commit 31825d8f82cda8cf65c4faef8216cbed4268e5af
Author: Ben Rohlfs <brohlfs@google.com>
Date:   Fri Oct 2 18:08:04 2020 +0200

    Change attention set logic to take unresolved state into account
    
    Change-Id: Iea08d3460c949c945a790c3316caf95e6fefe6b1

diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
index 87d443b..ad95b2a 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
@@ -41,7 +41,7 @@ import {
   NumericChangeId,
 } from '../../../types/common';
 import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-import {CommentThread} from '../../diff/gr-comment-api/gr-comment-api';
+import {CommentThread} from '../../../utils/comment-util';
 import {hasOwnProperty} from '../../../utils/common-util';
 
 const PATCH_SET_PREFIX_PATTERN = /^(?:Uploaded\s*)?(?:P|p)atch (?:S|s)et \d+:\s*(.*)/;
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
index bed78df..e85f9e4 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
@@ -411,6 +411,7 @@ class GrMessagesList extends KeyboardShortcutMixin(
     const labels = labelRecord.base;
     if (!labels) { return extremes; }
     for (const key of Object.keys(labels)) {
+      // TODO(TS): Let's use label-util!
       if (!labels[key] || !labels[key].values) { continue; }
       const values = Object.keys(labels[key].values)
           .map(v => parseInt(v, 10));
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
index 0732c0f..a2a75d0 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
@@ -102,12 +102,14 @@ import {
   assertNever,
   containsAll,
 } from '../../../utils/common-util';
-import {CommentThread, isDraft} from '../../diff/gr-comment-api/gr-comment-api';
+import {CommentThread} from '../../../utils/comment-util';
 import {GrTextarea} from '../../shared/gr-textarea/gr-textarea';
 import {GrAccountChip} from '../../shared/gr-account-chip/gr-account-chip';
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {GrStorage, StorageLocation} from '../../shared/gr-storage/gr-storage';
 import {isAttentionSetEnabled} from '../../../utils/attention-set-util';
+import {CODE_REVIEW, getMaxAccounts} from '../../../utils/label-util';
+import {isUnresolved} from '../../../utils/comment-util';
 
 const STORAGE_DEBOUNCE_INTERVAL_MS = 400;
 
@@ -937,7 +939,8 @@ export class GrReplyDialog extends KeyboardShortcutMixin(
     '_reviewers.*',
     '_ccs.*',
     'change',
-    'draftCommentThreads'
+    'draftCommentThreads',
+    '_includeComments'
   )
   _computeNewAttention(
     currentUser?: AccountInfo,
@@ -947,17 +950,22 @@ export class GrReplyDialog extends KeyboardShortcutMixin(
     >,
     _?: PolymerDeepPropertyChange<AccountInfoInput[], AccountInfoInput[]>,
     change?: ChangeInfo,
-    draftCommentThreads?: CommentThread[]
+    draftCommentThreads?: CommentThread[],
+    includeComments?: boolean
   ) {
     if (
       currentUser === undefined ||
       currentUser._account_id === undefined ||
       reviewers === undefined ||
       change === undefined ||
-      draftCommentThreads === undefined
+      draftCommentThreads === undefined ||
+      includeComments === undefined
     ) {
       return;
     }
+    // The draft comments are only relevant for the attention set as long as the
+    // user actually plans to publish their drafts.
+    draftCommentThreads = includeComments ? draftCommentThreads : [];
     this._currentAttentionSet = new Set(
       Object.keys(change.attention_set || {}).map(
         id => parseInt(id) as AccountId
@@ -993,8 +1001,9 @@ export class GrReplyDialog extends KeyboardShortcutMixin(
       }
     } else {
       // The only reason for adding someone to the attention set for merged or
-      // abandoned changes is that someone adds a new comment thread.
-      if (change.owner && this._containsNewCommentThread(draftCommentThreads)) {
+      // abandoned changes is that someone makes a comment thread unresolved.
+      const hasUnresolvedDraft = draftCommentThreads.some(isUnresolved);
+      if (change.owner && hasUnresolvedDraft) {
         // A change owner must have an _account_id.
         newAttention.add(change.owner._account_id!);
       }
@@ -1033,25 +1042,23 @@ export class GrReplyDialog extends KeyboardShortcutMixin(
   }
 
   _computeCommentAccounts(threads: CommentThread[]) {
+    const crLabel = this.change?.labels?.[CODE_REVIEW];
+    const maxCrVoteAccountIds = getMaxAccounts(crLabel).map(a => a._account_id);
     const accountIds = new Set<AccountId>();
     threads.forEach(thread => {
+      const unresolved = isUnresolved(thread);
       thread.comments.forEach(comment => {
         if (comment.author) {
           // A comment author must have an _account_id.
-          accountIds.add(comment.author._account_id!);
+          const authorId = comment.author._account_id!;
+          const hasGivenMaxReviewVote = maxCrVoteAccountIds.includes(authorId);
+          if (unresolved || !hasGivenMaxReviewVote) accountIds.add(authorId);
         }
       });
     });
     return accountIds;
   }
 
-  _containsNewCommentThread(threads: CommentThread[]) {
-    return threads.some(
-      thread =>
-        !!thread.comments && !!thread.comments[0] && isDraft(thread.comments[0])
-    );
-  }
-
   _isNewAttentionEmpty(
     config?: ServerInfo,
     currentAttentionSet?: Set<AccountId>,
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
index 301715c..2e05ed7 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
@@ -203,7 +203,8 @@ suite('gr-reply-dialog tests', () => {
   });
 
   function checkComputeAttention(status, userId, reviewerIds, ownerId,
-      attSetIds, replyToIds, expectedIds, uploaderId, hasDraft) {
+      attSetIds, replyToIds, expectedIds, uploaderId, hasDraft,
+      includeComments = true) {
     const user = {_account_id: userId};
     const reviewers = {base: reviewerIds.map(id => {
       return {_account_id: id};
@@ -212,7 +213,7 @@ suite('gr-reply-dialog tests', () => {
       {comments: []},
     ];
     if (hasDraft) {
-      draftThreads[0].comments.push({__draft: true});
+      draftThreads[0].comments.push({__draft: true, unresolved: true});
     }
     replyToIds.forEach(id => draftThreads[0].comments.push({
       author: {_account_id: id},
@@ -230,7 +231,8 @@ suite('gr-reply-dialog tests', () => {
     element.change = change;
     element._reviewers = reviewers.base;
     flush();
-    element._computeNewAttention(user, reviewers, [], change, draftThreads);
+    element._computeNewAttention(
+        user, reviewers, [], change, draftThreads, includeComments);
     assert.sameMembers([...element._newAttentionSet], expectedIds);
   }
 
@@ -262,6 +264,8 @@ suite('gr-reply-dialog tests', () => {
     checkComputeAttention('MERGED', null, [], 999, [], [], []);
     checkComputeAttention('MERGED', 1, [], 999, [], [], []);
     checkComputeAttention('MERGED', 1, [], 999, [], [], [999], undefined, true);
+    checkComputeAttention(
+        'MERGED', 1, [], 999, [], [], [], undefined, true, false);
     checkComputeAttention('MERGED', 1, [], 999, [1], [], []);
     checkComputeAttention('MERGED', 1, [22], 999, [], [], []);
     checkComputeAttention('MERGED', 1, [22], 999, [22], [], [22]);
@@ -300,6 +304,45 @@ suite('gr-reply-dialog tests', () => {
     assert.sameMembers(compute([999], [7, 123, 999]), [7, 123]);
   });
 
+  test('_computeCommentAccounts', () => {
+    element.change = {
+      labels: {
+        'Code-Review': {
+          all: [
+            {_account_id: 1, value: 0},
+            {_account_id: 2, value: 1},
+            {_account_id: 3, value: 2},
+          ],
+          values: {
+            '-2': 'Do not submit',
+            '-1': 'I would prefer that you didnt submit this',
+            ' 0': 'No score',
+            '+1': 'Looks good to me, but someone else must approve',
+            '+2': 'Looks good to me, approved',
+          },
+        },
+      },
+    };
+    const threads = [
+      {
+        comments: [
+          {author: {_account_id: 1}, unresolved: false},
+          {author: {_account_id: 2}, unresolved: true},
+        ],
+      },
+      {
+        comments: [
+          {author: {_account_id: 3}, unresolved: false},
+          {author: {_account_id: 4}, unresolved: false},
+        ],
+      },
+    ];
+    const actualAccounts = [...element._computeCommentAccounts(threads)];
+    // Account 3 is not included, because the comment is resolved *and* they
+    // have given the highest possible vote on the Code-Review label.
+    assert.sameMembers(actualAccounts, [1, 2, 4]);
+  });
+
   test('toggle resolved checkbox', done => {
     // Async tick is needed because iron-selector content is distributed and
     // distributed content requires an observer to be set up.
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
index 4b02075..7585d16 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.ts
@@ -27,11 +27,7 @@ import {parseDate} from '../../../utils/date-util';
 import {NO_THREADS_MSG} from '../../../constants/messages';
 import {CommentSide, SpecialFilePath} from '../../../constants/constants';
 import {customElement, observe, property} from '@polymer/decorators';
-import {
-  CommentThread,
-  isDraft,
-  UIRobot,
-} from '../../diff/gr-comment-api/gr-comment-api';
+import {CommentThread, isDraft, UIRobot} from '../../../utils/comment-util';
 import {PolymerSpliceChange} from '@polymer/polymer/interfaces';
 import {ChangeInfo} from '../../../types/common';
 
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
index 675a048..2236db2 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.ts
@@ -40,7 +40,7 @@ import {
 import {GrOverlay} from '../../shared/gr-overlay/gr-overlay';
 import {CommentEventDetail} from '../../shared/gr-comment/gr-comment';
 import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-import {isRobot} from '../gr-comment-api/gr-comment-api';
+import {isRobot} from '../../../utils/comment-util';
 
 export interface GrApplyFixDialog {
   $: {
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
index deecdbf..33c1346 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
@@ -19,7 +19,6 @@ import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-l
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-comment-api_html';
-import {parseDate} from '../../../utils/date-util';
 import {
   getParentIndex,
   isMergeParent,
@@ -28,121 +27,33 @@ import {
 import {customElement, property} from '@polymer/decorators';
 import {
   CommentBasics,
-  CommentInfo,
   ConfigInfo,
   ParentPatchSetNum,
   PatchRange,
   PatchSetNum,
   PathToRobotCommentsInfoMap,
   RobotCommentInfo,
-  Timestamp,
   UrlEncodedCommentId,
   NumericChangeId,
 } from '../../../types/common';
 import {hasOwnProperty} from '../../../utils/common-util';
-import {CommentSide, Side} from '../../../constants/constants';
+import {CommentSide} from '../../../constants/constants';
 import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
-
-export interface DraftCommentProps {
-  __draft?: boolean;
-  __draftID?: string;
-  __date?: Date;
-}
-
-export type DraftInfo = CommentBasics & DraftCommentProps;
-
-/**
- * Each of the type implements or extends CommentBasics.
- */
-export type Comment = DraftInfo | CommentInfo | RobotCommentInfo;
-
-export interface UIStateCommentProps {
-  // The `side` of the comment is PARENT or REVISION, but this is LEFT or RIGHT.
-  // TODO(TS): Remove the naming confusion of commentSide being of type of Side,
-  // but side being of type CommentSide. :-)
-  __commentSide?: Side;
-  // TODO(TS): Remove this. Seems to be exactly the same as `path`??
-  __path?: string;
-  collapsed?: boolean;
-  // TODO(TS): Consider allowing this only for drafts.
-  __editing?: boolean;
-  __otherEditing?: boolean;
-}
-
-export type UIDraft = DraftInfo & UIStateCommentProps;
-
-export type UIHuman = CommentInfo & UIStateCommentProps;
-
-export type UIRobot = RobotCommentInfo & UIStateCommentProps;
-
-export type UIComment = UIHuman | UIRobot | UIDraft;
-
-export type CommentMap = {[path: string]: boolean};
-
-export function isRobot<T extends CommentInfo>(
-  x: T | DraftInfo | RobotCommentInfo | undefined
-): x is RobotCommentInfo {
-  return !!x && !!(x as RobotCommentInfo).robot_id;
-}
-
-export function isDraft<T extends CommentInfo>(
-  x: T | UIDraft | undefined
-): x is UIDraft {
-  return !!x && !!(x as UIDraft).__draft;
-}
-
-export interface PatchSetFile {
-  path: string;
-  basePath?: string;
-  patchNum?: PatchSetNum;
-}
-
-export interface PatchNumOnly {
-  patchNum: PatchSetNum;
-}
-
-export function isPatchSetFile(
-  x: PatchSetFile | PatchNumOnly
-): x is PatchSetFile {
-  return !!(x as PatchSetFile).path;
-}
-
-interface SortableComment {
-  __draft?: boolean;
-  __date?: Date;
-  updated?: Timestamp;
-  id?: UrlEncodedCommentId;
-}
-
-export function sortComments<T extends SortableComment>(comments: T[]): T[] {
-  return comments.slice(0).sort((c1, c2) => {
-    const d1 = !!c1.__draft;
-    const d2 = !!c2.__draft;
-    if (d1 !== d2) return d1 ? 1 : -1;
-
-    const date1 = (c1.updated && parseDate(c1.updated)) || c1.__date;
-    const date2 = (c2.updated && parseDate(c2.updated)) || c2.__date;
-    const dateDiff = date1!.valueOf() - date2!.valueOf();
-    if (dateDiff !== 0) return dateDiff;
-
-    const id1 = c1.id ?? '';
-    const id2 = c2.id ?? '';
-    return id1.localeCompare(id2);
-  });
-}
-
-export interface CommentThread {
-  comments: UIComment[];
-  patchNum?: PatchSetNum;
-  path: string;
-  // TODO(TS): It would be nice to use LineNumber here, but the comment thread
-  // element actually relies on line to be undefined for file comments. Be
-  // aware of element attribute getters and setters, if you try to refactor
-  // this. :-) Still worthwhile to do ...
-  line?: number;
-  rootId: UrlEncodedCommentId;
-  commentSide?: CommentSide;
-}
+import {
+  Comment,
+  CommentMap,
+  CommentThread,
+  DraftInfo,
+  isPatchSetFile,
+  isUnresolved,
+  PatchNumOnly,
+  PatchSetFile,
+  sortComments,
+  UIComment,
+  UIDraft,
+  UIHuman,
+  UIRobot,
+} from '../../../utils/comment-util';
 
 export type CommentIdToCommentThreadMap = {
   [urlEncodedCommentId: string]: CommentThread;
@@ -560,15 +471,8 @@ export class ChangeComments {
     }
 
     comments = comments.concat(drafts);
-
     const threads = this.getCommentThreads(sortComments(comments));
-
-    const unresolvedThreads = threads.filter(
-      thread =>
-        thread.comments.length &&
-        thread.comments[thread.comments.length - 1].unresolved
-    );
-
+    const unresolvedThreads = threads.filter(isUnresolved);
     return unresolvedThreads.length;
   }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
index d33e1c1..951a56c 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
@@ -36,9 +36,9 @@ import {
   isDraft,
   PatchSetFile,
   sortComments,
-  TwoSidesComments,
   UIComment,
-} from '../gr-comment-api/gr-comment-api';
+} from '../../../utils/comment-util';
+import {TwoSidesComments} from '../gr-comment-api/gr-comment-api';
 import {customElement, observe, property} from '@polymer/decorators';
 import {
   CommitRange,
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
index 3c12a50..c772d51 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
@@ -20,7 +20,7 @@ import './gr-diff-host.js';
 import {GrDiffBuilderImage} from '../gr-diff-builder/gr-diff-builder-image.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {dom} from '@polymer/polymer/lib/legacy/polymer.dom.js';
-import {sortComments} from '../gr-comment-api/gr-comment-api.js';
+import {sortComments} from '../../../utils/comment-util.js';
 import {Side} from '../../../constants/constants.js';
 
 const basicFixture = fixtureFromElement('gr-diff-host');
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
index fe6a0fd..de283d8 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.ts
@@ -34,7 +34,7 @@ import {
   UIComment,
   UIDraft,
   UIRobot,
-} from '../../diff/gr-comment-api/gr-comment-api';
+} from '../../../utils/comment-util';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {appContext} from '../../../services/app-context';
 import {CommentSide, Side, SpecialFilePath} from '../../../constants/constants';
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js
index 52264ec..1833b73 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_test.js
@@ -19,7 +19,7 @@ import '../../../test/common-test-setup-karma.js';
 import './gr-comment-thread.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {SpecialFilePath} from '../../../constants/constants.js';
-import {sortComments} from '../../diff/gr-comment-api/gr-comment-api.js';
+import {sortComments} from '../../../utils/comment-util.js';
 
 const basicFixture = fixtureFromElement('gr-comment-thread');
 
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index d68da94..9a1d789 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -58,7 +58,7 @@ import {
   UIComment,
   UIDraft,
   UIRobot,
-} from '../../diff/gr-comment-api/gr-comment-api';
+} from '../../../utils/comment-util';
 
 const STORAGE_DEBOUNCE_INTERVAL = 400;
 const TOAST_DEBOUNCE_INTERVAL = 200;
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
index b6e664e..a10f931 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
@@ -40,6 +40,7 @@ import {
 } from '../../../types/common';
 import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
 import {GrButton} from '../gr-button/gr-button';
+import {getVotingRange} from '../../../utils/label-util';
 
 export interface GrLabelInfo {
   $: {
@@ -125,23 +126,20 @@ export class GrLabelInfo extends GestureEventListeners(
     const votes = (labelInfo.all || []).sort(
       (a, b) => (a.value || 0) - (b.value || 0)
     );
-    const values = Object.keys(labelInfo.values || {});
+    const votingRange = getVotingRange(labelInfo);
     for (const label of votes) {
       if (label.value && label.value !== labelInfo.default_value) {
         let labelClassName;
         let labelValPrefix = '';
         if (label.value > 0) {
           labelValPrefix = '+';
-          if (
-            parseInt(`${label.value}`, 10) ===
-            parseInt(values[values.length - 1], 10)
-          ) {
+          if (label.value === votingRange.max) {
             labelClassName = LabelClassName.MAX;
           } else {
             labelClassName = LabelClassName.POSITIVE;
           }
         } else if (label.value < 0) {
-          if (parseInt(`${label.value}`, 10) === parseInt(values[0], 10)) {
+          if (label.value === votingRange.min) {
             labelClassName = LabelClassName.MIN;
           } else {
             labelClassName = LabelClassName.NEGATIVE;
diff --git a/polygerrit-ui/app/types/common.ts b/polygerrit-ui/app/types/common.ts
index caa5f7f..e71f09b 100644
--- a/polygerrit-ui/app/types/common.ts
+++ b/polygerrit-ui/app/types/common.ts
@@ -145,7 +145,8 @@ export type LabelNameToValueMap = {[labelName: string]: string[]};
 export type LabelValueToDescriptionMap = {[labelValue: string]: string};
 
 /**
- * The LabelInfo entity contains information about a label on a change, always corresponding to the current patch set.
+ * The LabelInfo entity contains information about a label on a change, always
+ * corresponding to the current patch set.
  * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#label-info
  */
 export type LabelInfo = QuickLabelInfo | DetailedLabelInfo;
@@ -164,12 +165,24 @@ export interface QuickLabelInfo extends LabelCommonInfo {
   default_value?: number;
 }
 
+/**
+ * LabelInfo when DETAILED_LABELS are requested.
+ * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#_fields_set_by_code_detailed_labels_code
+ */
 export interface DetailedLabelInfo extends LabelCommonInfo {
-  all?: ApprovalInfo[];
-  values?: LabelValueToDescriptionMap; // A map of all values that are allowed for this label
+  // Docs claim that 'all' is optional, but it is actually always set.
+  all: ApprovalInfo[];
+  // Docs claim that 'values' is optional, but it is actually always set.
+  values: LabelValueToDescriptionMap; // A map of all values that are allowed for this label
   default_value?: number;
 }
 
+export function isDetailedLabelInfo(
+  label: LabelInfo
+): label is DetailedLabelInfo {
+  return !!(label as DetailedLabelInfo).values;
+}
+
 // https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#contributor-agreement-input
 export interface ContributorAgreementInput {
   name?: string;
diff --git a/polygerrit-ui/app/utils/attention-set-util_test.js b/polygerrit-ui/app/utils/attention-set-util_test.js
index 0273a33..71735d5 100644
--- a/polygerrit-ui/app/utils/attention-set-util_test.js
+++ b/polygerrit-ui/app/utils/attention-set-util_test.js
@@ -20,6 +20,13 @@ import {
   hasAttention, getReason,
 } from './attention-set-util.js';
 
+const KERMIT = {
+  email: 'kermit@gmail.com',
+  username: 'kermit',
+  name: 'Kermit The Frog',
+  _account_id: '31415926535',
+};
+
 suite('attention-set-util', () => {
   test('hasAttention', () => {
     const config = {
@@ -32,14 +39,8 @@ suite('attention-set-util', () => {
         },
       },
     };
-    const account = {
-      email: 'kermit@gmail.com',
-      username: 'kermit',
-      name: 'Kermit The Frog',
-      _account_id: '31415926535',
-    };
 
-    assert.isTrue(hasAttention(config, account, change));
+    assert.isTrue(hasAttention(config, KERMIT, change));
   });
 
   test('getReason', () => {
@@ -50,13 +51,7 @@ suite('attention-set-util', () => {
         },
       },
     };
-    const account = {
-      email: 'kermit@gmail.com',
-      username: 'kermit',
-      name: 'Kermit The Frog',
-      _account_id: '31415926535',
-    };
 
-    assert.equal(getReason(account, change), 'a good reason');
+    assert.equal(getReason(KERMIT, change), 'a good reason');
   });
 });
diff --git a/polygerrit-ui/app/utils/comment-util.ts b/polygerrit-ui/app/utils/comment-util.ts
new file mode 100644
index 0000000..e598e2b
--- /dev/null
+++ b/polygerrit-ui/app/utils/comment-util.ts
@@ -0,0 +1,140 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  CommentBasics,
+  CommentInfo,
+  PatchSetNum,
+  RobotCommentInfo,
+  Timestamp,
+  UrlEncodedCommentId,
+} from '../types/common';
+import {CommentSide, Side} from '../constants/constants';
+import {parseDate} from './date-util';
+
+export interface DraftCommentProps {
+  __draft?: boolean;
+  __draftID?: string;
+  __date?: Date;
+}
+
+export type DraftInfo = CommentBasics & DraftCommentProps;
+
+/**
+ * Each of the type implements or extends CommentBasics.
+ */
+export type Comment = DraftInfo | CommentInfo | RobotCommentInfo;
+
+export interface UIStateCommentProps {
+  // The `side` of the comment is PARENT or REVISION, but this is LEFT or RIGHT.
+  // TODO(TS): Remove the naming confusion of commentSide being of type of Side,
+  // but side being of type CommentSide. :-)
+  __commentSide?: Side;
+  // TODO(TS): Remove this. Seems to be exactly the same as `path`??
+  __path?: string;
+  collapsed?: boolean;
+  // TODO(TS): Consider allowing this only for drafts.
+  __editing?: boolean;
+  __otherEditing?: boolean;
+}
+
+export type UIDraft = DraftInfo & UIStateCommentProps;
+
+export type UIHuman = CommentInfo & UIStateCommentProps;
+
+export type UIRobot = RobotCommentInfo & UIStateCommentProps;
+
+export type UIComment = UIHuman | UIRobot | UIDraft;
+
+export type CommentMap = {[path: string]: boolean};
+
+export function isRobot<T extends CommentInfo>(
+  x: T | DraftInfo | RobotCommentInfo | undefined
+): x is RobotCommentInfo {
+  return !!x && !!(x as RobotCommentInfo).robot_id;
+}
+
+export function isDraft<T extends CommentInfo>(
+  x: T | UIDraft | undefined
+): x is UIDraft {
+  return !!x && !!(x as UIDraft).__draft;
+}
+
+export interface PatchSetFile {
+  path: string;
+  basePath?: string;
+  patchNum?: PatchSetNum;
+}
+
+export interface PatchNumOnly {
+  patchNum: PatchSetNum;
+}
+
+export function isPatchSetFile(
+  x: PatchSetFile | PatchNumOnly
+): x is PatchSetFile {
+  return !!(x as PatchSetFile).path;
+}
+
+interface SortableComment {
+  __draft?: boolean;
+  __date?: Date;
+  updated?: Timestamp;
+  id?: UrlEncodedCommentId;
+}
+
+export function sortComments<T extends SortableComment>(comments: T[]): T[] {
+  return comments.slice(0).sort((c1, c2) => {
+    const d1 = !!c1.__draft;
+    const d2 = !!c2.__draft;
+    if (d1 !== d2) return d1 ? 1 : -1;
+
+    const date1 = (c1.updated && parseDate(c1.updated)) || c1.__date;
+    const date2 = (c2.updated && parseDate(c2.updated)) || c2.__date;
+    const dateDiff = date1!.valueOf() - date2!.valueOf();
+    if (dateDiff !== 0) return dateDiff;
+
+    const id1 = c1.id ?? '';
+    const id2 = c2.id ?? '';
+    return id1.localeCompare(id2);
+  });
+}
+
+export interface CommentThread {
+  comments: UIComment[];
+  patchNum?: PatchSetNum;
+  path: string;
+  // TODO(TS): It would be nice to use LineNumber here, but the comment thread
+  // element actually relies on line to be undefined for file comments. Be
+  // aware of element attribute getters and setters, if you try to refactor
+  // this. :-) Still worthwhile to do ...
+  line?: number;
+  rootId: UrlEncodedCommentId;
+  commentSide?: CommentSide;
+}
+
+export function getLastComment(thread?: CommentThread): UIComment | undefined {
+  const len = thread?.comments.length;
+  return thread && len ? thread.comments[len - 1] : undefined;
+}
+
+export function isUnresolved(thread?: CommentThread): boolean {
+  return !!getLastComment(thread)?.unresolved;
+}
+
+export function isDraftThread(thread?: CommentThread): boolean {
+  return isDraft(getLastComment(thread));
+}
diff --git a/polygerrit-ui/app/utils/comment-util_test.js b/polygerrit-ui/app/utils/comment-util_test.js
new file mode 100644
index 0000000..ad19974
--- /dev/null
+++ b/polygerrit-ui/app/utils/comment-util_test.js
@@ -0,0 +1,34 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../test/common-test-setup-karma.js';
+import {
+  isUnresolved,
+} from './comment-util.js';
+
+suite('comment-util', () => {
+  test('isUnresolved', () => {
+    assert.isFalse(isUnresolved(undefined));
+    assert.isFalse(isUnresolved({comments: []}));
+    assert.isTrue(isUnresolved({comments: [{unresolved: true}]}));
+    assert.isFalse(isUnresolved({comments: [{unresolved: false}]}));
+    assert.isTrue(isUnresolved(
+        {comments: [{unresolved: false}, {unresolved: true}]}));
+    assert.isFalse(isUnresolved(
+        {comments: [{unresolved: true}, {unresolved: false}]}));
+  });
+});
diff --git a/polygerrit-ui/app/utils/label-util.ts b/polygerrit-ui/app/utils/label-util.ts
new file mode 100644
index 0000000..78151be
--- /dev/null
+++ b/polygerrit-ui/app/utils/label-util.ts
@@ -0,0 +1,39 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  ApprovalInfo,
+  isDetailedLabelInfo,
+  LabelInfo,
+  VotingRangeInfo,
+} from '../types/common';
+
+// Name of the standard Code-Review label.
+export const CODE_REVIEW = 'Code-Review';
+
+export function getVotingRange(label?: LabelInfo): VotingRangeInfo {
+  if (!label || !isDetailedLabelInfo(label)) return {min: 0, max: 0};
+  const values = Object.keys(label.values).map(v => parseInt(v, 10));
+  values.sort((a, b) => a - b);
+  if (!values.length) return {min: 0, max: 0};
+  return {min: values[0], max: values[values.length - 1]};
+}
+
+export function getMaxAccounts(label?: LabelInfo): ApprovalInfo[] {
+  if (!label || !isDetailedLabelInfo(label)) return [];
+  const votingRange = getVotingRange(label);
+  return label.all.filter(account => account.value === votingRange.max);
+}
diff --git a/polygerrit-ui/app/utils/label-util_test.js b/polygerrit-ui/app/utils/label-util_test.js
new file mode 100644
index 0000000..5bd48a1
--- /dev/null
+++ b/polygerrit-ui/app/utils/label-util_test.js
@@ -0,0 +1,49 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import '../test/common-test-setup-karma.js';
+import {
+  getVotingRange,
+} from './label-util.js';
+
+suite('label-util', () => {
+  test('getVotingRange -1 to +1', () => {
+    const label = {
+      values: {
+        '-1': 'bad',
+        '0': 'neutral',
+        '+1': 'good',
+      },
+    };
+    const expectedRange = {min: -1, max: 1};
+    assert.deepEqual(getVotingRange(label), expectedRange);
+  });
+
+  test('getVotingRange -2 to +2', () => {
+    const label = {
+      values: {
+        '-1': 'bad',
+        '+2': 'perfect',
+        '0': 'neutral',
+        '-2': 'blocking',
+        '+1': 'good',
+      },
+    };
+    const expectedRange = {min: -2, max: 2};
+    assert.deepEqual(getVotingRange(label), expectedRange);
+  });
+});