// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import {LitElement, html, css} from 'lit-element';
import {equalsIgnoreCase} from 'shared/helpers.js';

/**
 * `<mr-grid-dropdown>`
 *
 * Component used by the user to select what grid options to use.
 */
export class MrGridDropdown extends LitElement {
  /** @override */
  render() {
    return html`
      ${this.text}:
      <select
        class="drop-down"
        @change=${this._optionChanged}
      >
        ${(this.items).map((item) => html`
          <option .selected=${equalsIgnoreCase(item, this.selection)}>
            ${item}
          </option>
        `)}
      </select>
      `;
  }

  /** @override */
  static get properties() {
    return {
      text: {type: String},
      items: {type: Array},
      selection: {type: String},
    };
  };

  /** @override */
  constructor() {
    super();
    this.items = [];
    this.selection = 'None';
  };

  /** @override */
  static get styles() {
    return css`
      :host {
        font-size: var(--chops-large-font-size);
      }
      .drop-down {
        font-size: var(--chops-large-font-size);
      }
    `;
  };

  /**
   * Syncs values when the user updates their selection.
   * @param {Event} e
   * @fires CustomEvent#change
   * @private
   */
  _optionChanged(e) {
    this.selection = e.target.value;
    this.dispatchEvent(new CustomEvent('change'));
  };
};

customElements.define('mr-grid-dropdown', MrGridDropdown);