'use strict';

var cls = require('../lib/class')
  , d = require('../lib/dom')
  , defaultSettings = require('./default-setting')
  , EventManager = require('../lib/event-manager')
  , guid = require('../lib/guid')
  , h = require('../lib/helper');

var instances = {};

function Instance(element) {
  var i = this;

  i.settings = h.clone(defaultSettings);
  i.containerWidth = null;
  i.containerHeight = null;
  i.contentWidth = null;
  i.contentHeight = null;

  i.isRtl = d.css(element, 'direction') === "rtl";
  i.isNegativeScroll = (function () {
    var originalScrollLeft = element.scrollLeft;
    var result = null;
    element.scrollLeft = -1;
    result = element.scrollLeft < 0;
    element.scrollLeft = originalScrollLeft;
    return result;
  })();
  i.negativeScrollAdjustment = i.isNegativeScroll ? element.scrollWidth - element.clientWidth : 0;
  i.event = new EventManager();
  i.ownerDocument = element.ownerDocument || document;

  function focus() {
    cls.add(element, 'ps-focus');
  }

  function blur() {
    cls.remove(element, 'ps-focus');
  }

  i.scrollbarXRail = d.appendTo(d.e('div', 'ps-scrollbar-x-rail'), element);
  i.scrollbarX = d.appendTo(d.e('div', 'ps-scrollbar-x'), i.scrollbarXRail);
  i.scrollbarX.setAttribute('tabindex', 0);
  i.event.bind(i.scrollbarX, 'focus', focus);
  i.event.bind(i.scrollbarX, 'blur', blur);
  i.scrollbarXActive = null;
  i.scrollbarXWidth = null;
  i.scrollbarXLeft = null;
  i.scrollbarXBottom = h.toInt(d.css(i.scrollbarXRail, 'bottom'));
  i.isScrollbarXUsingBottom = i.scrollbarXBottom === i.scrollbarXBottom; // !isNaN
  i.scrollbarXTop = i.isScrollbarXUsingBottom ? null : h.toInt(d.css(i.scrollbarXRail, 'top'));
  i.railBorderXWidth = h.toInt(d.css(i.scrollbarXRail, 'borderLeftWidth')) + h.toInt(d.css(i.scrollbarXRail, 'borderRightWidth'));
  // Set rail to display:block to calculate margins
  d.css(i.scrollbarXRail, 'display', 'block');
  i.railXMarginWidth = h.toInt(d.css(i.scrollbarXRail, 'marginLeft')) + h.toInt(d.css(i.scrollbarXRail, 'marginRight'));
  d.css(i.scrollbarXRail, 'display', '');
  i.railXWidth = null;
  i.railXRatio = null;

  i.scrollbarYRail = d.appendTo(d.e('div', 'ps-scrollbar-y-rail'), element);
  i.scrollbarY = d.appendTo(d.e('div', 'ps-scrollbar-y'), i.scrollbarYRail);
  i.scrollbarY.setAttribute('tabindex', 0);
  i.event.bind(i.scrollbarY, 'focus', focus);
  i.event.bind(i.scrollbarY, 'blur', blur);
  i.scrollbarYActive = null;
  i.scrollbarYHeight = null;
  i.scrollbarYTop = null;
  i.scrollbarYRight = h.toInt(d.css(i.scrollbarYRail, 'right'));
  i.isScrollbarYUsingRight = i.scrollbarYRight === i.scrollbarYRight; // !isNaN
  i.scrollbarYLeft = i.isScrollbarYUsingRight ? null : h.toInt(d.css(i.scrollbarYRail, 'left'));
  i.scrollbarYOuterWidth = i.isRtl ? h.outerWidth(i.scrollbarY) : null;
  i.railBorderYWidth = h.toInt(d.css(i.scrollbarYRail, 'borderTopWidth')) + h.toInt(d.css(i.scrollbarYRail, 'borderBottomWidth'));
  d.css(i.scrollbarYRail, 'display', 'block');
  i.railYMarginHeight = h.toInt(d.css(i.scrollbarYRail, 'marginTop')) + h.toInt(d.css(i.scrollbarYRail, 'marginBottom'));
  d.css(i.scrollbarYRail, 'display', '');
  i.railYHeight = null;
  i.railYRatio = null;
}

function getId(element) {
  if (typeof element.dataset === 'undefined') {
    return element.getAttribute('data-ps-id');
  } else {
    return element.dataset.psId;
  }
}

function setId(element, id) {
  if (typeof element.dataset === 'undefined') {
    element.setAttribute('data-ps-id', id);
  } else {
    element.dataset.psId = id;
  }
}

function removeId(element) {
  if (typeof element.dataset === 'undefined') {
    element.removeAttribute('data-ps-id');
  } else {
    delete element.dataset.psId;
  }
}

exports.add = function (element) {
  var newId = guid();
  setId(element, newId);
  instances[newId] = new Instance(element);
  return instances[newId];
};

exports.remove = function (element) {
  delete instances[getId(element)];
  removeId(element);
};

exports.get = function (element) {
  return instances[getId(element)];
};