'use strict';

var cmdHelper = require('../../../../helper/CmdHelper');

var domQuery = require('min-dom').query,
    domify = require('min-dom').domify,
    domAttr = require('min-dom').attr;

var forEach = require('lodash/forEach'),
    find = require('lodash/find');

var elementHelper = require('../../../../helper/ElementHelper');
var utils = require('../../../../Utils'),
    escapeHTML = utils.escapeHTML;

var selector = 'select[name=selectedElement]';

/**
 * Get select box containing all elements.
 *
 * @param {DOMElement} node
 *
 * @return {DOMElement} the select box
 */
function getSelectBox(node) {
  return domQuery(selector, node.parentElement);
}

/**
 * Find element by given id.
 *
 * @param {ModdleElement} eventDefinition
 *
 * @return {ModdleElement} an element
 */
function findElementById(eventDefinition, type, id) {
  var elements = utils.findRootElementsByType(eventDefinition, type);
  return find(elements, function(element) {
    return element.id === id;
  });
}

/**
 * Create an entry to modify the reference to an element from an
 * event definition.
 *
 * @param  {djs.model.Base} element
 * @param  {ModdleElement} definition
 * @param  {BpmnFactory} bpmnFactory
 * @param  {Object} options
 * @param  {string} options.label the label of the entry
 * @param  {string} options.description the description of the entry
 * @param  {string} options.elementName the name of the element
 * @param  {string} options.elementType the type of the element
 * @param  {string} options.referenceProperty the name of referencing property
 * @param  {string} options.newElementIdPrefix the prefix of a new created element
 *
 * @return {Array<Object>} return an array containing the entries
 */
module.exports = function(element, definition, bpmnFactory, options) {

  var elementName = options.elementName || '',
      elementType = options.elementType,
      referenceProperty = options.referenceProperty;

  var newElementIdPrefix = options.newElementIdPrefix || 'elem_';

  var label = options.label || '',
      description = options.description || '';

  var entries = [];

  entries.push({

    id: 'event-definitions-' + elementName,
    description: description,
    html: '<div class="bpp-row bpp-select">' +
             '<label for="camunda-' + escapeHTML(elementName) + '">' + escapeHTML(label) + '</label>' +
             '<div class="bpp-field-wrapper">' +
               '<select id="camunda-' + escapeHTML(elementName) + '" name="selectedElement" data-value>' +
               '</select>' +
               '<button class="add" id="addElement" data-action="addElement"><span>+</span></button>' +
             '</div>' +
          '</div>',

    get: function(element, entryNode) {
      utils.updateOptionsDropDown(selector, definition, elementType, entryNode);
      var reference = definition.get(referenceProperty);
      return {
        selectedElement: (reference && reference.id) || ''
      };
    },

    set: function(element, values) {
      var selection = values.selectedElement;

      var props = {};

      if (!selection || typeof selection === 'undefined') {
        // remove reference to element
        props[referenceProperty] = undefined;
        return cmdHelper.updateBusinessObject(element, definition, props);
      }

      var commands = [];

      var selectedElement = findElementById(definition, elementType, selection);
      if (!selectedElement) {
        var root = utils.getRoot(definition);

        // create a new element
        selectedElement = elementHelper.createElement(elementType, { name: selection }, root, bpmnFactory);
        commands.push(cmdHelper.addAndRemoveElementsFromList(element, root, 'rootElements', null, [ selectedElement ]));
      }

      // update reference to element
      props[referenceProperty] = selectedElement;
      commands.push(cmdHelper.updateBusinessObject(element, definition, props));

      return commands;
    },

    addElement: function(element, inputNode) {
      // note: this generated id will be used as name
      // of the element and not as id
      var id = utils.nextId(newElementIdPrefix);

      var optionTemplate = domify('<option value="' + escapeHTML(id) + '"> (id='+escapeHTML(id)+')' + '</option>');

      // add new option
      var selectBox = getSelectBox(inputNode);
      selectBox.insertBefore(optionTemplate, selectBox.firstChild);

      // select new element in the select box
      forEach(selectBox, function(option) {
        if (option.value === id) {
          domAttr(option, 'selected', 'selected');
        } else {
          domAttr(option, 'selected', null);
        }
      });

      return true;
    }

  });

  return entries;

};