'use client'

import { useState, useEffect, useCallback } from 'react'
import { useRouter } from 'next/navigation'
import { Button } from '@/components/ui/button'
import { Badge } from '@/components/ui/badge'
import { Bell, Check, X, Clock, AlertCircle, CheckCircle2, Circle, Share2, Bot, Trash2, Download, Pencil, Presentation, Wind } from 'lucide-react'
import {
  Popover,
  PopoverContent,
  PopoverTrigger,
} from '@/components/ui/popover'
import { getPendingShareRequests, respondToShareRequest, getNotesWithReminders, toggleReminderDone } from '@/app/actions/notes'
import { getPendingBrainstormShares, respondToBrainstormShare } from '@/app/actions/brainstorm'
import { getUnreadNotifications, markNotificationRead, markAllNotificationsRead, type AppNotification } from '@/app/actions/notifications'
import { toast } from 'sonner'
import { useRefresh } from '@/lib/use-refresh'
import { cn } from '@/lib/utils'
import { useLanguage } from '@/lib/i18n'
import { formatDistanceToNow } from 'date-fns'

interface ShareRequest {
  id: string
  status: string
  permission: string
  createdAt: Date
  note: {
    id: string
    title: string | null
    content: string
    color: string
    createdAt: Date
  }
  sharer: {
    id: string
    name: string | null
    email: string
    image: string | null
  }
}

interface ReminderNote {
  id: string
  title: string | null
  content: string
  reminder: Date | string | null
  isReminderDone: boolean
}

// ── Memento brand tokens ──────────────────────────────────────────────────────
const C = {
  blue:   '#FDFDFE',
  gold:   '#D4A373',
  green:  '#A3B18A',
  dark:   '#1C1C1C',
  beige:  '#FDFDFE',
}

export function NotificationPanel() {
  const { refreshNotes } = useRefresh()
  const { t } = useLanguage()
  const router = useRouter()
  const [requests, setRequests] = useState<ShareRequest[]>([])
  const [brainstormShares, setBrainstormShares] = useState<any[]>([])
  const [reminders, setReminders] = useState<ReminderNote[]>([])
  const [appNotifications, setAppNotifications] = useState<AppNotification[]>([])
  const [isLoading, setIsLoading] = useState(false)
  const [open, setOpen] = useState(false)

  const loadData = useCallback(async () => {
    setIsLoading(true)
    try {
      const [shareData, brainstormData, reminderData, notifData] = await Promise.all([
        getPendingShareRequests(),
        getPendingBrainstormShares(),
        getNotesWithReminders(),
        getUnreadNotifications(),
      ])
      setRequests(shareData as any)
      setBrainstormShares(brainstormData as any || [])
      setReminders((reminderData as any) || [])
      setAppNotifications(notifData || [])
    } catch (error: any) {
      console.error('Failed to load notifications:', error)
    } finally {
      setIsLoading(false)
    }
  }, [])

  useEffect(() => {
    loadData()
    const interval = setInterval(loadData, 30000)
    const onFocus = () => loadData()
    window.addEventListener('focus', onFocus)
    return () => {
      clearInterval(interval)
      window.removeEventListener('focus', onFocus)
    }
  }, [loadData])

  const now = new Date()
  const activeReminders = reminders.filter(r => !r.isReminderDone && r.reminder)
  const overdueReminders = activeReminders.filter(r => new Date(r.reminder!) < now)
  const upcomingReminders = activeReminders.filter(r => new Date(r.reminder!) >= now)

  const pendingCount = requests.length + brainstormShares.length + overdueReminders.length + appNotifications.length

  const handleAccept = async (shareId: string) => {
    try {
      await respondToShareRequest(shareId, 'accept')
      setRequests(prev => prev.filter(r => r.id !== shareId))
      toast.success(t('notification.accepted'), {
        description: t('collaboration.nowHasAccess', { name: 'Note' }),
        duration: 3000,
      })
      refreshNotes(null)
      setOpen(false)
    } catch (error: any) {
      toast.error(error.message || t('general.error'))
    }
  }

  const handleDecline = async (shareId: string) => {
    try {
      await respondToShareRequest(shareId, 'decline')
      setRequests(prev => prev.filter(r => r.id !== shareId))
      toast.info(t('notification.declined'))
      if (requests.length <= 1) setOpen(false)
    } catch (error: any) {
      toast.error(error.message || t('general.error'))
    }
  }

  const handleToggleReminder = async (noteId: string, done: boolean) => {
    try {
      await toggleReminderDone(noteId, done)
      setReminders(prev => prev.map(r => r.id === noteId ? { ...r, isReminderDone: done } : r))
      refreshNotes(null)
    } catch {
      toast.error(t('general.error'))
    }
  }

  const handleMarkNotifRead = async (notifId: string) => {
    await markNotificationRead(notifId)
    setAppNotifications(prev => prev.filter(n => n.id !== notifId))
  }

  const handleMarkAllRead = async () => {
    await markAllNotificationsRead()
    setAppNotifications([])
  }

  const handleAcceptBrainstorm = async (shareId: string) => {
    try {
      await respondToBrainstormShare(shareId, 'accept')
      setBrainstormShares(prev => prev.filter(s => s.id !== shareId))
      toast.success(t('notification.accepted') || 'Accepted')
      setOpen(false)
    } catch (error: any) {
      toast.error(error.message || t('general.error'))
    }
  }

  const handleDeclineBrainstorm = async (shareId: string) => {
    try {
      await respondToBrainstormShare(shareId, 'decline')
      setBrainstormShares(prev => prev.filter(s => s.id !== shareId))
      toast.info(t('notification.declined') || 'Declined')
      if (brainstormShares.length <= 1) setOpen(false)
    } catch (error: any) {
      toast.error(error.message || t('general.error'))
    }
  }

  const hasContent = requests.length > 0 || brainstormShares.length > 0 || activeReminders.length > 0 || appNotifications.length > 0

  // ── icon bg/color per notification type ──────────────────────────────────
  const notifIconStyle = (type: string) => {
    if (type === 'agent_success')       return { bg: 'rgba(164,113,72,0.12)',  color: '#A47148'  }
    if (type === 'agent_slides_ready')  return { bg: 'rgba(164,113,72,0.12)',  color: '#A47148'  }
    if (type === 'agent_canvas_ready')  return { bg: 'rgba(164,113,72,0.12)',  color: '#A47148'  }
    if (type === 'agent_failure')       return { bg: 'rgba(239,68,68,0.12)',   color: '#EF4444' }
    if (type === 'brainstorm_invite')   return { bg: 'rgba(163,177,138,0.12)', color: '#A3B18A' }
    if (type === 'brainstorm_joined')   return { bg: 'rgba(163,177,138,0.12)', color: '#A3B18A' }
    return                                     { bg: 'rgba(163,177,138,0.12)',  color: '#A3B18A'  }
  }

  const notifLabelColor = (type: string) => {
    if (type.startsWith('agent')) {
    if (type === 'agent_failure') return '#EF4444'
    if (type === 'brainstorm_invite') return '#A3B18A'
    if (type === 'brainstorm_joined') return '#A3B18A'
    return '#A47148'
    }
    return '#A3B18A'
  }

  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <button
          className="relative p-1.5 text-muted-ink hover:text-ink transition-all hover:bg-white/50 dark:hover:bg-white/10 rounded-lg border border-transparent hover:border-border"
        >
          <Bell className="h-4 w-4 transition-transform duration-200 hover:scale-110" />
          {pendingCount > 0 && (
            <span
              className="absolute -top-1 -right-1 h-4 w-4 flex items-center justify-center rounded-full text-white text-[9px] font-bold border border-white shadow-sm bg-brand-accent"
            >
              {pendingCount > 9 ? '9+' : pendingCount}
            </span>
          )}
        </button>
      </PopoverTrigger>

      <PopoverContent align="end" className="w-80 p-0 rounded-2xl overflow-hidden shadow-2xl border border-black/20">
        {/* Header */}
        <div className="px-4 py-3 border-b flex items-center justify-between" style={{ background: '#FDFDFE' }}>
          <div className="flex items-center gap-2">
            <Bell className="h-4 w-4" style={{ color: C.dark }} />
            <span className="font-bold text-sm tracking-tight" style={{ color: C.dark }}>
              {t('notification.notifications')}
            </span>
          </div>
          <div className="flex items-center gap-2">
            {appNotifications.length > 0 && (
              <button
                onClick={handleMarkAllRead}
                className="text-[10px] text-foreground/40 hover:text-foreground transition-colors"
                title={t('notification.markAllRead') || 'Mark all read'}
              >
                <Check className="h-3.5 w-3.5" />
              </button>
            )}
            {pendingCount > 0 && (
              <span
                className="h-5 px-1.5 flex items-center justify-center rounded-full text-white text-[9px] font-bold bg-brand-accent"
              >
                {pendingCount}
              </span>
            )}
          </div>
        </div>

        {isLoading ? (
          <div className="p-6 text-center text-sm text-muted-foreground">
            <div className="animate-spin h-6 w-6 border-2 border-t-transparent rounded-full mx-auto mb-2" style={{ borderColor: C.blue, borderTopColor: 'transparent' }} />
          </div>
        ) : !hasContent ? (
          <div className="p-8 text-center">
            <Bell className="h-9 w-9 mx-auto mb-3 opacity-20" />
            <p className="text-[12px] font-medium text-foreground/40">{t('notification.noNotifications') || 'Aucune notification'}</p>
          </div>
        ) : (
          <div className="max-h-96 overflow-y-auto divide-y divide-black/5">

            {/* ── App notifications (agents, system) ── */}
            {appNotifications.map((notif) => {
              const isSlides = notif.type === 'agent_slides_ready'
              const isCanvas = notif.type === 'agent_canvas_ready'
              const canvasId = notif.relatedId
              const iconStyle = notifIconStyle(notif.type)

              return (
                <div key={notif.id} className="p-3 hover:bg-black/[0.02] transition-colors">
                  <div
                    className="flex items-start gap-3 cursor-pointer"
                    onClick={() => {
                      if (notif.actionUrl) {
                        handleMarkNotifRead(notif.id)
                        setOpen(false)
                        router.push(notif.actionUrl)
                      }
                    }}
                  >
                    {/* Icon badge */}
                    <div
                      className="mt-0.5 flex-none rounded-lg p-1.5"
                      style={{ background: iconStyle.bg, color: iconStyle.color }}
                    >
                      {isSlides ? <Presentation className="w-3.5 h-3.5" />
                        : isCanvas ? <Pencil className="w-3.5 h-3.5" />
                        : notif.type === 'brainstorm_invite' ? <Wind className="w-3.5 h-3.5" />
                        : notif.type === 'brainstorm_joined' ? <Wind className="w-3.5 h-3.5" />
                        : notif.type.startsWith('agent') ? <Bot className="w-3.5 h-3.5" />
                        : <AlertCircle className="w-3.5 h-3.5" />}
                    </div>

                    <div className="flex-1 min-w-0">
                      <span
                        className="text-[9px] font-bold uppercase tracking-[0.2em]"
                        style={{ color: notifLabelColor(notif.type) }}
                      >
                        {notif.type === 'agent_slides_ready'  && (t('notification.slidesReady')  || 'Présentation prête')}
                        {notif.type === 'agent_canvas_ready'  && (t('notification.canvasReady')  || 'Diagramme prêt')}
                        {notif.type === 'agent_success'       && (t('notification.agentSuccess') || 'Agent terminé')}
                        {notif.type === 'agent_failure'       && (t('notification.agentFailed')  || 'Agent échoué')}
                        {notif.type === 'brainstorm_invite'   && (t('notification.brainstormInvite') || 'Brainstorm')}
                        {notif.type === 'brainstorm_joined'   && (t('notification.brainstormJoined') || 'Brainstorm')}
                        {notif.type === 'system'              && t('notification.systemNotification')}
                      </span>
                      <p className="text-[13px] font-semibold truncate mt-0.5">{notif.title}</p>
                      {notif.message && (
                        <p className="text-[11px] text-foreground/50 mt-0.5 line-clamp-2">{notif.message}</p>
                      )}
                      <div className="flex items-center gap-1 mt-1 text-[10px] text-foreground/30">
                        <Clock className="w-3 h-3" />
                        {formatDistanceToNow(new Date(notif.createdAt), { addSuffix: true })}
                      </div>
                    </div>

                    <button
                      onClick={(e) => { e.stopPropagation(); handleMarkNotifRead(notif.id) }}
                      className="mt-0.5 text-foreground/20 hover:text-foreground transition-colors"
                    >
                      <X className="w-3.5 h-3.5" />
                    </button>
                  </div>

                  {/* Download PPTX button */}
                  {isSlides && canvasId && (
                    <div className="mt-2 ml-8">
                      <button
                        onClick={async () => {
                          handleMarkNotifRead(notif.id)
                          try {
                            const res = await fetch(`/api/canvas?id=${canvasId}`)
                            const data = await res.json()
                            if (!data.canvas?.data) throw new Error()
                            const parsed = JSON.parse(data.canvas.data)
                            if (!parsed.base64) throw new Error()
                            const bytes = Uint8Array.from(atob(parsed.base64), c => c.charCodeAt(0))
                            const blob = new Blob([bytes], { type: 'application/vnd.openxmlformats-officedocument.presentationml.presentation' })
                            const url = URL.createObjectURL(blob)
                            const a = document.createElement('a')
                            a.href = url
                            a.download = parsed.filename || `${data.canvas.name || 'presentation'}.pptx`
                            document.body.appendChild(a); a.click()
                            document.body.removeChild(a); URL.revokeObjectURL(url)
                          } catch { toast.error(t('notification.downloadFailed')) }
                        }}
                        className="flex items-center gap-1.5 px-3 py-1.5 text-[10px] font-bold rounded-lg text-white uppercase tracking-wide transition-all hover:opacity-90 active:scale-95 shadow-sm"
                        style={{ background: C.blue }}
                      >
                        <Download className="w-3 h-3" />
                        {t('notification.downloadPptx') || 'Télécharger .pptx'}
                      </button>
                    </div>
                  )}
                </div>
              )
            })}

            {/* ── Overdue reminders ── */}
            {overdueReminders.map((note) => (
              <div key={note.id} className="p-3 hover:bg-black/[0.02] transition-colors">
                <div className="flex items-start gap-3">
                  <button
                    onClick={() => handleToggleReminder(note.id, true)}
                    className="mt-0.5 flex-none transition-colors hover:opacity-70"
                    style={{ color: C.green }}
                    title={t('reminders.markDone')}
                  >
                    <Circle className="w-4 h-4" />
                  </button>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-1.5 mb-0.5">
                      <AlertCircle className="w-3 h-3" style={{ color: C.green }} />
                      <span className="text-[9px] font-bold uppercase tracking-[0.2em]" style={{ color: C.green }}>
                        {t('reminders.overdue')}
                      </span>
                    </div>
                    <p className="text-[13px] font-semibold truncate">{note.title || t('notification.untitled')}</p>
                    <div className="flex items-center gap-1 mt-1 text-[10px] text-foreground/30">
                      <Clock className="w-3 h-3" />
                      {note.reminder && formatDistanceToNow(new Date(note.reminder), { addSuffix: true })}
                    </div>
                  </div>
                </div>
              </div>
            ))}

            {/* ── Upcoming reminders ── */}
            {upcomingReminders.slice(0, 5).map((note) => (
              <div key={note.id} className="p-3 hover:bg-black/[0.02] transition-colors">
                <div className="flex items-start gap-3">
                  <Clock className="w-4 h-4 mt-0.5 flex-none" style={{ color: C.blue }} />
                  <div className="flex-1 min-w-0">
                    <p className="text-[13px] font-semibold truncate">{note.title || t('notification.untitled')}</p>
                    <div className="text-[11px] text-foreground/40 mt-0.5">
                      {note.reminder && new Date(note.reminder).toLocaleDateString(undefined, {
                        month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit'
                      })}
                    </div>
                  </div>
                </div>
              </div>
            ))}

            {/* ── Brainstorm share invites ── */}
            {brainstormShares.map((share) => (
              <div key={share.id} className="p-4 hover:bg-black/[0.02] transition-colors space-y-3">
                <div className="flex items-start gap-3">
                  <div
                    className="h-8 w-8 rounded-full flex items-center justify-center text-white font-bold text-[11px] shrink-0 shadow-sm"
                    style={{ background: `linear-gradient(135deg, #A47148, #A47148)` }}
                  >
                    {(share.sharer?.name || share.sharer?.email || '?')[0].toUpperCase()}
                  </div>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-1.5 mb-0.5">
                      <Wind className="w-3 h-3" style={{ color: '#A47148' }} />
                      <span className="text-[9px] font-bold uppercase tracking-[0.2em]" style={{ color: '#A47148' }}>
                        Brainstorm
                      </span>
                    </div>
                    <p className="text-[13px] font-semibold truncate">
                      {share.sharer?.name || share.sharer?.email}
                    </p>
                    <p className="text-[11px] text-foreground/50 truncate">
                      {t('notification.brainstormShared') || 'invited you to a brainstorm'} « {share.session?.seedIdea?.length > 35 ? share.session.seedIdea.substring(0, 35) + '…' : share.session?.seedIdea} »
                    </p>
                  </div>
                </div>
                <div className="flex gap-2 ml-11">
                  <button
                    onClick={() => handleDeclineBrainstorm(share.id)}
                    className="flex-1 h-7 px-3 text-[11px] font-semibold rounded-lg border border-black/15 text-foreground/60 hover:bg-black/5 transition-all active:scale-95 flex items-center justify-center gap-1"
                  >
                    <X className="h-3 w-3" />
                    {t('notification.decline') || 'Decline'}
                  </button>
                  <button
                    onClick={() => handleAcceptBrainstorm(share.id)}
                    className="flex-1 h-7 px-3 text-[11px] font-bold rounded-lg text-white transition-all active:scale-95 flex items-center justify-center gap-1 shadow-sm hover:opacity-90 bg-brand-accent"
                  >
                    <Check className="h-3 w-3" />
                    {t('notification.accept') || 'Accept'}
                  </button>
                </div>
              </div>
            ))}

            {/* ── Share requests ── */}
            {requests.map((request) => (
              <div key={request.id} className="p-4 hover:bg-black/[0.02] transition-colors space-y-3">
                <div className="flex items-start gap-3">
                  {/* Avatar */}
                  <div
                    className="h-8 w-8 rounded-full flex items-center justify-center text-white font-bold text-[11px] shrink-0 shadow-sm"
                    style={{ background: `linear-gradient(135deg, ${C.blue}, ${C.green})` }}
                  >
                    {(request.sharer.name || request.sharer.email)[0].toUpperCase()}
                  </div>
                  <div className="flex-1 min-w-0">
                    <div className="flex items-center gap-1.5 mb-0.5">
                      <Share2 className="w-3 h-3" style={{ color: C.blue }} />
                      <span className="text-[9px] font-bold uppercase tracking-[0.2em]" style={{ color: C.blue }}>
                        Partage
                      </span>
                    </div>
                    <p className="text-[13px] font-semibold truncate">
                      {request.sharer.name || request.sharer.email}
                    </p>
                    <p className="text-[11px] text-foreground/50 truncate">
                      {t('notification.shared', { title: request.note.title || t('notification.untitled') })}
                    </p>
                  </div>
                </div>

                <div className="flex gap-2 ml-11">
                  <button
                    onClick={() => handleDecline(request.id)}
                    className="flex-1 h-7 px-3 text-[11px] font-semibold rounded-lg border border-black/15 text-foreground/60 hover:bg-black/5 transition-all active:scale-95 flex items-center justify-center gap-1"
                  >
                    <X className="h-3 w-3" />
                    {t('notification.decline') || 'Refuser'}
                  </button>
                  <button
                    onClick={() => handleAccept(request.id)}
                    className="flex-1 h-7 px-3 text-[11px] font-bold rounded-lg text-white transition-all active:scale-95 flex items-center justify-center gap-1 shadow-sm hover:opacity-90"
                    style={{ background: C.blue }}
                  >
                    <Check className="h-3 w-3" />
                    {t('notification.accept') || 'Accepter'}
                  </button>
                </div>
              </div>
            ))}
          </div>
        )}

        {/* Footer */}
        {activeReminders.length > 0 && (
          <div className="px-4 py-2.5 border-t bg-black/[0.02]">
            <a
              href="/reminders"
              className="text-[11px] font-semibold hover:opacity-70 transition-opacity"
              style={{ color: C.blue }}
            >
              {t('reminders.viewAll') || 'Voir tous les rappels →'}
            </a>
          </div>
        )}
      </PopoverContent>
    </Popover>
  )
}