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 { AlertComponent } from '@shared/ui/alert/alert.component';
import {
  WizardShellComponent,
  WizardError,
  WizardPhase,
  naarStapLabel,
} from '@shared/layout/wizard-shell/wizard-shell.component';
import { ConfirmationComponent } from '@shared/ui/confirmation/confirmation.component';
import { createStore } from '@shared/application/store';
import { whenTag } from '@shared/kernel/fp';
import { BigProfileStore } from '@registratie/application/big-profile.store';
import {
  WizardState,
  WizardMsg,
  Draft,
  initial,
  reduce,
  hasProgress,
} from '@herregistratie/domain/herregistratie.machine';
import { createDraftSync } from '@registratie/application/draft-sync';
import { DocumentUploadComponent } from '@shared/ui/upload/document-upload/document-upload.component';
import { createUploadController } from '@shared/application/upload-controller';
import { UploadState, initialUpload, deliveryRefs } from '@shared/domain/upload.machine';

/** 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,
    AlertComponent,
    ConfirmationComponent,
    WizardShellComponent,
    DocumentUploadComponent,
  ],
  template: `
    <app-wizard-shell
      [steps]="stepLabels"
      [current]="step() - 1"
      [stepTitle]="stepTitle()"
      i18n-processName="@@herregWizard.processName"
      processName="Herregistratie aanvragen"
      [phase]="phase()"
      [primaryLabel]="primaryLabel()"
      [canGoBack]="step() > 1"
      [errors]="errorList()"
      (primary)="dispatch({ tag: 'Primary' })"
      (back)="dispatch({ tag: 'Back' })"
      (cancel)="restart()"
      (retry)="dispatch({ tag: 'Retry' })"
      (goToStep)="goToStep($event)"
    >
      @switch (step()) {
        @case (1) {
          <fieldset>
            <app-form-field
              i18n-label="@@herregWizard.urenLabel"
              label="Gewerkte uren (afgelopen 5 jaar)"
              fieldId="uren"
              required
              [error]="errUren()"
            >
              <app-text-input
                inputId="uren"
                [ngModel]="draft().uren"
                (ngModelChange)="dispatch({ tag: 'SetField', key: 'uren', value: $event })"
                name="uren"
                [invalid]="!!errUren()"
                i18n-placeholder="@@herregWizard.urenPlaceholder"
                placeholder="bijv. 4160"
              />
            </app-form-field>
            <app-form-field
              i18n-label="@@herregWizard.jarenLabel"
              label="Aantal jaren werkzaam"
              fieldId="jaren"
              required
              [error]="errJaren()"
            >
              <app-text-input
                inputId="jaren"
                [ngModel]="draft().jaren"
                (ngModelChange)="dispatch({ tag: 'SetField', key: 'jaren', value: $event })"
                name="jaren"
                [invalid]="!!errJaren()"
                i18n-placeholder="@@herregWizard.jarenPlaceholder"
                placeholder="bijv. 5"
              />
            </app-form-field>
          </fieldset>
        }
        @case (2) {
          <fieldset>
            <app-form-field
              i18n-label="@@herregWizard.puntenLabel"
              label="Behaalde nascholingspunten"
              fieldId="punten"
              required
              [error]="errPunten()"
            >
              <app-text-input
                inputId="punten"
                [ngModel]="draft().punten"
                (ngModelChange)="dispatch({ tag: 'SetField', key: 'punten', value: $event })"
                name="punten"
                [invalid]="!!errPunten()"
                i18n-placeholder="@@herregWizard.puntenPlaceholder"
                placeholder="bijv. 200"
              />
            </app-form-field>
          </fieldset>
        }
        @case (3) {
          <app-document-upload
            [state]="upload()"
            [previewUrlFor]="previewUrlFor"
            (fileSelected)="uploadCtl.onFileSelected($event.categoryId, $event.files)"
            (removeUpload)="uploadCtl.onRemove($event)"
            (retryUpload)="uploadCtl.onRetry($event)"
            (deleteUpload)="uploadCtl.onDelete($event)"
            (channelChange)="uploadCtl.onChannelChange($event.categoryId, $event.channel)"
          />
          @if (errDocumenten()) {
            <app-alert type="warning">{{ errDocumenten() }}</app-alert>
          }
        }
      }

      <div wizardSuccess>
        <app-confirmation
          i18n-title="@@herregWizard.success.title"
          title="Uw aanvraag tot herregistratie is ontvangen"
        />
      </div>
    </app-wizard-shell>
  `,
})
export class HerregistratieWizardComponent {
  private profile = inject(BigProfileStore);
  // Effect fires once, on Editing -> Submitting (RD-05's tag-transition rule; `Seed` is
  // exempt, so a story mounting straight into `Submitting` does not call the network).
  private store = createStore<WizardState, WizardMsg>(initial, reduce, {
    Submitting: async (s, store) => {
      this.profile.beginHerregistratie();
      const r = await this.draftSync.submit({ uren: s.data.uren, documents: s.data.documents });
      if (r.ok) {
        store.dispatch({ tag: 'SubmitConfirmed' });
        this.profile.confirmHerregistratie();
      } else {
        store.dispatch({ tag: 'SubmitFailed', error: r.error });
        this.profile.rollbackHerregistratie();
      }
    },
  });

  /** Preview/download link for a completed upload; delegates to the upload
      controller (application layer), which knows the dev-simulation `demo-*` ids
      have no stored bytes and returns no link for them. */
  protected previewUrlFor = (documentId: string): string | undefined =>
    this.uploadCtl.previewUrlFor(documentId);

  /** 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;

  // Backend draft-sync (new persistence for this wizard): create a Concept on first
  // progress, debounced-sync the snapshot, resume by `?aanvraag=<id>`.
  private draftSync = createDraftSync({
    type: 'herregistratie',
    snapshot: () => {
      const s = this.state();
      if (s.tag !== 'Editing' || !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.step - 1, stepCount: this.stepLabels.length, documentIds };
    },
    onResume: (draft) => this.dispatch({ tag: 'Seed', state: draft as WizardState }),
    enabled: () => this.seed() === initial,
  });

  // Stepper labels + per-step heading titles (presentational only).
  readonly stepLabels = [
    $localize`:@@herregWizard.step.werkervaring:Werkervaring`,
    $localize`:@@herregWizard.step.nascholing:Nascholing`,
    $localize`:@@herregWizard.step.documenten:Documenten`,
  ];
  private stepTitles = [
    $localize`:@@herregWizard.title.werkervaring:Werkervaring (afgelopen 5 jaar)`,
    $localize`:@@herregWizard.title.nascholing:Nascholing`,
    $localize`:@@herregWizard.title.documenten:Documenten aanleveren`,
  ];

  private editing = computed(() => whenTag(this.state(), 'Editing'));
  protected step = computed(() => this.editing()?.step ?? 1);
  protected draft = computed<Draft>(
    () => this.editing()?.draft ?? { uren: '', jaren: '', punten: '' },
  );
  protected upload = computed<UploadState>(() => this.editing()?.upload ?? initialUpload);
  protected errUren = computed(() => this.editing()?.errors.uren ?? '');
  protected errJaren = computed(() => this.editing()?.errors.jaren ?? '');
  protected errPunten = computed(() => this.editing()?.errors.punten ?? '');
  protected errDocumenten = computed(() => this.editing()?.errors.documenten ?? '');
  protected uploadCtl = createUploadController({
    wizardId: 'herregistratie',
    getUpload: () => this.upload(),
    dispatch: (msg) => this.dispatch({ tag: 'Upload', msg }),
  });

  // --- Presentational wiring for the shared wizard shell ---------------------
  protected stepTitle = computed(() => this.stepTitles[this.step() - 1]);
  protected primaryLabel = computed(() => {
    const step = this.step();
    return step < 3
      ? naarStapLabel(step + 1, this.stepLabels[step])
      : $localize`:@@herregWizard.indienen:Herregistratie aanvragen`;
  });

  /** Stepper emits a 0-based index for an earlier (visited) step. */
  protected goToStep(index: number) {
    this.dispatch({ tag: 'GaNaarStap', step: (index + 1) as 1 | 2 | 3 });
  }
  /** 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 'Editing':
        return { tag: 'Editing' };
      case 'Submitting':
        return { tag: 'Submitting' };
      case 'Submitted':
        return { tag: 'Submitted' };
      case 'Failed':
        return {
          tag: 'Failed',
          message: $localize`:@@wizard.indienenMislukt:Indienen mislukt:` + ` ${s.error}`,
        };
    }
  });
  /** Current step's field errors, flattened for the shell's error summary. */
  protected errorList = computed<WizardError[]>(() => {
    const e = this.editing()?.errors ?? {};
    return (Object.keys(e) as (keyof typeof e)[])
      .filter((k) => e[k])
      .map((k) => ({ id: k, message: e[k]! }));
  });

  constructor() {
    // An explicit seed (stories/tests) wins; otherwise resume 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(),
    );
  }

  /** Reset the wizard to a fresh, empty start. */
  restart() {
    this.draftSync.reset();
    this.dispatch({ tag: 'Seed', state: initial });
  }
}