/**
 * Client-side BFF auth helper.
 *
 * All calls run in the browser with `credentials: "include"` so the httpOnly
 * session cookie set by the BFF on /auth/login is sent back on every
 * subsequent request.
 *
 * For dev: localhost:3000 (Next.js) and localhost:8080 (BFF) are same-site
 * per browser definition, so SameSite=Lax cookies are accepted.
 * For prod: set COOKIE_DOMAIN=.prabhupadasays.org on the BFF so the cookie
 * is shared between prabhupadasays.org and api.prabhupadasays.org.
 */

const BFF_BASE =
  process.env.NEXT_PUBLIC_BFF_URL || "http://localhost:8080";

export type User = {
  id: string;
  email: string;
  name: string;
  avatar_url: string | null;
  role: string;
  email_verified_at: string | null;
  created_at: string;
  updated_at: string;
};

/** Error shape returned by the BFF envelope. */
export class AuthError extends Error {
  constructor(
    public status: number,
    message: string,
  ) {
    super(message);
    this.name = "AuthError";
  }
}

type Envelope<T> = {
  success: boolean;
  data?: T;
  error?: { code: number; message: string };
};

/** Low-level fetch helper that unwraps the BFF envelope. */
async function authFetch<T>(
  path: string,
  init?: RequestInit,
): Promise<T> {
  const res = await fetch(`${BFF_BASE}/api/v1${path}`, {
    credentials: "include",
    headers: { "Content-Type": "application/json", ...(init?.headers ?? {}) },
    ...init,
  });

  // 204 No Content
  if (res.status === 204) return undefined as T;

  const body = (await res.json().catch(() => ({}))) as Envelope<T>;

  if (!res.ok || body.success === false) {
    throw new AuthError(res.status, body.error?.message || res.statusText);
  }
  return (body.data ?? (undefined as unknown as T)) as T;
}

export const auth = {
  signUp: (email: string, password: string, name: string) =>
    authFetch<User>("/auth/signup", {
      method: "POST",
      body: JSON.stringify({ email, password, name }),
    }),

  logIn: (email: string, password: string) =>
    authFetch<User>("/auth/login", {
      method: "POST",
      body: JSON.stringify({ email, password }),
    }),

  logOut: () => authFetch<{ ok: boolean }>("/auth/logout", { method: "POST" }),

  /** Returns the current user, or null when not authenticated. */
  me: async (): Promise<User | null> => {
    try {
      return await authFetch<User>("/auth/me");
    } catch (e) {
      if (e instanceof AuthError && e.status === 401) return null;
      throw e;
    }
  },

  forgotPassword: (email: string) =>
    authFetch<{ ok: boolean }>("/auth/forgot-password", {
      method: "POST",
      body: JSON.stringify({ email }),
    }),

  resetPassword: (token: string, newPassword: string) =>
    authFetch<{ ok: boolean }>("/auth/reset-password", {
      method: "POST",
      body: JSON.stringify({ token, new_password: newPassword }),
    }),

  verifyEmail: (token: string) =>
    authFetch<{ ok: boolean }>("/auth/verify-email", {
      method: "POST",
      body: JSON.stringify({ token }),
    }),

  resendVerification: () =>
    authFetch<{ ok: boolean }>("/auth/resend-verification", { method: "POST" }),

  updateProfile: (name?: string, avatarURL?: string | null) =>
    authFetch<User>("/users/me", {
      method: "PATCH",
      body: JSON.stringify({
        name: name ?? undefined,
        avatar_url: avatarURL === undefined ? undefined : avatarURL,
      }),
    }),

  /**
   * Two-step avatar upload:
   *   1. Ask the BFF for a presigned R2 PUT URL.
   *   2. PUT the file directly to R2.
   *   3. Caller persists the returned publicURL via updateProfile().
   */
  uploadAvatar: async (file: File): Promise<string> => {
    const { upload_url, public_url } = await authFetch<{
      upload_url: string;
      public_url: string;
    }>("/users/me/avatar-presign", {
      method: "POST",
      body: JSON.stringify({ content_type: file.type }),
    });

    const put = await fetch(upload_url, {
      method: "PUT",
      body: file,
      headers: { "Content-Type": file.type },
    });
    if (!put.ok) {
      throw new AuthError(put.status, "avatar upload failed");
    }
    return public_url;
  },
};