import { Component, computed, inject, input } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { FormFieldComponent } from '@shared/ui/form-field/form-field.component';
import { TextInputComponent } from '@shared/ui/text-input/text-input.component';
import { ButtonComponent } from '@shared/ui/button/button.component';
import { AlertComponent } from '@shared/ui/alert/alert.component';
import { SpinnerComponent } from '@shared/ui/spinner/spinner.component';
import { createStore } from '@shared/application/store';
import { BigProfileStore } from '@registratie/application/big-profile.store';
import { WizardState, WizardMsg, Draft, initial, reduce } from '@herregistratie/domain/herregistratie.machine';
import { submitHerregistratie } from '@herregistratie/application/submit-herregistratie';

/** Organism: multi-step herregistratie wizard. ALL state lives in one signal
    driven by the pure `reduce` function (see herregistratie.machine.ts) via an
    Elm-style store. The UI just sends messages and folds over the state's tag —
    no booleans like `submitting`/`submitted` that could contradict each other.
    Submitting also flips an optimistic flag on the shared BigProfileStore, so
    the dashboard shows "in behandeling" immediately. */
@Component({
  selector: 'app-herregistratie-wizard',
  imports: [FormsModule, FormFieldComponent, TextInputComponent, ButtonComponent, AlertComponent, SpinnerComponent],
  template: `
    @switch (state().tag) {
      @case ('Editing') {
        <p class="rhc-paragraph" style="color:var(--rhc-color-grijs-700)">Stap {{ step() }} van 2</p>
        <form (ngSubmit)="onPrimary()" style="max-width:28rem">
          @if (step() === 1) {
            <app-form-field label="Gewerkte uren (afgelopen 5 jaar)" fieldId="uren" [error]="errUren()">
              <app-text-input inputId="uren" [ngModel]="draft().uren" (ngModelChange)="dispatch({ tag: 'SetField', key: 'uren', value: $event })"
                name="uren" [invalid]="!!errUren()" placeholder="bijv. 4160" />
            </app-form-field>
            <app-form-field label="Aantal jaren werkzaam" fieldId="jaren" [error]="errJaren()">
              <app-text-input inputId="jaren" [ngModel]="draft().jaren" (ngModelChange)="dispatch({ tag: 'SetField', key: 'jaren', value: $event })"
                name="jaren" [invalid]="!!errJaren()" placeholder="bijv. 5" />
            </app-form-field>
            <app-button type="submit" variant="primary">Volgende</app-button>
          } @else {
            <app-form-field label="Behaalde nascholingspunten" fieldId="punten" [error]="errPunten()">
              <app-text-input inputId="punten" [ngModel]="draft().punten" (ngModelChange)="dispatch({ tag: 'SetField', key: 'punten', value: $event })"
                name="punten" [invalid]="!!errPunten()" placeholder="bijv. 200" />
            </app-form-field>
            <div style="display:flex;gap:0.5rem">
              <app-button type="button" variant="secondary" (click)="dispatch({ tag: 'Back' })">Vorige</app-button>
              <app-button type="submit" variant="primary">Herregistratie aanvragen</app-button>
            </div>
          }
        </form>
      }
      @case ('Submitting') {
        <app-spinner /> <span>Aanvraag wordt verwerkt…</span>
      }
      @case ('Submitted') {
        <app-alert type="ok">Uw aanvraag tot herregistratie is ontvangen.</app-alert>
      }
      @case ('Failed') {
        <app-alert type="error">Indienen mislukt: {{ failedError() }}</app-alert>
        <div style="margin-top:1rem">
          <app-button variant="secondary" (click)="onRetry()">Opnieuw proberen</app-button>
        </div>
      }
    }
  `,
})
export class HerregistratieWizardComponent {
  private profile = inject(BigProfileStore);
  private store = createStore<WizardState, WizardMsg>(initial, reduce);

  /** Optional seed so Storybook / the showcase can mount any state directly. */
  seed = input<WizardState>(initial);

  readonly state = this.store.model; // public so the showcase can highlight the live state
  protected dispatch = this.store.dispatch;

  private editing = computed(() => (this.state().tag === 'Editing' ? (this.state() as Extract<WizardState, { tag: 'Editing' }>) : null));
  protected step = computed(() => this.editing()?.step ?? 1);
  protected draft = computed<Draft>(() => this.editing()?.draft ?? { uren: '', jaren: '', punten: '' });
  protected errUren = computed(() => this.editing()?.errors.uren ?? '');
  protected errJaren = computed(() => this.editing()?.errors.jaren ?? '');
  protected errPunten = computed(() => this.editing()?.errors.punten ?? '');
  protected failedError = computed(() => (this.state().tag === 'Failed' ? (this.state() as Extract<WizardState, { tag: 'Failed' }>).error : ''));

  constructor() {
    queueMicrotask(() => this.dispatch({ tag: 'Seed', state: this.seed() }));
  }

  onPrimary() {
    const s = this.state();
    if (s.tag !== 'Editing') return;
    this.dispatch(s.step === 1 ? { tag: 'Next' } : { tag: 'Submit' });
    this.runIfSubmitting();
  }

  onRetry() {
    this.dispatch({ tag: 'Retry' });
    this.runIfSubmitting();
  }

  /** The effect: when we entered Submitting, call the backend command, flip the
      optimistic cross-page flag, then dispatch the result (and commit/rollback). */
  private async runIfSubmitting() {
    const s = this.state();
    if (s.tag !== 'Submitting') return;
    this.profile.beginHerregistratie();
    const r = await submitHerregistratie(s.data);
    if (r.ok) {
      this.dispatch({ tag: 'SubmitConfirmed' });
      this.profile.confirmHerregistratie();
    } else {
      this.dispatch({ tag: 'SubmitFailed', error: r.error });
      this.profile.rollbackHerregistratie();
    }
  }
}