/**
 * @license
 * Copyright (C) 2017 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 {
  BranchName,
  ChangeInfo,
  PatchSetNum,
  ProjectName,
  TopicName,
  RepositoryName,
  GroupId,
  DashboardId,
  NumericChangeId,
  LegacyChangeId,
  EditPatchSetNum,
  ChangeConfigInfo,
  CommitId,
  Hashtag,
  UrlEncodedCommentId,
} from '../../../types/common';

// Navigation parameters object format:
//
// Each object has a `view` property with a value from GerritNav.View. The
// remaining properties depend on the value used for view.
//
//  - GerritNav.View.CHANGE:
//    - `changeNum`, required, String: the numeric ID of the change.
//    - `project`, optional, String: the project name.
//    - `patchNum`, optional, Number: the patch for the right-hand-side of
//        the diff.
//    - `basePatchNum`, optional, Number: the patch for the left-hand-side
//        of the diff. If `basePatchNum` is provided, then `patchNum` must
//        also be provided.
//    - `edit`, optional, Boolean: whether or not to load the file list with
//        edit controls.
//    - `messageHash`, optional, String: the hash of the change message to
//        scroll to.
//
// - GerritNav.View.SEARCH:
//    - `query`, optional, String: the literal search query. If provided,
//        the string will be used as the query, and all other params will be
//        ignored.
//    - `owner`, optional, String: the owner name.
//    - `project`, optional, String: the project name.
//    - `branch`, optional, String: the branch name.
//    - `topic`, optional, String: the topic name.
//    - `hashtag`, optional, String: the hashtag name.
//    - `statuses`, optional, Array<String>: the list of change statuses to
//        search for. If more than one is provided, the search will OR them
//        together.
//    - `offset`, optional, Number: the offset for the query.
//
//  - GerritNav.View.DIFF:
//    - `changeNum`, required, String: the numeric ID of the change.
//    - `path`, required, String: the filepath of the diff.
//    - `patchNum`, required, Number: the patch for the right-hand-side of
//        the diff.
//    - `basePatchNum`, optional, Number: the patch for the left-hand-side
//        of the diff. If `basePatchNum` is provided, then `patchNum` must
//        also be provided.
//    - `lineNum`, optional, Number: the line number to be selected on load.
//    - `leftSide`, optional, Boolean: if a `lineNum` is provided, a value
//        of true selects the line from base of the patch range. False by
//        default.
//
//  - GerritNav.View.GROUP:
//    - `groupId`, required, String: the ID of the group.
//    - `detail`, optional, String: the name of the group detail view.
//      Takes any value from GerritNav.GroupDetailView.
//
//  - GerritNav.View.REPO:
//    - `repoName`, required, String: the name of the repo
//    - `detail`, optional, String: the name of the repo detail view.
//      Takes any value from GerritNav.RepoDetailView.
//
//  - GerritNav.View.DASHBOARD
//    - `repo`, optional, String.
//    - `sections`, optional, Array of objects with `title` and `query`
//      strings.
//    - `user`, optional, String.
//
//  - GerritNav.View.ROOT:
//    - no possible parameters.

const uninitialized = () => {
  console.warn('Use of uninitialized routing');
};

const uninitializedNavigate: NavigateCallback = () => {
  uninitialized();
  return '';
};

const uninitializedGenerateUrl: GenerateUrlCallback = () => {
  uninitialized();
  return '';
};

const uninitializedGenerateWebLinks: GenerateWebLinksCallback = () => {
  uninitialized();
  return [];
};

const uninitializedMapCommentLinks: MapCommentLinksCallback = () => {
  uninitialized();
  return '';
};

// TODO(TS): PatchSetNum type express an API type, it is not good to add
// PARENT into it. Find a better way to add PARENT patchset into our code
type ParentPatchSetNum = 'PARENT';
const PARENT_PATCHNUM: ParentPatchSetNum = 'PARENT';

const USER_PLACEHOLDER_PATTERN = /\${user}/g;

export interface DashboardSection {
  name: string;
  query: string;
  suffixForDashboard: string;
  attentionSetOnly?: boolean;
  selfOnly?: boolean;
  hideIfEmpty?: boolean;
  assigneeOnly?: boolean;
  isOutgoing?: boolean;
}

export interface UserDashboardConfig {
  change?: ChangeConfigInfo;
}

export interface UserDashboard {
  title: string;
  sections: DashboardSection[];
}

// NOTE: These queries are tested in Java. Any changes made to definitions
// here require corresponding changes to:
// javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
const DEFAULT_SECTIONS: DashboardSection[] = [
  {
    // Changes with unpublished draft comments. This section is omitted when
    // viewing other users, so we don't need to filter anything out.
    name: 'Has draft comments',
    query: 'has:draft',
    selfOnly: true,
    hideIfEmpty: true,
    suffixForDashboard: 'limit:10',
  },
  {
    // Changes where the user is in the attention set.
    name: 'Your Turn',
    query: 'attention:${user}',
    hideIfEmpty: false,
    suffixForDashboard: 'limit:25',
    attentionSetOnly: true,
  },
  {
    // Changes that are assigned to the viewed user.
    name: 'Assigned reviews',
    query:
      'assignee:${user} (-is:wip OR owner:self OR assignee:self) ' +
      'is:open -is:ignored',
    hideIfEmpty: true,
    suffixForDashboard: 'limit:25',
    assigneeOnly: true,
  },
  {
    // WIP open changes owned by viewing user. This section is omitted when
    // viewing other users, so we don't need to filter anything out.
    name: 'Work in progress',
    query: 'is:open owner:${user} is:wip',
    selfOnly: true,
    hideIfEmpty: true,
    suffixForDashboard: 'limit:25',
  },
  {
    // Non-WIP open changes owned by viewed user. Filter out changes ignored
    // by the viewing user.
    name: 'Outgoing reviews',
    query: 'is:open owner:${user} -is:wip -is:ignored',
    isOutgoing: true,
    suffixForDashboard: 'limit:25',
  },
  {
    // Non-WIP open changes not owned by the viewed user, that the viewed user
    // is associated with (as either a reviewer or the assignee). Changes
    // ignored by the viewing user are filtered out.
    name: 'Incoming reviews',
    query:
      'is:open -owner:${user} -is:wip -is:ignored ' +
      '(reviewer:${user} OR assignee:${user})',
    suffixForDashboard: 'limit:25',
  },
  {
    // Open changes the viewed user is CCed on. Changes ignored by the viewing
    // user are filtered out.
    name: 'CCed on',
    query: 'is:open -is:ignored cc:${user}',
    suffixForDashboard: 'limit:10',
  },
  {
    name: 'Recently closed',
    // Closed changes where viewed user is owner, reviewer, or assignee.
    // Changes ignored by the viewing user are filtered out, and so are WIP
    // changes not owned by the viewing user (the one instance of
    // 'owner:self' is intentional and implements this logic).
    query:
      'is:closed -is:ignored (-is:wip OR owner:self) ' +
      '(owner:${user} OR reviewer:${user} OR assignee:${user} ' +
      'OR cc:${user})',
    suffixForDashboard: '-age:4w limit:10',
  },
];

export interface GenerateUrlSearchViewParameters {
  view: GerritView.SEARCH;
  query?: string;
  offset?: number;
  project?: ProjectName;
  branch?: BranchName;
  topic?: TopicName;
  // TODO(TS): Define more precise type (enum?)
  statuses?: string[];
  hashtag?: string;
  host?: string;
  owner?: string;
}

export interface GenerateUrlChangeViewParameters {
  view: GerritView.CHANGE;
  // TODO(TS): NumericChangeId - not sure about it, may be it can be removeds
  changeNum: NumericChangeId | LegacyChangeId;
  project: ProjectName;
  patchNum?: PatchSetNum;
  basePatchNum?: PatchSetNum;
  edit?: boolean;
  host?: string;
  messageHash?: string;
}

export interface GenerateUrlRepoViewParameters {
  view: GerritView.REPO;
  repoName: RepositoryName;
  detail?: RepoDetailView;
}

export interface GenerateUrlDashboardViewParameters {
  view: GerritView.DASHBOARD;
  user?: string;
  repo?: RepositoryName;
  dashboard?: DashboardId;
}

export interface GenerateUrlGroupViewParameters {
  view: GerritView.GROUP;
  groupId: GroupId;
  detail?: GroupDetailView;
}

export interface GenerateUrlEditViewParameters {
  view: GerritView.EDIT;
  changeNum: NumericChangeId | LegacyChangeId;
  project: ProjectName;
  path: string;
  patchNum: PatchSetNum;
  lineNum?: number;
}

export interface GenerateUrlRootViewParameters {
  view: GerritView.ROOT;
}

export interface GenerateUrlSettingsViewParameters {
  view: GerritView.SETTINGS;
}

export interface GenerateUrlDiffViewParameters {
  view: GerritView.DIFF;
  changeNum: NumericChangeId | LegacyChangeId;
  project: ProjectName;
  path?: string;
  patchNum?: PatchSetNum;
  basePatchNum?: PatchSetNum | ParentPatchSetNum;
  lineNum?: number;
  leftSide?: boolean;
  commentId?: UrlEncodedCommentId;
}

export type GenerateUrlParameters =
  | GenerateUrlSearchViewParameters
  | GenerateUrlChangeViewParameters
  | GenerateUrlRepoViewParameters
  | GenerateUrlDashboardViewParameters
  | GenerateUrlGroupViewParameters
  | GenerateUrlEditViewParameters
  | GenerateUrlRootViewParameters
  | GenerateUrlSettingsViewParameters
  | GenerateUrlDiffViewParameters;

export interface GenerateWebLinksPatchsetParameters {
  type: WeblinkType.PATCHSET;
  repo: RepositoryName;
  commit: CommitId;
  // TODO(TS): provide better typing
  options?: unknown;
}
export interface GenerateWebLinksFileParameters {
  type: WeblinkType.FILE;
  repo: RepositoryName;
  commit: CommitId;
  file: string;
  // TODO(TS): provide better typing
  options?: unknown;
}
export interface GenerateWebLinksChangeParameters {
  type: WeblinkType.CHANGE;
  repo: RepositoryName;
  commit: CommitId;
  // TODO(TS): provide better typing
  options?: unknown;
}

export type GenerateWebLinksParameters =
  | GenerateWebLinksPatchsetParameters
  | GenerateWebLinksFileParameters
  | GenerateWebLinksChangeParameters;

export type NavigateCallback = (target: string, redirect?: boolean) => void;
export type GenerateUrlCallback = (params: GenerateUrlParameters) => string;
export type GenerateWebLinksCallback = (
  params: GenerateWebLinksParameters
) => WebLink[] | WebLink;

// TODO(TS): type is not clear until more code converted to a typescript.
export type MapCommentLinksCallback = (commentLink: unknown) => unknown;

export interface WebLink {
  label: string;
  url: string;
}

export enum GerritView {
  ADMIN = 'admin',
  AGREEMENTS = 'agreements',
  CHANGE = 'change',
  DASHBOARD = 'dashboard',
  DIFF = 'diff',
  DOCUMENTATION_SEARCH = 'documentation-search',
  EDIT = 'edit',
  GROUP = 'group',
  PLUGIN_SCREEN = 'plugin-screen',
  REPO = 'repo',
  ROOT = 'root',
  SEARCH = 'search',
  SETTINGS = 'settings',
}

export enum GroupDetailView {
  MEMBERS = 'members',
  LOG = 'log',
}

export enum RepoDetailView {
  ACCESS = 'access',
  BRANCHES = 'branches',
  COMMANDS = 'commands',
  DASHBOARDS = 'dashboards',
  TAGS = 'tags',
}

export enum WeblinkType {
  CHANGE = 'change',
  FILE = 'file',
  PATCHSET = 'patchset',
}

// TODO(dmfilippov) Convert to class, extract consts, give better name and
// expose as a service from appContext
export const GerritNav = {
  View: GerritView,

  GroupDetailView,

  RepoDetailView,

  WeblinkType,

  _navigate: uninitializedNavigate,

  _generateUrl: uninitializedGenerateUrl,

  _generateWeblinks: uninitializedGenerateWebLinks,

  mapCommentlinks: uninitializedMapCommentLinks,

  _checkPatchRange(
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum | ParentPatchSetNum
  ) {
    if (basePatchNum && !patchNum) {
      throw new Error('Cannot use base patch number without patch number.');
    }
  },

  /**
   * Setup router implementation.
   *
   * @param navigate the router-abstracted equivalent of
   *     `window.location.href = ...` or window.location.replace(...). The
   *     string is a new location and boolean defines is it redirect or not
   *     (true means redirect, i.e. equivalent of window.location.replace).
   * @param generateUrl generates a URL given
   *     navigation parameters, detailed in the file header.
   * @param generateWeblinks weblinks generator
   *     function takes single payload parameter with type property that
   *  determines which
   *     part of the UI is the consumer of the weblinks. type property can
   *     be one of file, change, or patchset.
   *     - For file type, payload will also contain string properties: repo,
   *         commit, file.
   *     - For patchset type, payload will also contain string properties:
   *         repo, commit.
   *     - For change type, payload will also contain string properties:
   *         repo, commit. If server provides weblinks, those will be passed
   *         as options.weblinks property on the main payload object.
   * @param mapCommentlinks provides an escape
   *     hatch to modify the commentlinks object, e.g. if it contains any
   *     relative URLs.
   */
  setup(
    navigate: NavigateCallback,
    generateUrl: GenerateUrlCallback,
    generateWeblinks: GenerateWebLinksCallback,
    mapCommentlinks: MapCommentLinksCallback
  ) {
    this._navigate = navigate;
    this._generateUrl = generateUrl;
    this._generateWeblinks = generateWeblinks;
    this.mapCommentlinks = mapCommentlinks;
  },

  destroy() {
    this._navigate = uninitializedNavigate;
    this._generateUrl = uninitializedGenerateUrl;
    this._generateWeblinks = uninitializedGenerateWebLinks;
    this.mapCommentlinks = uninitializedMapCommentLinks;
  },

  /**
   * Generate a URL for the given route parameters.
   */
  _getUrlFor(params: GenerateUrlParameters) {
    return this._generateUrl(params);
  },

  getUrlForSearchQuery(query: string, offset?: number) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      query,
      offset,
    });
  },

  /**
   * @param openOnly When true, only search open changes in the project.
   * @param host The host in which to search.
   */
  getUrlForProjectChanges(
    project: ProjectName,
    openOnly?: boolean,
    host?: string
  ) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      project,
      statuses: openOnly ? ['open'] : [],
      host,
    });
  },

  /**
   * @param status The status to search.
   * @param host The host in which to search.
   */
  getUrlForBranch(
    branch: BranchName,
    project: ProjectName,
    status?: string,
    host?: string
  ) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      branch,
      project,
      statuses: status ? [status] : undefined,
      host,
    });
  },

  /**
   * @param topic The name of the topic.
   * @param host The host in which to search.
   */
  getUrlForTopic(topic: TopicName, host?: string) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      topic,
      statuses: ['open', 'merged'],
      host,
    });
  },

  /**
   * @param hashtag The name of the hashtag.
   */
  getUrlForHashtag(hashtag: Hashtag) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      hashtag,
      statuses: ['open', 'merged'],
    });
  },

  /**
   * Navigate to a search for changes with the given status.
   */
  navigateToStatusSearch(status: string) {
    this._navigate(
      this._getUrlFor({
        view: GerritView.SEARCH,
        statuses: [status],
      })
    );
  },

  /**
   * Navigate to a search query
   */
  navigateToSearchQuery(query: string, offset?: number) {
    return this._navigate(this.getUrlForSearchQuery(query, offset));
  },

  /**
   * Navigate to the user's dashboard
   */
  navigateToUserDashboard() {
    return this._navigate(this.getUrlForUserDashboard('self'));
  },

  /**
   * @param basePatchNum The string 'PARENT' can be used for none.
   */
  getUrlForChange(
    change: ChangeInfo,
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum | ParentPatchSetNum,
    isEdit?: boolean,
    messageHash?: string
  ) {
    if (basePatchNum === PARENT_PATCHNUM) {
      basePatchNum = undefined;
    }

    this._checkPatchRange(patchNum, basePatchNum);
    return this._getUrlFor({
      view: GerritView.CHANGE,
      changeNum: change._number,
      project: change.project,
      patchNum,
      basePatchNum,
      edit: isEdit,
      host: change.internalHost || undefined,
      messageHash,
    });
  },

  getUrlForChangeById(
    changeNum: NumericChangeId,
    project: ProjectName,
    patchNum?: PatchSetNum
  ) {
    return this._getUrlFor({
      view: GerritView.CHANGE,
      changeNum,
      project,
      patchNum,
    });
  },

  /**
   * @param basePatchNum The string 'PARENT' can be used for none.
   * @param redirect redirect to a change - if true, the current
   *     location (i.e. page which makes redirect) is not added to a history.
   *     I.e. back/forward buttons skip current location
   *
   */
  navigateToChange(
    change: ChangeInfo,
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum,
    isEdit?: boolean,
    redirect?: boolean
  ) {
    this._navigate(
      this.getUrlForChange(change, patchNum, basePatchNum, isEdit),
      redirect
    );
  },

  /**
   * @param basePatchNum The string 'PARENT' can be used for none.
   */
  getUrlForDiff(
    change: ChangeInfo,
    filePath: string,
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum | ParentPatchSetNum,
    lineNum?: number
  ) {
    return this.getUrlForDiffById(
      change._number,
      change.project,
      filePath,
      patchNum,
      basePatchNum,
      lineNum
    );
  },

  getUrlForComment(
    changeNum: NumericChangeId | LegacyChangeId,
    project: ProjectName,
    commentId: UrlEncodedCommentId
  ) {
    return this._getUrlFor({
      view: GerritView.DIFF,
      changeNum,
      project,
      commentId,
    });
  },

  /**
   * @param basePatchNum The string 'PARENT' can be used for none.
   */
  getUrlForDiffById(
    changeNum: NumericChangeId | LegacyChangeId,
    project: ProjectName,
    filePath: string,
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum | ParentPatchSetNum,
    lineNum?: number,
    leftSide?: boolean
  ) {
    if (basePatchNum === PARENT_PATCHNUM) {
      basePatchNum = undefined;
    }

    this._checkPatchRange(patchNum, basePatchNum);
    return this._getUrlFor({
      view: GerritView.DIFF,
      changeNum,
      project,
      path: filePath,
      patchNum,
      basePatchNum,
      lineNum,
      leftSide,
    });
  },

  getEditUrlForDiff(
    change: ChangeInfo,
    filePath: string,
    patchNum?: PatchSetNum,
    lineNum?: number
  ) {
    return this.getEditUrlForDiffById(
      change._number,
      change.project,
      filePath,
      patchNum,
      lineNum
    );
  },

  /**
   * @param patchNum The patchNum the file content should be based on, or
   *   ${EditPatchSetNum} if left undefined.
   * @param lineNum The line number to pass to the inline editor.
   */
  getEditUrlForDiffById(
    changeNum: NumericChangeId | LegacyChangeId,
    project: ProjectName,
    filePath: string,
    patchNum?: PatchSetNum,
    lineNum?: number
  ) {
    return this._getUrlFor({
      view: GerritView.EDIT,
      changeNum,
      project,
      path: filePath,
      patchNum: patchNum || EditPatchSetNum,
      lineNum,
    });
  },

  /**
   * @param basePatchNum The string 'PARENT' can be used for none.
   */
  navigateToDiff(
    change: ChangeInfo,
    filePath: string,
    patchNum?: PatchSetNum,
    basePatchNum?: PatchSetNum | ParentPatchSetNum
  ) {
    this._navigate(
      this.getUrlForDiff(change, filePath, patchNum, basePatchNum)
    );
  },

  /**
   * @param owner The name of the owner.
   */
  getUrlForOwner(owner: string) {
    return this._getUrlFor({
      view: GerritView.SEARCH,
      owner,
    });
  },

  /**
   * @param user The name of the user.
   */
  getUrlForUserDashboard(user: string) {
    return this._getUrlFor({
      view: GerritView.DASHBOARD,
      user,
    });
  },

  getUrlForRoot() {
    return this._getUrlFor({
      view: GerritView.ROOT,
    });
  },

  /**
   * @param repo The name of the repo.
   * @param dashboard The ID of the dashboard, in the form of '<ref>:<path>'.
   */
  getUrlForRepoDashboard(repo: RepositoryName, dashboard: DashboardId) {
    return this._getUrlFor({
      view: GerritView.DASHBOARD,
      repo,
      dashboard,
    });
  },

  /**
   * Navigate to an arbitrary relative URL.
   */
  navigateToRelativeUrl(relativeUrl: string) {
    if (!relativeUrl.startsWith('/')) {
      throw new Error('navigateToRelativeUrl with non-relative URL');
    }
    this._navigate(relativeUrl);
  },

  getUrlForRepo(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
    });
  },

  /**
   * Navigate to a repo settings page.
   */
  navigateToRepo(repoName: RepositoryName) {
    this._navigate(this.getUrlForRepo(repoName));
  },

  getUrlForRepoTags(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
      detail: RepoDetailView.TAGS,
    });
  },

  getUrlForRepoBranches(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
      detail: GerritNav.RepoDetailView.BRANCHES,
    });
  },

  getUrlForRepoAccess(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
      detail: GerritNav.RepoDetailView.ACCESS,
    });
  },

  getUrlForRepoCommands(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
      detail: GerritNav.RepoDetailView.COMMANDS,
    });
  },

  getUrlForRepoDashboards(repoName: RepositoryName) {
    return this._getUrlFor({
      view: GerritView.REPO,
      repoName,
      detail: GerritNav.RepoDetailView.DASHBOARDS,
    });
  },

  getUrlForGroup(groupId: GroupId) {
    return this._getUrlFor({
      view: GerritView.GROUP,
      groupId,
    });
  },

  getUrlForGroupLog(groupId: GroupId) {
    return this._getUrlFor({
      view: GerritView.GROUP,
      groupId,
      detail: GerritNav.GroupDetailView.LOG,
    });
  },

  getUrlForGroupMembers(groupId: GroupId) {
    return this._getUrlFor({
      view: GerritView.GROUP,
      groupId,
      detail: GroupDetailView.MEMBERS,
    });
  },

  getUrlForSettings() {
    return this._getUrlFor({view: GerritView.SETTINGS});
  },

  getFileWebLinks(
    repo: RepositoryName,
    commit: CommitId,
    file: string,
    options?: unknown
  ): WebLink[] {
    const params: GenerateWebLinksFileParameters = {
      type: WeblinkType.FILE,
      repo,
      commit,
      file,
    };
    if (options) {
      params.options = options;
    }
    return ([] as WebLink[]).concat(this._generateWeblinks(params));
  },

  getPatchSetWeblink(
    repo: RepositoryName,
    commit: CommitId,
    options?: unknown
  ): WebLink {
    const params: GenerateWebLinksPatchsetParameters = {
      type: WeblinkType.PATCHSET,
      repo,
      commit,
    };
    if (options) {
      params.options = options;
    }
    const result = this._generateWeblinks(params);
    if (Array.isArray(result)) {
      // TODO(TS): Unclear what to do with empty array.
      // Either write a comment why result can't be empty or change the return
      // type or add a check.
      return result.pop() as WebLink;
    } else {
      return result;
    }
  },

  getChangeWeblinks(
    repo: RepositoryName,
    commit: CommitId,
    options?: unknown
  ): WebLink[] {
    const params: GenerateWebLinksChangeParameters = {
      type: WeblinkType.CHANGE,
      repo,
      commit,
    };
    if (options) {
      params.options = options;
    }
    return ([] as WebLink[]).concat(this._generateWeblinks(params));
  },

  getUserDashboard(
    user = 'self',
    sections = DEFAULT_SECTIONS,
    title = '',
    config: UserDashboardConfig = {}
  ): UserDashboard {
    const attentionEnabled =
      config.change && !!config.change.enable_attention_set;
    const assigneeEnabled = config.change && !!config.change.enable_assignee;
    sections = sections
      .filter(section => attentionEnabled || !section.attentionSetOnly)
      .filter(section => assigneeEnabled || !section.assigneeOnly)
      .filter(section => user === 'self' || !section.selfOnly)
      .map(section => {
        return {
          ...section,
          name: section.name,
          query: section.query.replace(USER_PLACEHOLDER_PATTERN, user),
        };
      });
    return {title, sections};
  },
};