'use client'

import Link from 'next/link'
import { useState } from 'react'
import { Bell } from 'lucide-react'
import { Button } from '@/components/ui/button'
import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
import { useNotifications } from '@/contexts/notification-context'
import { cn } from '@/lib/utils'
import type { NotificationResponse, NotificationSeverity } from '@/types/notifications'

const SEVERITY_DOT: Record<NotificationSeverity, string> = {
  Info: 'bg-sky-500',
  Success: 'bg-emerald-500',
  Warning: 'bg-amber-500',
  Critical: 'bg-red-500',
}

export function timeAgo(iso: string): string {
  const seconds = Math.max(0, Math.floor((Date.now() - new Date(iso).getTime()) / 1000))
  if (seconds < 60) return 'just now'
  const minutes = Math.floor(seconds / 60)
  if (minutes < 60) return `${minutes}m ago`
  const hours = Math.floor(minutes / 60)
  if (hours < 24) return `${hours}h ago`
  const days = Math.floor(hours / 24)
  if (days < 7) return `${days}d ago`
  return new Date(iso).toLocaleDateString()
}

export function NotificationRow({
  notification: n,
  onOpen,
}: {
  notification: NotificationResponse
  onOpen: (n: NotificationResponse) => void
}) {
  return (
    <button
      type="button"
      onClick={() => onOpen(n)}
      className={cn(
        'flex w-full items-start gap-3 px-4 py-3 text-left transition-colors hover:bg-muted/60',
        !n.isRead && 'bg-muted/30'
      )}
    >
      <span className={cn('mt-1.5 size-2 shrink-0 rounded-full', n.isRead ? 'bg-transparent' : SEVERITY_DOT[n.severity])} />
      <span className="flex min-w-0 flex-1 flex-col gap-0.5">
        <span className={cn('truncate text-sm', n.isRead ? 'text-foreground' : 'font-medium text-foreground')}>
          {n.title}
        </span>
        <span className="line-clamp-2 text-xs text-muted-foreground">{n.message}</span>
        <span className="text-[11px] text-muted-foreground/70">{timeAgo(n.createdAt)}</span>
      </span>
    </button>
  )
}

export function NotificationBell() {
  const { recent, unreadCount, open, markAllRead } = useNotifications()
  const [isOpen, setIsOpen] = useState(false)

  return (
    <Popover open={isOpen} onOpenChange={setIsOpen}>
      <PopoverTrigger
        render={
          <Button
            variant="ghost"
            size="icon"
            className="relative h-8 w-8 text-muted-foreground hover:text-foreground"
            aria-label={unreadCount > 0 ? `Notifications (${unreadCount} unread)` : 'Notifications'}
          />
        }
      >
        <Bell size={16} />
        {unreadCount > 0 && (
          <span className="absolute -top-0.5 -right-0.5 flex h-4 min-w-4 items-center justify-center rounded-full bg-red-500 px-1 text-[10px] font-semibold leading-none text-white">
            {unreadCount > 99 ? '99+' : unreadCount}
          </span>
        )}
      </PopoverTrigger>

      <PopoverContent>
        <div className="flex items-center justify-between border-b border-border px-4 py-3">
          <span className="text-sm font-medium">Notifications</span>
          <Button
            variant="ghost"
            size="xs"
            disabled={unreadCount === 0}
            onClick={() => { void markAllRead() }}
          >
            Mark all read
          </Button>
        </div>

        <div className="max-h-96 divide-y divide-border overflow-y-auto">
          {recent.length === 0 ? (
            <p className="px-4 py-10 text-center text-sm text-muted-foreground">You&apos;re all caught up.</p>
          ) : (
            recent.map(n => (
              <NotificationRow
                key={n.id}
                notification={n}
                onOpen={item => { setIsOpen(false); void open(item) }}
              />
            ))
          )}
        </div>

        <div className="border-t border-border p-2">
          <Link
            href="/notifications"
            onClick={() => setIsOpen(false)}
            className="block rounded-xl px-3 py-2 text-center text-sm text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
          >
            View all
          </Link>
        </div>
      </PopoverContent>
    </Popover>
  )
}