import { navigateTo, useRuntimeConfig } from 'nuxt/app'
import { reactive, ref } from 'vue'
import { toast } from '~/composables/useToast'
import { authState, getToken } from '~/utils/auth'
import { reactionEmojiMap } from '~/utils/reactions'

export const notificationState = reactive({ unreadCount: 0 })

const iconMap = {
  POST_VIEWED: 'fas fa-eye',
  COMMENT_REPLY: 'fas fa-reply',
  POST_REVIEWED: 'fas fa-shield-alt',
  POST_REVIEW_REQUEST: 'fas fa-gavel',
  POST_UPDATED: 'fas fa-comment-dots',
  USER_ACTIVITY: 'fas fa-user',
  FOLLOWED_POST: 'fas fa-feather-alt',
  USER_FOLLOWED: 'fas fa-user-plus',
  USER_UNFOLLOWED: 'fas fa-user-minus',
  POST_SUBSCRIBED: 'fas fa-bookmark',
  POST_UNSUBSCRIBED: 'fas fa-bookmark',
  REGISTER_REQUEST: 'fas fa-user-clock',
  ACTIVITY_REDEEM: 'fas fa-coffee',
  POINT_REDEEM: 'fas fa-gift',
  LOTTERY_WIN: 'fas fa-trophy',
  LOTTERY_DRAW: 'fas fa-bullhorn',
  MENTION: 'fas fa-at',
}

export async function fetchUnreadCount() {
  const config = useRuntimeConfig()
  const API_BASE_URL = config.public.apiBaseUrl
  try {
    const token = getToken()
    if (!token) {
      notificationState.unreadCount = 0
      return 0
    }
    const res = await fetch(`${API_BASE_URL}/api/notifications/unread-count`, {
      headers: { Authorization: `Bearer ${token}` },
    })
    if (!res.ok) {
      notificationState.unreadCount = 0
      return 0
    }
    const data = await res.json()
    notificationState.unreadCount = data.count
    return data.count
  } catch (e) {
    notificationState.unreadCount = 0
    return 0
  }
}

export async function markNotificationsRead(ids) {
  try {
    const config = useRuntimeConfig()
    const API_BASE_URL = config.public.apiBaseUrl
    const token = getToken()
    if (!token || !ids || ids.length === 0) return false
    const res = await fetch(`${API_BASE_URL}/api/notifications/read`, {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ ids }),
    })
    return res.ok
  } catch (e) {
    return false
  }
}

export async function fetchNotificationPreferences() {
  try {
    const config = useRuntimeConfig()
    const API_BASE_URL = config.public.apiBaseUrl
    const token = getToken()
    if (!token) return []
    const res = await fetch(`${API_BASE_URL}/api/notifications/prefs`, {
      headers: { Authorization: `Bearer ${token}` },
    })
    if (!res.ok) return []
    return await res.json()
  } catch (e) {
    return []
  }
}

export async function updateNotificationPreference(type, enabled) {
  try {
    const config = useRuntimeConfig()
    const API_BASE_URL = config.public.apiBaseUrl
    const token = getToken()
    if (!token) return false
    const res = await fetch(`${API_BASE_URL}/api/notifications/prefs`, {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ type, enabled }),
    })
    return res.ok
  } catch (e) {
    return false
  }
}

/**
 * 提供通知列表的分页获取与状态管理
 */
function createFetchNotifications() {
  const allNotifications = ref([])
  const unreadNotifications = ref([])
  const pageAll = ref(0)
  const pageUnread = ref(0)
  const isLoadingAll = ref(false)
  const isLoadingUnread = ref(false)

  const processAndPush = (data, target) => {
    for (const n of data) {
      if (n.type === 'COMMENT_REPLY') {
        target.push({
          ...n,
          src: n.comment.author.avatar,
          iconClick: () => {
            markRead(n.id)
            navigateTo(`/users/${n.comment.author.id}`, { replace: true })
          },
        })
      } else if (n.type === 'REACTION') {
        target.push({
          ...n,
          emoji: reactionEmojiMap[n.reactionType],
          iconClick: () => {
            if (n.fromUser) {
              markRead(n.id)
              navigateTo(`/users/${n.fromUser.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'POST_VIEWED') {
        target.push({
          ...n,
          src: n.fromUser ? n.fromUser.avatar : null,
          icon: n.fromUser ? undefined : iconMap[n.type],
          iconClick: () => {
            if (n.fromUser) {
              markRead(n.id)
              navigateTo(`/users/${n.fromUser.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'LOTTERY_WIN') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.post) {
              markRead(n.id)
              navigateTo(`/posts/${n.post.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'LOTTERY_DRAW') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.post) {
              markRead(n.id)
              navigateTo(`/posts/${n.post.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'POST_UPDATED') {
        target.push({
          ...n,
          src: n.comment.author.avatar,
          iconClick: () => {
            markRead(n.id)
            navigateTo(`/users/${n.comment.author.id}`, { replace: true })
          },
        })
      } else if (n.type === 'USER_ACTIVITY') {
        target.push({
          ...n,
          src: n.comment.author.avatar,
          iconClick: () => {
            markRead(n.id)
            navigateTo(`/users/${n.comment.author.id}`, { replace: true })
          },
        })
      } else if (n.type === 'MENTION') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.fromUser) {
              markRead(n.id)
              navigateTo(`/users/${n.fromUser.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'USER_FOLLOWED' || n.type === 'USER_UNFOLLOWED') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.fromUser) {
              markRead(n.id)
              navigateTo(`/users/${n.fromUser.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'FOLLOWED_POST') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.post) {
              markRead(n.id)
              navigateTo(`/posts/${n.post.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'POST_SUBSCRIBED' || n.type === 'POST_UNSUBSCRIBED') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {
            if (n.post) {
              markRead(n.id)
              navigateTo(`/posts/${n.post.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'POST_REVIEW_REQUEST') {
        target.push({
          ...n,
          src: n.fromUser ? n.fromUser.avatar : null,
          icon: n.fromUser ? undefined : iconMap[n.type],
          iconClick: () => {
            if (n.post) {
              markRead(n.id)
              navigateTo(`/posts/${n.post.id}`, { replace: true })
            }
          },
        })
      } else if (n.type === 'REGISTER_REQUEST') {
        target.push({
          ...n,
          icon: iconMap[n.type],
          iconClick: () => {},
        })
      } else {
        target.push({
          ...n,
          icon: iconMap[n.type],
        })
      }
    }
  }

  const fetchAllNotifications = async () => {
    const config = useRuntimeConfig()
    const API_BASE_URL = config.public.apiBaseUrl
    const token = getToken()
    if (!token) {
      toast.error('请先登录')
      return { done: true }
    }
    isLoadingAll.value = true
    const res = await fetch(`${API_BASE_URL}/api/notifications?page=${pageAll.value}`, {
      headers: { Authorization: `Bearer ${token}` },
    })
    isLoadingAll.value = false
    if (!res.ok) {
      toast.error('获取通知失败')
      return { done: true }
    }
    const data = await res.json()
    processAndPush(data, allNotifications.value)
    pageAll.value++
    return { done: data.length < 50 }
  }

  const fetchUnreadNotifications = async () => {
    const config = useRuntimeConfig()
    const API_BASE_URL = config.public.apiBaseUrl
    const token = getToken()
    if (!token) {
      toast.error('请先登录')
      return { done: true }
    }
    isLoadingUnread.value = true
    const res = await fetch(`${API_BASE_URL}/api/notifications/unread?page=${pageUnread.value}`, {
      headers: { Authorization: `Bearer ${token}` },
    })
    isLoadingUnread.value = false
    if (!res.ok) {
      toast.error('获取通知失败')
      return { done: true }
    }
    const data = await res.json()
    processAndPush(data, unreadNotifications.value)
    pageUnread.value++
    return { done: data.length < 50 }
  }

  const markRead = async (id) => {
    if (!id) return
    const nAll = allNotifications.value.find((n) => n.id === id)
    const idxUnread = unreadNotifications.value.findIndex((n) => n.id === id)
    const unreadItem = idxUnread !== -1 ? unreadNotifications.value[idxUnread] : null
    if (nAll) nAll.read = true
    if (idxUnread !== -1) unreadNotifications.value.splice(idxUnread, 1)
    if (notificationState.unreadCount > 0) notificationState.unreadCount--
    const ok = await markNotificationsRead([id])
    if (!ok) {
      if (nAll) nAll.read = false
      if (idxUnread !== -1 && unreadItem) unreadNotifications.value.splice(idxUnread, 0, unreadItem)
      notificationState.unreadCount++
    } else {
      fetchUnreadCount()
    }
  }

  const markAllRead = async () => {
    const idsToMark = [
      ...new Set(
        [...allNotifications.value, ...unreadNotifications.value]
          .filter((n) => n.type !== 'REGISTER_REQUEST' && !n.read)
          .map((n) => n.id),
      ),
    ]
    if (idsToMark.length === 0) return
    allNotifications.value.forEach((n) => {
      if (n.type !== 'REGISTER_REQUEST') n.read = true
    })
    const prevUnread = [...unreadNotifications.value]
    unreadNotifications.value = unreadNotifications.value.filter(
      (n) => n.type === 'REGISTER_REQUEST',
    )
    notificationState.unreadCount = unreadNotifications.value.length
    const ok = await markNotificationsRead(idsToMark)
    if (!ok) {
      allNotifications.value.forEach((n) => {
        if (idsToMark.includes(n.id)) n.read = false
      })
      unreadNotifications.value = prevUnread
      await fetchUnreadCount()
      return
    }
    fetchUnreadCount()
    if (authState.role === 'ADMIN') {
      toast.success('已读所有消息（注册请求除外）')
    } else {
      toast.success('已读所有消息')
    }
  }

  const resetAll = () => {
    pageAll.value = 0
    allNotifications.value = []
  }

  const resetUnread = () => {
    pageUnread.value = 0
    unreadNotifications.value = []
  }

  return {
    fetchAllNotifications,
    fetchUnreadNotifications,
    markRead,
    markAllRead,
    allNotifications,
    unreadNotifications,
    isLoadingAll,
    isLoadingUnread,
    resetAll,
    resetUnread,
  }
}

export const {
  fetchAllNotifications,
  fetchUnreadNotifications,
  markRead,
  markAllRead,
  allNotifications,
  unreadNotifications,
  isLoadingAll,
  isLoadingUnread,
  resetAll,
  resetUnread,
} = createFetchNotifications()