var Item = require('./Item');
var util = require('../../../util');

/**
 * @constructor BoxItem
 * @extends Item
 * @param {Object} data             Object containing parameters start
 *                                  content, className.
 * @param {{toScreen: function, toTime: function}} conversion
 *                                  Conversion functions from time to screen and vice versa
 * @param {Object} [options]        Configuration options
 *                                  // TODO: describe available options
 */
function BoxItem (data, conversion, options) {
  this.props = {
    dot: {
      width: 0,
      height: 0
    },
    line: {
      width: 0,
      height: 0
    }
  };

  // validate data
  if (data) {
    if (data.start == undefined) {
      throw new Error('Property "start" missing in item ' + data);
    }
  }

  Item.call(this, data, conversion, options);
}

BoxItem.prototype = new Item (null, null, null);

/**
 * Check whether this item is visible inside given range
 * @returns {{start: Number, end: Number}} range with a timestamp for start and end
 * @returns {boolean} True if visible
 */
BoxItem.prototype.isVisible = function(range) {
  // determine visibility
  // TODO: account for the real width of the item. Right now we just add 1/4 to the window
  var interval = (range.end - range.start) / 4;
  return (this.data.start > range.start - interval) && (this.data.start < range.end + interval);
};

/**
 * Repaint the item
 */
BoxItem.prototype.redraw = function() {
  var dom = this.dom;
  if (!dom) {
    // create DOM
    this.dom = {};
    dom = this.dom;

    // create main box
    dom.box = document.createElement('DIV');

    // contents box (inside the background box). used for making margins
    dom.content = document.createElement('DIV');
    dom.content.className = 'vis-item-content';
    dom.box.appendChild(dom.content);

    // line to axis
    dom.line = document.createElement('DIV');
    dom.line.className = 'vis-line';

    // dot on axis
    dom.dot = document.createElement('DIV');
    dom.dot.className = 'vis-dot';

    // attach this item as attribute
    dom.box['timeline-item'] = this;

    this.dirty = true;
  }

  // append DOM to parent DOM
  if (!this.parent) {
    throw new Error('Cannot redraw item: no parent attached');
  }
  if (!dom.box.parentNode) {
    var foreground = this.parent.dom.foreground;
    if (!foreground) throw new Error('Cannot redraw item: parent has no foreground container element');
    foreground.appendChild(dom.box);
  }
  if (!dom.line.parentNode) {
    var background = this.parent.dom.background;
    if (!background) throw new Error('Cannot redraw item: parent has no background container element');
    background.appendChild(dom.line);
  }
  if (!dom.dot.parentNode) {
    var axis = this.parent.dom.axis;
    if (!background) throw new Error('Cannot redraw item: parent has no axis container element');
    axis.appendChild(dom.dot);
  }
  this.displayed = true;

  // Update DOM when item is marked dirty. An item is marked dirty when:
  // - the item is not yet rendered
  // - the item's data is changed
  // - the item is selected/deselected
  if (this.dirty) {
    this._updateContents(this.dom.content);
    this._updateTitle(this.dom.box);
    this._updateDataAttributes(this.dom.box);
    this._updateStyle(this.dom.box);

    // update class
    var className = (this.data.className? ' ' + this.data.className : '') +
        (this.selected ? ' vis-selected' : '');
    dom.box.className = 'vis-item vis-box' + className;
    dom.line.className = 'vis-item vis-line' + className;
    dom.dot.className  = 'vis-item vis-dot' + className;

    // recalculate size
    this.props.dot.height = dom.dot.offsetHeight;
    this.props.dot.width = dom.dot.offsetWidth;
    this.props.line.width = dom.line.offsetWidth;
    this.width = dom.box.offsetWidth;
    this.height = dom.box.offsetHeight;

    this.dirty = false;
  }

  this._repaintDeleteButton(dom.box);
};

/**
 * Show the item in the DOM (when not already displayed). The items DOM will
 * be created when needed.
 */
BoxItem.prototype.show = function() {
  if (!this.displayed) {
    this.redraw();
  }
};

/**
 * Hide the item from the DOM (when visible)
 */
BoxItem.prototype.hide = function() {
  if (this.displayed) {
    var dom = this.dom;

    if (dom.box.parentNode)   dom.box.parentNode.removeChild(dom.box);
    if (dom.line.parentNode)  dom.line.parentNode.removeChild(dom.line);
    if (dom.dot.parentNode)   dom.dot.parentNode.removeChild(dom.dot);

    this.top = null;
    this.left = null;

    this.displayed = false;
  }
};

/**
 * Reposition the item horizontally
 * @Override
 */
BoxItem.prototype.repositionX = function() {
  var start = this.conversion.toScreen(this.data.start);
  var align = this.options.align;
  var left;
  var box = this.dom.box;
  var line = this.dom.line;
  var dot = this.dom.dot;

  // calculate left position of the box
  if (align == 'right') {
    this.left = start - this.width;
  }
  else if (align == 'left') {
    this.left = start;
  }
  else {
    // default or 'center'
    this.left = start - this.width / 2;
  }

  // reposition box
  box.style.left = this.left + 'px';

  // reposition line
  line.style.left = (start - this.props.line.width / 2) + 'px';

  // reposition dot
  dot.style.left = (start - this.props.dot.width / 2) + 'px';
};

/**
 * Reposition the item vertically
 * @Override
 */
BoxItem.prototype.repositionY = function() {
  var orientation = this.options.orientation;
  var box = this.dom.box;
  var line = this.dom.line;
  var dot = this.dom.dot;

  if (orientation == 'top') {
    box.style.top     = (this.top || 0) + 'px';

    line.style.top    = '0';
    line.style.height = (this.parent.top + this.top + 1) + 'px';
    line.style.bottom = '';
  }
  else { // orientation 'bottom'
    var itemSetHeight = this.parent.itemSet.props.height; // TODO: this is nasty
    var lineHeight = itemSetHeight - this.parent.top - this.parent.height + this.top;

    box.style.top     = (this.parent.height - this.top - this.height || 0) + 'px';
    line.style.top    = (itemSetHeight - lineHeight) + 'px';
    line.style.bottom = '0';
  }

  dot.style.top = (-this.props.dot.height / 2) + 'px';
};

module.exports = BoxItem;