/**
 * Copyright Aquera Inc 2023
 *
 * This source code is licensed under the BSD-3-Clause license found in the
 * LICENSE file in the root directory of this source tree.
 */

import {
  LitElement,
  html,
  CSSResultArray,
  TemplateResult,
} from 'lit';
import { customElement, property } from 'lit/decorators.js';
import { styles } from './nile-menu-item.css';
import '../nile-icon';
import { classMap } from 'lit/directives/class-map.js';
import { query } from 'lit/decorators.js';
import { getTextContent } from '../internal/slot';
import { watch } from '../internal/watch';
import NileElement from '../internal/nile-element';
import type { CSSResultGroup } from 'lit';
/**
 * Nile icon component.
 *
 * @tag nile-menu-item
 *
 * @summary Menu items provide options for the user to pick from in a menu.
 * @status stable
 * @since 2.0
 *
 * @dependency nile-icon
 *
 * @slot - The menu item's label.
 * @slot prefix - Used to prepend an icon or similar element to the menu item.
 * @slot suffix - Used to append an icon or similar element to the menu item.
 *
 * @csspart base - The component's base wrapper.
 * @csspart checked-icon - The checked icon, which is only visible when the menu item is checked.
 * @csspart prefix - The prefix container.
 * @csspart label - The menu item label.
 * @csspart suffix - The suffix container.
 * @csspart submenu-icon - The submenu icon, visible only when the menu item has a submenu (not yet implemented).
 */

@customElement('nile-menu-item')
export class NileMenuItem extends NileElement {
  static styles: CSSResultGroup = styles;

  private cachedTextLabel: string;

  @query('slot:not([name])') defaultSlot: HTMLSlotElement;

  @query('.menu-item') menuItem: HTMLElement;

  /** The type of menu item to render. To use `checked`, this value must be set to `checkbox`. */
  @property() type: 'normal' | 'checkbox' = 'normal';

  /** Draws the item in a checked state. */
  @property({ type: Boolean, reflect: true }) checked = false;

  /** A unique value to store in the menu item. This can be used as a way to identify menu items when selected. */
  @property() value = '';

  /** Draws the menu item in a disabled state, preventing selection. */
  @property({ type: Boolean, reflect: true }) disabled = false;

  /** Draws the menu item in an active/selected state. */
  @property({ type: Boolean, reflect: true }) active = false;

  /** Draws the item in a checked state. */
  @property({ type: Boolean, reflect: true }) hasSubMenu = false;

  connectedCallback() {
    super.connectedCallback();
    this.handleHostClick = this.handleHostClick.bind(this);
    this.addEventListener('click', this.handleHostClick);
  }

  disconnectedCallback() {
    super.disconnectedCallback();
    this.removeEventListener('click', this.handleHostClick);
  }

  private handleDefaultSlotChange() {
    const textLabel = this.getTextLabel();

    // Ignore the first time the label is set
    if (typeof this.cachedTextLabel === 'undefined') {
      this.cachedTextLabel = textLabel;
      return;
    }

    // When the label changes, emit a slotchange event so parent controls see it
    if (textLabel !== this.cachedTextLabel) {
      this.cachedTextLabel = textLabel;
      this.emit('slotchange');
    }
  }

  private handleHostClick(event: MouseEvent) {
    // Prevent the click event from being emitted when the button is disabled or loading
    if (this.disabled) {
      event.preventDefault();
      event.stopImmediatePropagation();
    }
  }

  @watch('checked')
  handleCheckedChange() {
    // For proper accessibility, users have to use type="checkbox" to use the checked attribute
    if (this.checked && this.type !== 'checkbox') {
      this.checked = false;
      console.error(
        'The checked attribute can only be used on menu items with type="checkbox"',
        this
      );
      return;
    }

    // Only checkbox types can receive the aria-checked attribute
    if (this.type === 'checkbox') {
      this.setAttribute('aria-checked', this.checked ? 'true' : 'false');
    } else {
      this.removeAttribute('aria-checked');
    }
  }

  @watch('disabled')
  handleDisabledChange() {
    this.setAttribute('aria-disabled', this.disabled ? 'true' : 'false');
  }

  @watch('type')
  handleTypeChange() {
    if (this.type === 'checkbox') {
      this.setAttribute('role', 'menuitemcheckbox');
      this.setAttribute('aria-checked', this.checked ? 'true' : 'false');
    } else {
      this.setAttribute('role', 'menuitem');
      this.removeAttribute('aria-checked');
    }
  }

  /** Returns a text label based on the contents of the menu item's default slot. */
  getTextLabel() {
    return getTextContent(this.defaultSlot);
  }

  render() {
    return html`
      <div
        part="base"
        class=${classMap({
          'menu-item': true,
          'menu-item--checked': this.checked,
          'menu-item--disabled': this.disabled,
          'menu-item--active': this.active,
          'menu-item--has-submenu': this.hasSubMenu,
        })}
      >
        ${this.checked
          ? html`
              <span part="checked-icon" class="menu-item__check">
                <nile-icon
                  name="var(--nile-icon-tick, var(--ng-icon-check))"
                  method="var(--nile-svg-method-fill, var(--ng-svg-method-stroke))"
                  library="system"
                  aria-hidden="true"
                ></nile-icon>
              </span>
            `
          : ``}

        <slot name="prefix" part="prefix" class="menu-item__prefix"></slot>

        <slot
          part="label"
          class="menu-item__label"
          @slotchange=${this.handleDefaultSlotChange}
        ></slot>

        <slot name="suffix" part="suffix" class="menu-item__suffix"></slot>

        ${this.hasSubMenu
          ? html` <span part="submenu-icon" class="menu-item__chevron">
              <nile-icon
                name="var(--nile-icon-arrow-right, var(--ng-icon-chevron-right))"
                method="var(--nile-svg-method-fill, var(--ng-svg-method-stroke))"
                library="system"
                aria-hidden="true"
              ></nile-icon>
            </span>`
          : ``}
      </div>
    `;
  }
}

export default NileMenuItem;

declare global {
  interface HTMLElementTagNameMap {
    'nile-menu-item': NileMenuItem;
  }
}