// Import lo-dash lang category
import lang from 'lodash/lang';
// Import lo-dash template string function
import stringTemplate from 'lodash/string/template';
// import assign from 'lodash/object/assign';
import forEach from 'lodash/collection/foreach';

// Loop through configs stored and return the matching config (value) element (key)
function reverseMapFind(id, map) {
  let resp = false;
  for (var [node, config] of map.entries()) {
    if (config.id === id) {
      resp = node;
      break;
    }
  }
  return resp;
}

// Store elements and config object associations
function Elements(parent, data) {
  // this._data = new WeakMap().set(this._parent, data);
  // this._data.set(this._parent, data);
  this.parent = parent;
  // I wonder if we can just use a weakmap for storing templates
  // and we use the parent element as the single key
  // this._config = new WeakMap().set(this.parent, data);
  this._nodeConfig = new Map();
  this._templates = new Map();
  // Add the templates
  forEach(data.templates, function(config) {
    this.addTemplate(config)
  }, this);

  return this;
};
// Store the config object
Elements.prototype.addConfig = function(node, config) {
  this._nodeConfig.set(node, config);
};
// Get the config object
Elements.prototype.getConfig = function(node) {
  return this._nodeConfig.get(node);
};
// Remove the element and config association / storage
Elements.prototype.removeConfig = function(node) {
  return this._nodeConfig.delete(node);
};
// Get the element (key) by reverse lookup with config ID
Elements.prototype.getConfigElement = function(configID) {
  return reverseMapFind(configID, this._nodeConfig);
};
// Maybe a better name for what we are doing here
Elements.prototype.getElementByConfigId = Elements.prototype.getConfigElement;
// Add a Template config
Elements.prototype.addTemplate = function(config) {
  this._templates.set(config.id, config);
};
// Get a Template config
Elements.prototype.getTemplate = function(configID) {
  return this._templates.get(configID);
};
// Render a template
Elements.prototype.template = function(itemConfig) {
  // require a template key to do anything
  // return empty string for easy API use
  if (!itemConfig.hasOwnProperty('template')) {
    return '';
  }
  // An itemConfig can contain either a template ID reference or a complete template
  let template = lang.isPlainObject(itemConfig.template) ? itemConfig.template : this.getTemplate(itemConfig.template);
  let text = template.hasOwnProperty('text') ? template.text : '';
  let data = itemConfig.hasOwnProperty('data') ? itemConfig.data : {};
  let compiled = stringTemplate(text);
  // return templated markup string
  return compiled(itemConfig.data);
};

export default Elements;