/**
 * Auth API client for login, register, me, refresh.
 * Uses NEXT_PUBLIC_BASE_API_URL on client (defaults to same as BASE_API_URL for server).
 */

const getBaseUrl = () =>
  typeof window !== "undefined"
    ? process.env.NEXT_PUBLIC_BASE_API_URL ?? "http://127.0.0.1:8080"
    : process.env.BASE_API_URL ?? process.env.NEXT_PUBLIC_BASE_API_URL ?? "http://127.0.0.1:8080";

const API_PREFIX = "/api/v1/auth";

export interface AuthUser {
  id: number;
  email: string;
  first_name: string;
  last_name: string;
  username?: string;
  is_admin: boolean;
  email_verified?: boolean;
}

export interface LoginResponse {
  access_token: string;
  refresh_token: string;
  user: AuthUser;
}

export interface RegisterResponse {
  message: string;
  user: AuthUser;
}

export interface RefreshResponse {
  access_token: string;
  refresh_token: string;
}

/** POST /api/v1/auth/login – doğrudan backend (token client’ta; cookie için loginViaCookie kullanın) */
export async function login(
  email: string,
  password: string
): Promise<LoginResponse> {
  const base = getBaseUrl();
  const res = await fetch(`${base}${API_PREFIX}/login`, {
    method: "POST",
    headers: { "Content-Type": "application/json", accept: "application/json" },
    body: JSON.stringify({ email, password }),
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error((err as { detail?: string }).detail ?? "Giriş başarısız");
  }
  return res.json();
}

/** Cookie tabanlı giriş – token’lar HTTP-only secure cookie’de saklanır */
export async function loginViaCookie(
  email: string,
  password: string
): Promise<{ user: AuthUser }> {
  const res = await fetch("/api/auth/cookie-login", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ email: email.trim(), password }),
    credentials: "include",
  });
  const data = await res.json().catch(() => ({}));
  if (!res.ok) {
    throw new Error((data as { error?: string }).error ?? "Giriş başarısız");
  }
  return data as { user: AuthUser };
}

/** Cookie tabanlı çıkış */
export async function logoutViaCookie(): Promise<void> {
  await fetch("/api/auth/cookie-logout", {
    method: "POST",
    credentials: "include",
  });
}

/** Cookie oturumunu kontrol et (client tarafında oturum bilgisi için) */
export async function getCookieSession(): Promise<{
  loggedIn: boolean;
  user?: AuthUser;
}> {
  const res = await fetch("/api/auth/cookie-session", { credentials: "include" });
  const data = await res.json().catch(() => ({ loggedIn: false }));
  return data as { loggedIn: boolean; user?: AuthUser };
}

/** POST /api/v1/auth/register */
export async function register(body: {
  email: string;
  first_name: string;
  last_name: string;
  password: string;
  username: string;
}): Promise<RegisterResponse> {
  const base = getBaseUrl();
  const res = await fetch(`${base}${API_PREFIX}/register`, {
    method: "POST",
    headers: { "Content-Type": "application/json", accept: "application/json" },
    body: JSON.stringify(body),
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    const detail = (err as { detail?: string | string[] }).detail;
    const message = Array.isArray(detail) ? detail.join(" ") : detail ?? "Kayıt başarısız";
    throw new Error(message);
  }
  return res.json();
}

/** GET /api/v1/auth/me */
export async function me(accessToken: string): Promise<{ user: AuthUser }> {
  const base = getBaseUrl();
  const res = await fetch(`${base}${API_PREFIX}/me`, {
    headers: {
      accept: "application/json",
      Authorization: `Bearer ${accessToken}`,
    },
  });
  if (!res.ok) throw new Error("Oturum bilgisi alınamadı");
  return res.json();
}

/** POST /api/v1/auth/refresh */
export async function refresh(refreshToken: string): Promise<RefreshResponse> {
  const base = getBaseUrl();
  const res = await fetch(`${base}${API_PREFIX}/refresh`, {
    method: "POST",
    headers: { "Content-Type": "application/json", accept: "application/json" },
    body: JSON.stringify({ refresh_token: refreshToken }),
  });
  if (!res.ok) throw new Error("Token yenilenemedi");
  return res.json();
}

const ACCESS_KEY = "auth_access_token";
const REFRESH_KEY = "auth_refresh_token";

const AUTH_CHANGE_EVENT = "auth-change";

/** Header vb. bileşenlerin oturum değişikliğini algılaması için tetiklenir. */
export function notifyAuthChange(): void {
  if (typeof window === "undefined") return;
  window.dispatchEvent(new Event(AUTH_CHANGE_EVENT));
}

export function setTokens(access: string, refreshToken: string): void {
  if (typeof window === "undefined") return;
  localStorage.setItem(ACCESS_KEY, access);
  localStorage.setItem(REFRESH_KEY, refreshToken);
  notifyAuthChange();
}

export function getAccessToken(): string | null {
  if (typeof window === "undefined") return null;
  return localStorage.getItem(ACCESS_KEY);
}

export function getRefreshToken(): string | null {
  if (typeof window === "undefined") return null;
  return localStorage.getItem(REFRESH_KEY);
}

export function clearTokens(): void {
  if (typeof window === "undefined") return;
  localStorage.removeItem(ACCESS_KEY);
  localStorage.removeItem(REFRESH_KEY);
  notifyAuthChange();
}

export { AUTH_CHANGE_EVENT };