import { Injectable } from '@angular/core';
import { Result, ok, err } from '@shared/kernel/fp';
import { currentRole } from '@shared/infrastructure/role';
import { problemDetail } from '@shared/infrastructure/api-error';
import { environment } from '@shared/environments/environment';

const REVEAL_FAILED = $localize`:@@brief.reveal.failed:Het BIG-nummer kon niet worden getoond.`;

/**
 * Field-level PII reveal (PRD-0002 §5c). The case screen ships the BIG-nummer masked;
 * this unmasks it, gated server-side by the reveal capability AND a step-up. The
 * step-up is stubbed as the `X-Step-Up` header — the caller sends it only after the
 * user's confirm gesture, so a plain call (or a role without the capability) 403s.
 *
 * Hand-written fetch (not the `ApiClient`) because the call needs a per-request header;
 * `.ExcludeFromDescription()` on the endpoint keeps the generated client JSON-only, the
 * same seam as `/brief/preview` and uploads — which also means `X-Role` is set here.
 */
@Injectable({ providedIn: 'root' })
export class RevealBigNummerAdapter {
  async reveal(): Promise<Result<string, string>> {
    let res: Response;
    try {
      res = await fetch(`${environment.apiBaseUrl}/api/v1/brief/reveal-bignummer`, {
        method: 'POST',
        headers: { 'X-Role': currentRole(), 'X-Step-Up': 'true' },
      });
    } catch {
      return err(REVEAL_FAILED);
    }
    if (!res.ok) return err(await errorMessage(res));
    const body: unknown = await res.json().catch(() => null);
    // Trust boundary: validate the shape before handing back a plain string.
    if (
      typeof body === 'object' &&
      body !== null &&
      typeof (body as { bigNummer?: unknown }).bigNummer === 'string'
    ) {
      return ok((body as { bigNummer: string }).bigNummer);
    }
    return err(REVEAL_FAILED);
  }
}

async function errorMessage(res: Response): Promise<string> {
  try {
    return problemDetail(await res.json(), REVEAL_FAILED);
  } catch {
    return REVEAL_FAILED;
  }
}