diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-add-upload.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-add-upload.js
index 876ac3ae9ae..f1adac356a4 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-add-upload.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-add-upload.js
@@ -1,6 +1,8 @@
-import Controller, { inject as controller } from "@ember/controller";
+import { action } from "@ember/object";
 import { and, not } from "@ember/object/computed";
-import discourseComputed, { observes } from "discourse-common/utils/decorators";
+import Controller, { inject as controller } from "@ember/controller";
+import discourseComputed from "discourse-common/utils/decorators";
+import { observes } from "@ember-decorators/object";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { ajax } from "discourse/lib/ajax";
@@ -53,18 +55,20 @@ const SCSS_VARIABLE_NAMES = [
   "love-low",
 ];
 
-export default Controller.extend(ModalFunctionality, {
-  adminCustomizeThemesShow: controller(),
+export default class AdminAddUploadController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminCustomizeThemesShow;
 
-  uploadUrl: "/admin/themes/upload_asset",
+  uploadUrl = "/admin/themes/upload_asset";
+
+  @and("nameValid", "fileSelected") enabled;
+  @not("enabled") disabled;
 
   onShow() {
     this.set("name", null);
     this.set("fileSelected", false);
-  },
-
-  enabled: and("nameValid", "fileSelected"),
-  disabled: not("enabled"),
+  }
 
   @discourseComputed("name", "adminCustomizeThemesShow.model.theme_fields")
   errorMessage(name, themeFields) {
@@ -89,54 +93,54 @@ export default Controller.extend(ModalFunctionality, {
     }
 
     return null;
-  },
+  }
 
   @discourseComputed("errorMessage")
   nameValid(errorMessage) {
     return null === errorMessage;
-  },
+  }
 
   @observes("name")
   uploadChanged() {
     const file = $("#file-input")[0];
     this.set("fileSelected", file && file.files[0]);
-  },
+  }
 
-  actions: {
-    updateName() {
-      let name = this.name;
-      if (isEmpty(name)) {
-        name = $("#file-input")[0].files[0].name;
-        this.set("name", name.split(".")[0]);
-      }
-      this.uploadChanged();
-    },
+  @action
+  updateName() {
+    let name = this.name;
+    if (isEmpty(name)) {
+      name = $("#file-input")[0].files[0].name;
+      this.set("name", name.split(".")[0]);
+    }
+    this.uploadChanged();
+  }
 
-    upload() {
-      const file = $("#file-input")[0].files[0];
+  @action
+  upload() {
+    const file = $("#file-input")[0].files[0];
 
-      const options = {
-        type: "POST",
-        processData: false,
-        contentType: false,
-        data: new FormData(),
-      };
+    const options = {
+      type: "POST",
+      processData: false,
+      contentType: false,
+      data: new FormData(),
+    };
 
-      options.data.append("file", file);
+    options.data.append("file", file);
 
-      ajax(this.uploadUrl, options)
-        .then((result) => {
-          const upload = {
-            upload_id: result.upload_id,
-            name: this.name,
-            original_filename: file.name,
-          };
-          this.adminCustomizeThemesShow.send("addUpload", upload);
-          this.send("closeModal");
-        })
-        .catch((e) => {
-          popupAjaxError(e);
-        });
-    },
-  },
-});
+    ajax(this.uploadUrl, options)
+      .then((result) => {
+        const upload = {
+          upload_id: result.upload_id,
+          name: this.name,
+          original_filename: file.name,
+        };
+        this.adminCustomizeThemesShow.send("addUpload", upload);
+        this.send("closeModal");
+      })
+      .catch((e) => {
+        popupAjaxError(e);
+      });
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-badge-preview.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-badge-preview.js
index 322436303f9..f86c04e56e2 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-badge-preview.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-badge-preview.js
@@ -4,39 +4,12 @@ import I18n from "I18n";
 import discourseComputed from "discourse-common/utils/decorators";
 import { escapeExpression } from "discourse/lib/utilities";
 
-export default Controller.extend({
-  sample: alias("model.sample"),
-  errors: alias("model.errors"),
-  count: alias("model.grant_count"),
+export default class AdminBadgePreviewController extends Controller {
+  @alias("model.sample") sample;
+  @alias("model.errors") errors;
+  @alias("model.grant_count") count;
 
-  @discourseComputed("count", "sample.length")
-  countWarning(count, sampleLength) {
-    if (count <= 10) {
-      return sampleLength !== count;
-    } else {
-      return sampleLength !== 10;
-    }
-  },
-
-  @discourseComputed("model.query_plan")
-  hasQueryPlan(queryPlan) {
-    return !!queryPlan;
-  },
-
-  @discourseComputed("model.query_plan")
-  queryPlanHtml(queryPlan) {
-    let output = `<pre class="badge-query-plan">`;
-
-    queryPlan.forEach((linehash) => {
-      output += escapeExpression(linehash["QUERY PLAN"]);
-      output += "<br>";
-    });
-
-    output += "</pre>";
-    return output;
-  },
-
-  processedSample: map("model.sample", (grant) => {
+  @map("model.sample", (grant) => {
     let i18nKey = "admin.badges.preview.grant.with";
     const i18nParams = { username: escapeExpression(grant.username) };
 
@@ -55,5 +28,33 @@ export default Controller.extend({
     }
 
     return I18n.t(i18nKey, i18nParams);
-  }),
-});
+  })
+  processedSample;
+
+  @discourseComputed("count", "sample.length")
+  countWarning(count, sampleLength) {
+    if (count <= 10) {
+      return sampleLength !== count;
+    } else {
+      return sampleLength !== 10;
+    }
+  }
+
+  @discourseComputed("model.query_plan")
+  hasQueryPlan(queryPlan) {
+    return !!queryPlan;
+  }
+
+  @discourseComputed("model.query_plan")
+  queryPlanHtml(queryPlan) {
+    let output = `<pre class="badge-query-plan">`;
+
+    queryPlan.forEach((linehash) => {
+      output += escapeExpression(linehash["QUERY PLAN"]);
+      output += "<br>";
+    });
+
+    output += "</pre>";
+    return output;
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-color-scheme-select-base.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-color-scheme-select-base.js
index 07f673728fe..81892e0404b 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-color-scheme-select-base.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-color-scheme-select-base.js
@@ -1,27 +1,29 @@
+import { action } from "@ember/object";
 import Controller, { inject as controller } from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 
-export default Controller.extend(ModalFunctionality, {
-  adminCustomizeColors: controller(),
+export default class AdminColorSchemeSelectBaseController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminCustomizeColors;
 
-  selectedBaseThemeId: null,
+  selectedBaseThemeId = null;
 
   init() {
-    this._super(...arguments);
+    super.init(...arguments);
 
     const defaultScheme = this.get(
       "adminCustomizeColors.baseColorSchemes.0.base_scheme_id"
     );
     this.set("selectedBaseThemeId", defaultScheme);
-  },
+  }
 
-  actions: {
-    selectBase() {
-      this.adminCustomizeColors.send(
-        "newColorSchemeWithBase",
-        this.selectedBaseThemeId
-      );
-      this.send("closeModal");
-    },
-  },
-});
+  @action
+  selectBase() {
+    this.adminCustomizeColors.send(
+      "newColorSchemeWithBase",
+      this.selectedBaseThemeId
+    );
+    this.send("closeModal");
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-posts-confirmation.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-posts-confirmation.js
index 106b459f0ce..b07fa7f7830 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-posts-confirmation.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-posts-confirmation.js
@@ -1,18 +1,21 @@
+import { alias } from "@ember/object/computed";
 import Controller, { inject as controller } from "@ember/controller";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { action } from "@ember/object";
-import { alias } from "@ember/object/computed";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default Controller.extend(ModalFunctionality, {
-  adminUserIndex: controller(),
-  username: alias("model.username"),
-  postCount: alias("model.post_count"),
+export default class AdminDeletePostsConfirmationController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminUserIndex;
+
+  @alias("model.username") username;
+  @alias("model.post_count") postCount;
 
   onShow() {
     this.set("value", null);
-  },
+  }
 
   @discourseComputed("username", "postCount")
   text(username, postCount) {
@@ -20,27 +23,27 @@ export default Controller.extend(ModalFunctionality, {
       username,
       postCount,
     });
-  },
+  }
 
   @discourseComputed("username")
   deleteButtonText(username) {
     return I18n.t(`admin.user.delete_posts.confirmation.delete`, {
       username,
     });
-  },
+  }
 
   @discourseComputed("value", "text")
   deleteDisabled(value, text) {
     return !value || text !== value;
-  },
+  }
 
   @action
   confirm() {
     this.adminUserIndex.send("deleteAllPosts");
-  },
+  }
 
   @action
   close() {
     this.send("closeModal");
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-user-posts-progress.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-user-posts-progress.js
index 61b9bae999c..62723a4ab3f 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-user-posts-progress.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-delete-user-posts-progress.js
@@ -1,6 +1,8 @@
 import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 
-export default Controller.extend(ModalFunctionality, {
-  deletedPercentage: 0,
-});
+export default class AdminDeleteUserPostsProgressController extends Controller.extend(
+  ModalFunctionality
+) {
+  deletedPercentage = 0;
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-edit-badge-groupings.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-edit-badge-groupings.js
index c453a4f8b41..d23b9131ed1 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-edit-badge-groupings.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-edit-badge-groupings.js
@@ -1,13 +1,16 @@
+import { action } from "@ember/object";
+import { inject as service } from "@ember/service";
 import { A } from "@ember/array";
 import Controller from "@ember/controller";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { ajax } from "discourse/lib/ajax";
 import { observes } from "discourse-common/utils/decorators";
-import { inject as service } from "@ember/service";
 
-export default Controller.extend(ModalFunctionality, {
-  dialog: service(),
+export default class AdminEditBadgeGroupingsController extends Controller.extend(
+  ModalFunctionality
+) {
+  @service dialog;
 
   @observes("model")
   modelChanged() {
@@ -22,7 +25,7 @@ export default Controller.extend(ModalFunctionality, {
     }
 
     this.set("workingCopy", copy);
-  },
+  }
 
   moveItem(item, delta) {
     const copy = this.workingCopy;
@@ -33,55 +36,68 @@ export default Controller.extend(ModalFunctionality, {
 
     copy.removeAt(index);
     copy.insertAt(index + delta, item);
-  },
+  }
 
-  actions: {
-    up(item) {
-      this.moveItem(item, -1);
-    },
-    down(item) {
-      this.moveItem(item, 1);
-    },
-    delete(item) {
-      this.workingCopy.removeObject(item);
-    },
-    cancel() {
-      this.setProperties({ model: null, workingCopy: null });
-      this.send("closeModal");
-    },
-    edit(item) {
-      item.set("editing", true);
-    },
-    save(item) {
-      item.set("editing", false);
-    },
-    add() {
-      const obj = this.store.createRecord("badge-grouping", {
-        editing: true,
-        name: I18n.t("admin.badges.badge_grouping"),
-      });
-      this.workingCopy.pushObject(obj);
-    },
-    saveAll() {
-      let items = this.workingCopy;
-      const groupIds = items.map((i) => i.get("id") || -1);
-      const names = items.map((i) => i.get("name"));
+  @action
+  up(item) {
+    this.moveItem(item, -1);
+  }
 
-      ajax("/admin/badges/badge_groupings", {
-        data: { ids: groupIds, names },
-        type: "POST",
-      }).then(
-        (data) => {
-          items = this.model;
-          items.clear();
-          data.badge_groupings.forEach((g) => {
-            items.pushObject(this.store.createRecord("badge-grouping", g));
-          });
-          this.setProperties({ model: null, workingCopy: null });
-          this.send("closeModal");
-        },
-        () => this.dialog.alert(I18n.t("generic_error"))
-      );
-    },
-  },
-});
+  @action
+  down(item) {
+    this.moveItem(item, 1);
+  }
+
+  @action
+  delete(item) {
+    this.workingCopy.removeObject(item);
+  }
+
+  @action
+  cancel() {
+    this.setProperties({ model: null, workingCopy: null });
+    this.send("closeModal");
+  }
+
+  @action
+  edit(item) {
+    item.set("editing", true);
+  }
+
+  @action
+  save(item) {
+    item.set("editing", false);
+  }
+
+  @action
+  add() {
+    const obj = this.store.createRecord("badge-grouping", {
+      editing: true,
+      name: I18n.t("admin.badges.badge_grouping"),
+    });
+    this.workingCopy.pushObject(obj);
+  }
+
+  @action
+  saveAll() {
+    let items = this.workingCopy;
+    const groupIds = items.map((i) => i.get("id") || -1);
+    const names = items.map((i) => i.get("name"));
+
+    ajax("/admin/badges/badge_groupings", {
+      data: { ids: groupIds, names },
+      type: "POST",
+    }).then(
+      (data) => {
+        items = this.model;
+        items.clear();
+        data.badge_groupings.forEach((g) => {
+          items.pushObject(this.store.createRecord("badge-grouping", g));
+        });
+        this.setProperties({ model: null, workingCopy: null });
+        this.send("closeModal");
+      },
+      () => this.dialog.alert(I18n.t("generic_error"))
+    );
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-incoming-email.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-incoming-email.js
index 6055baa1fe4..3724332cee7 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-incoming-email.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-incoming-email.js
@@ -5,15 +5,17 @@ import discourseComputed from "discourse-common/utils/decorators";
 import { longDate } from "discourse/lib/formatter";
 import { popupAjaxError } from "discourse/lib/ajax-error";
 
-export default Controller.extend(ModalFunctionality, {
+export default class AdminIncomingEmailController extends Controller.extend(
+  ModalFunctionality
+) {
   @discourseComputed("model.date")
   date(d) {
     return longDate(d);
-  },
+  }
 
   load(id) {
     return IncomingEmail.find(id).then((result) => this.set("model", result));
-  },
+  }
 
   loadFromBounced(id) {
     return IncomingEmail.findByBounced(id)
@@ -22,5 +24,5 @@ export default Controller.extend(ModalFunctionality, {
         this.send("closeModal");
         popupAjaxError(error);
       });
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-install-theme.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-install-theme.js
index f96e2f4dc72..a64387f7d94 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-install-theme.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-install-theme.js
@@ -1,46 +1,46 @@
+import { alias, equal, match } from "@ember/object/computed";
 import { COMPONENTS, THEMES } from "admin/models/theme";
 import Controller, { inject as controller } from "@ember/controller";
-import { alias, equal, match } from "@ember/object/computed";
-import discourseComputed, { observes } from "discourse-common/utils/decorators";
+import discourseComputed from "discourse-common/utils/decorators";
+import { observes } from "@ember-decorators/object";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { POPULAR_THEMES } from "discourse-common/helpers/popular-themes";
 import { ajax } from "discourse/lib/ajax";
 import { popupAjaxError } from "discourse/lib/ajax-error";
-import { set } from "@ember/object";
+import { action, set } from "@ember/object";
 
 const MIN_NAME_LENGTH = 4;
 
-export default Controller.extend(ModalFunctionality, {
-  adminCustomizeThemes: controller(),
-  themesController: controller("adminCustomizeThemes"),
-  popular: equal("selection", "popular"),
-  local: equal("selection", "local"),
-  remote: equal("selection", "remote"),
-  create: equal("selection", "create"),
-  directRepoInstall: equal("selection", "directRepoInstall"),
-  selection: "popular",
-  loading: false,
-  keyGenUrl: "/admin/themes/generate_key_pair",
-  importUrl: "/admin/themes/import",
-  recordType: "theme",
-  checkPrivate: match("uploadUrl", /^ssh:\/\/.+@.+$|.+@.+:.+$/),
-  localFile: null,
-  uploadUrl: null,
-  uploadName: null,
-  advancedVisible: false,
-  selectedType: alias("themesController.currentTab"),
-  component: equal("selectedType", COMPONENTS),
-  urlPlaceholder: "https://github.com/discourse/sample_theme",
+export default class AdminInstallThemeController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminCustomizeThemes;
+  @controller("adminCustomizeThemes") themesController;
 
-  init() {
-    this._super(...arguments);
+  @equal("selection", "popular") popular;
+  @equal("selection", "local") local;
+  @equal("selection", "remote") remote;
+  @equal("selection", "create") create;
+  @equal("selection", "directRepoInstall") directRepoInstall;
+  selection = "popular";
+  loading = false;
+  keyGenUrl = "/admin/themes/generate_key_pair";
+  importUrl = "/admin/themes/import";
+  recordType = "theme";
+  @match("uploadUrl", /^ssh:\/\/.+@.+$|.+@.+:.+$/) checkPrivate;
+  localFile = null;
+  uploadUrl = null;
+  uploadName = null;
+  advancedVisible = false;
+  @alias("themesController.currentTab") selectedType;
+  @equal("selectedType", COMPONENTS) component;
+  urlPlaceholder = "https://github.com/discourse/sample_theme";
 
-    this.createTypes = [
-      { name: I18n.t("admin.customize.theme.theme"), value: THEMES },
-      { name: I18n.t("admin.customize.theme.component"), value: COMPONENTS },
-    ];
-  },
+  createTypes = [
+    { name: I18n.t("admin.customize.theme.theme"), value: THEMES },
+    { name: I18n.t("admin.customize.theme.component"), value: COMPONENTS },
+  ];
 
   @discourseComputed("themesController.installedThemes")
   themes(installedThemes) {
@@ -52,7 +52,7 @@ export default Controller.extend(ModalFunctionality, {
       }
       return t;
     });
-  },
+  }
 
   @discourseComputed(
     "loading",
@@ -78,12 +78,12 @@ export default Controller.extend(ModalFunctionality, {
       (isLocal && !localFile) ||
       (isCreate && nameTooShort)
     );
-  },
+  }
 
   @discourseComputed("name")
   nameTooShort(name) {
     return !name || name.length < MIN_NAME_LENGTH;
-  },
+  }
 
   @discourseComputed("component")
   placeholder(component) {
@@ -92,7 +92,7 @@ export default Controller.extend(ModalFunctionality, {
     } else {
       return I18n.t("admin.customize.theme.theme_name");
     }
-  },
+  }
 
   @observes("checkPrivate")
   privateWasChecked() {
@@ -108,7 +108,7 @@ export default Controller.extend(ModalFunctionality, {
           this._keyLoading = false;
         });
     }
-  },
+  }
 
   @discourseComputed("selection", "themeCannotBeInstalled")
   submitLabel(selection, themeCannotBeInstalled) {
@@ -119,12 +119,12 @@ export default Controller.extend(ModalFunctionality, {
     return `admin.customize.theme.${
       selection === "create" ? "create" : "install"
     }`;
-  },
+  }
 
   @discourseComputed("checkPrivate", "publicKey")
   showPublicKey(checkPrivate, publicKey) {
     return checkPrivate && publicKey;
-  },
+  }
 
   onClose() {
     this.setProperties({
@@ -140,7 +140,7 @@ export default Controller.extend(ModalFunctionality, {
       repoName: null,
       repoUrl: null,
     });
-  },
+  }
 
   themeHasSameUrl(theme, url) {
     const themeUrl = theme.remote_theme && theme.remote_theme.remote_url;
@@ -149,100 +149,101 @@ export default Controller.extend(ModalFunctionality, {
       url &&
       url.replace(/\.git$/, "") === themeUrl.replace(/\.git$/, "")
     );
-  },
+  }
 
-  actions: {
-    uploadLocaleFile() {
-      this.set("localFile", $("#file-input")[0].files[0]);
-    },
+  @action
+  uploadLocaleFile() {
+    this.set("localFile", $("#file-input")[0].files[0]);
+  }
 
-    toggleAdvanced() {
-      this.toggleProperty("advancedVisible");
-    },
+  @action
+  toggleAdvanced() {
+    this.toggleProperty("advancedVisible");
+  }
 
-    installThemeFromList(url) {
-      this.set("uploadUrl", url);
-      this.send("installTheme");
-    },
-
-    installTheme() {
-      if (this.create) {
-        this.set("loading", true);
-        const theme = this.store.createRecord(this.recordType);
-        theme
-          .save({ name: this.name, component: this.component })
-          .then(() => {
-            this.themesController.send("addTheme", theme);
-            this.send("closeModal");
-          })
-          .catch(popupAjaxError)
-          .finally(() => this.set("loading", false));
-
-        return;
-      }
-
-      let options = {
-        type: "POST",
-      };
-
-      if (this.local) {
-        options.processData = false;
-        options.contentType = false;
-        options.data = new FormData();
-        options.data.append("theme", this.localFile);
-      }
-
-      if (this.remote || this.popular || this.directRepoInstall) {
-        const duplicate = this.themesController.model.content.find((theme) =>
-          this.themeHasSameUrl(theme, this.uploadUrl)
-        );
-        if (duplicate && !this.duplicateRemoteThemeWarning) {
-          const warning = I18n.t(
-            "admin.customize.theme.duplicate_remote_theme",
-            { name: duplicate.name }
-          );
-          this.set("duplicateRemoteThemeWarning", warning);
-          return;
-        }
-        options.data = {
-          remote: this.uploadUrl,
-          branch: this.branch,
-          public_key: this.publicKey,
-        };
-      }
-
-      // User knows that theme cannot be installed, but they want to continue
-      // to force install it.
-      if (this.themeCannotBeInstalled) {
-        options.data["force"] = true;
-      }
-
-      if (this.get("model.user_id")) {
-        // Used by theme-creator
-        options.data["user_id"] = this.get("model.user_id");
-      }
+  @action
+  installThemeFromList(url) {
+    this.set("uploadUrl", url);
+    this.send("installTheme");
+  }
 
+  @action
+  installTheme() {
+    if (this.create) {
       this.set("loading", true);
-      ajax(this.importUrl, options)
-        .then((result) => {
-          const theme = this.store.createRecord(this.recordType, result.theme);
-          this.adminCustomizeThemes.send("addTheme", theme);
+      const theme = this.store.createRecord(this.recordType);
+      theme
+        .save({ name: this.name, component: this.component })
+        .then(() => {
+          this.themesController.send("addTheme", theme);
           this.send("closeModal");
         })
-        .then(() => {
-          this.set("publicKey", null);
-        })
-        .catch((error) => {
-          if (!this.publicKey || this.themeCannotBeInstalled) {
-            return popupAjaxError(error);
-          }
-
-          this.set(
-            "themeCannotBeInstalled",
-            I18n.t("admin.customize.theme.force_install")
-          );
-        })
+        .catch(popupAjaxError)
         .finally(() => this.set("loading", false));
-    },
-  },
-});
+
+      return;
+    }
+
+    let options = {
+      type: "POST",
+    };
+
+    if (this.local) {
+      options.processData = false;
+      options.contentType = false;
+      options.data = new FormData();
+      options.data.append("theme", this.localFile);
+    }
+
+    if (this.remote || this.popular || this.directRepoInstall) {
+      const duplicate = this.themesController.model.content.find((theme) =>
+        this.themeHasSameUrl(theme, this.uploadUrl)
+      );
+      if (duplicate && !this.duplicateRemoteThemeWarning) {
+        const warning = I18n.t("admin.customize.theme.duplicate_remote_theme", {
+          name: duplicate.name,
+        });
+        this.set("duplicateRemoteThemeWarning", warning);
+        return;
+      }
+      options.data = {
+        remote: this.uploadUrl,
+        branch: this.branch,
+        public_key: this.publicKey,
+      };
+    }
+
+    // User knows that theme cannot be installed, but they want to continue
+    // to force install it.
+    if (this.themeCannotBeInstalled) {
+      options.data["force"] = true;
+    }
+
+    if (this.get("model.user_id")) {
+      // Used by theme-creator
+      options.data["user_id"] = this.get("model.user_id");
+    }
+
+    this.set("loading", true);
+    ajax(this.importUrl, options)
+      .then((result) => {
+        const theme = this.store.createRecord(this.recordType, result.theme);
+        this.adminCustomizeThemes.send("addTheme", theme);
+        this.send("closeModal");
+      })
+      .then(() => {
+        this.set("publicKey", null);
+      })
+      .catch((error) => {
+        if (!this.publicKey || this.themeCannotBeInstalled) {
+          return popupAjaxError(error);
+        }
+
+        this.set(
+          "themeCannotBeInstalled",
+          I18n.t("admin.customize.theme.force_install")
+        );
+      })
+      .finally(() => this.set("loading", false));
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-confirmation.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-confirmation.js
index 7c37ddd0179..24c23e8ed51 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-confirmation.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-confirmation.js
@@ -1,18 +1,21 @@
+import { alias } from "@ember/object/computed";
 import Controller, { inject as controller } from "@ember/controller";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { action } from "@ember/object";
-import { alias } from "@ember/object/computed";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default Controller.extend(ModalFunctionality, {
-  adminUserIndex: controller(),
-  username: alias("model.username"),
-  targetUsername: alias("model.targetUsername"),
+export default class AdminMergeUsersConfirmationController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminUserIndex;
+
+  @alias("model.username") username;
+  @alias("model.targetUsername") targetUsername;
 
   onShow() {
     this.set("value", null);
-  },
+  }
 
   @discourseComputed("username", "targetUsername")
   text(username, targetUsername) {
@@ -20,28 +23,28 @@ export default Controller.extend(ModalFunctionality, {
       username,
       targetUsername,
     });
-  },
+  }
 
   @discourseComputed("username")
   mergeButtonText(username) {
     return I18n.t(`admin.user.merge.confirmation.transfer_and_delete`, {
       username,
     });
-  },
+  }
 
   @discourseComputed("value", "text")
   mergeDisabled(value, text) {
     return !value || text !== value;
-  },
+  }
 
   @action
   confirm() {
     this.adminUserIndex.send("merge", this.targetUsername);
     this.send("closeModal");
-  },
+  }
 
   @action
   close() {
     this.send("closeModal");
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-progress.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-progress.js
index bdbcf2d220c..3c16b7539bd 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-progress.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-progress.js
@@ -4,16 +4,18 @@ import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { bind } from "discourse-common/utils/decorators";
 
-export default Controller.extend(ModalFunctionality, {
-  message: I18n.t("admin.user.merging_user"),
+export default class AdminMergeUsersProgressController extends Controller.extend(
+  ModalFunctionality
+) {
+  message = I18n.t("admin.user.merging_user");
 
   onShow() {
     this.messageBus.subscribe("/merge_user", this.onMessage);
-  },
+  }
 
   onClose() {
     this.messageBus.unsubscribe("/merge_user", this.onMessage);
-  },
+  }
 
   @bind
   onMessage(data) {
@@ -30,5 +32,5 @@ export default Controller.extend(ModalFunctionality, {
     } else if (data.failed) {
       this.set("message", I18n.t("admin.user.merge_failed"));
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-prompt.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-prompt.js
index 46e23305f2b..3b2b86bf4ff 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-prompt.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-merge-users-prompt.js
@@ -1,43 +1,46 @@
+import { alias } from "@ember/object/computed";
 import Controller, { inject as controller } from "@ember/controller";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { action, get } from "@ember/object";
-import { alias } from "@ember/object/computed";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default Controller.extend(ModalFunctionality, {
-  adminUserIndex: controller(),
-  username: alias("model.username"),
+export default class AdminMergeUsersPromptController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminUserIndex;
+
+  @alias("model.username") username;
 
   onShow() {
     this.set("targetUsername", null);
-  },
+  }
 
   @discourseComputed("username", "targetUsername")
   mergeDisabled(username, targetUsername) {
     return !targetUsername || username === targetUsername;
-  },
+  }
 
   @discourseComputed("username")
   mergeButtonText(username) {
     return I18n.t(`admin.user.merge.confirmation.transfer_and_delete`, {
       username,
     });
-  },
+  }
 
   @action
   showConfirmation() {
     this.send("closeModal");
     this.adminUserIndex.send("showMergeConfirmation", this.targetUsername);
-  },
+  }
 
   @action
   close() {
     this.send("closeModal");
-  },
+  }
 
   @action
   updateUsername(selected) {
     this.set("targetUsername", get(selected, "firstObject"));
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-penalize-user.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-penalize-user.js
index 4120bc34ff4..2fde82fe8f2 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-penalize-user.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-penalize-user.js
@@ -1,29 +1,31 @@
+import { inject as service } from "@ember/service";
 import Controller from "@ember/controller";
 import { action } from "@ember/object";
 import { next } from "@ember/runloop";
-import { inject as service } from "@ember/service";
 import { isEmpty } from "@ember/utils";
 import discourseComputed from "discourse-common/utils/decorators";
 import { extractError } from "discourse/lib/ajax-error";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import I18n from "I18n";
 
-export default Controller.extend(ModalFunctionality, {
-  dialog: service(),
+export default class AdminPenalizeUserController extends Controller.extend(
+  ModalFunctionality
+) {
+  @service dialog;
 
-  loadingUser: false,
-  errorMessage: null,
-  penaltyType: null,
-  penalizeUntil: null,
-  reason: null,
-  message: null,
-  postId: null,
-  postAction: null,
-  postEdit: null,
-  user: null,
-  otherUserIds: null,
-  loading: false,
-  confirmClose: false,
+  loadingUser = false;
+  errorMessage = null;
+  penaltyType = null;
+  penalizeUntil = null;
+  reason = null;
+  message = null;
+  postId = null;
+  postAction = null;
+  postEdit = null;
+  user = null;
+  otherUserIds = null;
+  loading = false;
+  confirmClose = false;
 
   onShow() {
     this.setProperties({
@@ -44,11 +46,11 @@ export default Controller.extend(ModalFunctionality, {
       message: null,
       confirmClose: false,
     });
-  },
+  }
 
   finishedSetup() {
     this.set("penalizeUntil", this.user?.next_penalty);
-  },
+  }
 
   beforeClose() {
     if (this.confirmClose) {
@@ -73,7 +75,7 @@ export default Controller.extend(ModalFunctionality, {
 
       return false;
     }
-  },
+  }
 
   @discourseComputed("penaltyType")
   modalTitle(penaltyType) {
@@ -82,7 +84,7 @@ export default Controller.extend(ModalFunctionality, {
     } else if (penaltyType === "silence") {
       return "admin.user.silence_modal_title";
     }
-  },
+  }
 
   @discourseComputed("penaltyType")
   buttonLabel(penaltyType) {
@@ -91,7 +93,7 @@ export default Controller.extend(ModalFunctionality, {
     } else if (penaltyType === "silence") {
       return "admin.user.silence";
     }
-  },
+  }
 
   @discourseComputed(
     "user.penalty_counts.suspended",
@@ -102,7 +104,7 @@ export default Controller.extend(ModalFunctionality, {
       SUSPENDED: suspendedCount,
       SILENCED: silencedCount,
     });
-  },
+  }
 
   @discourseComputed("penaltyType", "user.canSuspend", "user.canSilence")
   canPenalize(penaltyType, canSuspend, canSilence) {
@@ -113,12 +115,12 @@ export default Controller.extend(ModalFunctionality, {
     }
 
     return false;
-  },
+  }
 
   @discourseComputed("penalizing", "penalizeUntil", "reason")
   submitDisabled(penalizing, penalizeUntil, reason) {
     return penalizing || isEmpty(penalizeUntil) || !reason || reason.length < 1;
-  },
+  }
 
   @action
   async penalizeUser() {
@@ -164,5 +166,5 @@ export default Controller.extend(ModalFunctionality, {
     } finally {
       this.set("penalizing", false);
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-reseed.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-reseed.js
index 744921b02a5..bc84df55b49 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-reseed.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-reseed.js
@@ -1,15 +1,19 @@
+import { action } from "@ember/object";
+import { inject as service } from "@ember/service";
 import Controller from "@ember/controller";
 import I18n from "I18n";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { ajax } from "discourse/lib/ajax";
-import { inject as service } from "@ember/service";
 
-export default Controller.extend(ModalFunctionality, {
-  dialog: service(),
-  loading: true,
-  reseeding: false,
-  categories: null,
-  topics: null,
+export default class AdminReseedController extends Controller.extend(
+  ModalFunctionality
+) {
+  @service dialog;
+
+  loading = true;
+  reseeding = false;
+  categories = null;
+  topics = null;
 
   onShow() {
     ajax("/admin/customize/reseed")
@@ -20,27 +24,26 @@ export default Controller.extend(ModalFunctionality, {
         });
       })
       .finally(() => this.set("loading", false));
-  },
+  }
 
   _extractSelectedIds(items) {
     return items.filter((item) => item.selected).map((item) => item.id);
-  },
+  }
 
-  actions: {
-    reseed() {
-      this.set("reseeding", true);
-      ajax("/admin/customize/reseed", {
-        data: {
-          category_ids: this._extractSelectedIds(this.categories),
-          topic_ids: this._extractSelectedIds(this.topics),
-        },
-        type: "POST",
-      })
-        .catch(() => this.dialog.alert(I18n.t("generic_error")))
-        .finally(() => {
-          this.set("reseeding", false);
-          this.send("closeModal");
-        });
-    },
-  },
-});
+  @action
+  reseed() {
+    this.set("reseeding", true);
+    ajax("/admin/customize/reseed", {
+      data: {
+        category_ids: this._extractSelectedIds(this.categories),
+        topic_ids: this._extractSelectedIds(this.topics),
+      },
+      type: "POST",
+    })
+      .catch(() => this.dialog.alert(I18n.t("generic_error")))
+      .finally(() => {
+        this.set("reseeding", false);
+        this.send("closeModal");
+      });
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-staff-action-log-details.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-staff-action-log-details.js
index 06110e01130..7859abf24aa 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-staff-action-log-details.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-staff-action-log-details.js
@@ -1,4 +1,6 @@
 import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 
-export default Controller.extend(ModalFunctionality);
+export default class AdminStaffActionLogDetailsController extends Controller.extend(
+  ModalFunctionality
+) {}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-start-backup.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-start-backup.js
index f60908b0e2a..39e859cd8b7 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-start-backup.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-start-backup.js
@@ -1,35 +1,39 @@
+import { action } from "@ember/object";
 import Controller, { inject as controller } from "@ember/controller";
 import discourseComputed from "discourse-common/utils/decorators";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 
-export default Controller.extend(ModalFunctionality, {
-  adminBackupsLogs: controller(),
+export default class AdminStartBackupController extends Controller.extend(
+  ModalFunctionality
+) {
+  @controller adminBackupsLogs;
 
   @discourseComputed
   warningMessage() {
     // this is never shown here, but we may want to show different
     // messages in plugins
     return "";
-  },
+  }
 
   @discourseComputed
   yesLabel() {
     return "yes_value";
-  },
+  }
 
-  actions: {
-    startBackupWithUploads() {
-      this.send("closeModal");
-      this.send("startBackup", true);
-    },
+  @action
+  startBackupWithUploads() {
+    this.send("closeModal");
+    this.send("startBackup", true);
+  }
 
-    startBackupWithoutUploads() {
-      this.send("closeModal");
-      this.send("startBackup", false);
-    },
+  @action
+  startBackupWithoutUploads() {
+    this.send("closeModal");
+    this.send("startBackup", false);
+  }
 
-    cancel() {
-      this.send("closeModal");
-    },
-  },
-});
+  @action
+  cancel() {
+    this.send("closeModal");
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-theme-change.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-theme-change.js
index 3f58f36d2e1..56e85076019 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-theme-change.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-theme-change.js
@@ -2,7 +2,9 @@ import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import { ajax } from "discourse/lib/ajax";
 
-export default Controller.extend(ModalFunctionality, {
+export default class AdminThemeChangeController extends Controller.extend(
+  ModalFunctionality
+) {
   loadDiff() {
     this.set("loading", true);
     ajax(
@@ -11,5 +13,5 @@ export default Controller.extend(ModalFunctionality, {
       this.set("loading", false);
       this.set("diff", diff.side_by_side);
     });
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-uploaded-image-list.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-uploaded-image-list.js
index 8a60037a5ba..0b1503a83d7 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-uploaded-image-list.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-uploaded-image-list.js
@@ -1,30 +1,32 @@
-import { observes, on } from "discourse-common/utils/decorators";
+import { observes, on } from "@ember-decorators/object";
 import Controller from "@ember/controller";
 import { action } from "@ember/object";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 
-export default Controller.extend(ModalFunctionality, {
+export default class AdminUploadedImageListController extends Controller.extend(
+  ModalFunctionality
+) {
   @on("init")
   @observes("model.value")
   _setup() {
     const value = this.get("model.value");
     this.set("images", value && value.length ? value.split("|") : []);
-  },
+  }
 
   @action
   remove(url, event) {
     event?.preventDefault();
     this.images.removeObject(url);
-  },
+  }
 
-  actions: {
-    uploadDone({ url }) {
-      this.images.addObject(url);
-    },
+  @action
+  uploadDone({ url }) {
+    this.images.addObject(url);
+  }
 
-    close() {
-      this.save(this.images.join("|"));
-      this.send("closeModal");
-    },
-  },
-});
+  @action
+  close() {
+    this.save(this.images.join("|"));
+    this.send("closeModal");
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/admin-watched-word-test.js b/app/assets/javascripts/admin/addon/controllers/modals/admin-watched-word-test.js
index fc585c47ef6..5b8f9f3b132 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/admin-watched-word-test.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/admin-watched-word-test.js
@@ -1,16 +1,19 @@
+import { equal } from "@ember/object/computed";
 import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import discourseComputed from "discourse-common/utils/decorators";
-import { equal } from "@ember/object/computed";
 import {
   createWatchedWordRegExp,
   toWatchedWord,
 } from "discourse-common/utils/watched-words";
 
-export default Controller.extend(ModalFunctionality, {
-  isReplace: equal("model.nameKey", "replace"),
-  isTag: equal("model.nameKey", "tag"),
-  isLink: equal("model.nameKey", "link"),
+export default class AdminWatchedWordTestController extends Controller.extend(
+  ModalFunctionality
+) {
+  @equal("model.nameKey", "replace") isReplace;
+
+  @equal("model.nameKey", "tag") isTag;
+  @equal("model.nameKey", "link") isLink;
 
   @discourseComputed(
     "value",
@@ -71,5 +74,5 @@ export default Controller.extend(ModalFunctionality, {
 
       return matches;
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/admin/addon/controllers/modals/site-setting-default-categories.js b/app/assets/javascripts/admin/addon/controllers/modals/site-setting-default-categories.js
index 8c3a2648989..e7e970578bd 100644
--- a/app/assets/javascripts/admin/addon/controllers/modals/site-setting-default-categories.js
+++ b/app/assets/javascripts/admin/addon/controllers/modals/site-setting-default-categories.js
@@ -2,4 +2,7 @@ import Controller from "@ember/controller";
 import ModalFunctionality from "discourse/mixins/modal-functionality";
 import ModalUpdateExistingUsers from "discourse/mixins/modal-update-existing-users";
 
-export default Controller.extend(ModalFunctionality, ModalUpdateExistingUsers);
+export default class SiteSettingDefaultCategoriesController extends Controller.extend(
+  ModalFunctionality,
+  ModalUpdateExistingUsers
+) {}