refactor: component manager usecases (#2354)

packages/snjs/lib/Services/ComponentManager/UseCase/GetDefaultEditorIdentifier.ts

@@ -0,0 +1,36 @@
+import { Result, SyncUseCaseInterface } from '@standardnotes/domain-core'
+import { ComponentArea, EditorIdentifier, FeatureIdentifier } from '@standardnotes/features'
+import { ComponentInterface, PrefKey, SNTag } from '@standardnotes/models'
+import { ItemManagerInterface, PreferenceServiceInterface } from '@standardnotes/services'
+
+export class GetDefaultEditorIdentifier implements SyncUseCaseInterface<EditorIdentifier> {
+  constructor(private preferences: PreferenceServiceInterface, private items: ItemManagerInterface) {}
+
+  execute(currentTag?: SNTag): Result<EditorIdentifier> {
+    if (currentTag) {
+      const editorIdentifier = currentTag?.preferences?.editorIdentifier
+      if (editorIdentifier) {
+        return Result.ok(editorIdentifier)
+      }
+    }
+
+    const preferenceValue = this.preferences.getValue(PrefKey.DefaultEditorIdentifier)
+    if (preferenceValue) {
+      return Result.ok(preferenceValue)
+    }
+
+    const editors = this.thirdPartyComponentsForArea(ComponentArea.Editor)
+    const matchingEditor = editors.filter((e) => e.legacyIsDefaultEditor())[0]
+    if (matchingEditor) {
+      return Result.ok(matchingEditor.identifier)
+    }
+
+    return Result.ok(FeatureIdentifier.PlainEditor)
+  }
+
+  thirdPartyComponentsForArea(area: ComponentArea): ComponentInterface[] {
+    return this.items.getDisplayableComponents().filter((component) => {
+      return component.area === area
+    })
+  }
+}