var Emitter = require('emitter-component');
var Hammer = require('../module/hammer');
var util = require('../util');
var DataSet = require('../DataSet');
var DataView = require('../DataView');
var Range = require('./Range');
var Core = require('./Core');
var TimeAxis = require('./component/TimeAxis');
var CurrentTime = require('./component/CurrentTime');
var CustomTime = require('./component/CustomTime');
var ItemSet = require('./component/ItemSet');

/**
 * Create a timeline visualization
 * @param {HTMLElement} container
 * @param {vis.DataSet | Array | google.visualization.DataTable} [items]
 * @param {Object} [options]  See Timeline.setOptions for the available options.
 * @constructor
 * @extends Core
 */
function Timeline (container, items, groups, options) {
  if (!(this instanceof Timeline)) {
    throw new SyntaxError('Constructor must be called with the new operator');
  }

  // if the third element is options, the forth is groups (optionally);
  if (!(groups instanceof Array || groups instanceof DataSet) && groups instanceof Object) {
    var forthArgument = options;
    options = groups;
    groups = forthArgument;
  }

  var me = this;
  this.defaultOptions = {
    start: null,
    end:   null,

    autoResize: true,

    orientation: 'bottom',
    width: null,
    height: null,
    maxHeight: null,
    minHeight: null
  };
  this.options = util.deepExtend({}, this.defaultOptions);

  // Create the DOM, props, and emitter
  this._create(container);

  // all components listed here will be repainted automatically
  this.components = [];

  this.body = {
    dom: this.dom,
    domProps: this.props,
    emitter: {
      on: this.on.bind(this),
      off: this.off.bind(this),
      emit: this.emit.bind(this)
    },
    util: {
      snap: null, // will be specified after TimeAxis is created
      toScreen: me._toScreen.bind(me),
      toGlobalScreen: me._toGlobalScreen.bind(me), // this refers to the root.width
      toTime: me._toTime.bind(me),
      toGlobalTime : me._toGlobalTime.bind(me)
    }
  };

  // range
  this.range = new Range(this.body);
  this.components.push(this.range);
  this.body.range = this.range;

  // time axis
  this.timeAxis = new TimeAxis(this.body);
  this.components.push(this.timeAxis);
  this.body.util.snap = this.timeAxis.snap.bind(this.timeAxis);

  // current time bar
  this.currentTime = new CurrentTime(this.body);
  this.components.push(this.currentTime);

  // custom time bar
  // Note: time bar will be attached in this.setOptions when selected
  this.customTime = new CustomTime(this.body);
  this.components.push(this.customTime);

  // item set
  this.itemSet = new ItemSet(this.body);
  this.components.push(this.itemSet);

  this.itemsData = null;      // DataSet
  this.groupsData = null;     // DataSet

  // apply options
  if (options) {
    this.setOptions(options);
  }

  // IMPORTANT: THIS HAPPENS BEFORE SET ITEMS!
  if (groups) {
    this.setGroups(groups);
  }

  // create itemset
  if (items) {
    this.setItems(items);
  }
  else {
    this.redraw();
  }
}

// Extend the functionality from Core
Timeline.prototype = new Core();

/**
 * Set items
 * @param {vis.DataSet | Array | google.visualization.DataTable | null} items
 */
Timeline.prototype.setItems = function(items) {
  var initialLoad = (this.itemsData == null);

  // convert to type DataSet when needed
  var newDataSet;
  if (!items) {
    newDataSet = null;
  }
  else if (items instanceof DataSet || items instanceof DataView) {
    newDataSet = items;
  }
  else {
    // turn an array into a dataset
    newDataSet = new DataSet(items, {
      type: {
        start: 'Date',
        end: 'Date'
      }
    });
  }

  // set items
  this.itemsData = newDataSet;
  this.itemSet && this.itemSet.setItems(newDataSet);

  if (initialLoad) {
    if (this.options.start != undefined || this.options.end != undefined) {
      var start = this.options.start != undefined ? this.options.start : null;
      var end   = this.options.end != undefined   ? this.options.end : null;

      this.setWindow(start, end, {animate: false});
    }
    else {
      this.fit({animate: false});
    }
  }
};

/**
 * Set groups
 * @param {vis.DataSet | Array | google.visualization.DataTable} groups
 */
Timeline.prototype.setGroups = function(groups) {
  // convert to type DataSet when needed
  var newDataSet;
  if (!groups) {
    newDataSet = null;
  }
  else if (groups instanceof DataSet || groups instanceof DataView) {
    newDataSet = groups;
  }
  else {
    // turn an array into a dataset
    newDataSet = new DataSet(groups);
  }

  this.groupsData = newDataSet;
  this.itemSet.setGroups(newDataSet);
};

/**
 * Set selected items by their id. Replaces the current selection
 * Unknown id's are silently ignored.
 * @param {string[] | string} [ids]  An array with zero or more id's of the items to be
 *                                selected. If ids is an empty array, all items will be
 *                                unselected.
 * @param {Object} [options]      Available options:
 *                                `focus: boolean`
 *                                    If true, focus will be set to the selected item(s)
 *                                `animate: boolean | number`
 *                                    If true (default), the range is animated
 *                                    smoothly to the new window.
 *                                    If a number, the number is taken as duration
 *                                    for the animation. Default duration is 500 ms.
 *                                    Only applicable when option focus is true.
 */
Timeline.prototype.setSelection = function(ids, options) {
  this.itemSet && this.itemSet.setSelection(ids);

  if (options && options.focus) {
    this.focus(ids, options);
  }
};

/**
 * Get the selected items by their id
 * @return {Array} ids  The ids of the selected items
 */
Timeline.prototype.getSelection = function() {
  return this.itemSet && this.itemSet.getSelection() || [];
};

/**
 * Adjust the visible window such that the selected item (or multiple items)
 * are centered on screen.
 * @param {String | String[]} id     An item id or array with item ids
 * @param {Object} [options]      Available options:
 *                                `animate: boolean | number`
 *                                    If true (default), the range is animated
 *                                    smoothly to the new window.
 *                                    If a number, the number is taken as duration
 *                                    for the animation. Default duration is 500 ms.
 *                                    Only applicable when option focus is true
 */
Timeline.prototype.focus = function(id, options) {
  if (!this.itemsData || id == undefined) return;

  var ids = Array.isArray(id) ? id : [id];

  // get the specified item(s)
  var itemsData = this.itemsData.getDataSet().get(ids, {
    type: {
      start: 'Date',
      end: 'Date'
    }
  });

  // calculate minimum start and maximum end of specified items
  var start = null;
  var end = null;
  itemsData.forEach(function (itemData) {
    var s = itemData.start.valueOf();
    var e = 'end' in itemData ? itemData.end.valueOf() : itemData.start.valueOf();

    if (start === null || s < start) {
      start = s;
    }

    if (end === null || e > end) {
      end = e;
    }
  });

  if (start !== null && end !== null) {
    // calculate the new middle and interval for the window
    var middle = (start + end) / 2;
    var interval = Math.max((this.range.end - this.range.start), (end - start) * 1.1);

    var animate = (options && options.animate !== undefined) ? options.animate : true;
    this.range.setRange(middle - interval / 2, middle + interval / 2, animate);
  }
};

/**
 * Get the data range of the item set.
 * @returns {{min: Date, max: Date}} range  A range with a start and end Date.
 *                                          When no minimum is found, min==null
 *                                          When no maximum is found, max==null
 */
Timeline.prototype.getItemRange = function() {
  // calculate min from start filed
  var dataset = this.itemsData.getDataSet(),
    min = null,
    max = null;

  if (dataset) {
    // calculate the minimum value of the field 'start'
    var minItem = dataset.min('start');
    min = minItem ? util.convert(minItem.start, 'Date').valueOf() : null;
    // Note: we convert first to Date and then to number because else
    // a conversion from ISODate to Number will fail

    // calculate maximum value of fields 'start' and 'end'
    var maxStartItem = dataset.max('start');
    if (maxStartItem) {
      max = util.convert(maxStartItem.start, 'Date').valueOf();
    }
    var maxEndItem = dataset.max('end');
    if (maxEndItem) {
      if (max == null) {
        max = util.convert(maxEndItem.end, 'Date').valueOf();
      }
      else {
        max = Math.max(max, util.convert(maxEndItem.end, 'Date').valueOf());
      }
    }
  }

  return {
    min: (min != null) ? new Date(min) : null,
    max: (max != null) ? new Date(max) : null
  };
};


module.exports = Timeline;