%% REQ-坐席-010 AI回复三态开关 — 时序图②：路径B 员工发消息在三态下的门控与推送分支
%% （时序图①「坐席切换 mode 调用链」见 技术方案-REQ-坐席-010-AI回复三态开关.md §4.1）
%% 架构师 高见远（Gao） 2026-08-04
sequenceDiagram
    autonumber
    actor Emp as 员工(H5)
    participant H5 as api/h5.py<br/>send_message
    participant DB as conversations / messages
    participant Gate as ai_reply_gate
    participant Task as tasks/h5_ai_task.py<br/>process_h5_ai_reply
    participant Dify as Dify
    participant WS as ws_manager
    actor AgentUI as 坐席工作台

    Emp->>H5: POST /api/h5/.../messages {content}
    H5->>DB: 查/建 conversation（新建 status=ai_handling）
    H5->>DB: INSERT message(sender_type=employee)
    H5->>WS: broadcast(new_message, sender=employee)
    WS-->>AgentUI: 员工消息（不受本开关影响，始终可见）
    H5->>DB: COMMIT（保证后台任务读得到）

    rect rgb(255, 244, 230)
        Note over H5,Gate: 门控必须在 asyncio.create_task 之前（h5.py:939 / ws.py:472）
        H5->>Gate: can_ai_auto_reply_path_b(conversation)
        Gate->>Gate: status in {ai_handling, queued}?<br/>AND ai_reply_mode != "off"?
    end

    alt mode == "off"
        Gate-->>H5: False
        H5->>H5: logger.info("AI自动回复已关闭，跳过")
        H5-->>Emp: 200 {user_message, ai_reply:null}
        Note over Task: 后台任务从未创建 → 零 DB session / 零 Dify 调用
    else status == "serving"（本次修复的缺口）
        Gate-->>H5: False
        H5->>H5: logger.info("坐席已接管，跳过AI自动回复")
        H5-->>Emp: 200 {user_message, ai_reply:null}
        Note over AgentUI: 坐席独占对话，AI 不再抢话（PRD G2 / US2）
    else 允许触发
        Gate-->>H5: True
        H5->>Task: asyncio.create_task(process_h5_ai_reply(...))
        H5-->>Emp: 200（立即返回，AI 回复走 WS 异步推）

        Task->>DB: _step_load_conversation
        Task->>Dify: _step_call_dify
        Note over Task,WS: ai_thinking 坐席广播（h5_ai_task.py:1603）<br/>同样受 should_push_to_agent 门控
        Task->>Gate: should_push_to_agent(conversation)
        alt mode == employee_and_agent
            Task->>WS: broadcast(ai_thinking)
            WS-->>AgentUI: AI 思考中…
        end
        Dify-->>Task: AIReplyResult

        Task->>DB: _persist_and_push*：INSERT message(sender_type=ai)
        Task->>WS: broadcast_to_employees([emp], ai_reply)
        WS-->>Emp: AI 回复（三态下只要触发就必推员工）

        rect rgb(232, 245, 233)
            Note over Task,Gate: 坐席广播门控（4 处：L482 / L749 / L891 / L1603）
            Task->>Gate: should_push_to_agent(conversation)
        end

        alt mode == "employee_and_agent"
            Gate-->>Task: True
            Task->>WS: broadcast(new_message, sender_type=ai)
            Task->>WS: broadcast(conversation_updated)
            WS-->>AgentUI: 坐席同步看到 AI 回复内容（P0-7 / US3）
        else mode == "employee_only"（默认）
            Gate-->>Task: False
            Note over Task,AgentUI: 行为变更：不再广播坐席<br/>员工-AI 会话对坐席不可见
        end
    end

    Note over H5,Task: ADR-6：切 off / 转 serving 不 cancel 已提交的在途 task，<br/>让其自然结束（PRD P1-4，避免半截消息）