refactor: rename states to view controllers (#1060)

app/assets/javascripts/Controllers/FilePreviewModalController.ts

@@ -0,0 +1,34 @@
+import { FileItem } from '@standardnotes/snjs'
+import { action, makeObservable, observable } from 'mobx'
+
+export class FilePreviewModalController {
+  isOpen = false
+  currentFile: FileItem | undefined = undefined
+  otherFiles: FileItem[] = []
+
+  constructor() {
+    makeObservable(this, {
+      isOpen: observable,
+      currentFile: observable,
+      otherFiles: observable,
+
+      activate: action,
+      dismiss: action,
+      setCurrentFile: action,
+    })
+  }
+
+  setCurrentFile = (currentFile: FileItem) => {
+    this.currentFile = currentFile
+  }
+
+  activate = (currentFile: FileItem, otherFiles: FileItem[]) => {
+    this.currentFile = currentFile
+    this.otherFiles = otherFiles
+    this.isOpen = true
+  }
+
+  dismiss = () => {
+    this.isOpen = false
+  }
+}