119 lines
4.6 KiB
JavaScript
119 lines
4.6 KiB
JavaScript
/*
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* vim: ts=4:sw=4:expandtab
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*/
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(function () {
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'use strict';
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window.Whisper = window.Whisper || {};
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Whisper.MessageListView = Whisper.ListView.extend({
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tagName: 'ul',
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className: 'message-list',
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itemView: Whisper.MessageView,
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events: {
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'scroll': 'onScroll',
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},
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initialize: function() {
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Whisper.ListView.prototype.initialize.call(this);
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this.triggerLazyScroll = _.debounce(function() {
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this.$el.trigger('lazyScroll');
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}.bind(this), 500);
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},
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onScroll: function() {
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this.measureScrollPosition();
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if (this.$el.scrollTop() === 0) {
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this.$el.trigger('loadMore');
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}
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if (this.atBottom()) {
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this.$el.trigger('atBottom');
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} else if (this.bottomOffset > this.outerHeight) {
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this.$el.trigger('farFromBottom');
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}
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this.triggerLazyScroll();
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},
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atBottom: function() {
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return this.bottomOffset < 30;
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},
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measureScrollPosition: function() {
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if (this.el.scrollHeight === 0) { // hidden
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return;
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}
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this.outerHeight = this.$el.outerHeight();
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this.scrollPosition = this.$el.scrollTop() + this.outerHeight;
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this.scrollHeight = this.el.scrollHeight;
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this.bottomOffset = this.scrollHeight - this.scrollPosition;
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},
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resetScrollPosition: function() {
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this.$el.scrollTop(this.scrollPosition - this.$el.outerHeight());
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},
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scrollToBottomIfNeeded: function() {
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// This is counter-intuitive. Our current bottomOffset is reflective of what
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// we last measured, not necessarily the current state. And this is called
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// after we just made a change to the DOM: inserting a message, or an image
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// finished loading. So if we were near the bottom before, we _need_ to be
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// at the bottom again. So we scroll to the bottom.
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if (this.atBottom()) {
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this.scrollToBottom();
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}
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},
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scrollToBottom: function() {
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this.$el.scrollTop(this.el.scrollHeight);
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this.measureScrollPosition();
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},
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addOne: function(model) {
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var view;
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if (model.isExpirationTimerUpdate()) {
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view = new Whisper.ExpirationTimerUpdateView({model: model}).render();
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} else if (model.get('type') === 'keychange') {
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view = new Whisper.KeyChangeView({model: model}).render();
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} else if (model.get('type') === 'verified-change') {
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view = new Whisper.VerifiedChangeView({model: model}).render();
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} else {
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view = new this.itemView({model: model}).render();
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this.listenTo(view, 'beforeChangeHeight', this.measureScrollPosition);
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this.listenTo(view, 'afterChangeHeight', this.scrollToBottomIfNeeded);
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}
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var index = this.collection.indexOf(model);
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this.measureScrollPosition();
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if (model.get('unread') && !this.atBottom()) {
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this.$el.trigger('newOffscreenMessage');
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}
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if (index === this.collection.length - 1) {
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// add to the bottom.
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this.$el.append(view.el);
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} else if (index === 0) {
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// add to top
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this.$el.prepend(view.el);
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} else {
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// insert
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var next = this.$('#' + this.collection.at(index + 1).id);
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var prev = this.$('#' + this.collection.at(index - 1).id);
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if (next.length > 0) {
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view.$el.insertBefore(next);
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} else if (prev.length > 0) {
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view.$el.insertAfter(prev);
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} else {
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// scan for the right spot
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var elements = this.$el.children();
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if (elements.length > 0) {
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for (var i = 0; i < elements.length; ++i) {
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var m = this.collection.get(elements[i].id);
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var m_index = this.collection.indexOf(m);
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if (m_index > index) {
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view.$el.insertBefore(elements[i]);
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break;
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}
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}
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} else {
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this.$el.append(view.el);
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}
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}
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}
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this.scrollToBottomIfNeeded();
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},
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});
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})();
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