/**
 * @module modules/query-values-sk
 * @description <h2><code>query-values-sk</code></h2>
 *
 * The right-hand side of the query-sk element, the values for a single key
 * in a query/paramset.
 *
 * @evt query-values-changed - Trigggered only when the selections have actually
 *     changed. The selection is available in e.detail.
 *
 */
import { define } from 'elements-sk/define'
import { html, render } from 'lit-html'
import { ElementSk } from '../../../infra-sk/modules/ElementSk'
import 'elements-sk/checkbox-sk'
import 'elements-sk/multi-select-sk'


const values = (ele) => {
  return ele._options.map((v) => html`
    <div value=${v} ?selected=${ele._selected.indexOf(v) != -1}>${v}</div>
  `);
};

const template = (ele) => html`
  <checkbox-sk id=invert @change=${ele._invertChange} title='Match items not selected below.' label='Invert'> </checkbox-sk>
  <checkbox-sk id=regex @change=${ele._regexChange} title='Match items via regular expression.' label='Regex'> </checkbox-sk>
  <input type=text id=regexValue class=hidden @input=${ele._regexInputChange}>
  <multi-select-sk
    id=values
    @selection-changed=${ele._selectionChange}>
    ${values(ele)}
  </multi-select-sk>
  `;

define('query-values-sk', class extends ElementSk {
  constructor() {
    super(template);
    this._options = [];
    this._selected = [];
  }

  connectedCallback() {
    super.connectedCallback();
    this._render();
    this._invert = this.querySelector('#invert');
    this._regex = this.querySelector('#regex');
    this._values = this.querySelector('#values');
    this._regexValue = this.querySelector('#regexValue');
    this._upgradeProperty('options');
    this._upgradeProperty('selected');
  }

  _invertChange(e) {
    if (this._regex.checked) {
      this._regex.checked = false;
    }
    this._render();
    this._fireEvent();
  }

  _regexChange(e) {
    if (this._invert.checked) {
      this._invert.checked = false;
    }
    this._render();
    this._fireEvent();
  }

  _regexInputChange(e) {
    this._fireEvent();
  }

  _selectionChange(e) {
    this._selected = e.detail.selection.map((i) =>  this._options[i]);
    this._render();
    this._fireEvent();
  }

  _fireEvent() {
    const prefix = this._invert.checked ? '!' : '';
    let selected = this._values.selection.map((i) =>  prefix + this._options[i]);
    if (this._regex.checked) {
      selected = [`~${this._regexValue.value}`];
    }
    this.dispatchEvent(new CustomEvent('query-values-changed', {
      detail: selected,
      bubbles: true,
    }));
  }

  /** @prop options {Array} The available options as an Array of strings. */
  get options() { return this._options }
  set options(val) {
    this._options = val;
    this._selected = [];
    this._render();
  }

  /** @prop selected {Array} Current selections. */
  get selected() { return this._selected }
  set selected(val) {
    this._selected = val;
    this._invert.checked = !!(this._selected.length >= 1 && this._selected[0][0] === '!');
    this._regex.checked = !!(this._selected.length == 1 && this._selected[0][0] === '~');
    this._cleanSelected();
    if (this._selected.length && this._regex.checked) {
      this._regexValue.value = this._selected[0];
    }
    this._render();
  }

  _cleanSelected() {
    // Remove prefixes from _selected.
    this._selected = this._selected.map(val => {
      if ('~!'.includes(val[0])) {
        return val.slice(1);
      } else {
        return val;
      }
    });
  }

});