import { Component, computed, inject, input, OnInit, output, signal } from '@angular/core';
import { firstValueFrom } from 'rxjs';
import { DanceGroup, Dancer } from '../core/api-models';
import { SchoolApi } from '../core/school-api';
import { apiError } from '../core/api-error';
import { DialogFrame } from './dialog-frame';

@Component({
  selector: 'app-group-members',
  imports: [DialogFrame],
  template: `
    <app-dialog-frame
      [title]="'Dansers in ' + group().category"
      [busy]="busy()"
      (dismissed)="closed.emit()"
    >
      <p class="muted">
        Koppel dansers aan deze groep. Een danser kan in meerdere groepen zitten. Wijzigingen worden
        direct opgeslagen.
      </p>
      @if (error()) {
        <p class="alert error" role="alert">{{ error() }}</p>
      }
      <p class="member-count" role="status">
        {{
          busy()
            ? 'Koppeling opslaan…'
            : memberIds().length + ' van ' + dancers().length + ' dansers gekoppeld'
        }}
      </p>
      <div class="member-list" [attr.aria-busy]="busy()">
        @for (dancer of sortedDancers(); track dancer.id) {
          <label class="member-row"
            ><span aria-hidden="true" class="avatar small">{{
              dancer.name.charAt(0).toUpperCase()
            }}</span>
            <span>{{ dancer.name }}</span>
            <input
              type="checkbox"
              [checked]="memberIds().includes(dancer.id)"
              [disabled]="busy()"
              (change)="toggle(dancer.id, $event)"
            />
          </label>
        } @empty {
          <p class="empty-inline">
            Er zijn nog geen dansers. Voeg eerst een danser toe via het tabblad Dansers.
          </p>
        }
      </div>
      <div class="dialog-actions">
        <button class="button primary" type="button" [disabled]="busy()" (click)="closed.emit()">
          Gereed
        </button>
      </div>
    </app-dialog-frame>
  `,
})
export class GroupMembers implements OnInit {
  readonly revision = input<number>();
  private originalRevision?: number;
  readonly schoolId = input.required<number>();
  readonly group = input.required<DanceGroup>();
  readonly dancers = input.required<Dancer[]>();
  readonly closed = output<void>();
  readonly changed = output<number[]>();
  readonly memberIds = signal<number[]>([]);
  readonly busy = signal(false);
  readonly error = signal('');
  readonly sortedDancers = computed(() =>
    [...this.dancers()].sort((a, b) => a.name.localeCompare(b.name, 'nl')),
  );
  private readonly api = inject(SchoolApi);
  ngOnInit(): void {
    this.originalRevision = this.revision();
    this.memberIds.set([...this.group().dancerIds]);
  }
  async toggle(dancerId: number, event: Event): Promise<void> {
    const checkbox = event.target as HTMLInputElement;
    const add = checkbox.checked;
    if (this.busy()) {
      checkbox.checked = this.memberIds().includes(dancerId);
      return;
    }
    this.busy.set(true);
    this.error.set('');
    try {
      await firstValueFrom(
        this.api.membership(this.schoolId(), this.group().id, dancerId, add, this.originalRevision),
      );
      if (this.originalRevision !== undefined) this.originalRevision++;
      this.memberIds.update((ids) =>
        add ? [...ids, dancerId] : ids.filter((id) => id !== dancerId),
      );
      checkbox.checked = add;
      this.changed.emit(this.memberIds());
    } catch (error: unknown) {
      checkbox.checked = this.memberIds().includes(dancerId);
      this.error.set(apiError(error));
    } finally {
      this.busy.set(false);
    }
  }
}