Collapse all comments but draft when showing threads in the reply dialog

Change-Id: I2d5d826fded70c8682ca989c14907609e8beb60a

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js

@@ -820,7 +820,7 @@ class GrChangeView extends mixinBehaviors( [
     // in the comment thread view.
     this._reloadDrafts().then(() => {
       this._commentThreads = this._changeComments.getAllThreadsForChange()
-          .map(c => Object.assign({}, c));
+          .map(thread => { return {...thread}; });
       flush();
     });
   }
@@ -1725,11 +1725,19 @@ class GrChangeView extends mixinBehaviors( [
 
   _recomputeComments(comments) {
     this._changeComments = comments;
-    this._diffDrafts = Object.assign({}, this._changeComments.drafts);
+    this._diffDrafts = {...this._changeComments.drafts};
     this._commentThreads = this._changeComments.getAllThreadsForChange()
-        .map(c => Object.assign({}, c));
+        .map(thread => { return {...thread}; });
     this._draftCommentThreads = this._commentThreads
-        .filter(c => c.comments[c.comments.length - 1].__draft);
+        .filter(thread => thread.comments[thread.comments.length - 1].__draft)
+        .map(thread => {
+          const copiedThread = {...thread};
+          // Make a hardcopy of all comments and collapse all but last one
+          const commentsInThread = copiedThread.comments = thread.comments
+              .map(comment => { return {...comment, collapsed: true}; });
+          commentsInThread[commentsInThread.length - 1].collapsed = false;
+          return copiedThread;
+        });
   }
 
   /**

polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html

@@ -76,6 +76,7 @@ suite('gr-change-view tests', () => {
 
   const ROBOT_COMMENTS_LIMIT = 10;
 
+  // TODO: should have a mock service to generate VALID fake data
   const THREADS = [
     {
       comments: [
@@ -88,7 +89,7 @@ suite('gr-change-view tests', () => {
           },
           patch_set: 2,
           robot_id: 'rb1',
-          id: 'ecf9fa_fe1a5f62',
+          id: 'ecf0b9fa_fe1a5f62',
           line: 5,
           updated: '2018-02-08 18:49:18.000000000',
           message: 'test',
@@ -102,7 +103,7 @@ suite('gr-change-view tests', () => {
             username: 'user',
           },
           patch_set: 4,
-          id: 'ecf0b9fa_fe1a5f62',
+          id: 'ecf0b9fa_fe1a5f62_1',
           line: 5,
           updated: '2018-02-08 18:49:18.000000000',
           message: 'test',
@@ -714,6 +715,56 @@ suite('gr-change-view tests', () => {
     });
   });
 
+  suite('_recomputeComments', () => {
+    setup(() => {
+      // Fake computeDraftCount as its required for ChangeComments,
+      // see gr-comment-api#reloadDrafts.
+      sandbox.stub(element.$.commentAPI, 'reloadDrafts')
+          .returns(Promise.resolve({
+            drafts: {},
+            getAllThreadsForChange: () => THREADS,
+            computeDraftCount: () => 0,
+          }));
+    });
+
+    test('draft threads should be a new copy with correct states', done => {
+      element.$.fileList.dispatchEvent(
+          new CustomEvent('reload-drafts', {
+            detail: {
+              resolve: () => {
+                assert.equal(element._draftCommentThreads.length, 2);
+                assert.equal(
+                    element._draftCommentThreads[0].rootId,
+                    THREADS[0].rootId
+                );
+                assert.notEqual(
+                    element._draftCommentThreads[0].comments,
+                    THREADS[0].comments
+                );
+                assert.notEqual(
+                    element._draftCommentThreads[0].comments[0],
+                    THREADS[0].comments[0]
+                );
+                assert.isTrue(
+                    element._draftCommentThreads[0]
+                        .comments
+                        .slice(0, 2)
+                        .every(c => c.collapsed === true)
+                );
+
+                assert.isTrue(
+                    element._draftCommentThreads[0]
+                        .comments[2]
+                        .collapsed === false
+                );
+                done();
+              },
+            },
+            composed: true, bubbles: true,
+          }));
+    });
+  });
+
   test('diff comments modified', () => {
     sandbox.spy(element, '_handleReloadCommentThreads');
     return element._reloadComments().then(() => {