const SessionManager = {
    sessions: [],
    currentSessionId: null,

    async loadSessions() {
        try {
            const res = await api.get('/sessions');
            this.sessions = res.data || [];
            this.renderSessionList();
        } catch (err) {
            console.error('加载会话失败:', err);
        }
    },

    renderSessionList() {
        const list = document.getElementById('sessionList');
        if (!list) return;
        
        list.innerHTML = this.sessions.map(s => `
            <div class="session-item ${s.id === this.currentSessionId ? 'active' : ''}" 
                 onclick="SessionManager.switchSession(${s.id})">
                <span class="session-name">${this.escapeHtml(s.name)}</span>
                <button class="session-delete" onclick="event.stopPropagation(); SessionManager.deleteSession(${s.id})" title="删除">×</button>
            </div>
        `).join('');
    },

    async createSession() {
        try {
            const res = await api.post('/sessions', {});
            this.sessions.unshift(res.data);
            this.currentSessionId = res.data.id;
            this.renderSessionList();
            ChatManager.clearMessages();
            return res.data;
        } catch (err) {
            console.error('创建会话失败:', err);
        }
    },

    async switchSession(id) {
        this.currentSessionId = id;
        this.renderSessionList();
        await ChatManager.loadMessages(id);
    },

    async deleteSession(id) {
        if (!confirm('确定要删除这个会话吗？')) return;
        try {
            await api.delete('/sessions/' + id);
            this.sessions = this.sessions.filter(s => s.id !== id);
            Storage.clearCachedMessages(id);
            
            if (this.currentSessionId === id) {
                this.currentSessionId = null;
                ChatManager.clearMessages();
                if (this.sessions.length > 0) {
                    await this.switchSession(this.sessions[0].id);
                }
            }
            this.renderSessionList();
        } catch (err) {
            alert('删除会话失败: ' + err.message);
        }
    },

    escapeHtml(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }
};