Switched offer unsaved changes modal to new modal pattern

refs https://github.com/TryGhost/Team/issues/1734
refs https://github.com/TryGhost/Team/issues/559
refs https://github.com/TryGhost/Ghost/issues/14101

- switches to newer modal patterns ready for later Ember upgrades

ghost/admin/app/controllers/offer.js

@@ -24,7 +24,6 @@ export default class OffersController extends Controller {
     @tracked cadences = [];
     @tracked tiers = [];
     @tracked portalPreviewUrl = '';
-    @tracked showUnsavedChangesModal = false;
 
     @tracked defaultSiteUrl = this.config.get('blogUrl');
 
@@ -58,7 +57,6 @@ export default class OffersController extends Controller {
     @tracked isDisplayTitleEdited = false;
     @tracked isOfferCodeEdited = false;
 
-    leaveScreenTransition = null;
     portalPreviewGuid = Date.now().valueOf();
 
     constructor() {
@@ -255,37 +253,6 @@ export default class OffersController extends Controller {
         return this.saveTask.perform();
     }
 
-    @action
-    leaveScreen() {
-        this.offer.rollbackAttributes();
-        return this.leaveScreenTransition.retry();
-    }
-
-    @action
-    toggleUnsavedChangesModal(transition) {
-        let leaveTransition = this.leaveScreenTransition;
-
-        if (!transition && this.showUnsavedChangesModal) {
-            this.leaveScreenTransition = null;
-            this.showUnsavedChangesModal = false;
-            return;
-        }
-
-        if (!leaveTransition || transition.targetName === leaveTransition.targetName) {
-            this.leaveScreenTransition = transition;
-
-            // if a save is running, wait for it to finish then transition
-            if (this.save.isRunning) {
-                return this.save.last.then(() => {
-                    transition.retry();
-                });
-            }
-
-            // we genuinely have unsaved data, show the modal
-            this.showUnsavedChangesModal = true;
-        }
-    }
-
     @action
     setup() {
         this.fetchTiers.perform();

ghost/admin/app/routes/offer.js

@@ -1,19 +1,14 @@
 import AdminRoute from 'ghost-admin/routes/admin';
+import ConfirmUnsavedChangesModal from '../components/modals/confirm-unsaved-changes';
 import {action} from '@ember/object';
 import {inject as service} from '@ember/service';
 
 export default class OffersRoute extends AdminRoute {
+    @service modals;
     @service router;
 
     _requiresBackgroundRefresh = true;
 
-    constructor() {
-        super(...arguments);
-        this.router.on('routeWillChange', (transition) => {
-            this.showUnsavedChangesModal(transition);
-        });
-    }
-
     model(params) {
         this._requiresBackgroundRefresh = false;
 
@@ -26,6 +21,7 @@ export default class OffersRoute extends AdminRoute {
 
     setupController(controller, offer) {
         super.setupController(...arguments);
+
         if (this._requiresBackgroundRefresh) {
             // `offer` is passed directly in `<LinkTo>` so it can be a proxy
             // object used by the sparse list requiring the use of .get()
@@ -34,12 +30,47 @@ export default class OffersRoute extends AdminRoute {
     }
 
     deactivate() {
-        super.deactivate(...arguments);
         // clean up newly created records and revert unsaved changes to existing
         this.controller.offer.rollbackAttributes();
         this._requiresBackgroundRefresh = true;
     }
 
+    @action
+    async willTransition(transition) {
+        if (this.hasConfirmed) {
+            return true;
+        }
+
+        transition.abort();
+
+        // wait for any existing confirm modal to be closed before allowing transition
+        if (this.confirmModal) {
+            return;
+        }
+
+        const shouldLeave = await this.confirmUnsavedChanges();
+
+        if (shouldLeave) {
+            this.controller.model.rollbackAttributes();
+            this.hasConfirmed = true;
+            return transition.retry();
+        }
+    }
+
+    async confirmUnsavedChanges() {
+        if (this.controller.model?.hasDirtyAttributes) {
+            this.confirmModal = this.modals
+                .open(ConfirmUnsavedChangesModal)
+                .finally(() => {
+                    this.confirmModal = null;
+                });
+
+            return this.confirmModal;
+        }
+
+        return true;
+    }
+
     @action
     save() {
         this.controller.save();
@@ -48,19 +79,4 @@ export default class OffersRoute extends AdminRoute {
     titleToken() {
         return this.controller.offer.name;
     }
-
-    showUnsavedChangesModal(transition) {
-        if (transition.from && transition.from.name === this.routeName && transition.targetName) {
-            let {controller} = this;
-
-            // offer.changedAttributes is always true for new offers but number of changed attrs is reliable
-            let isChanged = Object.keys(controller.offer.changedAttributes()).length > 0;
-
-            if (!controller.offer.isDeleted && isChanged) {
-                transition.abort();
-                controller.toggleUnsavedChangesModal(transition);
-                return;
-            }
-        }
-    }
 }

ghost/admin/app/templates/offer.hbs

@@ -342,11 +342,3 @@
         </div>
     </section>
 </section>
-
-{{#if this.showUnsavedChangesModal}}
-    <GhFullscreenModal
-        @modal="leave-settings"
-        @confirm={{this.leaveScreen}}
-        @close={{this.toggleUnsavedChangesModal}}
-        @modifier="action wide" />
-{{/if}}