Ask to delete orphaned speakers when deleting a session

After a session is deleted, check if any of its speakers are not linked
to any other session. If orphaned speakers are found, show a dialog with
checkboxes letting the user select which ones to delete.

https://claude.ai/code/session_01SdkRECfqLSaJCouvYNPuKB

Author: claude

src/events/page/sessions/EventSession.tsx

@@ -1,19 +1,31 @@
-import { useState } from 'react'
-import { Event } from '../../../types'
-import { Box, Button, Card, Container, DialogContentText, Typography } from '@mui/material'
+import { useCallback, useState } from 'react'
+import { Event, Speaker } from '../../../types'
+import {
+    Box,
+    Button,
+    Card,
+    Checkbox,
+    Container,
+    DialogContentText,
+    FormControlLabel,
+    List,
+    ListItem,
+    Typography,
+} from '@mui/material'
 import { useSession } from '../../../services/hooks/useSession'
 import { useLocation, useRoute } from 'wouter'
 import { FirestoreQueryLoaderAndErrorDisplay } from '../../../components/FirestoreQueryLoaderAndErrorDisplay'
 import { ArrowBack } from '@mui/icons-material'
 import { getQueryParams } from '../../../utils/getQuerySearchParameters'
 import { EventSessionForm } from './EventSessionForm'
-import { doc } from 'firebase/firestore'
+import { deleteDoc, doc, getDocs, query, where } from 'firebase/firestore'
 import { collections } from '../../../services/firebase'
 import { ConfirmDialog } from '../../../components/ConfirmDialog'
 import {
     useFirestoreDocumentDeletion,
     useFirestoreDocumentMutation,
 } from '../../../services/hooks/firestoreMutationHooks'
+import { useSpeakersMap } from '../../../services/hooks/useSpeakersMap'
 
 export type EventSessionProps = {
     event: Event
@@ -24,10 +36,49 @@ export const EventSession = ({ event }: EventSessionProps) => {
 
     const sessionId = params?.sessionId || ''
     const sessionResult = useSession(event.id, sessionId)
+    const speakersMap = useSpeakersMap(event.id)
     const [deleteOpen, setDeleteOpen] = useState(false)
+    const [orphanedSpeakers, setOrphanedSpeakers] = useState<Speaker[]>([])
+    const [orphanDeleteOpen, setOrphanDeleteOpen] = useState(false)
+    const [orphanDeleting, setOrphanDeleting] = useState(false)
+    const [selectedOrphanIds, setSelectedOrphanIds] = useState<Set<string>>(new Set())
     const documentDeletion = useFirestoreDocumentDeletion(doc(collections.sessions(event.id), sessionId))
     const mutation = useFirestoreDocumentMutation(doc(collections.sessions(event.id), sessionId))
 
+    const findOrphanedSpeakers = useCallback(
+        async (speakerIds: string[]) => {
+            const orphaned: Speaker[] = []
+            for (const speakerId of speakerIds) {
+                const sessionsQuery = query(
+                    collections.sessions(event.id),
+                    where('speakers', 'array-contains', speakerId)
+                )
+                const snapshot = await getDocs(sessionsQuery)
+                if (snapshot.empty) {
+                    const speaker = speakersMap.data?.[speakerId]
+                    if (speaker) {
+                        orphaned.push(speaker)
+                    }
+                }
+            }
+            return orphaned
+        },
+        [event.id, speakersMap.data]
+    )
+
+    const deleteSelectedOrphans = useCallback(async () => {
+        setOrphanDeleting(true)
+        try {
+            for (const speakerId of selectedOrphanIds) {
+                await deleteDoc(doc(collections.speakers(event.id), speakerId))
+            }
+        } finally {
+            setOrphanDeleting(false)
+            setOrphanDeleteOpen(false)
+            setLocation('/sessions')
+        }
+    }, [event.id, selectedOrphanIds])
+
     if (sessionResult.isLoading || !sessionResult.data) {
         return <FirestoreQueryLoaderAndErrorDisplay hookResult={sessionResult} />
     }
@@ -73,15 +124,68 @@ export const EventSession = ({ event }: EventSessionProps) => {
                 cancelButton="cancel"
                 handleClose={() => setDeleteOpen(false)}
                 handleAccept={async () => {
+                    const speakerIds = session.speakers || []
                     await documentDeletion.mutate()
                     setDeleteOpen(false)
+
+                    if (speakerIds.length > 0) {
+                        const orphaned = await findOrphanedSpeakers(speakerIds)
+                        if (orphaned.length > 0) {
+                            setOrphanedSpeakers(orphaned)
+                            setSelectedOrphanIds(new Set(orphaned.map((s) => s.id)))
+                            setOrphanDeleteOpen(true)
+                            return
+                        }
+                    }
                     setLocation('/sessions')
                 }}>
                 <DialogContentText id="alert-dialog-description">
                     {' '}
                     Delete the session {session.title} from this event (not the session's speaker(s))
                 </DialogContentText>
             </ConfirmDialog>
+
+            <ConfirmDialog
+                open={orphanDeleteOpen}
+                title="Delete orphaned speaker(s)?"
+                acceptButton="Delete selected speaker(s)"
+                disabled={orphanDeleting || selectedOrphanIds.size === 0}
+                loading={orphanDeleting}
+                cancelButton="Keep all"
+                handleClose={() => {
+                    setOrphanDeleteOpen(false)
+                    setLocation('/sessions')
+                }}
+                handleAccept={deleteSelectedOrphans}>
+                <DialogContentText>
+                    The following speaker(s) are not linked to any other session. Do you want to delete them?
+                </DialogContentText>
+                <List dense>
+                    {orphanedSpeakers.map((speaker) => (
+                        <ListItem key={speaker.id} disablePadding>
+                            <FormControlLabel
+                                control={
+                                    <Checkbox
+                                        checked={selectedOrphanIds.has(speaker.id)}
+                                        onChange={(e) => {
+                                            setSelectedOrphanIds((prev) => {
+                                                const next = new Set(prev)
+                                                if (e.target.checked) {
+                                                    next.add(speaker.id)
+                                                } else {
+                                                    next.delete(speaker.id)
+                                                }
+                                                return next
+                                            })
+                                        }}
+                                    />
+                                }
+                                label={speaker.name}
+                            />
+                        </ListItem>
+                    ))}
+                </List>
+            </ConfirmDialog>
         </Container>
     )
 }