mky-vent-base/src/views/ventAI/manageAssistent/hooks/useChatTasks.ts

import { computed, ref } from 'vue';
import dayjs from 'dayjs';
import { message } from 'ant-design-vue';
import { buildReportDownloadUrl, editSessionTitle, getHistoryList, pinSession } from '/@/views/ventAI/manageAssistent/api';
import type { Message, Task } from '/@/views/ventAI/manageAssistent/types/index';
import { normalizeLineBreaks } from '/@/views/ventAI/manageAssistent/lib/index';

/**
 * 会话（任务）状态与列表：taskList / currentTaskId / 当前会话消息，以及列表拉取、置顶、标题、
 * 会话 id 迁移与历史消息转换。
 *
 * messages 是唯一数据源：直接读写 currentTask.messages，不再维护两份拷贝；
 * 切换任务、创建任务这类会牵动面板/额度/滚动的编排逻辑仍留在组件里，此处只提供状态与纯函数。
 */
export const useChatTasks = () => {
  const taskList = ref<Task[]>([]);

  // 已从接口拉取过的会话 id，用于识别流式期间后端新建的会话
  const knownApiSessionIds = new Set<string>();

  // 从接口获取会话列表
  const fetchSessionList = async () => {
    try {
      const res = await getHistoryList({});
      const sessions = res?.sessions || res?.data || [];
      if (Array.isArray(sessions)) {
        const apiTasks: Task[] = sessions.map((item: { session_id: string; title: string; updated_at: string; sort_order?: number }) => ({
          id: item.session_id,
          name: item.title || '未命名会话',
          sessionId: item.session_id,
          messages: [],
          attachedFiles: [],
          updatedAt: item.updated_at,
          sortOrder: item.sort_order,
        }));

        // Build lookup maps for O(1) access
        const existingTaskMap = new Map(taskList.value.map((t) => [t.id, t]));
        const apiTaskIds = new Set(apiTasks.map((t) => t.id));

        // 流式中的空白任务：后端已为其创建会话，但前端要等流结束才拿到 session_id。
        // 该会话在接口里是一条全新记录，归并回空白任务而不是单独插入，避免列表出现重复条目
        let blankStreamingTask: Task | null = taskList.value.find((t) => !t.sessionId && t.isStreaming) || null;

        const mergedTasks: Task[] = [];
        for (const apiTask of apiTasks) {
          if (blankStreamingTask && (blankStreamingTask.pendingSessionId === apiTask.id || !knownApiSessionIds.has(apiTask.id))) {
            blankStreamingTask.pendingSessionId = apiTask.id;
            blankStreamingTask.name = apiTask.name;
            blankStreamingTask.updatedAt = apiTask.updatedAt;
            blankStreamingTask.sortOrder = apiTask.sortOrder;
            blankStreamingTask = null;
            continue;
          }

          const existing = existingTaskMap.get(apiTask.id);
          if (existing) {
            // 原地更新以保持对象引用，避免流式回调持有的任务引用失效（isStreaming 等状态丢失）
            existing.name = apiTask.name;
            existing.updatedAt = apiTask.updatedAt;
            existing.sortOrder = apiTask.sortOrder;
            mergedTasks.push(existing);
          } else {
            mergedTasks.push(apiTask);
          }
        }

        apiTasks.forEach((apiTask) => knownApiSessionIds.add(apiTask.id));

        const localOnlyTasks = taskList.value.filter((t) => !t.sessionId && !apiTaskIds.has(t.id));

        taskList.value = [...localOnlyTasks, ...mergedTasks];
        return mergedTasks;
      }
    } catch (error) {
      console.error('获取会话列表失败:', error);
    }
    return [];
  };

  const currentTaskId = ref('');
  const currentTask = computed(() => taskList.value.find((t) => t.id === currentTaskId.value));

  // 当前会话的消息。单一数据源：直接读写 currentTask.messages，不再维护
  // 「视图数组 + 任务数组」两份拷贝——历史实现需要在每次流式事件后手工同步两者，
  // 是任务切换/流式并存时视图错乱的根源。
  // fallbackMessages 仅用于「任务已全部删除」这类没有当前任务的瞬时状态，行为与旧 ref([]) 一致。
  const fallbackMessages: Message[] = [];
  const messages = computed<Message[]>({
    get: () => currentTask.value?.messages ?? fallbackMessages,
    set: (value: Message[]) => {
      const task = currentTask.value;
      if (task) task.messages = value;
    },
  });

  // Non-reactive lookup cache - Vue 3 does not track Set mutations on ref<Set>
  const historyLoadedTasks = new Set<string>();

  const setCurrentSessionId = (sessionId: string) => {
    const currentTask = taskList.value.find((t) => t.id === currentTaskId.value);
    if (currentTask && currentTask.id !== sessionId) {
      taskList.value = taskList.value.filter((t) => t.id !== sessionId);
      currentTask.id = sessionId;
      currentTask.sessionId = sessionId;
      currentTaskId.value = sessionId;
      historyLoadedTasks.add(sessionId);
    }
  };

  const handlePinTask = async (task: Task) => {
    if (!task.sessionId) {
      message.warning('请先发送消息后再置顶');
      return;
    }
    try {
      await pinSession(task.sessionId);
      await fetchSessionList();
    } catch {
      message.error('置顶操作失败');
    }
  };

  // 标题保存（由 ChatHeader 子组件触发，父组件负责 API 调用和状态更新）
  const handleSaveTitle = async (newTitle: string) => {
    if (!currentTask.value?.sessionId) return;
    try {
      await editSessionTitle(currentTask.value.sessionId, newTitle);
      currentTask.value.name = newTitle;
      message.success('标题修改成功');
    } catch {
      message.error('标题修改失败');
    }
  };

  const getDefaultMessages = (): Message[] => {
    return [];
  };

  const transformHistoryToMessages = (
    data: Array<{
      id?: number;
      role?: string;
      type?: string;
      content: string;
      created_at?: string;
      report_url?: string;
      report_filename?: string;
      citations?: any;
    }>
  ): Message[] => {
    const messages: Message[] = [];

    for (const item of data) {
      const normalizedContent = normalizeLineBreaks(item.content);
      const time = item.created_at ? dayjs(item.created_at).format('HH:mm') : '';
      const createdAt = item.created_at || '';

      // 新格式：role 字段 (user/assistant)
      if (item.role === 'user') {
        messages.push({ id: item.id, type: 'user', content: normalizedContent, time, createdAt });
      } else if (item.role === 'assistant') {
        const msg: Message = { id: item.id, type: 'ai', content: normalizedContent, time, createdAt };
        if (item.report_url && item.report_filename) {
          // 后端返回的报告地址前缀不稳定（绝对地址 / 缺 /ventAI 的相对路径），入前端状态前统一归一
          msg.downloadFiles = [{ url: buildReportDownloadUrl(item.report_url), filename: item.report_filename }];
        }
        if (item.citations) {
          // 历史接口返回 citations 为扁平数组，SSE 事件返回 { items, model_only }，统一归一化
          const raw = item.citations;
          if (Array.isArray(raw)) {
            msg.citations = { items: raw, model_only: raw.length === 0 };
          } else {
            msg.citations = raw;
          }
        }
        messages.push(msg);
      }
      // 兼容旧格式：type 字段
      else if (item.type === 'user_message') {
        messages.push({ id: item.id, type: 'user', content: normalizedContent, time, createdAt });
      } else if (item.type === 'model_thinking') {
        const lastAiMsg = messages[messages.length - 1];
        if (lastAiMsg && lastAiMsg.type === 'ai') {
          lastAiMsg.content += normalizedContent;
          lastAiMsg.content = lastAiMsg.content.replace(/\|\|\|SPLIT_CONTENT\|\|\|/g, '');
        } else {
          messages.push({ type: 'ai', content: normalizedContent, time, createdAt });
        }
      }
    }

    return messages;
  };
  return {
    taskList,
    currentTaskId,
    currentTask,
    messages,
    historyLoadedTasks,
    getDefaultMessages,
    transformHistoryToMessages,
    fetchSessionList,
    handlePinTask,
    handleSaveTitle,
    setCurrentSessionId,
  };
};