export default defineNuxtPlugin(() => {
  // Only run on client side
  if (import.meta.server) return

  let refreshTimer: NodeJS.Timeout | null = null
  let isRefreshing = false

  const scheduleTokenRefresh = (expiresAt: number) => {
    // Clear existing timer
    if (refreshTimer) {
      clearTimeout(refreshTimer)
      refreshTimer = null
    }

    // Calculate time until refresh (refresh 2 minutes before expiry)
    const refreshBuffer = 2 * 60 * 1000 // 2 minutes in milliseconds
    const timeUntilRefresh = expiresAt - Date.now() - refreshBuffer

    console.log('[AUTH_REFRESH] Scheduling token refresh in:', Math.max(0, timeUntilRefresh), 'ms')

    // Only schedule if we have time left
    if (timeUntilRefresh > 0) {
      refreshTimer = setTimeout(async () => {
        if (isRefreshing) return
        
        try {
          isRefreshing = true
          console.log('[AUTH_REFRESH] Attempting automatic token refresh...')
          
          const response = await $fetch<{ success: boolean; expiresAt?: number }>('/api/auth/refresh', {
            method: 'POST'
          })

          if (response.success && response.expiresAt) {
            console.log('[AUTH_REFRESH] Token refresh successful, scheduling next refresh')
            scheduleTokenRefresh(response.expiresAt)
          } else {
            console.error('[AUTH_REFRESH] Token refresh failed, redirecting to login')
            await navigateTo('/login')
          }
        } catch (error) {
          console.error('[AUTH_REFRESH] Token refresh error:', error)
          // If refresh fails, redirect to login
          await navigateTo('/login')
        } finally {
          isRefreshing = false
        }
      }, timeUntilRefresh)
    } else {
      // Token already expired or very close to expiry, try immediate refresh
      setTimeout(async () => {
        if (isRefreshing) return
        
        try {
          isRefreshing = true
          console.log('[AUTH_REFRESH] Token expired, attempting immediate refresh...')
          
          const response = await $fetch<{ success: boolean; expiresAt?: number }>('/api/auth/refresh', {
            method: 'POST'
          })

          if (response.success && response.expiresAt) {
            console.log('[AUTH_REFRESH] Immediate refresh successful')
            scheduleTokenRefresh(response.expiresAt)
          } else {
            console.error('[AUTH_REFRESH] Immediate refresh failed, redirecting to login')
            await navigateTo('/login')
          }
        } catch (error) {
          console.error('[AUTH_REFRESH] Immediate refresh error:', error)
          await navigateTo('/login')
        } finally {
          isRefreshing = false
        }
      }, 100) // Small delay to avoid immediate execution
    }
  }

  const checkAndScheduleRefresh = async () => {
    try {
      // Use middleware cache instead of API call
      const nuxtApp = useNuxtApp()
      const authState = nuxtApp.payload?.data?.authState
      const sessionCache = nuxtApp.payload?.data?.['auth:session:cache']
      
      const sessionData = authState || sessionCache
      
      if (sessionData?.authenticated) {
        // Get the session cookie to extract expiry time
        const sessionCookie = useCookie('nuxt-oidc-auth')
        
        if (sessionCookie.value) {
          try {
            const parsedSession = typeof sessionCookie.value === 'string' 
              ? JSON.parse(sessionCookie.value) 
              : sessionCookie.value

            if (parsedSession.expiresAt) {
              console.log('[AUTH_REFRESH] Found session with expiry:', new Date(parsedSession.expiresAt))
              scheduleTokenRefresh(parsedSession.expiresAt)
            }
          } catch (parseError) {
            console.error('[AUTH_REFRESH] Failed to parse session cookie:', parseError)
          }
        }
      } else {
        console.log('[AUTH_REFRESH] No authenticated session found in cache')
      }
    } catch (error) {
      console.error('[AUTH_REFRESH] Failed to check session:', error)
    }
  }

  // Check authentication status and schedule refresh on plugin initialization
  onMounted(() => {
    checkAndScheduleRefresh()
  })

  // Listen for route changes to re-check auth status
  const router = useRouter()
  router.afterEach((to) => {
    // Only check on protected routes
    if (to.meta.auth !== false) {
      checkAndScheduleRefresh()
    }
  })

  // Listen for visibility changes to refresh when tab becomes active
  if (typeof document !== 'undefined') {
    document.addEventListener('visibilitychange', () => {
      if (!document.hidden) {
        // Tab became visible, check if we need to refresh
        checkAndScheduleRefresh()
      }
    })
  }

  // Clean up timer on plugin destruction
  onBeforeUnmount(() => {
    if (refreshTimer) {
      clearTimeout(refreshTimer)
      refreshTimer = null
    }
  })
})