#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
TopicBuild Agent 执行上下文管理器

用于在 TopicBuildAgent 执行过程中共享 execution 上下文信息。
使用 contextvars.ContextVar 实现并发隔离，支持多 Agent 并发执行。

为什么用 contextvars 而非 threading.local:
  - Agent 在线程 A 设置 context，Tool 通过 asyncio.to_thread() 在线程池线程 B 执行
  - threading.local 按线程隔离，线程 B 看不到线程 A 的数据
  - contextvars 按 asyncio Task 隔离，且 asyncio.to_thread() 会自动将当前
    context 拷贝到目标线程，Tool 可以正确读取 Agent 设置的值
"""
import contextvars
from typing import Optional, Dict, Any

_execution_id_var: contextvars.ContextVar[Optional[int]] = contextvars.ContextVar('execution_id', default=None)
_topic_build_id_var: contextvars.ContextVar[Optional[int]] = contextvars.ContextVar('topic_build_id', default=None)
_demand_var: contextvars.ContextVar[Optional[str]] = contextvars.ContextVar('demand', default=None)
_demand_constraints_var: contextvars.ContextVar[Optional[Dict]] = contextvars.ContextVar('demand_constraints', default=None)
_metadata_var: contextvars.ContextVar[Dict[str, Any]] = contextvars.ContextVar('metadata', default=None)
_on_demand_strategies_var: contextvars.ContextVar[list] = contextvars.ContextVar('on_demand_strategies', default=[])


class TopicBuildAgentContext:
    """
    选题构建 Agent 执行上下文

    使用 contextvars.ContextVar 存储当前 asyncio Task 的 Agent 执行上下文信息，
    每个 Agent 执行拥有独立的上下文，跨线程（asyncio.to_thread）自动传播。
    """

    @classmethod
    def set_execution_id(cls, execution_id: int):
        _execution_id_var.set(execution_id)
        from log_capture import log
        log(f"[TopicBuildAgentContext] 设置 execution_id = {execution_id}")

    @classmethod
    def get_execution_id(cls) -> Optional[int]:
        return _execution_id_var.get()

    @classmethod
    def set_topic_build_id(cls, topic_build_id: int):
        _topic_build_id_var.set(topic_build_id)
        from log_capture import log
        log(f"[TopicBuildAgentContext] 设置 topic_build_id = {topic_build_id}")

    @classmethod
    def get_topic_build_id(cls) -> Optional[int]:
        return _topic_build_id_var.get()

    @classmethod
    def set_demand(cls, demand: str, constraints: Dict = None):
        _demand_var.set(demand)
        _demand_constraints_var.set(constraints)

    @classmethod
    def get_demand(cls) -> Optional[str]:
        return _demand_var.get()

    @classmethod
    def get_demand_constraints(cls) -> Optional[Dict]:
        return _demand_constraints_var.get()

    @classmethod
    def set_metadata(cls, key: str, value: Any):
        metadata = _metadata_var.get()
        if metadata is None:
            metadata = {}
            _metadata_var.set(metadata)
        metadata[key] = value

    @classmethod
    def get_metadata(cls, key: str, default: Any = None) -> Any:
        metadata = _metadata_var.get()
        if metadata is None:
            return default
        return metadata.get(key, default)

    @classmethod
    def set_on_demand_strategies(cls, names: list[str]):
        _on_demand_strategies_var.set(names or [])

    @classmethod
    def get_on_demand_strategies(cls) -> list[str]:
        return _on_demand_strategies_var.get()

    @classmethod
    def clear(cls):
        from log_capture import log
        log(f"[TopicBuildAgentContext] 清除上下文")
        _execution_id_var.set(None)
        _topic_build_id_var.set(None)
        _demand_var.set(None)
        _demand_constraints_var.set(None)
        _metadata_var.set(None)
        _on_demand_strategies_var.set([])


class TopicBuildAgentContextManager:
    """上下文管理器：使用 with 语句管理 TopicBuildAgent 上下文"""

    def __init__(self, execution_id: int, topic_build_id: int = None,
                 demand: str = None, demand_constraints: dict = None):
        self.execution_id = execution_id
        self.topic_build_id = topic_build_id
        self.demand = demand
        self.demand_constraints = demand_constraints

    def __enter__(self):
        TopicBuildAgentContext.set_execution_id(self.execution_id)
        if self.topic_build_id:
            TopicBuildAgentContext.set_topic_build_id(self.topic_build_id)
        if self.demand:
            TopicBuildAgentContext.set_demand(self.demand, self.demand_constraints)
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        TopicBuildAgentContext.clear()
        return False