feat(email): suggest entity links with AI when opening messages

backend/src/routes/emailAsUser.ts

@@ -1,3 +1,4 @@
+import { suggestEmailEntities, type EntityCandidate, type EntitySuggestion } from "../modules/email/email.entity-suggestions"
 import nodemailer from "nodemailer"
 import { FastifyInstance } from "fastify"
 import { and, desc, eq, isNotNull } from "drizzle-orm"
@@ -21,6 +22,7 @@ import { ImapFlow } from "imapflow"
 
 export default async function emailAsUserRoutes(server: FastifyInstance) {
     const emailSync = emailSyncService(server)
+    const pendingSuggestions = new Map<string, Promise<EntitySuggestion[]>>()
 
     const encryptedValue = (value: unknown) => value ? decrypt(value as any) : null
 
@@ -555,6 +557,66 @@ export default async function emailAsUserRoutes(server: FastifyInstance) {
         }
     })
 
+    server.post("/email/messages/:id/entity-suggestions", async (req, reply) => {
+        if (!req.user?.tenant_id) return reply.code(400).send({ error: "No tenant selected" })
+        try {
+            const { id } = req.params as { id: string }
+            const tenantId = req.user.tenant_id
+            const message = await emailSync.getMessage(tenantId, req.user.user_id, id)
+            if (!message) return reply.code(404).send({ error: "E-Mail nicht gefunden" })
+            const refresh = (req.body as { refresh?: boolean } | null)?.refresh === true
+            const key = `${tenantId}:${req.user.user_id}:${id}`
+            let suggestions = message.entitySuggestions
+            if (!suggestions || refresh) {
+                let pending = pendingSuggestions.get(key)
+                if (!pending) {
+                    pending = (async () => {
+                        const candidates: EntityCandidate[] = []
+                        for (const [entityType, definition] of Object.entries(entityDefinitions)) {
+                            const table = definition.table
+                            const rows = await server.db.select({
+                                id: table.id, name: table.name,
+                                ...("infoData" in table ? { infoData: table.infoData } : {}),
+                                ...(entityType === "customers" ? { number: customers.customerNumber }
+                                    : entityType === "vendors" ? { number: vendors.vendorNumber }
+                                    : entityType === "projects" ? { number: projects.projectNumber } : {}),
+                            }).from(table).where(and(eq(definition.tenantColumn, tenantId), eq(table.archived, false)))
+                            for (const row of rows as any[]) {
+                                candidates.push({
+                                    entityType: entityType as EmailEntityType, entityId: row.id,
+                                    entityName: row.name, entityTypeLabel: definition.label, number: row.number,
+                                    email: typeof row.infoData?.email === "string" ? row.infoData.email : null,
+                                    invoiceEmail: typeof row.infoData?.invoiceEmail === "string" ? row.infoData.invoiceEmail : null,
+                                })
+                            }
+                        }
+                        const result = await suggestEmailEntities(message, candidates)
+                        await server.db.update(emailMessages).set({ entitySuggestions: result }).where(and(
+                            eq(emailMessages.id, id), eq(emailMessages.tenantId, tenantId),
+                            eq(emailMessages.userId, req.user.user_id),
+                        ))
+                        return result
+                    })()
+                    pendingSuggestions.set(key, pending)
+                    void pending.finally(() => pendingSuggestions.delete(key)).catch(() => {})
+                }
+                suggestions = await pending
+            }
+            const links = await listMessageEntityLinks(tenantId, id)
+            const resolved = await Promise.all(suggestions.map(async suggestion => {
+                if (links.some(link => link.entityType === suggestion.entityType && link.entityId === suggestion.entityId)) return null
+                const entity = await loadEntity(tenantId, suggestion.entityType, suggestion.entityId)
+                return entity ? { ...suggestion, entityName: entity.name, entityTypeLabel: entity.typeLabel } : null
+            }))
+            return reply.send({ suggestions: resolved.filter(Boolean) })
+        } catch (err: any) {
+            req.log.error(err)
+            return reply.code(err.statusCode === 503 ? 503 : 500).send({
+                error: err.statusCode === 503 ? err.message : "KI-Vorschläge konnten nicht geladen werden. Bitte erneut versuchen.",
+            })
+        }
+    })
+
     server.post("/email/messages/:id/entity-links", async (req, reply) => {
         try {
             if (!req.user?.tenant_id) {