// components/layout/SessionManager.tsx
'use client'

import { useSession } from "next-auth/react"
import { useEffect, useState, useCallback } from "react"
import { useRouter } from "next/navigation"
import { AlertCircle, Clock, RefreshCw, X } from "lucide-react"
import { Button } from "@/components/ui/button"
import { Alert, AlertDescription } from "@/components/ui/alert"
import { Progress } from "@/components/ui/progress"
import { useToast } from "@/hooks/use-toast"
import { Card, CardContent } from "@/components/ui/card"
import { cn } from "@/lib/utils"

interface SessionManagerProps {
  lng: string;
}

// 다국어 메시지
const messages = {
  ko: {
    sessionExpiring: "세션 만료 경고",
    sessionWillExpire: "세션이 {minutes}분 후에 만료됩니다.",
    sessionExpired: "세션이 만료되었습니다",
    pleaseRelogin: "다시 로그인해주세요.",
    extend: "연장",
    extending: "연장 중...",
    close: "닫기",
    sessionExtended: "세션이 연장되었습니다",
    sessionExtendFailed: "세션 연장에 실패했습니다",
    autoLogoutIn: "{seconds}초 후 자동 로그아웃됩니다",
    staySignedIn: "로그인 유지",
    logout: "로그아웃"
  },
  en: {
    sessionExpiring: "Session Expiring",
    sessionWillExpire: "Your session will expire in {minutes} minute(s).",
    sessionExpired: "Session Expired",
    pleaseRelogin: "Please log in again.",
    extend: "Extend",
    extending: "Extending...",
    close: "Close",
    sessionExtended: "Session has been extended",
    sessionExtendFailed: "Failed to extend session",
    autoLogoutIn: "Auto logout in {seconds} seconds",
    staySignedIn: "Stay Signed In",
    logout: "Logout"
  }
} as const;

export function SessionManager({ lng }: SessionManagerProps) {
  const { data: session, update } = useSession()
  const router = useRouter()
  const { toast } = useToast()
  
  const [showWarning, setShowWarning] = useState(false)
  const [showExpiredModal, setShowExpiredModal] = useState(false)
  const [isExtending, setIsExtending] = useState(false)
  const [autoLogoutCountdown, setAutoLogoutCountdown] = useState(0)
  const [timeLeft, setTimeLeft] = useState<number | null>(null)

  const t = messages[lng as keyof typeof messages] || messages.en

  // 세션 연장 함수
  const extendSession = useCallback(async () => {
    if (isExtending) return;
    
    setIsExtending(true)
    try {
      await update({
        reAuthTime: Date.now()
      })
      
      setShowWarning(false)
      setTimeLeft(null)
      
      toast({
        title: t.sessionExtended,
        description: "세션이 성공적으로 연장되었습니다.",
        duration: 3000,
      })
    } catch (error) {
      console.error('Failed to extend session:', error)
      toast({
        title: t.sessionExtendFailed,
        description: "다시 시도해주세요.",
        variant: "destructive",
        duration: 5000,
      })
    } finally {
      setIsExtending(false)
    }
  }, [isExtending, update, toast, t])

  // 자동 로그아웃 처리
  const handleAutoLogout = useCallback(() => {
    setShowExpiredModal(false)
    setShowWarning(false)
    window.location.href = `/${lng}/evcp?reason=expired`
  }, [lng])

  // 세션 만료 체크
  useEffect(() => {
    if (!session?.user?.sessionExpiredAt) return

    const checkSession = () => {
      const now = Date.now()
      const expiresAt = session.user.sessionExpiredAt!
      const timeUntilExpiry = expiresAt - now
      const warningThreshold = 5 * 60 * 1000 // 5분
      const criticalThreshold = 1 * 60 * 1000 // 1분

      setTimeLeft(timeUntilExpiry)

      // 세션 만료됨
      if (timeUntilExpiry <= 0) {
        setShowWarning(false)
        setShowExpiredModal(true)
        setAutoLogoutCountdown(10) // 10초 후 자동 로그아웃
        return
      }

      // 1분 이내 - 긴급 경고
      if (timeUntilExpiry <= criticalThreshold) {
        setShowWarning(true)
        return
      }

      // 5분 이내 - 일반 경고
      if (timeUntilExpiry <= warningThreshold && !showWarning) {
        setShowWarning(true)
        return
      }

      // 경고 해제
      if (timeUntilExpiry > warningThreshold && showWarning) {
        setShowWarning(false)
      }
    }

    // 즉시 체크
    checkSession()

    // 5초마다 체크 (더 정확한 카운트다운을 위해)
    const interval = setInterval(checkSession, 5000)

    return () => clearInterval(interval)
  }, [session, showWarning])

  // 자동 로그아웃 카운트다운
  useEffect(() => {
    if (autoLogoutCountdown <= 0) return

    const timer = setTimeout(() => {
      if (autoLogoutCountdown === 1) {
        handleAutoLogout()
      } else {
        setAutoLogoutCountdown(prev => prev - 1)
      }
    }, 1000)

    return () => clearTimeout(timer)
  }, [autoLogoutCountdown, handleAutoLogout])

  // 사용자 활동 감지
  useEffect(() => {
    let activityTimer: NodeJS.Timeout
    let lastActivity = Date.now()

    const resetActivityTimer = () => {
      const now = Date.now()
      const timeSinceLastActivity = now - lastActivity
      
      // 5분 이상 비활성 후 첫 활동이면 세션 연장
      if (timeSinceLastActivity > 5 * 60 * 1000) {
        extendSession()
      }
      
      lastActivity = now
      clearTimeout(activityTimer)
      
      // 10분간 비활성이면 경고 표시
      activityTimer = setTimeout(() => {
        if (!showWarning && session?.user?.sessionExpiredAt) {
          const timeUntilExpiry = session.user.sessionExpiredAt - Date.now()
          if (timeUntilExpiry > 0 && timeUntilExpiry <= 10 * 60 * 1000) {
            setShowWarning(true)
          }
        }
      }, 10 * 60 * 1000)
    }

    const activities = ['mousedown', 'keydown', 'scroll', 'touchstart', 'click']
    
    activities.forEach(activity => {
      document.addEventListener(activity, resetActivityTimer, true)
    })

    resetActivityTimer() // 초기 타이머 설정

    return () => {
      clearTimeout(activityTimer)
      activities.forEach(activity => {
        document.removeEventListener(activity, resetActivityTimer, true)
      })
    }
  }, [extendSession, showWarning, session])

  const formatTime = (ms: number) => {
    const minutes = Math.floor(ms / (1000 * 60))
    const seconds = Math.floor((ms % (1000 * 60)) / 1000)
    return { minutes, seconds }
  }

  // 세션 만료 모달
  if (showExpiredModal) {
    return (
      <div className="fixed inset-0 bg-black/50 flex items-center justify-center z-[100]">
        <Card className="w-full max-w-md mx-4">
          <CardContent className="p-6">
            <div className="flex items-center space-x-3 mb-4">
              <AlertCircle className="h-6 w-6 text-destructive" />
              <h3 className="text-lg font-semibold">{t.sessionExpired}</h3>
            </div>
            
            <p className="text-muted-foreground mb-4">
              {t.pleaseRelogin}
            </p>
            
            {autoLogoutCountdown > 0 && (
              <div className="mb-4">
                <p className="text-sm text-muted-foreground mb-2">
                  {t.autoLogoutIn.replace('{seconds}', autoLogoutCountdown.toString())}
                </p>
                <Progress 
                  value={(10 - autoLogoutCountdown) * 10} 
                  className="h-2" 
                />
              </div>
            )}
            
            <div className="flex space-x-2">
              <Button 
                onClick={() => {
                  setAutoLogoutCountdown(0)
                  extendSession()
                  setShowExpiredModal(false)
                }}
                className="flex-1"
                disabled={isExtending}
              >
                {isExtending ? (
                  <>
                    <RefreshCw className="h-4 w-4 mr-2 animate-spin" />
                    {t.extending}
                  </>
                ) : (
                  t.staySignedIn
                )}
              </Button>
              <Button 
                variant="outline" 
                onClick={handleAutoLogout}
                className="flex-1"
              >
                {t.logout}
              </Button>
            </div>
          </CardContent>
        </Card>
      </div>
    )
  }

  // 세션 경고 알림
  if (showWarning && timeLeft) {
    const { minutes, seconds } = formatTime(timeLeft)
    const isCritical = timeLeft <= 60000 // 1분 이내
    const progressValue = Math.max(0, Math.min(100, (timeLeft / (5 * 60 * 1000)) * 100))

    return (
      <div className={cn(
        "fixed top-4 right-4 z-50 w-full max-w-sm",
        "animate-in slide-in-from-right-full duration-300"
      )}>
        <Alert className={cn(
          "border-2 shadow-lg",
          isCritical 
            ? "border-destructive bg-destructive/5" 
            : "border-warning bg-warning/5"
        )}>
          <Clock className={cn(
            "h-4 w-4",
            isCritical ? "text-destructive" : "text-warning"
          )} />
          
          <div className="flex-1">
            <div className="flex items-center justify-between mb-2">
              <h4 className="font-medium text-sm">
                {t.sessionExpiring}
              </h4>
              <Button
                variant="ghost"
                size="sm"
                className="h-auto p-1 hover:bg-transparent"
                onClick={() => setShowWarning(false)}
              >
                <X className="h-3 w-3" />
              </Button>
            </div>
            
            <AlertDescription className="text-xs mb-3">
              {minutes > 0 
                ? t.sessionWillExpire.replace('{minutes}', minutes.toString())
                : `${seconds}초 후 세션이 만료됩니다.`
              }
            </AlertDescription>
            
            <div className="space-y-2">
              <Progress 
                value={progressValue} 
                className={cn(
                  "h-1.5",
                  isCritical && "bg-destructive/20"
                )}
              />
              
              <div className="flex space-x-2">
                <Button
                  size="sm"
                  onClick={extendSession}
                  disabled={isExtending}
                  className="flex-1 h-7 text-xs"
                >
                  {isExtending ? (
                    <>
                      <RefreshCw className="h-3 w-3 mr-1 animate-spin" />
                      {t.extending}
                    </>
                  ) : (
                    t.extend
                  )}
                </Button>
                <Button
                  variant="outline"
                  size="sm"
                  onClick={() => setShowWarning(false)}
                  className="h-7 text-xs px-2"
                >
                  {t.close}
                </Button>
              </div>
            </div>
          </div>
        </Alert>
      </div>
    )
  }

  return null
}