1
0
mirror of https://github.com/moparisthebest/kaiwa synced 2024-12-25 08:58:53 -05:00
kaiwa/clientapp/helpers/chatHelpers.js
2013-09-26 12:34:31 -07:00

118 lines
3.5 KiB
JavaScript

/*global app, $*/
"use strict";
var _ = require('underscore');
var raf = require('raf-component');
module.exports = {
initializeScroll: function () {
var check = _.bind(_.throttle(this.handleScroll, 100), this);
var self = this;
function animate() {
self.rafID = raf(animate);
check();
}
animate();
this.pinnedToBottom = true;
this.lastScrollTop = 0;
},
scrollPageLoad: function () {
if (typeof this.lastScrollPosition === 'number') {
this.scrollTo(this.lastScrollPosition);
} else {
this.scrollToBottom();
}
},
scrollPageUnload: function () {
this.savePosition();
this.trimOldChats();
raf.cancel(this.rafID);
},
savePosition: function () {
this.lastScrollPosition = this.pinnedToBottom ? '' : this.$scrollContainer.scrollTop();
},
trimOldChats: function () {
var self = this;
var removedIds;
if (this.pinnedToBottom) {
_.delay(function () {
removedIds = [];//self.collection.trimOlderChats();
removedIds.forEach(function (id) {
self.$('#chat' + id).remove();
});
}, 500);
}
},
handleScroll: function (e) {
var scrollTop = this.$scrollContainer[0].scrollTop;
var direction = scrollTop >= this.lastScrollTop ? 'down' : 'up';
if (direction === 'up' && !this.isBottom()) {
this.pinnedToBottom = false;
} else if (this.isBottom()) {
this.handleAtBottom();
}
this.lastScrollTop = scrollTop;
},
scrollIfPinned: function (animate) {
if (this.pinnedToBottom) this.scrollToBottom(animate);
},
handleAtBottom: function () {
if (this.isVisible()) {
this.pinnedToBottom = true;
}
},
isBottom: function () {
var scrollTop = this.$scrollContainer[0].scrollTop;
var scrollHeight = this.$scrollContainer[0].scrollHeight;
var height = this.$scrollContainer.height();
var fromBottom = scrollHeight - (scrollTop + height);
return fromBottom < 80;
},
resizeInput: function () {
var height;
var scrollHeight;
var newHeight;
var newPadding;
var paddingDelta;
var maxHeight = 102;
this.$chatInput.removeAttr('style');
height = this.$chatInput.height() + 10,
scrollHeight = this.$chatInput.get(0).scrollHeight,
newHeight = scrollHeight + 2;
if (newHeight > maxHeight) newHeight = maxHeight;
if (newHeight > height) {
this.$chatInput.css('height', newHeight);
newPadding = newHeight + 21;
paddingDelta = newPadding - parseInt(this.$messageList.css('paddingBottom'), 10);
if (!!paddingDelta) {
this.$messageList.css('paddingBottom', newPadding);
}
}
},
scrollTo: function (height, animate) {
if (animate) {
this.$scrollContainer.animate({
scrollTop: height
}, {
duration: 500,
queue: false
});
} else {
this.$scrollContainer[0].scrollTop = height;
}
},
scrollToBottom: function (animate) {
if (!this.isVisible()) return;
var height = this.$scrollContainer[0].scrollHeight;
this.scrollTo(height, animate);
},
isVisible: function () {
return app.currentPage === this;
}
};