feat: add snjs package

packages/snjs/lib/Client/ItemGroupController.ts

@@ -0,0 +1,125 @@
+import { ApplicationEvent } from '../Application/Event'
+import { FileItem, PrefKey, SNNote } from '@standardnotes/models'
+import { removeFromArray } from '@standardnotes/utils'
+import { SNApplication } from '../Application/Application'
+import { NoteViewController } from './NoteViewController'
+import { FileViewController } from './FileViewController'
+import { TemplateNoteViewControllerOptions } from './TemplateNoteViewControllerOptions'
+
+type ItemControllerGroupChangeCallback = (activeController: NoteViewController | FileViewController | undefined) => void
+
+type CreateItemControllerOptions = FileItem | SNNote | TemplateNoteViewControllerOptions
+
+export class ItemGroupController {
+  public itemControllers: (NoteViewController | FileViewController)[] = []
+  private addTagHierarchy: boolean
+  changeObservers: ItemControllerGroupChangeCallback[] = []
+  eventObservers: (() => void)[] = []
+
+  constructor(private application: SNApplication) {
+    this.addTagHierarchy = application.getPreference(PrefKey.NoteAddToParentFolders, true)
+
+    this.eventObservers.push(
+      application.addSingleEventObserver(ApplicationEvent.PreferencesChanged, async () => {
+        this.addTagHierarchy = application.getPreference(PrefKey.NoteAddToParentFolders, true)
+      }),
+    )
+  }
+
+  public deinit(): void {
+    ;(this.application as unknown) = undefined
+
+    this.eventObservers.forEach((removeObserver) => {
+      removeObserver()
+    })
+
+    this.changeObservers.length = 0
+
+    for (const controller of this.itemControllers) {
+      this.closeItemController(controller, { notify: false })
+    }
+
+    this.itemControllers.length = 0
+  }
+
+  async createItemController(options: CreateItemControllerOptions): Promise<NoteViewController | FileViewController> {
+    if (this.activeItemViewController) {
+      this.closeItemController(this.activeItemViewController, { notify: false })
+    }
+
+    let controller!: NoteViewController | FileViewController
+
+    if (options instanceof FileItem) {
+      const file = options
+      controller = new FileViewController(this.application, file)
+    } else if (options instanceof SNNote) {
+      const note = options
+      controller = new NoteViewController(this.application, note)
+    } else {
+      controller = new NoteViewController(this.application, undefined, options)
+    }
+
+    this.itemControllers.push(controller)
+
+    await controller.initialize(this.addTagHierarchy)
+
+    this.notifyObservers()
+
+    return controller
+  }
+
+  public closeItemController(
+    controller: NoteViewController | FileViewController,
+    { notify = true }: { notify: boolean } = { notify: true },
+  ): void {
+    controller.deinit()
+
+    removeFromArray(this.itemControllers, controller)
+
+    if (notify) {
+      this.notifyObservers()
+    }
+  }
+
+  closeActiveItemController(): void {
+    const activeController = this.activeItemViewController
+
+    if (activeController) {
+      this.closeItemController(activeController, { notify: true })
+    }
+  }
+
+  closeAllItemControllers(): void {
+    for (const controller of this.itemControllers) {
+      this.closeItemController(controller, { notify: false })
+    }
+
+    this.notifyObservers()
+  }
+
+  get activeItemViewController(): NoteViewController | FileViewController | undefined {
+    return this.itemControllers[0]
+  }
+
+  /**
+   * Notifies observer when the active controller has changed.
+   */
+  public addActiveControllerChangeObserver(callback: ItemControllerGroupChangeCallback): () => void {
+    this.changeObservers.push(callback)
+
+    if (this.activeItemViewController) {
+      callback(this.activeItemViewController)
+    }
+
+    const thislessChangeObservers = this.changeObservers
+    return () => {
+      removeFromArray(thislessChangeObservers, callback)
+    }
+  }
+
+  private notifyObservers(): void {
+    for (const observer of this.changeObservers) {
+      observer(this.activeItemViewController)
+    }
+  }
+}