feat(mail): inbox mirror + INTERNAL (app-to-app) delivery

MailService renders a template then deposits it as an EMAIL interaction on a per-email thread (thread model: one thread per email), reusing IngestService. Because ingest adds no participants and a thread is only visible to its participants, it ensureParticipant()s BOTH sender and recipient — so the mirror is actually visible. - postInternal: app-to-app mail, no SMTP → recipient's in-app inbox. - sendExternalWithMirror: SMTP send (TemplatedSender) + mirror an interaction ONLY for a registered recipient (pre-registration sends are email-only — no inbox exists yet). Idempotent across both the send and the mirror. - Writes Interactions, NEVER InboxItems (the projector owns those — KG-15). - POST /v1/mail/internal, POST /v1/mail/send. MailModule in AppModule. Verified over HTTP: internal mail → recipient SEES the thread in their inbox; external send → command + mirror; no-source/no-auth 400. 7 unit tests. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-18 13:54:32 +05:30
parent bba5fae061
commit 9b075f46f9
6 changed files with 316 additions and 0 deletions
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+import { Injectable } from '@nestjs/common';
+import { IngestService } from '../interactions/ingest.service';
+import { ActorResolver, type MessagePrincipal } from '../identity/actor.resolver';
+import { TemplateService } from '../templates/template.service';
+import { TemplatedSender } from '../templates/templated-sender';
+import type { RenderedContent } from '../templates/template.renderer';
+import type { TemplateSource } from '../templates/template.model';
+
+export interface MailPart { kind: 'HTML' | 'TEXT'; bodyText: string }
+
+/** Turn rendered content into ingest parts (HTML + TEXT) + the thread subject. Pure. */
+export function contentToParts(content: RenderedContent): { subject?: string; parts: MailPart[] } {
+  const parts: MailPart[] = [];
+  if (content.html != null) parts.push({ kind: 'HTML', bodyText: content.html });
+  if (content.text != null) parts.push({ kind: 'TEXT', bodyText: content.text });
+  // A message must carry at least one part; fall back to an empty text part rather than fail ingest.
+  if (parts.length === 0) parts.push({ kind: 'TEXT', bodyText: '' });
+  return { ...(content.subject != null ? { subject: content.subject } : {}), parts };
+}
+
+export interface PostInternalInput {
+  source: TemplateSource;
+  recipientUserId: string;
+  vars?: Record<string, unknown>;
+  locale?: string;
+  idempotencyKey: string;
+}
+
+export interface SendExternalInput {
+  source: TemplateSource;
+  target: string;               // email address (external)
+  vars?: Record<string, unknown>;
+  locale?: string;
+  idempotencyKey: string;
+  purpose?: string;
+  /** The registered recipient to mirror to; omit for a pre-registration send (email only, no mirror). */
+  mirrorToUserId?: string;
+}
+
+/**
+ * Mail orchestration: render a template, then deliver it.
+ *  - INTERNAL (app-to-app): create an EMAIL interaction on a per-email thread — no SMTP.
+ *  - EXTERNAL: send via SMTP (TemplatedSender) AND mirror a copy into the recipient's in-app inbox,
+ *    but only when they are a registered user (pre-registration sends have no inbox yet).
+ *
+ * ingest() writes the interaction + thread but adds no participants, and a thread is only visible to
+ * its participants — so after each ingest we add BOTH the sender and the recipient as participants.
+ */
+@Injectable()
+export class MailService {
+  constructor(
+    private readonly templates: TemplateService,
+    private readonly ingest: IngestService,
+    private readonly sender: TemplatedSender,
+    private readonly actors: ActorResolver,
+  ) {}
+
+  async postInternal(principal: MessagePrincipal, input: PostInternalInput): Promise<{ threadId: string; interactionId: string }> {
+    const { content } = await this.templates.render(input.source, input.vars ?? {}, { channel: 'INTERNAL', ...(input.locale ? { locale: input.locale } : {}) });
+    return this.deposit(principal, input.recipientUserId, content, input.idempotencyKey, 'PORTAL');
+  }
+
+  async sendExternalWithMirror(principal: MessagePrincipal, input: SendExternalInput): Promise<{ commandId: string; mirror?: { threadId: string; interactionId: string } }> {
+    const command = await this.sender.sendTemplated({
+      source: input.source, channel: 'EMAIL', target: input.target, vars: input.vars ?? {},
+      ...(input.locale ? { locale: input.locale } : {}), idempotencyKey: input.idempotencyKey, ...(input.purpose ? { purpose: input.purpose } : {}),
+    });
+
+    // Mirror only for a registered recipient (timing rule: no inbox exists pre-registration).
+    if (!input.mirrorToUserId) return { commandId: command.id };
+
+    const { content } = await this.templates.render(input.source, input.vars ?? {}, { channel: 'EMAIL', ...(input.locale ? { locale: input.locale } : {}) });
+    const mirror = await this.deposit(principal, input.mirrorToUserId, content, `mirror:${input.idempotencyKey}`, 'EMAIL');
+    return { commandId: command.id, mirror };
+  }
+
+  /** Ingest the rendered content as an EMAIL interaction on a per-email thread, visible to both parties. */
+  private async deposit(principal: MessagePrincipal, recipientUserId: string, content: RenderedContent, key: string, channelType: string): Promise<{ threadId: string; interactionId: string }> {
+    const { subject, parts } = contentToParts(content);
+    const res = await this.ingest.ingest(
+      {
+        scope: { orgId: principal.orgId, appId: principal.appId, ...(principal.tenantId ? { tenantId: principal.tenantId } : {}) },
+        channel: { type: channelType, externalChannelId: channelType.toLowerCase() },
+        source: { handleKind: 'PORTAL_USER', externalId: principal.userId, ...(principal.displayName ? { displayName: principal.displayName } : {}) },
+        kind: 'EMAIL',
+        thread: { externalThreadId: key, ...(subject ? { subject } : {}) },
+        parts,
+        occurredAt: new Date().toISOString(),
+        providerEventId: key,
+      },
+      key,
+    );
+
+    // Make the thread visible to both the sender and the recipient (ingest adds no participants).
+    const scope = await this.actors.resolveScope(principal);
+    const senderActor = await this.actors.resolveActor(scope.id, principal);
+    const recipientActor = await this.actors.resolveActor(scope.id, {
+      userId: recipientUserId, appId: principal.appId, orgId: principal.orgId, ...(principal.tenantId ? { tenantId: principal.tenantId } : {}),
+    });
+    await this.actors.ensureParticipant(res.threadId, senderActor.id);
+    await this.actors.ensureParticipant(res.threadId, recipientActor.id);
+
+    return { threadId: res.threadId, interactionId: res.interactionId };
+  }
+}