import {Component, Directive, ElementRef, Host, Optional, Query, QueryList} from 'angular2/core';
import {NgControl} from 'angular2/common';

import {Config} from '../../config/config';
import {Ion} from '../ion';
import {ListHeader} from '../list/list';
import {Form} from '../../util/form';


/**
 * A radio group is a group of radio components.
 *
 * Selecting a radio button in the group unselects all others in the group.
 *
 * New radios can be registered dynamically.
 *
 * See the [Angular 2 Docs](https://angular.io/docs/js/latest/api/forms/) for more info on forms and input.
 *
 * @usage
 * ```html
 * <ion-list radio-group ngControl="clientside">
 *
 *   <ion-list-header>
 *     Clientside
 *   </ion-list-header>
 *
 *   <ion-radio value="ember">
 *     Ember
 *   </ion-radio>
 *
 *   <ion-radio value="angular1">
 *     Angular 1
 *   </ion-radio>
 *
 *   <ion-radio value="angular2" checked="true">
 *     Angular 2
 *   </ion-radio>
 *
 *   <ion-radio value="react">
 *     React
 *   </ion-radio>
 *
 * </ion-list>
 * ```
 * @demo /docs/v2/demos/radio/
 * @see {@link /docs/v2/components#radio Radio Component Docs}
*/
@Directive({
  selector: '[radio-group]',
  host: {
    'role': 'radiogroup',
    '[attr.aria-activedescendant]': 'activeId',
    '[attr.aria-describedby]': 'describedById',
  }
})
export class RadioGroup extends Ion {
  radios: Array<RadioButton> = [];

  constructor(
    elementRef: ElementRef,
    config: Config,
    @Optional() ngControl: NgControl,
    @Query(ListHeader) private headerQuery: QueryList<ListHeader>
  ) {
    super(elementRef, config);
    this.ngControl = ngControl;
    this.id = ++radioGroupIds;
    this.radioIds = -1;
    this.onChange = (_) => {};
    this.onTouched = (_) => {};

    if (ngControl) this.ngControl.valueAccessor = this;
  }

  /**
   * @private
   */
  ngOnInit() {
    let header = this.headerQuery.first;
    if (header) {
      if (!header.id) {
        header.id = 'radio-header-' + this.id;
      }
      this.describedById = header.id;
    }
  }

  /**
   * @private
   * Register the specified radio button with the radio group.
   * @param {RadioButton} radio  The radio button to register.
   */
  registerRadio(radio) {
    radio.id = radio.id || ('radio-' + this.id + '-' + (++this.radioIds));
    this.radios.push(radio);

    if (this.value == radio.value) {
      radio.check(this.value);
    }

    if (radio.checked) {
      this.value = radio.value;
      this.onChange(this.value);
      this.activeId = radio.id;
    }
  }

  /**
   * @private
   * Update which radio button in the group is checked, unchecking all others.
   * @param {RadioButton} checkedRadio  The radio button to check.
   */
  update(checkedRadio) {
    this.value = checkedRadio.value;
    this.activeId = checkedRadio.id;

    for (let radio of this.radios) {
      radio.checked = (radio === checkedRadio);
    }

    this.onChange(this.value);
  }

  /**
   * @private
   * Angular2 Forms API method called by the model (Control) on change to update
   * the checked value.
   * https://github.com/angular/angular/blob/master/modules/angular2/src/forms/directives/shared.ts#L34
   */
  writeValue(value) {
    this.value = value;
    for (let radio of this.radios) {
      radio.checked = (radio.value == value);
    }
  }

  /**
   * @private
   * Angular2 Forms API method called by the view (NgControl) to register the
   * onChange event handler that updates the model (Control).
   * https://github.com/angular/angular/blob/master/modules/angular2/src/forms/directives/shared.ts#L27
   * @param {Function} fn  the onChange event handler.
   */
  registerOnChange(fn) { this.onChange = fn; }

  /**
   * @private
   * Angular2 Forms API method called by the the view (NgControl) to register
   * the onTouched event handler that marks the model (Control) as touched.
   * @param {Function} fn  onTouched event handler.
   */
  registerOnTouched(fn) { this.onTouched = fn; }
}


/**
 * @description
 * A single radio component.
 *
 * See the [Angular 2 Docs](https://angular.io/docs/js/latest/api/forms/) for more info on forms and input.
 *
 * @usage
 * ```html
 * <ion-radio value="isChecked" checked="true">
 *   Radio Label
 * </ion-radio>
 * ```
 * @demo /docs/v2/demos/radio/
 * @see {@link /docs/v2/components#radio Radio Component Docs}
 */
@Component({
  selector: 'ion-radio',
  inputs: [
    'value',
    'checked',
    'disabled',
    'id'
  ],
  host: {
    'role': 'radio',
    'tappable': 'true',
    '[attr.id]': 'id',
    '[attr.tab-index]': 'tabIndex',
    '[attr.aria-checked]': 'checked',
    '[attr.aria-disabled]': 'disabled',
    '[attr.aria-labelledby]': 'labelId',
    '(click)': 'click($event)',
    'class': 'item'
  },
  template:
    '<div class="item-inner">' +
      '<ion-item-content id="{{labelId}}">' +
        '<ng-content></ng-content>' +
      '</ion-item-content>' +
      '<div class="radio-media">' +
        '<div class="radio-icon"></div>' +
      '</div>' +
    '</div>'
})
export class RadioButton extends Ion {

  constructor(
    @Host() @Optional() group: RadioGroup,
    elementRef: ElementRef,
    config: Config,
    private form: Form
  ) {
    super(elementRef, config);

    this.group = group;
    this.tabIndex = 0;
  }

  /**
   * @private
   */
  ngOnInit() {
    super.ngOnInit();
    if (!this.id) {
      this.id = 'rb-' + this.form.nextId();
    }
    this.labelId = 'lbl-' + this.id;

    if (this.group) {
      this.group.registerRadio(this);
    } else {
      console.error('<ion-radio> must be within a <ion-list radio-group>');
    }
  }

  /**
   * @private
   */
  click(ev) {
    ev.preventDefault();
    ev.stopPropagation();
    this.check();
  }

  /**
   * Update the checked state of this radio button.
   * TODO: Call this toggle? Since unchecks as well
   */
  check() {
    this.checked = !this.checked;
    this.group.update(this);
  }

}

let radioGroupIds = -1;