feat: persist notes on realtime note unload and on interval

The realtime note map has been moved into its own class
to separate the realtime note business logic from the storing logic.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/realtime/realtime-note/realtime-note.service.ts

@@ -3,17 +3,47 @@
  *
  * SPDX-License-Identifier: AGPL-3.0-only
  */
-import { Injectable } from '@nestjs/common';
+import { Optional } from '@mrdrogdrog/optional';
+import { BeforeApplicationShutdown, Inject, Injectable } from '@nestjs/common';
+import { SchedulerRegistry } from '@nestjs/schedule';
 
+import appConfiguration, { AppConfig } from '../../config/app.config';
+import { ConsoleLoggerService } from '../../logger/console-logger.service';
 import { Note } from '../../notes/note.entity';
 import { RevisionsService } from '../../revisions/revisions.service';
 import { RealtimeNote } from './realtime-note';
+import { RealtimeNoteStore } from './realtime-note-store.service';
 
 @Injectable()
-export class RealtimeNoteService {
-  constructor(private revisionsService: RevisionsService) {}
+export class RealtimeNoteService implements BeforeApplicationShutdown {
+  constructor(
+    private revisionsService: RevisionsService,
+    private readonly logger: ConsoleLoggerService,
+    private realtimeNoteStore: RealtimeNoteStore,
+    private schedulerRegistry: SchedulerRegistry,
+    @Inject(appConfiguration.KEY)
+    private appConfig: AppConfig,
+  ) {}
 
-  private noteIdToRealtimeNote = new Map<string, RealtimeNote>();
+  beforeApplicationShutdown(): void {
+    this.realtimeNoteStore
+      .getAllRealtimeNotes()
+      .forEach((realtimeNote) => realtimeNote.destroy());
+  }
+
+  /**
+   * Reads the current content from the given {@link RealtimeNote} and creates a new {@link Revision} for the linked {@link Note}.
+   *
+   * @param realtimeNote The realtime note for which a revision should be created
+   */
+  public saveRealtimeNote(realtimeNote: RealtimeNote): void {
+    this.revisionsService
+      .createRevision(
+        realtimeNote.getNote(),
+        realtimeNote.getYDoc().getCurrentContent(),
+      )
+      .catch((reason) => this.logger.error(reason));
+  }
 
   /**
    * Creates or reuses a {@link RealtimeNote} that is handling the real time editing of the {@link Note} which is identified by the given note id.
@@ -23,13 +53,13 @@ export class RealtimeNoteService {
    */
   public async getOrCreateRealtimeNote(note: Note): Promise<RealtimeNote> {
     return (
-      this.noteIdToRealtimeNote.get(note.id) ??
+      this.realtimeNoteStore.find(note.id) ??
       (await this.createNewRealtimeNote(note))
     );
   }
 
   /**
-   * Creates a new {@link RealtimeNote} for the given {@link Note} and memorizes it.
+   * Creates a new {@link RealtimeNote} for the given {@link Note}.
    *
    * @param note The note for which the realtime note should be created
    * @throws NotInDBError if note doesn't exist or has no revisions.
@@ -38,20 +68,37 @@ export class RealtimeNoteService {
   private async createNewRealtimeNote(note: Note): Promise<RealtimeNote> {
     const initialContent = (await this.revisionsService.getLatestRevision(note))
       .content;
-    const realtimeNote = new RealtimeNote(note.id, initialContent);
-    realtimeNote.on('destroy', () => {
-      this.noteIdToRealtimeNote.delete(note.id);
+    const realtimeNote = this.realtimeNoteStore.create(note, initialContent);
+    realtimeNote.on('beforeDestroy', () => {
+      this.saveRealtimeNote(realtimeNote);
     });
-    this.noteIdToRealtimeNote.set(note.id, realtimeNote);
+    this.startPersistTimer(realtimeNote);
     return realtimeNote;
   }
 
   /**
-   * Retrieves a {@link RealtimeNote} that is linked to the given {@link Note} id.
-   * @param noteId The id of the {@link Note}
-   * @return A {@link RealtimeNote} or {@code undefined} if no instance is existing.
+   * Starts a timer that persists the realtime note in a periodic interval depending on the {@link AppConfig}.
+
+   * @param realtimeNote The realtime note for which the timer should be started
    */
-  public getRealtimeNote(noteId: string): RealtimeNote | undefined {
-    return this.noteIdToRealtimeNote.get(noteId);
+  private startPersistTimer(realtimeNote: RealtimeNote): void {
+    Optional.of(this.appConfig.persistInterval)
+      .filter((value) => value > 0)
+      .ifPresent((persistInterval) => {
+        const intervalId = setInterval(
+          this.saveRealtimeNote.bind(this, realtimeNote),
+          persistInterval * 60 * 1000,
+        );
+        this.schedulerRegistry.addInterval(
+          `periodic-persist-${realtimeNote.getNote().id}`,
+          intervalId,
+        );
+        realtimeNote.on('destroy', () => {
+          clearInterval(intervalId);
+          this.schedulerRegistry.deleteInterval(
+            `periodic-persist-${realtimeNote.getNote().id}`,
+          );
+        });
+      });
   }
 }