import { reactive, computed, nextTick } from 'vue'
import { ServeTalkRecords } from '@/api/chat'
import { useDialogueStore } from '@/store'
import { ITalkRecord } from '@/types/chat'
import { formatTalkRecord } from '@/utils/talk'
import { addClass, removeClass, scrollToBottom, isScrollAtBottom } from '@/utils/dom'

interface Params {
  receiver_id: number
  talk_type: number
  limit: number
}

interface SpecialParams extends Params {
  msg_id?: string
  cursor?: number
  direction?: 'up' | 'down'
  sort_sequence?: string
  type?: 'loadMore'
}

interface LoadOptions {
  specifiedMsg?: SpecialParams
  middleMsgCreatedAt?: string
}

export const useTalkRecord = (uid: number) => {
  const dialogueStore = useDialogueStore()

  const records = computed((): ITalkRecord[] => dialogueStore.records)

  const location = reactive({
    msgid: '',
    num: 0
  })

  const loadConfig = reactive({
    receiver_id: 0,
    talk_type: 0,
    status: 0,
    cursor: 0,
    specialParams: undefined as SpecialParams | undefined,
    isLocatingMessage: false,
    isLoadingMore: false,
    lastLoadMoreTime: 0,
    targetMessagePosition: 0
  })

  // 重置 loadConfig
  const resetLoadConfig = () => {
    loadConfig.receiver_id = 0
    loadConfig.talk_type = 0
    loadConfig.status = 0
    loadConfig.cursor = 0
    loadConfig.specialParams = undefined
  }

  const onJumpMessage = (msgid: string) => {
    const element = document.getElementById(msgid)
    if (!element) {
      if (location.msgid == '') {
        location.msgid = msgid
        location.num = 3
      } else {
        location.num--

        if (location.num === 0) {
          location.msgid = ''
          location.num = 0
          window['$message'].info('仅支持查看最近300条的记录')
          return
        }
      }

      const el = document.getElementById('imChatPanel')

      return el?.scrollTo({
        top: 0,
        behavior: 'smooth'
      })
    }

    location.msgid = ''
    location.num = 0

    element?.scrollIntoView({
      behavior: 'smooth'
    })

    addClass(element, 'border')

    setTimeout(() => {
      element && removeClass(element, 'border')
    }, 3000)
  }

  // 加载数据列表
  const load = async (params: Params) => {
    const request = {
      talk_type: params.talk_type,
      receiver_id: params.receiver_id,
      cursor: loadConfig.cursor,
      limit: 30
    }

    loadConfig.status = 0

    let scrollHeight = 0
    console.log('加载数据列表load')
    const el = document.getElementById('imChatPanel')
    if (el) {
      scrollHeight = el.scrollHeight
    }

    const { data, code } = await ServeTalkRecords(request)
    if (code != 200) {
      return (loadConfig.status = 1)
    }
    // 防止对话切换过快，数据渲染错误
    if (
      request.talk_type != loadConfig.talk_type ||
      request.receiver_id != loadConfig.receiver_id
    ) {
      return (location.msgid = '')
    }

    const items = (data.items || []).map((item: ITalkRecord) => formatTalkRecord(uid, item))

    if (request.cursor == 0) {
      // 判断是否是初次加载
      dialogueStore.clearDialogueRecord()
    }

    dialogueStore.unshiftDialogueRecord(items.reverse())

    loadConfig.status = items.length >= request.limit ? 1 : 2

    loadConfig.cursor = data.cursor

    nextTick(() => {
      const el = document.getElementById('imChatPanel')

      if (el) {
        if (request.cursor == 0) {
          // el.scrollTop = el.scrollHeight
          
          // setTimeout(() => {
          //   el.scrollTop = el.scrollHeight + 1000
          // }, 500)
          scrollToBottom()
        } else {
          el.scrollTop = el.scrollHeight - scrollHeight
        }
      }

      if (location.msgid) {
        onJumpMessage(location.msgid)
      }
    })
  }

  // 获取当前消息的最小 sequence
  const getMinSequence = () => {
    console.error('records.value', records.value)
    if (!records.value.length) return 0
    console.error(Math.min(...records.value.map((item) => item.sequence)))
    return Math.min(...records.value.map((item) => item.sequence))
  }
  // 获取当前消息的最大 sequence
  const getMaxSequence = () => {
    if (!records.value.length) return 0
    return Math.max(...records.value.map((item) => item.sequence))
  }

  /**
   * 加载数据主入口，支持指定消息定位模式
   * @param params 原有参数
   * @param options 可选，{ specifiedMsg } 指定消息对象
   */
  const onLoad = (params: Params, options?: LoadOptions) => {
    // 如果会话切换，重置所有状态
    if (
      params.talk_type !== loadConfig.talk_type ||
      params.receiver_id !== loadConfig.receiver_id
    ) {
      resetLoadConfig()
    }

    loadConfig.cursor = 0
    loadConfig.receiver_id = params.receiver_id
    loadConfig.talk_type = params.talk_type

    console.error('onLoad', params, options)

    // 新增：支持指定消息定位模式，参数以传入为准合并
    if (options?.specifiedMsg?.cursor !== undefined) {
      loadConfig.specialParams = { ...options.specifiedMsg } // 记录特殊参数，供分页加载用
      console.error('options', options)
      loadConfig.status = 0 // 复用主流程 loading 状态
      // 以 params 为基础，合并 specifiedMsg 的所有字段（只要有就覆盖）
      const contextParams = {
        ...params,
        ...options.specifiedMsg
      }
      //msg_id是用来做定位的，不做参数，所以这里清空
      contextParams.msg_id = ''
      ServeTalkRecords(contextParams).then(({ data, code }) => {
        if (code !== 200) {
          loadConfig.status = 2
          return
        }
        // 记录当前滚动高度
        const el = document.getElementById('imChatPanel')
        const scrollHeight = el?.scrollHeight || 0

        if (contextParams.direction === 'down' && !contextParams.type) {
          dialogueStore.clearDialogueRecord()
        }
        const items = (data.items || []).map((item: ITalkRecord) => formatTalkRecord(uid, item))
        if (contextParams.type && contextParams.type === 'loadMore') {
          dialogueStore.addDialogueRecordForLoadMore(items)
        } else {
          dialogueStore.unshiftDialogueRecord(
            contextParams.direction === 'down' ? items : items.reverse()
          )
        }
        if (
          contextParams.direction === 'up' ||
          (contextParams.direction === 'down' && !contextParams.type)
        ) {
          loadConfig.status = items[0].sequence == 1 || data.length === 0 ? 2 : 1
        }
        loadConfig.cursor = data.cursor

        // 使用 requestAnimationFrame 来确保在下一帧渲染前设置滚动位置
        requestAnimationFrame(() => {
          const el = document.getElementById('imChatPanel')
          const target = document.getElementById(options.specifiedMsg?.msg_id || '')
          if (el && target) {
            // 如果是向上加载更多，保持原有内容位置
            if (contextParams.direction === 'up') {
              el.scrollTop = el.scrollHeight - scrollHeight
            } else if (contextParams.type && contextParams.type === 'loadMore') {
              // 如果是向下加载更多，保持目标消息在可视区域底部
              // 使用可视区域高度来调整，而不是新内容的总高度
              nextTick(() => {
                if (el) {
                  el.scrollTop = scrollHeight - el.clientHeight
                }
              })
            } else {
              // 如果是定位到特定消息，计算并滚动到目标位置
              const containerRect = el.getBoundingClientRect()
              const targetRect = target.getBoundingClientRect()
              const offset = targetRect.top - containerRect.top
              loadConfig.isLocatingMessage = true
              // 居中
              const scrollTo = el.scrollTop + offset - el.clientHeight / 2 + target.clientHeight / 2
              el.scrollTo({ top: scrollTo, behavior: 'smooth' })
              addClass(target, 'border')
              setTimeout(() => removeClass(target, 'border'), 3000)
            }
          } else if (el) {
            // el.scrollTop = el.scrollHeight
            scrollToBottom()
          }
        })
      })
      return
    }

    loadConfig.specialParams = undefined // 普通模式清空
    // 原有逻辑
    load(params)
  }

  // 向上加载更多（兼容特殊参数模式）
  const onRefreshLoad = () => {
    console.error('loadConfig.status', loadConfig.status)
    if (loadConfig.status == 1) {
      console.log('specialParams', loadConfig.specialParams)
      // 判断是否是特殊参数模式
      if (loadConfig.specialParams && typeof loadConfig.specialParams === 'object') {
        // 检查特殊参数是否与当前会话匹配
        if (
          loadConfig.specialParams.talk_type === loadConfig.talk_type &&
          loadConfig.specialParams.receiver_id === loadConfig.receiver_id
        ) {
          // 特殊参数模式下，direction: 'up'，cursor: 当前最小 sequence
          onLoad(
            {
              receiver_id: loadConfig.receiver_id,
              talk_type: loadConfig.talk_type,
              limit: 30
            },
            {
              specifiedMsg: {
                ...loadConfig.specialParams,
                direction: 'up',
                sort_sequence: '',
                cursor: getMinSequence(),
                msg_id:
                  records.value.find((item) =>
                    item.sequence === getMinSequence() ? item.msg_id : ''
                  )?.msg_id || ''
              }
            }
          )
        } else {
          // 如果不匹配，重置为普通模式
          resetLoadConfig()
          load({
            receiver_id: loadConfig.receiver_id,
            talk_type: loadConfig.talk_type,
            limit: 30
          })
        }
      } else {
        // 原有逻辑
        load({
          receiver_id: loadConfig.receiver_id,
          talk_type: loadConfig.talk_type,
          limit: 30
        })
      }
    }
  }

  // 向下加载更多（特殊参数模式才生效，普通模式无效，因为普通模式的数据就是从最新开始加载历史的，所以不需要加载更新的数据）
  const onLoadMoreDown = () => {
    // 判断是否是特殊参数模式
    if (loadConfig.specialParams && typeof loadConfig.specialParams === 'object') {
      if (loadConfig.isLocatingMessage) {
        loadConfig.isLocatingMessage = false
        return
      }
      // 添加时间间隔限制，至少间隔 500ms 才能触发下一次加载
      const now = Date.now()
      if (now - loadConfig.lastLoadMoreTime < 500) {
        return
      }
      loadConfig.lastLoadMoreTime = now

      // 记录当前目标消息的位置
      const el = document.getElementById('imChatPanel')
      if (el) {
        loadConfig.targetMessagePosition = el.scrollHeight - el.scrollTop
      }

      console.log('onLoadMoreDown 特殊模式触底了')
      // 检查特殊参数是否与当前会话匹配
      if (
        loadConfig.specialParams.talk_type === loadConfig.talk_type &&
        loadConfig.specialParams.receiver_id === loadConfig.receiver_id
      ) {
        onLoad(
          {
            receiver_id: loadConfig.receiver_id,
            talk_type: loadConfig.talk_type,
            limit: 30
          },
          {
            specifiedMsg: {
              ...loadConfig.specialParams,
              direction: 'down',
              sort_sequence: 'asc',
              cursor: getMaxSequence(),
              type: 'loadMore'
            }
          }
        )
      }
    }
  }

  return {
    loadConfig,
    records,
    onLoad,
    onRefreshLoad,
    onLoadMoreDown,
    onJumpMessage,
    resetLoadConfig
  }
}