import { Component, computed, effect, inject, input, untracked } from '@angular/core';
import { ButtonComponent } from '@shared/ui/atoms/button/button.component';
import { ConfirmationComponent } from '@shared/ui/molecules/confirmation/confirmation.component';
import {
  WizardShellComponent,
  WizardError,
  WizardPhase,
  naarStapLabel,
} from '@shared/layout/wizard-shell/wizard-shell.component';
import { toWizardErrors } from '@shared/layout/wizard-shell/wizard-errors';
import { createStore } from '@shared/application/store';
import { whenTag } from '@shared/kernel/fp';
import { successOr } from '@shared/application/remote-data';
import { RegistratieLookupStore } from '@registratie/application/registratie-lookup.store';
import { DuoLookupDto } from '@registratie/contracts/duo-diplomas.dto';
import {
  RegistratieState,
  RegistratieMsg,
  Draft,
  Correspondentie,
  Errors,
  StepId,
  initial,
  reduce,
  hasProgress,
  STEPS,
} from '@registratie/domain/registratie-wizard.machine';
import { createDraftSync } from '@registratie/application/draft-sync';
import { UploadState, initialUpload, deliveryRefs } from '@shared/domain/upload.machine';
import { AdresStep } from './adres.step';
import { BeroepStep, HANDMATIG } from './beroep.step';
import { ControleStep } from './controle.step';

/** Organism: the BIG-registration wizard. All state lives in one signal driven by
    the pure `reduce` (registratie-wizard.machine.ts). The BRP address prefills the
    draft via an effect; the DUO diploma list renders through <app-async>; choosing
    a diploma reveals its server-derived beroep. The draft is persisted to the
    backend as a Concept aanvraag (createDraftSync) so a reload — or a"Verder gaan"
    from the dashboard via `?aanvraag=<id>` — resumes progress. Built from existing
    atoms/molecules. */
@Component({
  selector: 'app-registratie-wizard',
  imports: [
    ButtonComponent,
    ConfirmationComponent,
    WizardShellComponent,
    AdresStep,
    BeroepStep,
    ControleStep,
  ],
  template: `
    <app-wizard-shell
      [steps]="stepLabels"
      [current]="cursor()"
      [stepTitle]="stepTitle()"
      i18n-processName="@@regWizard.processName"
      processName="Inschrijven in het BIG-register"
      [phase]="phase()"
      [primaryLabel]="primaryLabel()"
      [canGoBack]="cursor() > 0"
      [errors]="errorList()"
      i18n-submittingLabel="@@regWizard.submitting"
      submittingLabel="Uw registratie wordt verwerkt…"
      (primary)="dispatch({ tag: 'Primary' })"
      (back)="dispatch({ tag: 'Back' })"
      (cancel)="restart()"
      (retry)="dispatch({ tag: 'Retry' })"
      (goToStep)="dispatch({ tag: 'GaNaarStap', cursor: $event })"
    >
      @switch (step()) {
        @case ('adres') {
          <app-reg-adres-step
            [draft]="draft()"
            [errors]="errors()"
            (fieldChange)="dispatch({ tag: 'SetField', key: $event.key, value: $event.value })"
            (kanaalChange)="onKanaalChange($event)"
          />
        }
        @case ('beroep') {
          <app-reg-beroep-step
            [draft]="draft()"
            [errors]="errors()"
            [upload]="upload()"
            (uploadMsg)="dispatch({ tag: 'Upload', msg: $event })"
            (antwoordChange)="
              dispatch({ tag: 'SetAntwoord', vraagId: $event.vraagId, value: $event.value })
            "
            (diplomaChosen)="onDiplomaKeuze($event)"
            (beroepDeclared)="dispatch({ tag: 'DeclareerBeroep', beroep: $event })"
          />
        }
        @case ('controle') {
          <app-reg-controle-step
            [draft]="draft()"
            (edit)="dispatch({ tag: 'GaNaarStap', cursor: $event })"
          />
        }
      }

      <div wizardSuccess>
        <app-confirmation
          i18n-title="@@regWizard.success.title"
          title="Uw registratie is ontvangen"
        >
          <p class="app-section" i18n="@@regWizard.success.referentie">
            Uw referentienummer is {{ referentie() }}. Bewaar dit nummer voor uw administratie.
          </p>
          <div class="app-section">
            <app-button variant="secondary" (click)="restart()" i18n="@@regWizard.nieuweRegistratie"
              >Nieuwe registratie starten</app-button
            >
          </div>
        </app-confirmation>
      </div>
    </app-wizard-shell>
  `,
})
export class RegistratieWizardComponent {
  private lookup = inject(RegistratieLookupStore);
  // Effect fires once, on Invullen -> Indienen (RD-05's tag-transition rule; `Seed` is
  // exempt, so a story mounting straight into `Indienen` does not call the network).
  private store = createStore<RegistratieState, RegistratieMsg>(initial, reduce, {
    Indienen: async (s, store) => {
      const r = await this.draftSync.submit({
        diplomaHerkomst: s.data.diplomaHerkomst,
        documents: s.data.documents,
      });
      if (r.ok) store.dispatch({ tag: 'SubmitConfirmed', referentie: r.value.referentie ?? '' });
      else store.dispatch({ tag: 'SubmitFailed', error: r.error });
    },
  });

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

  readonly stepLabels = [
    $localize`:@@regWizard.step.adres:Adres`,
    $localize`:@@regWizard.step.beroep:Beroep`,
    $localize`:@@regWizard.step.controle:Controle`,
  ]; // short labels for the stepper
  private stepTitles = [
    $localize`:@@regWizard.title.adres:Adres en correspondentievoorkeur`,
    $localize`:@@regWizard.title.beroep:Beroep op basis van uw diploma`,
    $localize`:@@regWizard.title.controle:Controleren en indienen`,
  ];
  readonly state = this.store.model;
  readonly dispatch = this.store.dispatch;

  private invullen = computed(() => whenTag(this.state(), 'Invullen'));
  protected cursor = computed(() => this.invullen()?.cursor ?? 0);
  protected draft = computed<Draft>(() => this.invullen()?.draft ?? { antwoorden: {} });
  protected errors = computed<Errors>(() => this.invullen()?.errors ?? {});
  protected upload = computed<UploadState>(() => this.invullen()?.upload ?? initialUpload);
  // Backend draft-sync (replaces sessionStorage): create a Concept once the user has
  // made progress, then debounced-sync the whole machine snapshot; resume by `?aanvraag`.
  private draftSync = createDraftSync({
    type: 'registratie',
    snapshot: () => {
      const s = this.state();
      if (s.tag !== 'Invullen' || !hasProgress(s)) return null;
      const documentIds = deliveryRefs(s.upload)
        .filter((r) => r.channel === 'digital' && r.documentId)
        .map((r) => r.documentId!);
      return { draft: s, stepIndex: s.cursor, stepCount: STEPS.length, documentIds };
    },
    onResume: (draft) => this.dispatch({ tag: 'Seed', state: draft as RegistratieState }),
    enabled: () => this.seed() === initial,
  });
  protected step = computed<StepId>(() => STEPS[Math.min(this.cursor(), STEPS.length - 1)]);
  protected stepTitle = computed(
    () => this.stepTitles[Math.min(this.cursor(), this.stepTitles.length - 1)],
  );
  protected referentie = computed(() => whenTag(this.state(), 'Ingediend')?.referentie ?? '');

  // --- Presentational wiring for the shared wizard shell ---------------------
  protected primaryLabel = computed(() => {
    if (this.step() === 'controle') return $localize`:@@regWizard.indienen:Registratie indienen`;
    const next = this.cursor() + 1;
    return naarStapLabel(next + 1, this.stepLabels[next]);
  });
  /** Maps this machine's own tags onto the shell's `WizardPhase` vocabulary,
      composing the localized failure prefix so the `Failed` message arrives intact. */
  protected phase = computed<WizardPhase>(() => {
    const s = this.state();
    switch (s.tag) {
      case 'Invullen':
        return { tag: 'Editing' };
      case 'Indienen':
        return { tag: 'Submitting' };
      case 'Ingediend':
        return { tag: 'Submitted' };
      case 'Mislukt':
        return {
          tag: 'Failed',
          message:
            $localize`:@@regWizard.indienenMislukt:Het indienen is niet gelukt:` + ` ${s.error}`,
        };
    }
  });
  /** Current step's errors (incl. per-question), flattened for the error summary. */
  protected errorList = computed<WizardError[]>(() => {
    const e = this.invullen()?.errors ?? {};
    return [...toWizardErrors(e), ...toWizardErrors(e.antwoorden ?? {}, 'vraag-')];
  });

  /** Parsed lookup as a plain value (or null) — needed here only to resolve
      `onDiplomaKeuze`'s message from an id (the DUO payload maps an id to a
      beroep and its question ids; that is machine-message construction, and it
      belongs in the container, not the beroep step). */
  protected duoData = computed<DuoLookupDto | null>(() => successOr(this.lookup.duoLookup(), null));

  protected onDiplomaKeuze(id: string) {
    const data = this.duoData();
    if (!data) return;
    if (id === HANDMATIG) {
      this.dispatch({
        tag: 'KiesHandmatig',
        vraagIds: data.handmatig.policyQuestions.map((q) => q.id),
      });
      return;
    }
    const d = data.diplomas.find((x) => x.id === id);
    if (d)
      this.dispatch({
        tag: 'KiesDiploma',
        diplomaId: d.id,
        beroep: d.beroep,
        vraagIds: d.policyQuestions.map((q) => q.id),
      });
  }

  /** Narrows the beroep step's plain-string `kanaalChange` into the machine's
      `Correspondentie` union before dispatching. */
  protected onKanaalChange(value: string) {
    this.dispatch({ tag: 'SetCorrespondentie', value: value as Correspondentie });
  }

  constructor() {
    // An explicit seed (stories/tests) wins; otherwise resume from the backend draft
    // (`?aanvraag=<id>`), or start fresh. Persistence is the draftSync controller's job.
    const seeded = this.seed();
    queueMicrotask(() =>
      seeded !== initial ? this.dispatch({ tag: 'Seed', state: seeded }) : this.draftSync.resume(),
    );
    // Prefill the address from the BRP lookup as it arrives. Track only the facade's
    // parsed prefill signal; untrack the dispatch (it reads the state signal, which
    // would otherwise make this effect loop on its own write). Don't clobber
    // edits/restored data. A null prefill (loading/error/geen adres) leaves manual entry.
    effect(() => {
      const a = this.lookup.prefillAdres();
      if (!a) return;
      untracked(() => {
        const s = this.state();
        if (s.tag !== 'Invullen' || s.draft.straat) return;
        this.dispatch({
          tag: 'PrefillAdres',
          straat: a.straat,
          postcode: a.postcode,
          woonplaats: a.woonplaats,
        });
      });
    });
    // A11y: focus management (step heading on step change, error summary on a
    // failed submit) now lives in the shared WizardShellComponent.
  }

  /** Reset the wizard to a fresh start. Reload the BRP lookup so the address
      re-prefills, keeping the form and the"vooraf ingevuld" note consistent. */
  restart() {
    this.draftSync.reset(); // discard the current Concept; a fresh one starts on next progress
    this.dispatch({ tag: 'Seed', state: initial });
    this.lookup.reloadAdres();
  }
}