/* eslint-disable no-new, class-methods-use-this */
/* global Breakpoints */
/* global Flash */
/* global notes */

import Cookies from 'js-cookie';
import './breakpoints';
import './flash';
import BlobForkSuggestion from './blob/blob_fork_suggestion';

/* eslint-disable max-len */
// MergeRequestTabs
//
// Handles persisting and restoring the current tab selection and lazily-loading
// content on the MergeRequests#show page.
//
// ### Example Markup
//
//   <ul class="nav-links merge-request-tabs">
//     <li class="notes-tab active">
//       <a data-action="notes" data-target="#notes" data-toggle="tab" href="/foo/bar/merge_requests/1">
//         Discussion
//       </a>
//     </li>
//     <li class="commits-tab">
//       <a data-action="commits" data-target="#commits" data-toggle="tab" href="/foo/bar/merge_requests/1/commits">
//         Commits
//       </a>
//     </li>
//     <li class="diffs-tab">
//       <a data-action="diffs" data-target="#diffs" data-toggle="tab" href="/foo/bar/merge_requests/1/diffs">
//         Diffs
//       </a>
//     </li>
//   </ul>
//
//   <div class="tab-content">
//     <div class="notes tab-pane active" id="notes">
//       Notes Content
//     </div>
//     <div class="commits tab-pane" id="commits">
//       Commits Content
//     </div>
//     <div class="diffs tab-pane" id="diffs">
//       Diffs Content
//     </div>
//   </div>
//
//   <div class="mr-loading-status">
//     <div class="loading">
//       Loading Animation
//     </div>
//   </div>
//
/* eslint-enable max-len */

(() => {
  // Store the `location` object, allowing for easier stubbing in tests
  let location = window.location;

  class MergeRequestTabs {

    constructor({ action, setUrl, stubLocation } = {}) {
      this.diffsLoaded = false;
      this.pipelinesLoaded = false;
      this.commitsLoaded = false;
      this.fixedLayoutPref = null;

      this.setUrl = setUrl !== undefined ? setUrl : true;
      this.setCurrentAction = this.setCurrentAction.bind(this);
      this.tabShown = this.tabShown.bind(this);
      this.showTab = this.showTab.bind(this);

      if (stubLocation) {
        location = stubLocation;
      }

      this.bindEvents();
      this.activateTab(action);
      this.initAffix();
    }

    bindEvents() {
      $(document)
        .on('shown.bs.tab', '.merge-request-tabs a[data-toggle="tab"]', this.tabShown)
        .on('click', '.js-show-tab', this.showTab);

      $('.merge-request-tabs a[data-toggle="tab"]')
        .on('click', this.clickTab);
    }

    // Used in tests
    unbindEvents() {
      $(document)
        .off('shown.bs.tab', '.merge-request-tabs a[data-toggle="tab"]', this.tabShown)
        .off('click', '.js-show-tab', this.showTab);

      $('.merge-request-tabs a[data-toggle="tab"]')
        .off('click', this.clickTab);
    }

    destroyPipelinesView() {
      if (this.commitPipelinesTable) {
        this.commitPipelinesTable.$destroy();
        this.commitPipelinesTable = null;

        document.querySelector('#commit-pipeline-table-view').innerHTML = '';
      }
    }

    showTab(e) {
      e.preventDefault();
      this.activateTab($(e.target).data('action'));
    }

    clickTab(e) {
      if (e.currentTarget && gl.utils.isMetaClick(e)) {
        const targetLink = e.currentTarget.getAttribute('href');
        e.stopImmediatePropagation();
        e.preventDefault();
        window.open(targetLink, '_blank');
      }
    }

    tabShown(e) {
      const $target = $(e.target);
      const action = $target.data('action');

      if (action === 'commits') {
        this.loadCommits($target.attr('href'));
        this.expandView();
        this.resetViewContainer();
        this.destroyPipelinesView();
      } else if (this.isDiffAction(action)) {
        this.loadDiff($target.attr('href'));
        if (Breakpoints.get().getBreakpointSize() !== 'lg') {
          this.shrinkView();
        }
        if (this.diffViewType() === 'parallel') {
          this.expandViewContainer();
        }
        this.destroyPipelinesView();
      } else if (action === 'pipelines') {
        this.resetViewContainer();
        this.mountPipelinesView();
      } else {
        this.expandView();
        this.resetViewContainer();
        this.destroyPipelinesView();
      }
      if (this.setUrl) {
        this.setCurrentAction(action);
      }
    }

    scrollToElement(container) {
      if (location.hash) {
        const offset = -$('.js-tabs-affix').outerHeight();
        const $el = $(`${container} ${location.hash}:not(.match)`);
        if ($el.length) {
          $.scrollTo($el[0], { offset });
        }
      }
    }

    // Activate a tab based on the current action
    activateTab(action) {
      const activate = action === 'show' ? 'notes' : action;
      // important note: the .tab('show') method triggers 'shown.bs.tab' event itself
      $(`.merge-request-tabs a[data-action='${activate}']`).tab('show');
    }

    // Replaces the current Merge Request-specific action in the URL with a new one
    //
    // If the action is "notes", the URL is reset to the standard
    // `MergeRequests#show` route.
    //
    // Examples:
    //
    //   location.pathname # => "/namespace/project/merge_requests/1"
    //   setCurrentAction('diffs')
    //   location.pathname # => "/namespace/project/merge_requests/1/diffs"
    //
    //   location.pathname # => "/namespace/project/merge_requests/1/diffs"
    //   setCurrentAction('notes')
    //   location.pathname # => "/namespace/project/merge_requests/1"
    //
    //   location.pathname # => "/namespace/project/merge_requests/1/diffs"
    //   setCurrentAction('commits')
    //   location.pathname # => "/namespace/project/merge_requests/1/commits"
    //
    // Returns the new URL String
    setCurrentAction(action) {
      this.currentAction = action === 'show' ? 'notes' : action;

      // Remove a trailing '/commits' '/diffs' '/pipelines' '/new' '/new/diffs'
      let newState = location.pathname.replace(/\/(commits|diffs|pipelines|new|new\/diffs)(\.html)?\/?$/, '');

      // Append the new action if we're on a tab other than 'notes'
      if (this.currentAction !== 'notes') {
        newState += `/${this.currentAction}`;
      }

      // Ensure parameters and hash come along for the ride
      newState += location.search + location.hash;

      // TODO: Consider refactoring in light of turbolinks removal.

      // Replace the current history state with the new one without breaking
      // Turbolinks' history.
      //
      // See https://github.com/rails/turbolinks/issues/363
      window.history.replaceState({
        url: newState,
      }, document.title, newState);

      return newState;
    }

    loadCommits(source) {
      if (this.commitsLoaded) {
        return;
      }
      this.ajaxGet({
        url: `${source}.json`,
        success: (data) => {
          document.querySelector('div#commits').innerHTML = data.html;
          gl.utils.localTimeAgo($('.js-timeago', 'div#commits'));
          this.commitsLoaded = true;
          this.scrollToElement('#commits');
        },
      });
    }

    mountPipelinesView() {
      this.commitPipelinesTable = new gl.CommitPipelinesTable().$mount();
      // $mount(el) replaces the el with the new rendered component. We need it in order to mount
      // it everytime this tab is clicked - https://vuejs.org/v2/api/#vm-mount
      document.querySelector('#commit-pipeline-table-view')
        .appendChild(this.commitPipelinesTable.$el);
    }

    loadDiff(source) {
      if (this.diffsLoaded) {
        return;
      }

      // We extract pathname for the current Changes tab anchor href
      // some pages like MergeRequestsController#new has query parameters on that anchor
      const urlPathname = gl.utils.parseUrlPathname(source);

      this.ajaxGet({
        url: `${urlPathname}.json${location.search}`,
        success: (data) => {
          const $container = $('#diffs');
          $container.html(data.html);

          if (typeof gl.diffNotesCompileComponents !== 'undefined') {
            gl.diffNotesCompileComponents();
          }

          gl.utils.localTimeAgo($('.js-timeago', 'div#diffs'));
          $('#diffs .js-syntax-highlight').syntaxHighlight();

          if (this.diffViewType() === 'parallel' && this.isDiffAction(this.currentAction)) {
            this.expandViewContainer();
          }
          this.diffsLoaded = true;

          new gl.Diff();
          this.scrollToElement('#diffs');

          $('.diff-file').each((i, el) => {
            new BlobForkSuggestion({
              openButtons: $(el).find('.js-edit-blob-link-fork-toggler'),
              forkButtons: $(el).find('.js-fork-suggestion-button'),
              cancelButtons: $(el).find('.js-cancel-fork-suggestion-button'),
              suggestionSections: $(el).find('.js-file-fork-suggestion-section'),
              actionTextPieces: $(el).find('.js-file-fork-suggestion-section-action'),
            })
              .init();
          });

          // Scroll any linked note into view
          // Similar to `toggler_behavior` in the discussion tab
          const hash = window.gl.utils.getLocationHash();
          const anchor = hash && $container.find(`[id="${hash}"]`);
          if (anchor) {
            const notesContent = anchor.closest('.notes_content');
            const lineType = notesContent.hasClass('new') ? 'new' : 'old';
            notes.toggleDiffNote({
              target: anchor,
              lineType,
              forceShow: true,
            });
            anchor[0].scrollIntoView();
            // We have multiple elements on the page with `#note_xxx`
            // (discussion and diff tabs) and `:target` only applies to the first
            anchor.addClass('target');
          }
        },
      });
    }

    // Show or hide the loading spinner
    //
    // status - Boolean, true to show, false to hide
    toggleLoading(status) {
      $('.mr-loading-status .loading').toggle(status);
    }

    ajaxGet(options) {
      const defaults = {
        beforeSend: () => this.toggleLoading(true),
        error: () => new Flash('An error occurred while fetching this tab.', 'alert'),
        complete: () => this.toggleLoading(false),
        dataType: 'json',
        type: 'GET',
      };
      $.ajax($.extend({}, defaults, options));
    }

    diffViewType() {
      return $('.inline-parallel-buttons a.active').data('view-type');
    }

    isDiffAction(action) {
      return action === 'diffs' || action === 'new/diffs';
    }

    expandViewContainer() {
      const $wrapper = $('.content-wrapper .container-fluid');
      if (this.fixedLayoutPref === null) {
        this.fixedLayoutPref = $wrapper.hasClass('container-limited');
      }
      $wrapper.removeClass('container-limited');
    }

    resetViewContainer() {
      if (this.fixedLayoutPref !== null) {
        $('.content-wrapper .container-fluid')
          .toggleClass('container-limited', this.fixedLayoutPref);
      }
    }

    shrinkView() {
      const $gutterIcon = $('.js-sidebar-toggle i:visible');

      // Wait until listeners are set
      setTimeout(() => {
        // Only when sidebar is expanded
        if ($gutterIcon.is('.fa-angle-double-right')) {
          $gutterIcon.closest('a').trigger('click', [true]);
        }
      }, 0);
    }

    // Expand the issuable sidebar unless the user explicitly collapsed it
    expandView() {
      if (Cookies.get('collapsed_gutter') === 'true') {
        return;
      }
      const $gutterIcon = $('.js-sidebar-toggle i:visible');

      // Wait until listeners are set
      setTimeout(() => {
        // Only when sidebar is collapsed
        if ($gutterIcon.is('.fa-angle-double-left')) {
          $gutterIcon.closest('a').trigger('click', [true]);
        }
      }, 0);
    }

    initAffix() {
      const $tabs = $('.js-tabs-affix');
      const $fixedNav = $('.navbar-gitlab');

      // Screen space on small screens is usually very sparse
      // So we dont affix the tabs on these
      if (Breakpoints.get().getBreakpointSize() === 'xs' || !$tabs.length) return;

      /**
        If the browser does not support position sticky, it returns the position as static.
        If the browser does support sticky, then we allow the browser to handle it, if not
        then we default back to Bootstraps affix
      **/
      if ($tabs.css('position') !== 'static') return;

      const $diffTabs = $('#diff-notes-app');

      $tabs.off('affix.bs.affix affix-top.bs.affix')
        .affix({
          offset: {
            top: () => (
              $diffTabs.offset().top - $tabs.height() - $fixedNav.height()
            ),
          },
        })
        .on('affix.bs.affix', () => $diffTabs.css({ marginTop: $tabs.height() }))
        .on('affix-top.bs.affix', () => $diffTabs.css({ marginTop: '' }));

      // Fix bug when reloading the page already scrolling
      if ($tabs.hasClass('affix')) {
        $tabs.trigger('affix.bs.affix');
      }
    }
  }

  window.gl = window.gl || {};
  window.gl.MergeRequestTabs = MergeRequestTabs;
})();
