import { Component, computed, effect, inject, input, untracked } 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 { RadioGroupComponent } from '@shared/ui/radio-group/radio-group.component';
import { ButtonComponent } from '@shared/ui/button/button.component';
import { AlertComponent } from '@shared/ui/alert/alert.component';
import { SkeletonComponent } from '@shared/ui/skeleton/skeleton.component';
import { DataRowComponent } from '@shared/ui/data-row/data-row.component';
import { WizardShellComponent, WizardError, WizardStatus } from '@shared/layout/wizard-shell/wizard-shell.component';
import { ASYNC } from '@shared/ui/async/async.component';
import { AddressFieldsComponent } from '@registratie/ui/address-fields/address-fields.component';
import { createStore } from '@shared/application/store';
import { RemoteData, fromResource } from '@shared/application/remote-data';
import { BrpAdapter, parseBrpAddress } from '@registratie/infrastructure/brp.adapter';
import { DuoAdapter, parseDuoLookup } from '@registratie/infrastructure/duo.adapter';
import { DuoLookupDto, PolicyQuestionDto } from '@registratie/contracts/duo-diplomas.dto';
import {
  RegistratieState,
  RegistratieMsg,
  Draft,
  DraftField,
  Correspondentie,
  StepId,
  initial,
  reduce,
  STEPS,
} from '@registratie/domain/registratie-wizard.machine';
import { submitRegistratie } from '@registratie/application/submit-registratie';
import { ApiClient } from '@shared/infrastructure/api-client';

const STORAGE_KEY = 'registratie-v1'; // ponytail: bump the suffix if the persisted shape changes; no migration.
const KANALEN = [{ value: 'email', label: 'E-mail' }, { value: 'post', label: 'Post' }];
const JA_NEE = [{ value: 'ja', label: 'Ja' }, { value: 'nee', label: 'Nee' }];
const HANDMATIG = '__handmatig__'; // sentinel option: "my diploma isn't listed"

/** 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
    localStorage so a reload keeps the user's progress. Built entirely from existing
    atoms/molecules. */
@Component({
  selector: 'app-registratie-wizard',
  imports: [
    FormsModule, FormFieldComponent, TextInputComponent, RadioGroupComponent, ButtonComponent,
    AlertComponent, SkeletonComponent, DataRowComponent, WizardShellComponent,
    AddressFieldsComponent, ...ASYNC,
  ],
  template: `
    <app-wizard-shell
      [steps]="stepLabels"
      [current]="cursor()"
      [stepTitle]="stepTitle()"
      [status]="shellStatus()"
      [primaryLabel]="primaryLabel()"
      [canGoBack]="cursor() > 0"
      [errors]="errorList()"
      [errorMessage]="errorMessage()"
      submittingLabel="Uw registratie wordt verwerkt…"
      (primary)="onPrimary()"
      (back)="dispatch({ tag: 'Back' })"
      (cancel)="restart()"
      (retry)="onRetry()">

      @switch (step()) {
        @case ('adres') {
              @if (adresStatus() === 'laden') {
                <app-skeleton height="2.5rem" [count]="4" />
              } @else {
                @switch (adresStatus()) {
                  @case ('gevonden') {
                    <app-alert type="info">Vooraf ingevuld op basis van de BRP. Controleer en pas zo nodig aan.</app-alert>
                  }
                  @case ('geen') {
                    <app-alert type="warning">We vonden geen adres in de BRP. Vul uw adres hieronder handmatig in.</app-alert>
                  }
                  @case ('fout') {
                    <app-alert type="warning">We konden de BRP nu niet bereiken. Vul uw adres hieronder handmatig in.</app-alert>
                  }
                }
                <app-address-fields
                  [value]="{ straat: draft().straat ?? '', postcode: draft().postcode ?? '', woonplaats: draft().woonplaats ?? '' }"
                  [errors]="{ straat: err('straat'), postcode: err('postcode'), woonplaats: err('woonplaats') }"
                  (fieldChange)="set($event.key, $event.value)" />
                <app-form-field label="Hoe wilt u correspondentie ontvangen?" fieldId="correspondentie" required [error]="err('correspondentie')">
                  <app-radio-group name="correspondentie" [options]="kanalen" [invalid]="!!err('correspondentie')"
                    [ngModel]="draft().correspondentie ?? ''" (ngModelChange)="setKanaal($event)" />
                </app-form-field>
                @if (draft().correspondentie === 'email') {
                  <app-form-field label="E-mailadres" fieldId="email" required [error]="err('email')">
                    <app-text-input inputId="email" type="email" [invalid]="!!err('email')" [ngModel]="draft().email ?? ''" (ngModelChange)="set('email', $event)" name="email" placeholder="naam@voorbeeld.nl" />
                  </app-form-field>
                }
              }
            }
            @case ('beroep') {
              <app-async [data]="lookupRd()">
                <ng-template appAsyncLoaded let-data>
                  <app-form-field label="Kies het diploma waarmee u zich wilt registreren" fieldId="diploma" required [error]="err('diploma')">
                    <app-radio-group name="diploma" [options]="diplomaOptions($any(data))" [invalid]="!!err('diploma')"
                      [ngModel]="diplomaKeuze()" (ngModelChange)="onDiplomaKeuze($any(data), $event)" />
                  </app-form-field>

                  @if (handmatigActief()) {
                    <app-alert type="warning">Een handmatig ingevoerd diploma kan niet automatisch worden geverifieerd. Kies uw beroep en beantwoord de aanvullende vragen; uw aanvraag wordt daarna handmatig beoordeeld.</app-alert>
                    <app-form-field label="Voor welk beroep wilt u zich registreren?" fieldId="hm-beroep" [error]="err('diploma')">
                      <app-radio-group name="hm-beroep" [options]="beroepOptions($any(data))" [invalid]="!!err('diploma')"
                        [ngModel]="draft().beroep ?? ''" (ngModelChange)="dispatch({ tag: 'DeclareerBeroep', beroep: $event })" />
                    </app-form-field>
                  } @else if (draft().beroep) {
                    <dl class="rhc-data-summary rhc-data-summary--row app-section">
                      <app-data-row key="Beroep (afgeleid uit diploma)" [value]="draft().beroep ?? ''" />
                    </dl>
                  }

                  @for (q of actieveVragen($any(data)); track q.id) {
                    <app-form-field [label]="q.vraag" [fieldId]="'vraag-' + q.id" [error]="vraagErr(q.id)">
                      @if (q.type === 'ja-nee') {
                        <app-radio-group [name]="'vraag-' + q.id" [options]="jaNee" [invalid]="!!vraagErr(q.id)"
                          [ngModel]="draft().antwoorden[q.id] ?? ''" (ngModelChange)="dispatch({ tag: 'SetAntwoord', vraagId: q.id, value: $event })" [ngModelOptions]="{ standalone: true }" />
                      } @else {
                        <app-text-input [inputId]="'vraag-' + q.id" [invalid]="!!vraagErr(q.id)" [ngModel]="draft().antwoorden[q.id] ?? ''"
                          (ngModelChange)="dispatch({ tag: 'SetAntwoord', vraagId: q.id, value: $event })" [ngModelOptions]="{ standalone: true }" />
                      }
                    </app-form-field>
                  }
                </ng-template>
                <ng-template appAsyncLoading>
                  <app-skeleton height="2.5rem" [count]="3" />
                </ng-template>
              </app-async>
            }
            @case ('controle') {
              <app-alert type="info">Controleer uw gegevens en dien de registratie in.</app-alert>
              <dl class="rhc-data-summary rhc-data-summary--row app-section">
                <app-data-row key="Adres" [value]="adresSamenvatting()" />
                <app-data-row key="Herkomst adres" [value]="adresHerkomstLabel()" />
                <app-data-row key="Correspondentie" [value]="correspondentieLabel()" />
                @if (draft().correspondentie === 'email') {
                  <app-data-row key="E-mailadres" [value]="draft().email ?? ''" />
                }
                <app-data-row key="Beroep" [value]="draft().beroep ?? ''" />
                <app-data-row key="Herkomst diploma" [value]="diplomaHerkomstLabel()" />
                @for (item of samenvattingVragen(); track item.vraag) {
                  <app-data-row [key]="item.vraag" [value]="item.antwoord" />
                }
              </dl>
              <div class="app-button-row app-section">
                <app-button type="button" variant="subtle" (click)="dispatch({ tag: 'GaNaarStap', cursor: 0 })">Adres wijzigen</app-button>
                <app-button type="button" variant="subtle" (click)="dispatch({ tag: 'GaNaarStap', cursor: 1 })">Diploma wijzigen</app-button>
              </div>
        }
      }

      <div wizardSuccess>
        <app-alert type="ok">Uw registratie is ontvangen. Uw referentienummer is {{ referentie() }}. Bewaar dit nummer voor uw administratie.</app-alert>
        <div class="app-section">
          <app-button variant="secondary" (click)="restart()">Nieuwe registratie starten</app-button>
        </div>
      </div>
    </app-wizard-shell>
  `,
})
export class RegistratieWizardComponent {
  private brp = inject(BrpAdapter);
  private duo = inject(DuoAdapter);
  private apiClient = inject(ApiClient);
  private store = createStore<RegistratieState, RegistratieMsg>(initial, reduce);

  protected adresRes = this.brp.adresResource();
  private diplomasRes = this.duo.diplomasResource();

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

  readonly kanalen = KANALEN;
  readonly stepLabels = ['Adres', 'Beroep', 'Controle']; // short labels for the stepper
  private stepTitles = ['Adres en correspondentievoorkeur', 'Beroep op basis van uw diploma', 'Controleren en indienen'];
  readonly state = this.store.model;
  readonly dispatch = this.store.dispatch;

  private invullen = computed(() => (this.state().tag === 'Invullen' ? (this.state() as Extract<RegistratieState, { tag: 'Invullen' }>) : null));
  protected cursor = computed(() => this.invullen()?.cursor ?? 0);
  protected draft = computed<Draft>(() => this.invullen()?.draft ?? { antwoorden: {} });
  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(() => (this.state().tag === 'Ingediend' ? (this.state() as Extract<RegistratieState, { tag: 'Ingediend' }>).referentie : ''));
  protected failedError = computed(() => (this.state().tag === 'Mislukt' ? (this.state() as Extract<RegistratieState, { tag: 'Mislukt' }>).error : ''));

  // --- Presentational wiring for the shared wizard shell ---------------------
  protected primaryLabel = computed(() => (this.step() === 'controle' ? 'Registratie indienen' : 'Volgende'));
  protected errorMessage = computed(() => `Het indienen is niet gelukt: ${this.failedError()}`);
  protected shellStatus = computed<WizardStatus>(() => {
    switch (this.state().tag) {
      case 'Invullen': return 'editing';
      case 'Indienen': return 'submitting';
      case 'Ingediend': return 'submitted';
      case 'Mislukt': return 'failed';
    }
  });
  /** Current step's errors (incl. per-question), flattened for the error summary. */
  protected errorList = computed<WizardError[]>(() => {
    const e = this.invullen()?.errors ?? {};
    const out: WizardError[] = [];
    for (const [k, v] of Object.entries(e)) {
      if (k !== 'antwoorden' && typeof v === 'string' && v) out.push({ id: k, message: v });
    }
    for (const [qid, msg] of Object.entries(e.antwoorden ?? {})) {
      if (msg) out.push({ id: 'vraag-' + qid, message: msg });
    }
    return out;
  });
  protected adresSamenvatting = computed(() => {
    const d = this.draft();
    return [d.straat, [d.postcode, d.woonplaats].filter(Boolean).join(' ')].filter(Boolean).join(', ');
  });
  // Readable labels for the controle summary (instead of raw enum values).
  protected adresHerkomstLabel = computed(() => ({ brp: 'Automatisch uit de BRP', handmatig: 'Handmatig ingevoerd' }[this.draft().adresHerkomst ?? 'handmatig']));
  protected correspondentieLabel = computed(() => ({ email: 'Per e-mail', post: 'Per post' }[this.draft().correspondentie ?? 'post']));
  protected diplomaHerkomstLabel = computed(() => ({ duo: 'Geverifieerd via DUO', handmatig: 'Handmatig ingevoerd (wordt beoordeeld)' }[this.draft().diplomaHerkomst ?? 'handmatig']));

  /** BRP lookup outcome. A failure or "geen adres" never blocks the wizard — both
      fall back to manual entry (PRD §7). 'geen' covers both no-address-found and a
      malformed response; 'fout' is an unreachable BRP. */
  protected adresStatus = computed<'laden' | 'gevonden' | 'geen' | 'fout'>(() => {
    const st = this.adresRes.status();
    if (st === 'loading' || st === 'reloading') return 'laden';
    if (st === 'error') return 'fout';
    const json = this.adresRes.value();
    const parsed = json !== undefined ? parseBrpAddress(json) : null;
    return parsed && parsed.ok && parsed.value.gevonden ? 'gevonden' : 'geen';
  });

  /** The DUO lookup (diplomas + manual fallback), validated at the trust boundary. */
  protected lookupRd = computed<RemoteData<Error | undefined, DuoLookupDto>>(() => {
    const rd = fromResource(this.diplomasRes);
    if (rd.tag !== 'Success') return rd;
    const parsed = parseDuoLookup(rd.value);
    return parsed.ok ? { tag: 'Success', value: parsed.value } : { tag: 'Failure', error: new Error(parsed.error) };
  });

  /** Parsed lookup as a plain value (or null) — used outside the beroep step (the
      controle summary) where the <app-async> template variable isn't in scope. */
  private duoData = computed<DuoLookupDto | null>(() => {
    const rd = this.lookupRd();
    return rd.tag === 'Success' ? rd.value : null;
  });

  readonly jaNee = JA_NEE;

  protected err = (k: DraftField | 'correspondentie' | 'diploma') => this.invullen()?.errors[k] ?? '';
  protected vraagErr = (id: string) => this.invullen()?.errors.antwoorden?.[id] ?? '';
  protected set = (key: DraftField, value: string) => this.dispatch({ tag: 'SetField', key, value });
  protected setKanaal = (value: string) => this.dispatch({ tag: 'SetCorrespondentie', value: value as Correspondentie });

  /** True while the user is entering a diploma manually (not in the DUO list). */
  protected handmatigActief = computed(() => this.draft().diplomaHerkomst === 'handmatig');
  /** The radio selection: a diploma id, or the "not listed" sentinel in manual mode. */
  protected diplomaKeuze = computed(() => (this.handmatigActief() ? HANDMATIG : this.draft().diplomaId ?? ''));

  protected diplomaOptions = (data: DuoLookupDto) => [
    ...data.diplomas.map((d) => ({ value: d.id, label: `${d.naam} — ${d.instelling} (${d.jaar})` })),
    { value: HANDMATIG, label: 'Mijn diploma staat er niet bij' },
  ];

  protected beroepOptions = (data: DuoLookupDto) => data.handmatig.beroepen.map((b) => ({ value: b, label: b }));

  /** The policy questions that apply to the current choice (server-decided). */
  protected actieveVragen = (data: DuoLookupDto): PolicyQuestionDto[] => {
    if (this.handmatigActief()) return data.handmatig.policyQuestions;
    return data.diplomas.find((d) => d.id === this.draft().diplomaId)?.policyQuestions ?? [];
  };

  /** Answered policy questions for the controle summary (question text + answer). */
  protected samenvattingVragen = computed(() => {
    const data = this.duoData();
    const d = this.draft();
    if (!data) return [] as { vraag: string; antwoord: string }[];
    const alle = [...data.diplomas.flatMap((x) => x.policyQuestions), ...data.handmatig.policyQuestions];
    return (d.vraagIds ?? []).map((id) => ({ vraag: alle.find((q) => q.id === id)?.vraag ?? id, antwoord: d.antwoorden[id] ?? '' }));
  });

  protected onDiplomaKeuze(data: DuoLookupDto, id: string) {
    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) });
  }

  constructor() {
    // An explicit seed (stories) wins; otherwise resume from localStorage.
    const seeded = this.seed();
    queueMicrotask(() => this.dispatch({ tag: 'Seed', state: seeded !== initial ? seeded : (this.restore() ?? initial) }));
    // Persist only while filling in; clear once the flow is done.
    effect(() => {
      const s = this.state();
      if (s.tag === 'Invullen') localStorage.setItem(STORAGE_KEY, JSON.stringify(s));
      else localStorage.removeItem(STORAGE_KEY);
    });
    // Prefill the address from the BRP lookup as it arrives. Track only the resource
    // value; 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.
    effect(() => {
      const json = this.adresRes.value();
      if (!json) return;
      const parsed = parseBrpAddress(json);
      untracked(() => {
        const s = this.state();
        if (s.tag !== 'Invullen' || s.draft.straat) return;
        // ponytail: slice 2 handles gevonden === false -> manual entry stays handmatig.
        if (parsed.ok && parsed.value.gevonden && parsed.value.adres) {
          const a = parsed.value.adres;
          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.
  }

  private restore(): RegistratieState | null {
    const raw = localStorage.getItem(STORAGE_KEY);
    if (!raw) return null;
    try {
      return JSON.parse(raw) as RegistratieState;
    } catch {
      return null; // ponytail: corrupt entry -> start fresh, no migration.
    }
  }

  onPrimary() {
    const s = this.state();
    if (s.tag !== 'Invullen') return;
    this.dispatch(this.step() === 'controle' ? { tag: 'Submit' } : { tag: 'Next' });
    this.runIfIndienen();
  }

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

  /** 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.dispatch({ tag: 'Seed', state: initial });
    this.adresRes.reload();
  }

  /** The effect: when we enter Indienen, call the backend, then dispatch the
      outcome (success carries the confirmation reference). */
  private async runIfIndienen() {
    const s = this.state();
    if (s.tag !== 'Indienen') return;
    const r = await submitRegistratie(this.apiClient, s.data);
    if (r.ok) this.dispatch({ tag: 'SubmitConfirmed', referentie: r.value });
    else this.dispatch({ tag: 'SubmitFailed', error: r.error });
  }
}