// Thin fetch wrapper used by every React page. Centralises auth
// header handling (cookie-based, credentials: 'include'), JSON
// parsing, and typed success-vs-error narrowing via shared/types.
import type { ApiResponse } from '@/shared/types';

export class ApiError extends Error {
  constructor(public status: number, message: string) {
    super(message);
  }
}

export async function apiFetch<TOk>(
  path: string,
  init: RequestInit = {},
): Promise<TOk> {
  const resp = await fetch(path, {
    credentials: 'include',
    headers: {
      'Content-Type': 'application/json',
      ...(init.headers || {}),
    },
    ...init,
  });

  // Non-JSON responses (e.g. audio blobs) — caller must handle.
  const ct = resp.headers.get('content-type') || '';
  if (!ct.includes('application/json')) {
    if (!resp.ok) throw new ApiError(resp.status, resp.statusText);
    return (await resp.blob()) as unknown as TOk;
  }

  const body = (await resp.json()) as ApiResponse<TOk>;
  if (!resp.ok || body.success === false) {
    throw new ApiError(resp.status, (body as { error?: string }).error || resp.statusText);
  }
  return body as unknown as TOk;
}

// Shortcuts for common verbs
export const api = {
  get:    <T>(path: string) => apiFetch<T>(path),
  post:   <T>(path: string, body: unknown) => apiFetch<T>(path, { method: 'POST', body: JSON.stringify(body) }),
  put:    <T>(path: string, body: unknown) => apiFetch<T>(path, { method: 'PUT', body: JSON.stringify(body) }),
  delete: <T>(path: string) => apiFetch<T>(path, { method: 'DELETE' }),
};