import { DfBaseComponent } from '@allianz/taly-core/dynamic-form';
import { Component, DoCheck, input, OnInit, Optional } from '@angular/core';
import { FormGroupDirective, NgForm, UntypedFormControl } from '@angular/forms';
import { ErrorStateMatcher } from '@aposin/ng-aquila/utils';
import { DfSwitcherConfig, SwitcherLabelPosition, SwitcherSize } from './switcher.model';

@Component({
  selector: 'df-switcher',
  styleUrls: ['./switcher.component.scss'],
  templateUrl: './switcher.component.html',
  standalone: false
})
export class DfSwitcherComponent
  extends DfBaseComponent<DfSwitcherConfig>
  implements OnInit, DoCheck
{
  override control = input<UntypedFormControl>(new UntypedFormControl());
  SwitcherLabelPosition = SwitcherLabelPosition;
  SwitcherSize = SwitcherSize;
  override deferSetupControl = true;

  protected errorState = false;

  constructor(
    @Optional() private readonly _parentForm: NgForm | null,
    @Optional() private readonly _parentFormGroup: FormGroupDirective | null,
    private readonly errorStateMatcher: ErrorStateMatcher
  ) {
    super();
  }

  override ngOnInit() {
    // Schedule async execution of `setupFormControl()` to avoid
    // `ExpressionChangedAfterItHasBeenCheckedError`
    // See: https://blog.angularindepth.com/everything-you-need-to-know-about-the-expressionchangedafterithasbeencheckederror-error-e3fd9ce7dbb4
    Promise.resolve(null).then(() => {
      this.setupFormControl();

      this.emitFormControlEventOnValueChanges();
    });
  }

  ngDoCheck(): void {
    if (this.control()) {
      // We follow the Aquila approach with the ErrorStateMatcher here:
      // We need to re-evaluate this on every change detection cycle, because there are some
      // error triggers that we can't subscribe to (e.g. parent form submissions). This means
      // that whatever logic is in here has to be super lean or we risk destroying the performance.
      const newErrorState = this.errorStateMatcher.isErrorState(
        this.control(),
        this._parentFormGroup || this._parentForm
      );

      if (this.errorState !== newErrorState) {
        this.errorState = newErrorState;
      }
    }
  }
}