import { create } from 'zustand';
import type { HumanSession, Mail, RenameProposal, Session, SessionBudget } from '../types';
import * as api from '../api/client';

interface SessionState {
  sessions: HumanSession[];
  currentSession: Session | null;
  currentSessionMails: Mail[];
  loading: boolean;
  error: string | null;

  /** Agent 在正文里提的改名建议；null = 无待处理建议 */
  renameProposal: RenameProposal | null;

  fetchSessions: () => Promise<void>;
  selectSession: (sessionId: string) => Promise<void>;
  clearSession: () => void;
  /** 重新拉取当前会话的改名建议（收到新邮件时调） */
  refreshRenameProposal: () => Promise<void>;
  /** 接受建议：改名成功后清掉提示条并刷新会话 */
  acceptRename: () => Promise<void>;
  /** 驳回建议：服务端记下来，不再反复弹同一个 */
  dismissRename: () => Promise<void>;

  /** 本任务的往返预算；null = 尚未取到 */
  budget: SessionBudget | null;
  /** 改本会话预算（对话页里随时调）。reset 把已用次数归零。 */
  setBudget: (patch: { max_rounds?: number; reset?: boolean }) => Promise<void>;
  /** 重新拉取预算（Agent 发信后剩余会变） */
  refreshBudget: () => Promise<void>;
  /** 归档后若正查看该会话则退出 */
  dropSessionIfCurrent: (sessionId: string) => void;
}

export const useSessionStore = create<SessionState>((set, get) => ({
  sessions: [],
  currentSession: null,
  currentSessionMails: [],
  renameProposal: null,
  budget: null,
  loading: false,
  error: null,

  fetchSessions: async () => {
    set({ loading: true, error: null });
    try {
      const { sessions } = await api.getHumanSessions();
      set({ sessions: sessions || [], loading: false });
    } catch (err) {
      set({ error: err instanceof Error ? err.message : String(err), loading: false });
    }
  },

  selectSession: async sessionId => {
    set({ loading: true, error: null, renameProposal: null, budget: null });
    try {
      const detail = await api.getSessionDetail(sessionId);
      set({
        currentSession: detail.session,
        currentSessionMails: detail.mails || [],
        loading: false
      });
      // 改名建议与预算单独取：拿不到不该让整个会话打不开
      get().refreshRenameProposal();
      get().refreshBudget();
    } catch (err) {
      set({ error: err instanceof Error ? err.message : String(err), loading: false });
    }
  },

  refreshRenameProposal: async () => {
    const id = get().currentSession?.session_id;
    if (!id) return;
    try {
      const { proposal } = await api.getRenameProposal(id);
      // 期间用户可能已切走，别把上一会话的建议贴到新会话上
      if (get().currentSession?.session_id === id) {
        set({ renameProposal: proposal });
      }
    } catch {
      // 建议是锦上添花，失败静默
    }
  },

  acceptRename: async () => {
    const s = get();
    const id = s.currentSession?.session_id;
    const alias = s.renameProposal?.alias;
    if (!id || !alias) return;
    try {
      await api.updateSessionAlias(id, alias);
      set({ renameProposal: null });
      // 别名变了，会话详情与列表里的地址都要跟着更新
      await get().selectSession(id);
      await get().fetchSessions();
    } catch (err) {
      // 别名被别人占用（409）等情况要让用户看到，不能默默失败
      set({ error: err instanceof Error ? err.message : String(err) });
    }
  },

  dismissRename: async () => {
    const id = get().currentSession?.session_id;
    if (!id) return;
    // 先隐藏提示条再发请求：驳回是纯本地意图，等一个往返才消失显得迟钝
    set({ renameProposal: null });
    try {
      await api.dismissRenameProposal(id);
    } catch {
      // 记不下来最坏的后果是下次打开又弹一次，不值得打扰用户
    }
  },

  refreshBudget: async () => {
    const id = get().currentSession?.session_id;
    if (!id) return;
    try {
      const b = await api.getSessionBudget(id);
      // 期间用户可能已切走，别把上一会话的预算贴到新会话上
      if (get().currentSession?.session_id === id) set({ budget: b });
    } catch {
      // 预算读不到不影响看邮件，静默
    }
  },

  setBudget: async patch => {
    const id = get().currentSession?.session_id;
    if (!id) return;
    try {
      const b = await api.updateSessionBudget(id, patch);
      set({ budget: b });
      // 列表里也显示预算，改完要跟着刷新
      await get().fetchSessions();
    } catch (err) {
      set({ error: err instanceof Error ? err.message : String(err) });
    }
  },

  clearSession: () =>
    set({ currentSession: null, currentSessionMails: [], renameProposal: null, budget: null }),

  dropSessionIfCurrent: sessionId => {
    if (get().currentSession?.session_id === sessionId) {
      set({ currentSession: null, currentSessionMails: [], renameProposal: null, budget: null });
    }
    set(state => ({
      sessions: state.sessions.filter(s => s.session_id !== sessionId)
    }));
  }
}));