'use client'

import Link from 'next/link'
import { Bell, Search, Settings } from 'lucide-react'
import { usePathname, useRouter } from 'next/navigation'
import { useState, useEffect } from 'react'
import { io } from 'socket.io-client'
import { EMPLOYEE_PROFILE_KEY, apiFetch } from '@/lib/api'
import { useDashboardI18n } from '@/components/I18nProvider'
import { toDashboardAppPath } from '@/lib/dashboardPaths'

function computeInitials(name: string): string {
  const parts = name.trim().split(/\s+/).filter(Boolean)
  if (parts.length === 0) return 'U'
  if (parts.length === 1) return parts[0].slice(0, 1).toUpperCase()
  return `${parts[0].slice(0, 1)}${parts[1].slice(0, 1)}`.toUpperCase()
}

function resolveSocketOrigin(): string | null {
  if (typeof window === 'undefined') return null

  const configuredApiUrl = process.env.NEXT_PUBLIC_API_URL
  if (configuredApiUrl) {
    try {
      return new URL(configuredApiUrl, window.location.origin).origin
    } catch {}
  }

  if (window.location.hostname === 'localhost' || window.location.hostname === '127.0.0.1') {
    return 'http://localhost:4000'
  }

  return window.location.origin
}

export default function TopBar() {
  const { dict } = useDashboardI18n()
  const pathname = usePathname()
  const appPath = toDashboardAppPath(pathname)
  const router = useRouter()
  const [unreadCount, setUnreadCount] = useState(0)
  const [showNotifs, setShowNotifs] = useState(false)
  const [userInitials, setUserInitials] = useState('W')
  const [notifications, setNotifications] = useState<Array<{
    id: string
    title: string
    body: string
    readAt: string | null
    createdAt: string
  }>>([])
  const [loadingNotifs, setLoadingNotifs] = useState(false)
  const [socketEnabled, setSocketEnabled] = useState(false)

  const [mounted, setMounted] = useState(false)
  useEffect(() => { setMounted(true) }, [])

  const title = (() => {
    if (!mounted) return dict.titles['/']
    if (dict.titles[appPath]) return dict.titles[appPath]
    if (appPath.startsWith('/contracts/')) return dict.titles['/contracts'] ?? dict.titles['/']
    if (appPath.startsWith('/reservations/')) return dict.titles['/reservations'] ?? dict.titles['/']
    return dict.titles['/']
  })()
  async function refreshUnreadCount() {
    try {
      const data = await apiFetch<{ unread: number }>('/notifications/unread-count')
      setUnreadCount(data.unread)
      setSocketEnabled(true)
    } catch {
      setUnreadCount(0)
      setSocketEnabled(false)
    }
  }

  useEffect(() => {
    refreshUnreadCount()
  }, [pathname])

  useEffect(() => {
    function onNotificationsUpdated() {
      refreshUnreadCount()
    }
    window.addEventListener('notifications:updated', onNotificationsUpdated)
    return () => window.removeEventListener('notifications:updated', onNotificationsUpdated)
  }, [])

  useEffect(() => {
    if (!socketEnabled) return

    const socketOrigin = resolveSocketOrigin()
    if (!socketOrigin) return

    const socket = io(socketOrigin, {
      autoConnect: false,
      withCredentials: true,
      transports: ['polling', 'websocket'],
    })

    const handleNotification = () => {
      setUnreadCount((prev) => prev + 1)
      window.dispatchEvent(new Event('notifications:updated'))
    }

    socket.on('notification', handleNotification)

    const connectTimer = window.setTimeout(() => {
      socket.connect()
    }, 0)

    return () => {
      window.clearTimeout(connectTimer)
      socket.off('notification', handleNotification)
      socket.disconnect()
    }
  }, [socketEnabled])

  useEffect(() => {
    if (!showNotifs) return

    let cancelled = false
    setLoadingNotifs(true)
    apiFetch<Array<{
      id: string
      title: string
      body: string
      readAt: string | null
      createdAt: string
    }>>('/notifications/company')
      .then((data) => {
        if (cancelled) return
        setNotifications(data.slice(0, 8))
      })
      .catch(() => {
        if (cancelled) return
        setNotifications([])
      })
      .finally(() => {
        if (cancelled) return
        setLoadingNotifs(false)
      })

    return () => { cancelled = true }
  }, [showNotifs])

  useEffect(() => {
    setShowNotifs(false)
  }, [pathname])

  useEffect(() => {
    const cached = window.localStorage.getItem(EMPLOYEE_PROFILE_KEY)
    if (cached) {
      try {
        const profile = JSON.parse(cached) as { email?: string; firstName?: string; lastName?: string }
        const fullName = `${profile.firstName ?? ''} ${profile.lastName ?? ''}`.trim()
        const email = profile.email ?? ''
        setUserInitials(computeInitials(fullName || email || dict.workspaceUser))
      } catch {}
    }

    let cancelled = false

    apiFetch<{
      employee: {
        email: string
        firstName: string
        lastName: string
      }
    }>('/auth/employee/me')
      .then(({ employee }) => {
        if (cancelled) return
        window.localStorage.setItem(EMPLOYEE_PROFILE_KEY, JSON.stringify(employee))
        const fullName = `${employee.firstName ?? ''} ${employee.lastName ?? ''}`.trim()
        const email = employee.email ?? ''
        setUserInitials(computeInitials(fullName || email || dict.workspaceUser))
      })
      .catch(() => {
        if (cancelled) return
        setUserInitials(computeInitials(dict.workspaceUser))
      })

    return () => { cancelled = true }
  }, [dict.workspaceUser])

  async function openNotificationsInbox(notificationId?: string) {
    if (notificationId) {
      try {
        await apiFetch(`/notifications/company/${notificationId}/read`, { method: 'POST' })
        setUnreadCount((current) => Math.max(current - 1, 0))
        window.dispatchEvent(new Event('notifications:updated'))
      } catch {}
    }
    setShowNotifs(false)
    router.push('/notifications')
  }

  return (
    <header className="rdg-topbar relative z-[70] px-4 sm:px-6">
      <div className="flex items-center gap-4 min-w-0">
        <div className="min-w-0 shrink-0">
          <p className="rdg-topbar-kicker hidden sm:block">RentalDriveGo</p>
          <h1 className="rdg-topbar-title truncate">{title}</h1>
        </div>
        <div className="rdg-topbar-search relative hidden w-[min(380px,34vw)] md:block">
          <Search className="pointer-events-none absolute start-3.5 top-1/2 h-4 w-4 -translate-y-1/2 text-slate-500" />
          <input
            type="search"
            placeholder="Search vehicles, bookings, customers..."
            className="rdg-search-field h-10 w-full ps-10 pe-4 text-sm outline-none"
          />
        </div>
        <div className="rdg-system-status hidden xl:inline-flex">
          System operational
        </div>
      </div>

      <div className="flex items-center gap-3">
        <div className="relative">
          <button
            onClick={() => setShowNotifs(!showNotifs)}
            className="relative inline-flex h-11 w-11 items-center justify-center rounded-[var(--rdg-radius-sm)] text-[var(--rdg-text-secondary)] transition-colors hover:bg-[var(--rdg-soft-blue)] hover:text-[var(--rdg-action-primary)]"
          >
            <Bell className="h-5 w-5" />
            {unreadCount > 0 ? (
              <span className="absolute right-1 top-1 flex h-4 min-w-[16px] items-center justify-center rounded-full bg-orange-500 px-1 text-[10px] font-bold text-white ring-2 ring-white dark:ring-[#0a0f1a]">
                {unreadCount > 99 ? '99+' : unreadCount}
              </span>
            ) : null}
          </button>

          {showNotifs ? (
            <div className="card absolute top-full z-[80] mt-2 w-80 p-4 [inset-inline-end:0]">
              <div className="mb-2 flex items-center justify-between gap-2">
                <p className="text-sm font-medium text-blue-950 dark:text-slate-100">{dict.notifications}</p>
                <button
                  type="button"
                  onClick={() => openNotificationsInbox()}
                  className="text-xs font-medium text-orange-700 hover:text-blue-950 dark:text-orange-300 dark:hover:text-white"
                >
                  View all
                </button>
              </div>

              {loadingNotifs ? (
                <p className="text-sm text-slate-500 dark:text-slate-400">Loading…</p>
              ) : notifications.length === 0 ? (
                <p className="text-sm text-slate-500 dark:text-slate-400">
                  {unreadCount === 0 ? dict.noNewNotifications : dict.unreadNotifications(unreadCount)}
                </p>
              ) : (
                <div className="space-y-1">
                  {notifications.map((notification) => (
                    <button
                      key={notification.id}
                      type="button"
                      onClick={() => openNotificationsInbox(notification.id)}
                      className={[
                        'w-full rounded-lg px-3 py-2 text-left transition-colors hover:bg-blue-500/10',
                        notification.readAt ? 'opacity-80' : '',
                      ].join(' ')}
                    >
                      <p className="truncate text-sm font-medium text-blue-950 dark:text-slate-100">
                        {notification.title}
                      </p>
                      <p className="truncate text-xs text-slate-500 dark:text-slate-400">
                        {notification.body}
                      </p>
                    </button>
                  ))}
                </div>
              )}
            </div>
          ) : null}
        </div>

        <Link
          href="/settings"
          className="hidden h-11 w-11 items-center justify-center rounded-[var(--rdg-radius-sm)] text-[var(--rdg-text-secondary)] transition-colors hover:bg-[var(--rdg-soft-blue)] hover:text-[var(--rdg-action-primary)] sm:inline-flex"
          aria-label="Settings"
        >
          <Settings className="h-5 w-5" />
        </Link>

        <div className="rdg-avatar flex h-9 w-9 items-center justify-center text-xs font-semibold">
          {userInitials}
        </div>
      </div>
    </header>
  )
}