Agent/agent/execution/websocket.py

"""
Trace WebSocket 推送

实时推送进行中 Trace 的更新，支持断线续传
"""

from typing import Dict, Set, Any
from datetime import datetime
from fastapi import APIRouter, WebSocket, WebSocketDisconnect, Query

from agent.execution.protocols import TraceStore


router = APIRouter(prefix="/api/traces", tags=["websocket"])


# ===== 全局状态 =====


_trace_store: TraceStore = None
_active_connections: Dict[str, Set[WebSocket]] = {}  # trace_id -> Set[WebSocket]


def set_trace_store(store: TraceStore):
    """设置 TraceStore 实例"""
    global _trace_store
    _trace_store = store


def get_trace_store() -> TraceStore:
    """获取 TraceStore 实例"""
    if _trace_store is None:
        raise RuntimeError("TraceStore not initialized")
    return _trace_store


# ===== WebSocket 路由 =====


@router.websocket("/{trace_id}/watch")
async def watch_trace(
    websocket: WebSocket,
    trace_id: str,
    since_event_id: int = Query(0, description="从哪个事件 ID 开始（0=补发所有历史）")
):
    """
    监听 Trace 的更新，支持断线续传

    事件类型：
    - connected: 连接成功，返回 goal_tree 和 branches
    - goal_added: 新增 Goal
    - goal_updated: Goal 状态变化（含级联完成）
    - message_added: 新 Message（含 affected_goals）
    - branch_started: 分支开始探索
    - branch_goal_added: 分支内新增 Goal
    - branch_completed: 分支完成
    - explore_completed: 所有分支完成
    - trace_completed: 执行完成

    Args:
        trace_id: Trace ID
        since_event_id: 从哪个事件 ID 开始
            - 0: 补发所有历史事件（初次连接）
            - >0: 补发指定 ID 之后的事件（断线重连）
    """
    await websocket.accept()

    # 验证 Trace 存在
    store = get_trace_store()
    trace = await store.get_trace(trace_id)
    if not trace:
        await websocket.send_json({
            "event": "error",
            "message": "Trace not found"
        })
        await websocket.close()
        return

    # 注册连接
    if trace_id not in _active_connections:
        _active_connections[trace_id] = set()
    _active_connections[trace_id].add(websocket)

    try:
        # 获取 GoalTree 和分支元数据
        goal_tree = await store.get_goal_tree(trace_id)
        branches = await store.list_branches(trace_id)

        # 发送连接成功消息 + 完整状态
        await websocket.send_json({
            "event": "connected",
            "trace_id": trace_id,
            "current_event_id": trace.last_event_id,
            "goal_tree": goal_tree.to_dict() if goal_tree else None,
            "branches": {b_id: b.to_dict() for b_id, b in branches.items()}
        })

        # 补发历史事件（since_event_id=0 表示补发所有历史）
        if since_event_id >= 0:
            missed_events = await store.get_events(trace_id, since_event_id)
            # 限制补发数量（最多 100 条）
            if len(missed_events) > 100:
                await websocket.send_json({
                    "event": "error",
                    "message": f"Too many missed events ({len(missed_events)}), please reload via REST API"
                })
            else:
                for evt in missed_events:
                    await websocket.send_json(evt)

        # 保持连接（等待客户端断开或接收消息）
        while True:
            try:
                # 接收客户端消息（心跳检测）
                data = await websocket.receive_text()
                if data == "ping":
                    await websocket.send_json({"event": "pong"})
            except WebSocketDisconnect:
                break

    finally:
        # 清理连接
        if trace_id in _active_connections:
            _active_connections[trace_id].discard(websocket)
            if not _active_connections[trace_id]:
                del _active_connections[trace_id]


# ===== 广播函数（由 AgentRunner 或 TraceStore 调用）=====


async def broadcast_goal_added(trace_id: str, goal_dict: Dict[str, Any]):
    """
    广播 Goal 添加事件

    Args:
        trace_id: Trace ID
        goal_dict: Goal 字典（完整数据，含 stats）
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "goal_added", {
        "goal": goal_dict
    })

    message = {
        "event": "goal_added",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "goal": goal_dict
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_goal_updated(
    trace_id: str,
    goal_id: str,
    updates: Dict[str, Any],
    affected_goals: list[Dict[str, Any]] = None
):
    """
    广播 Goal 更新事件（patch 语义）

    Args:
        trace_id: Trace ID
        goal_id: Goal ID
        updates: 更新字段（patch 格式）
        affected_goals: 受影响的 Goals（含级联完成的父节点）
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "goal_updated", {
        "goal_id": goal_id,
        "updates": updates,
        "affected_goals": affected_goals or []
    })

    message = {
        "event": "goal_updated",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "goal_id": goal_id,
        "patch": updates,
        "affected_goals": affected_goals or []
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_branch_started(trace_id: str, branch_dict: Dict[str, Any]):
    """
    广播分支开始事件

    Args:
        trace_id: Trace ID
        branch_dict: BranchContext 字典
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "branch_started", {
        "branch": branch_dict
    })

    message = {
        "event": "branch_started",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "branch": branch_dict
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_branch_goal_added(
    trace_id: str,
    branch_id: str,
    goal_dict: Dict[str, Any]
):
    """
    广播分支内新增 Goal

    Args:
        trace_id: Trace ID
        branch_id: 分支 ID
        goal_dict: Goal 字典
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "branch_goal_added", {
        "branch_id": branch_id,
        "goal": goal_dict
    })

    message = {
        "event": "branch_goal_added",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "branch_id": branch_id,
        "goal": goal_dict
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_branch_completed(
    trace_id: str,
    branch_id: str,
    summary: str,
    cumulative_stats: Dict[str, Any]
):
    """
    广播分支完成事件

    Args:
        trace_id: Trace ID
        branch_id: 分支 ID
        summary: 分支总结
        cumulative_stats: 分支累计统计
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "branch_completed", {
        "branch_id": branch_id,
        "summary": summary,
        "cumulative_stats": cumulative_stats
    })

    message = {
        "event": "branch_completed",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "branch_id": branch_id,
        "summary": summary,
        "cumulative_stats": cumulative_stats
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_explore_completed(
    trace_id: str,
    explore_start_id: str,
    merge_summary: str
):
    """
    广播探索完成事件

    Args:
        trace_id: Trace ID
        explore_start_id: explore_start Goal ID
        merge_summary: 汇总结果
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "explore_completed", {
        "explore_start_id": explore_start_id,
        "merge_summary": merge_summary
    })

    message = {
        "event": "explore_completed",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "explore_start_id": explore_start_id,
        "merge_summary": merge_summary
    }

    await _broadcast_to_trace(trace_id, message)


async def broadcast_trace_completed(trace_id: str, total_messages: int):
    """
    广播 Trace 完成事件

    Args:
        trace_id: Trace ID
        total_messages: 总 Message 数
    """
    if trace_id not in _active_connections:
        return

    store = get_trace_store()
    event_id = await store.append_event(trace_id, "trace_completed", {
        "total_messages": total_messages
    })

    message = {
        "event": "trace_completed",
        "event_id": event_id,
        "ts": datetime.now().isoformat(),
        "trace_id": trace_id,
        "total_messages": total_messages
    }

    await _broadcast_to_trace(trace_id, message)

    # 完成后清理所有连接
    if trace_id in _active_connections:
        del _active_connections[trace_id]


# ===== 内部辅助函数 =====


async def _broadcast_to_trace(trace_id: str, message: Dict[str, Any]):
    """
    向指定 Trace 的所有连接广播消息

    Args:
        trace_id: Trace ID
        message: 消息内容
    """
    if trace_id not in _active_connections:
        return

    disconnected = []
    for websocket in _active_connections[trace_id]:
        try:
            await websocket.send_json(message)
        except Exception:
            disconnected.append(websocket)

    # 清理断开的连接
    for ws in disconnected:
        _active_connections[trace_id].discard(ws)