import { Component, inject, type OnInit, signal } from '@angular/core';
import { BffApiV1Service, type CurrentRegistration, type SubmitAccepted } from 'api-client';
import { AuthService } from 'auth';
import { UtrechtComponentsModule } from 'ui';

/**
 * The self-service submit page: a signed-in zorgprofessional confirms and submits their BIG
 * registration. The bsn comes from the DigiD token (not a form field), so this is a confirm-and-
 * submit flow that posts to the BFF and shows the returned reference (ADR-0010; S-08c). After
 * submitting they can withdraw it — "trek aanvraag in" — keyed by that reference (S-11c).
 *
 * On load it asks the BFF for the caller's current open registration and restores the submitted view
 * if there is one, so a page refresh no longer strands an in-flight registration (S-26).
 */
@Component({
  selector: 'app-registration-page',
  imports: [UtrechtComponentsModule],
  templateUrl: './registration-page.html',
})
export class RegistrationPage implements OnInit {
  private readonly auth = inject(AuthService);
  private readonly bff = inject(BffApiV1Service);

  protected readonly bsn = this.auth.bsn;
  protected readonly submitting = signal(false);
  protected readonly reference = signal<string | undefined>(undefined);
  protected readonly submitted = signal(false);
  protected readonly failed = signal(false);
  protected readonly withdrawing = signal(false);
  protected readonly withdrawn = signal(false);
  protected readonly withdrawFailed = signal(false);
  protected readonly providingDocuments = signal(false);
  protected readonly documentsProvided = signal(false);
  protected readonly provideDocumentsFailed = signal(false);
  protected readonly selectedFile = signal<File | undefined>(undefined);

  /** Resume an existing in-flight registration after a refresh (S-26): the BFF returns the caller's
   * current open registration, or 204 (empty body) when there is none — in which case we show the
   * submit form as before. Failures are non-fatal for the same reason. */
  ngOnInit(): void {
    this.bff.getSelfServiceRegistrations().subscribe({
      next: (current: CurrentRegistration | void) => {
        if (current && current.registrationId) {
          this.reference.set(current.registrationId);
          this.submitted.set(true);
        }
      },
      error: () => {
        // No resumable registration (or the lookup failed) — fall back to the submit form.
      },
    });
  }

  submit(): void {
    this.submitting.set(true);
    this.failed.set(false);
    this.bff.postSelfServiceRegistrations().subscribe({
      next: (accepted: SubmitAccepted) => {
        this.reference.set(accepted.registrationId);
        this.submitted.set(true);
        this.submitting.set(false);
      },
      // Surface the failure instead of swallowing it: re-enable the button so the user can retry.
      error: () => {
        this.failed.set(true);
        this.submitting.set(false);
      },
    });
  }

  onFileSelected(event: Event): void {
    const input = event.target as HTMLInputElement;
    this.selectedFile.set(input.files?.[0] ?? undefined);
  }

  async provideDocuments(): Promise<void> {
    const reference = this.reference();
    const file = this.selectedFile();
    if (!reference || !file) {
      return;
    }
    this.providingDocuments.set(true);
    this.provideDocumentsFailed.set(false);
    let contentBase64: string;
    try {
      contentBase64 = await readAsBase64(file);
    } catch {
      this.provideDocumentsFailed.set(true);
      this.providingDocuments.set(false);
      return;
    }
    this.bff
      .postSelfServiceRegistrationsIdDocuments(reference, {
        contentBase64,
        fileName: file.name,
        contentType: file.type || 'application/pdf',
      })
      .subscribe({
        next: () => {
          this.documentsProvided.set(true);
          this.providingDocuments.set(false);
        },
        // Surface the failure instead of swallowing it: keep the action so the user can retry.
        error: () => {
          this.provideDocumentsFailed.set(true);
          this.providingDocuments.set(false);
        },
      });
  }

  withdraw(): void {
    const reference = this.reference();
    if (!reference) {
      return;
    }
    this.withdrawing.set(true);
    this.withdrawFailed.set(false);
    this.bff.postSelfServiceRegistrationsIdWithdraw(reference).subscribe({
      next: () => {
        this.withdrawn.set(true);
        this.withdrawing.set(false);
      },
      // Surface the failure instead of swallowing it: keep the action so the user can retry.
      error: () => {
        this.withdrawFailed.set(true);
        this.withdrawing.set(false);
      },
    });
  }
}

/** Read a file's bytes as a base64 string (without the `data:...;base64,` prefix). */
function readAsBase64(file: File): Promise<string> {
  return new Promise<string>((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = () => resolve(((reader.result as string) ?? '').split(',', 2)[1] ?? '');
    reader.onerror = () => reject(reader.error ?? new Error('Could not read the file.'));
    reader.readAsDataURL(file);
  });
}