import type { AuthAppRole, AuthSession } from '../types/auth';

const AUTH_BASE_URL = (import.meta.env.VITE_ATNMY_AUTH_URL ?? import.meta.env.VITE_ADS_IDE_AUTH_URL ?? 'https://auth.autonomystudio.net').replace(/\/+$/, '');
const ADMIN_SESSION_STORAGE_KEY = 'atnmy.lms.admin.auth.session';
const INSTRUCTOR_ROLES = new Set(['INSTRUCTOR', 'LMS_ADMIN']);

export const isInstructorSession = (session: AuthSession): boolean => {
  const roles = new Set(getSessionRoles(session));
  return [...INSTRUCTOR_ROLES].some((role) => roles.has(role));
};

const getSessionRoles = (session: AuthSession): string[] => {
  return [
    session.user.role,
    ...(session.user.roles ?? []),
    ...(session.roles ?? []),
    ...getAppRoleCodes(session.user.appRoles),
    ...getAppRoleCodes(session.user.app_roles),
    ...getAppRoleCodes(session.appRoles),
    ...getAppRoleCodes(session.app_roles),
  ]
    .filter((role): role is string => Boolean(role))
    .map((role) => role.toUpperCase());
};

const getAppRoleCodes = (roles: AuthAppRole[] | undefined): string[] => {
  if (!Array.isArray(roles)) return [];

  return roles
    .filter((role) => {
      const appKey = role.appKey ?? role.app_key;
      return !appKey || appKey.toUpperCase() === 'LMS';
    })
    .map((role) => role.roleCode ?? role.role_code ?? role.role ?? role.code)
    .filter((role): role is string => Boolean(role));
};

export const loadStoredSession = (): AuthSession | null => {
  try {
    const raw = window.localStorage.getItem(ADMIN_SESSION_STORAGE_KEY);
    if (!raw) return null;

    const session = JSON.parse(raw) as AuthSession;
    if (!isInstructorSession(session) || isStoredSessionExpired(session)) {
      clearStoredSession();
      return null;
    }

    return session;
  } catch {
    return null;
  }
};

export const storeSession = (session: AuthSession): void => {
  window.localStorage.setItem(ADMIN_SESSION_STORAGE_KEY, JSON.stringify({
    ...session,
    obtainedAt: session.obtainedAt ?? Date.now(),
  }));
};

export const clearStoredSession = (): void => {
  window.localStorage.removeItem(ADMIN_SESSION_STORAGE_KEY);
};

export const isStoredSessionExpired = (session: AuthSession): boolean => {
  const obtainedAt = session.obtainedAt ?? 0;
  if (!obtainedAt) return false;

  if (session.refreshToken && session.refreshTokenExpiresIn) {
    return Date.now() >= obtainedAt + session.refreshTokenExpiresIn * 1000;
  }

  return Date.now() >= obtainedAt + (session.accessTokenExpiresIn ?? 0) * 1000;
};

export const loginInstructor = async (email: string, password: string): Promise<AuthSession> => {
  const response = await fetch(`${AUTH_BASE_URL}/auth/login`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    credentials: 'include',
    body: JSON.stringify({ email, password })
  });

  if (!response.ok) {
    throw new Error(response.status === 429 ? '로그인 시도가 너무 많습니다. 잠시 후 다시 시도해주세요.' : '이메일 또는 비밀번호를 확인해주세요.');
  }

  const session = {
    ...(await response.json()) as AuthSession,
    obtainedAt: Date.now(),
  };
  if (!isInstructorSession(session)) {
    clearStoredSession();
    throw new Error('강사 계정만 로그인할 수 있습니다.');
  }

  storeSession(session);
  return session;
};

export const refreshInstructorSession = async (session: AuthSession): Promise<AuthSession> => {
  if (!session.refreshToken) {
    throw new Error('리프레시 토큰이 없습니다.');
  }

  const response = await fetch(`${AUTH_BASE_URL}/auth/refresh`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    credentials: 'include',
    body: JSON.stringify({ refreshToken: session.refreshToken })
  });

  if (!response.ok) {
    throw new Error('세션을 갱신하지 못했습니다.');
  }

  const nextSession = {
    ...(await response.json()) as AuthSession,
    obtainedAt: Date.now(),
  };

  if (!isInstructorSession(nextSession)) {
    clearStoredSession();
    throw new Error('강사 계정만 로그인할 수 있습니다.');
  }

  storeSession(nextSession);
  return nextSession;
};

export const refreshCurrentUser = async (session: AuthSession): Promise<AuthSession> => {
  const response = await fetch(`${AUTH_BASE_URL}/auth/me`, {
    headers: {
      Authorization: `Bearer ${session.accessToken}`
    }
  });

  if (!response.ok) {
    throw new Error('사용자 정보를 다시 가져오지 못했습니다.');
  }

  const payload = (await response.json()) as { user?: AuthSession['user'] };
  const nextSession = {
    ...session,
    user: payload.user ?? session.user
  };

  if (!isInstructorSession(nextSession)) {
    clearStoredSession();
    throw new Error('강사 계정만 로그인할 수 있습니다.');
  }

  storeSession(nextSession);
  return nextSession;
};

export const logoutInstructor = async (): Promise<void> => {
  try {
    await fetch(`${AUTH_BASE_URL}/auth/logout`, {
      method: 'POST',
      credentials: 'include'
    });
  } finally {
    clearStoredSession();
  }
};