import { ref, computed } from 'vue'
import { lnbitsAPI, type User, type LoginCredentials, type RegisterData } from '@/lib/api/lnbits'

const currentUser = ref<User | null>(null)
const isLoading = ref(false)
const error = ref<string | null>(null)

export function useAuth() {
  const isAuthenticated = computed(() => !!currentUser.value)

  /**
   * Initialize authentication on app start
   */
  async function initialize(): Promise<void> {
    try {
      isLoading.value = true
      error.value = null

      if (lnbitsAPI.isAuthenticated()) {
        const user = await lnbitsAPI.getCurrentUser()
        currentUser.value = user
      }
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Failed to initialize authentication'
      // Clear invalid token
      await logout()
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Login with username and password
   */
  async function login(credentials: LoginCredentials): Promise<void> {
    try {
      isLoading.value = true
      error.value = null

      await lnbitsAPI.login(credentials)
      
      // Get user details
      const user = await lnbitsAPI.getCurrentUser()
      currentUser.value = user
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Login failed'
      throw err
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Register new user
   */
  async function register(data: RegisterData): Promise<void> {
    try {
      isLoading.value = true
      error.value = null

      await lnbitsAPI.register(data)
      
      // Get user details
      const user = await lnbitsAPI.getCurrentUser()
      currentUser.value = user
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Registration failed'
      throw err
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Logout and clear user data
   */
  async function logout(): Promise<void> {
    // Clear local state
    lnbitsAPI.logout()
    currentUser.value = null
    error.value = null
  }

  /**
   * Update user password
   */
  async function updatePassword(currentPassword: string, newPassword: string): Promise<void> {
    try {
      isLoading.value = true
      error.value = null

      const updatedUser = await lnbitsAPI.updatePassword(currentPassword, newPassword)
      currentUser.value = updatedUser
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Failed to update password'
      throw err
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Update user profile
   */
  async function updateProfile(data: Partial<User>): Promise<void> {
    try {
      isLoading.value = true
      error.value = null

      const updatedUser = await lnbitsAPI.updateProfile(data)
      currentUser.value = updatedUser
    } catch (err) {
      error.value = err instanceof Error ? err.message : 'Failed to update profile'
      throw err
    } finally {
      isLoading.value = false
    }
  }

  /**
   * Check if user is authenticated
   */
  function checkAuth(): boolean {
    return lnbitsAPI.isAuthenticated()
  }

  /**
   * Get user display info
   */
  const userDisplay = computed(() => {
    if (!currentUser.value) return null
    
    return {
      name: currentUser.value.username || currentUser.value.email || 'Anonymous',
      username: currentUser.value.username,
      email: currentUser.value.email,
      id: currentUser.value.id,
      shortId: currentUser.value.id.slice(0, 8) + '...' + currentUser.value.id.slice(-8)
    }
  })



  return {
    // State
    currentUser: computed(() => currentUser.value),
    isAuthenticated,
    isLoading,
    error,
    userDisplay,

    // Actions
    initialize,
    login,
    register,
    logout,
    updatePassword,
    updateProfile,
    checkAuth
  }
}

// Export singleton instance for global state
export const auth = useAuth()