[MD History] Implement grouped history UI.

chrome/browser/resources/md_history/grouped_list.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @typedef {{domain: string,
+ *            visits: !Array<HistoryEntry>,
+ *            rendered: boolean,
+ *            expanded: boolean}}
+ */
+var HistoryDomain;
+
+/**
+ * @typedef {{title: string,
+ *            domains: !Array<HistoryDomain>}}
+ */
+var HistoryGroup;
+
+// TODO(calamity): Support selection by refactoring selection out of
+// history-list and into history-app.
+Polymer({
+  is: 'history-grouped-list',
+
+  properties: {
+    // An array of history entries in reverse chronological order.
+    historyData: {
+      type: Array,
+    },
+
+    /**
+     * @type {Array<HistoryGroup>}
+     */
+    groupedHistoryData_: {
+      type: Array,
+    },
+
+    searchedTerm: {
+      type: String,
+      value: ''
+    },
+
+    range: {
+      type: Number,
+    },
+
+    queryStartTime: String,
+    queryEndTime: String,
+  },
+
+  observers: [
+    'updateGroupedHistoryData_(range, historyData)'
+  ],
+
+  /**
+   * Make a list of domains from visits.
+   * @param {!Array<!HistoryEntry>} visits
+   * @return {!Array<!HistoryDomain>}
+   */
+  createHistoryDomains_: function(visits) {
+    var domainIndexes = {};
+    var domains = [];
+
+    // Group the visits into a dictionary and generate a list of domains.
+    for (var i = 0, visit; visit = visits[i]; i++) {
+      var domain = visit.domain;
+      if (domainIndexes[domain] == undefined) {
+        domainIndexes[domain] = domains.length;
+        domains.push({
+          domain: domain,
+          visits: [],
+          expanded: false,
+          rendered: false,
+        });
+      }
+      domains[domainIndexes[domain]].visits.push(visit);
+    }
+    var sortByVisits = function(a, b) {
+      return b.visits.length - a.visits.length;
+    };
+    domains.sort(sortByVisits);
+
+    return domains;
+  },
+
+  updateGroupedHistoryData_: function() {
+    if (this.historyData.length == 0) {
+      this.groupedHistoryData_ = [];
+      return;
+    }
+
+    if (this.range == HistoryRange.WEEK) {
+      // Group each day into a list of results.
+      var days = [];
+      var currentDayVisits = [this.historyData[0]];
+
+      var pushCurrentDay = function() {
+        days.push({
+          title: this.searchedTerm ? currentDayVisits[0].dateShort :
+              currentDayVisits[0].dateRelativeDay,
+          domains: this.createHistoryDomains_(currentDayVisits),
+        });
+      }.bind(this);
+
+      var visitsSameDay = function(a, b) {
+        if (this.searchedTerm)
+          return a.dateShort == b.dateShort;
+
+        return a.dateRelativeDay == b.dateRelativeDay;
+      }.bind(this);
+
+      for (var i = 1; i < this.historyData.length; i++) {
+        var visit = this.historyData[i];
+        if (!visitsSameDay(visit, currentDayVisits[0])) {
+          pushCurrentDay();
+          currentDayVisits = [];
+        }
+        currentDayVisits.push(visit);
+      }
+      pushCurrentDay();
+
+      this.groupedHistoryData_ = days;
+    } else if (this.range == HistoryRange.MONTH) {
+      // Group each all visits into a single list.
+      this.groupedHistoryData_ = [{
+        title: this.queryStartTime + ' – ' + this.queryEndTime,
+        domains: this.createHistoryDomains_(this.historyData)
+      }];
+    }
+  },
+
+  /**
+   * @param {{model:Object, currentTarget:IronCollapseElement}} e
+   */
+  toggleDomainExpanded_: function(e) {
+    var collapse = e.currentTarget.parentNode.querySelector('iron-collapse');
+    e.model.set('domain.rendered', true);
+
+    // Give the history-items time to render.
+    setTimeout(function() { collapse.toggle() }, 0);
+  },
+
+  /**
+   * Check whether the time difference between the given history item and the
+   * next one is large enough for a spacer to be required.
+   * @param {number} groupIndex
+   * @param {number} domainIndex
+   * @param {number} itemIndex
+   * @return {boolean} Whether or not time gap separator is required.
+   * @private
+   */
+  needsTimeGap_: function(groupIndex, domainIndex, itemIndex) {
+    var visits =
+        this.groupedHistoryData_[groupIndex].domains[domainIndex].visits;
+
+    return md_history.HistoryItem.needsTimeGap(
+        visits, itemIndex, this.searchedTerm);
+  },
+
+  hasResults: function(historyDataLength) {

[tsergeant, 2016/05/25 05:06:55]

Nit: The next 3 methods can be private

[calamity, 2016/05/25 05:51:41]

Done.

+    return historyDataLength > 0;
+  },
+
+  getWebsiteIconStyle: function(domain) {
+    return 'background-image: ' +
+        cr.icon.getFaviconImageSet(domain.visits[0].url);
+  },
+
+  getDropdownIcon: function(expanded) {
+    return expanded ? 'cr:expand-less' : 'cr:expand-more';
+  },
+
+  noResultsMessage_: function(searchedTerm) {
+    var messageId = searchedTerm !== '' ? 'noSearchResults' : 'noResults';
+    return loadTimeData.getString(messageId);
+  },
+});