8 @@ const nameError = ref('')
 const submitError = ref('')
 const submitting = ref(false)
 const rsvpName = ref<string | undefined>(undefined)
+const confirmCancelOpen = ref(false)
+const cancelError = ref('')
 const isOrganizer = ref(false)
 const attendeeNames = ref<string[] | null>(null)
 
@@ -228,6 +248,37 @@ async function submitRsvp() {
   }
 }
 
+async function handleCancelRsvp() {
+  confirmCancelOpen.value = false
+  cancelError.value = ''
+
+  const stored = getRsvp(route.params.eventToken as string)
+  if (!stored) return
+
+  try {
+    const { response } = await api.DELETE('/events/{token}/rsvps/{rsvpToken}', {
+      params: {
+        path: {
+          token: route.params.eventToken as string,
+          rsvpToken: stored.rsvpToken,
+        },
+      },
+    })
+
+    if (response.status === 204 || response.status === 404) {
+      removeRsvp(route.params.eventToken as string)
+      rsvpName.value = undefined
+      if (event.value) {
+        event.value.attendeeCount = Math.max(0, event.value.attendeeCount - 1)
+      }
+    } else {
+      cancelError.value = 'Could not cancel RSVP. Please try again.'
+    }
+  } catch {
+    cancelError.value = 'Could not cancel RSVP. Please try again.'
+  }
+}
+
 async function fetchAttendees(eventToken: string, organizerToken: string) {
   try {
     const { data, error } = await api.GET('/events/{token}/attendees', {

frontend/src/views/__tests__/EventCreateView.spec.ts

@@ -163,6 +163,7 @@ describe('EventCreateView', () => {
       getOrganizerToken: vi.fn(),
       saveRsvp: vi.fn(),
       getRsvp: vi.fn(),
+      removeRsvp: vi.fn(),
       removeEvent: vi.fn(),
     })