import type { AuthenticatedUser, LoginResponse } from '@/types/auth'

export const AUTH_TOKEN_KEY = 'token'
export const AUTH_USER_KEY = 'userInfo'
export const AUTH_EXPIRES_AT_KEY = 'tokenExpiresAt'

export interface StoredAuthSession {
  token: string
  user: AuthenticatedUser | null
  expiresAt: string | null
}

function readStoredUser(): AuthenticatedUser | null {
  const rawUser = localStorage.getItem(AUTH_USER_KEY)

  if (!rawUser) {
    return null
  }

  try {
    return JSON.parse(rawUser) as AuthenticatedUser
  } catch {
    localStorage.removeItem(AUTH_USER_KEY)
    return null
  }
}

export function readStoredAuthSession(): StoredAuthSession | null {
  const token = localStorage.getItem(AUTH_TOKEN_KEY)

  if (!token) {
    return null
  }

  const expiresAt = localStorage.getItem(AUTH_EXPIRES_AT_KEY)

  if (expiresAt && Date.parse(expiresAt) <= Date.now()) {
    clearAuthStorage()
    return null
  }

  return {
    token,
    user: readStoredUser(),
    expiresAt,
  }
}

export function saveAuthSession(session: LoginResponse) {
  localStorage.setItem(AUTH_TOKEN_KEY, session.token)
  localStorage.setItem(AUTH_EXPIRES_AT_KEY, session.expiresAt)
  localStorage.setItem(AUTH_USER_KEY, JSON.stringify(session.user))
}

export function clearAuthStorage() {
  localStorage.removeItem(AUTH_TOKEN_KEY)
  localStorage.removeItem(AUTH_EXPIRES_AT_KEY)
  localStorage.removeItem(AUTH_USER_KEY)
}