yunke/yunkes/src/views/ChatTimeline.vue

<script setup lang="ts">
import { computed, nextTick, onMounted, ref, watch } from 'vue'
import { useRouter } from 'vue-router'
import { ElMessage } from 'element-plus'
import { ArrowLeft } from '@element-plus/icons-vue'
import { getMessages } from '@/api'
import type { Channel, Message } from '@/api/types'
import MessageBubble from '@/components/MessageBubble.vue'
import { channelLabel } from '@/utils/format'

const props = defineProps<{
  channel: string
  ownerId: string
  talkerId: string
}>()

const router = useRouter()
const PAGE_SIZE = 50

const messages = ref<Message[]>([])
const loading = ref(false)
const loadingOlder = ref(false)
const errorMsg = ref<string | null>(null)

// Asc-ordered pagination: page 1 = oldest 50, last page = most recent 50.
// We land on the last page (most recent activity) and walk backwards to load
// older history. `currentPage` is the smallest page number currently loaded.
const currentPage = ref(1)
const totalPages = ref(1)
const total = ref(0)

const channelTyped = computed(() => props.channel as Channel)

const hasMoreOlder = computed(() => currentPage.value > 1)

const conversationTitle = computed(
  () => `与 ${props.talkerId} 的聊天记录`,
)

const subtitle = computed(
  () =>
    `渠道：${channelLabel(channelTyped.value)} · 归属账号：${props.ownerId}` +
    (total.value > 0 ? ` · 共 ${total.value} 条` : ''),
)

const streamRef = ref<HTMLElement | null>(null)

function scrollToBottom(): void {
  nextTick(() => {
    const el = streamRef.value
    if (el) el.scrollTop = el.scrollHeight
  })
}

/**
 * Fetch the last page (most recent messages) on entry. Page 1 is fetched first
 * purely to learn `total` so we can compute `lastPage` — the messages API
 * returns asc, so the last page holds the newest slice.
 */
async function loadInitial(): Promise<void> {
  loading.value = true
  errorMsg.value = null
  try {
    const first = await getMessages({
      channel: channelTyped.value,
      owner_account_id: props.ownerId,
      talker_id: props.talkerId,
      page: 1,
      page_size: PAGE_SIZE,
    })
    total.value = first.total
    totalPages.value = Math.max(1, Math.ceil(first.total / PAGE_SIZE))

    if (totalPages.value <= 1) {
      messages.value = first.items
    } else {
      const last = await getMessages({
        channel: channelTyped.value,
        owner_account_id: props.ownerId,
        talker_id: props.talkerId,
        page: totalPages.value,
        page_size: PAGE_SIZE,
      })
      messages.value = last.items
    }
    currentPage.value = totalPages.value
    scrollToBottom()
  } catch (e) {
    errorMsg.value = (e as Error).message
    messages.value = []
  } finally {
    loading.value = false
  }
}

/** Prepend the next older page (currentPage - 1). No-op on page 1. */
async function loadOlder(): Promise<void> {
  if (loadingOlder.value || !hasMoreOlder.value) return
  loadingOlder.value = true
  const prevHeight = streamRef.value?.scrollHeight ?? 0
  try {
    const prevPage = currentPage.value - 1
    const res = await getMessages({
      channel: channelTyped.value,
      owner_account_id: props.ownerId,
      talker_id: props.talkerId,
      page: prevPage,
      page_size: PAGE_SIZE,
    })
    // Backend returns asc, so res.items are older than everything currently
    // shown — prepend them.
    messages.value = [...res.items, ...messages.value]
    currentPage.value = prevPage
    // Keep the user's scroll anchored near where they were.
    nextTick(() => {
      const el = streamRef.value
      if (el) el.scrollTop = el.scrollHeight - prevHeight
    })
  } catch (e) {
    ElMessage.error(`加载更多失败：${(e as Error).message}`)
  } finally {
    loadingOlder.value = false
  }
}

function goBack(): void {
  // Prefer history back when there's somewhere to go; else the customer list.
  if (window.history.length > 1) {
    router.back()
  } else {
    router.push({ name: 'customers' })
  }
}

// Reload when the route params change (navigating between conversations).
watch(
  () => [props.channel, props.ownerId, props.talkerId] as const,
  () => {
    loadInitial()
  },
)

onMounted(loadInitial)
</script>

<template>
  <div class="yk-chat">
    <div class="yk-chat__header">
      <div>
        <div style="display: flex; align-items: center; gap: 8px">
          <el-button text size="small" @click="goBack">
            <el-icon><ArrowLeft /></el-icon>
            返回
          </el-button>
          <h2 class="yk-chat__title">{{ conversationTitle }}</h2>
        </div>
        <div class="yk-chat__sub">{{ subtitle }}</div>
      </div>
    </div>

    <el-alert
      v-if="errorMsg"
      :title="`聊天记录加载失败：${errorMsg}`"
      type="error"
      show-icon
      :closable="false"
      style="margin-bottom: 0"
    />

    <div v-loading="loading" class="yk-chat__stream" ref="streamRef">
      <div class="yk-chat__load">
        <el-button
          v-if="hasMoreOlder"
          size="small"
          plain
          :loading="loadingOlder"
          @click="loadOlder"
        >
          加载更多 / 上一页
        </el-button>
        <span v-else-if="!loading && messages.length > 0" class="yk-chat__end">
          —— 已加载全部历史 ——
        </span>
      </div>

      <template v-if="messages.length === 0 && !loading">
        <div class="yk-empty">暂无聊天记录</div>
      </template>

      <MessageBubble
        v-for="m in messages"
        :key="m.msg_id"
        :message="m"
      />
    </div>
  </div>
</template>

<style scoped>
/* Make the stream its own scroll region so scrollToBottom + load-older scroll
 * anchoring target the right element. Height reserves space for the app
 * header + chat header + main padding. */
.yk-chat__stream {
  max-height: calc(100vh - var(--yk-header-height) - 140px);
  overflow-y: auto;
}
</style>