/**
 * Thin fetch wrapper — always sends cookies (HttpOnly JWT).
 * All paths are relative so Next.js rewrites proxy them to the backend.
 */

async function request<T>(path: string, init: RequestInit = {}): Promise<T> {
  const res = await fetch(path, {
    ...init,
    credentials: "include",
    headers: {
      ...(init.body instanceof FormData ? {} : { "Content-Type": "application/json" }),
      ...init.headers,
    },
  });

  if (!res.ok) {
    const detail = await res.json().catch(() => ({ detail: res.statusText }));
    throw new Error(detail?.detail ?? "Request failed");
  }

  if (res.status === 204) return undefined as T;
  return res.json();
}

export const api = {
  // Auth
  me: () => request<import("@/types").User>("/api/auth/me"),
  login: (body: { username: string; password: string }) =>
    request<import("@/types").User>("/api/auth/login", { method: "POST", body: JSON.stringify(body) }),
  register: (body: { username: string; email: string; password: string }) =>
    request<import("@/types").User>("/api/auth/register", { method: "POST", body: JSON.stringify(body) }),
  logout: () => request<void>("/api/auth/logout", { method: "POST" }),

  // PDFs
  listPdfs: () => request<import("@/types").PDFItem[]>("/api/pdfs"),
  uploadPdfs: (formData: FormData) =>
    request<import("@/types").PDFUploadResult[]>("/api/pdfs/upload", { method: "POST", body: formData }),
  deletePdf: (id: number) => request<void>(`/api/pdfs/${id}`, { method: "DELETE" }),

  // Annotations
  getAnnotation: (pdfId: number, page: number) =>
    request<import("@/types").AnnotationData>(`/api/annotations/${pdfId}/${page}`),
  getAllAnnotations: (pdfId: number, page: number) =>
    request<import("@/types").AnnotationData>(`/api/annotations/${pdfId}/${page}/all`),
  upsertAnnotation: (pdfId: number, page: number, body: { canvas_data: object }) =>
    request<import("@/types").AnnotationData>(`/api/annotations/${pdfId}/${page}`, {
      method: "PUT",
      body: JSON.stringify(body),
    }),
};