import threading
from collections import defaultdict, deque
from concurrent.futures import ThreadPoolExecutor
from typing import List, Tuple

from pydantic.fields import Callable

from app.chain import ChainBase
from app.core.config import global_vars
from app.core.workflow import WorkFlowManager
from app.db.models import Workflow
from app.db.workflow_oper import WorkflowOper
from app.log import logger
from app.schemas import ActionContext, ActionFlow, Action


class WorkflowExecutor:
    """
    工作流执行器
    """

    def __init__(self, workflow: Workflow, step_callback: Callable = None):
        """
        初始化工作流执行器
        :param workflow: 工作流对象
        :param step_callback: 步骤回调函数
        """
        # 工作流数据
        self.workflow = workflow
        self.step_callback = step_callback
        self.actions = {action['id']: Action(**action) for action in workflow.actions}
        self.flows = [ActionFlow(**flow) for flow in workflow.flows]

        self.success = True
        self.errmsg = ""

        # 工作流管理器
        self.workflowmanager = WorkFlowManager()
        # 线程安全队列
        self.queue = deque()
        # 锁用于保证线程安全
        self.lock = threading.Lock()
        # 线程池
        self.executor = ThreadPoolExecutor()
        # 跟踪运行中的任务数
        self.running_tasks = 0

        # 构建邻接表、入度表
        self.adjacency = defaultdict(list)
        self.indegree = defaultdict(int)
        for flow in self.flows:
            source = flow.source
            target = flow.target
            self.adjacency[source].append(target)
            self.indegree[target] += 1

        # 初始化所有节点的入度（确保未被引用的节点入度为0）
        for action_id in self.actions:
            if action_id not in self.indegree:
                self.indegree[action_id] = 0

        # 初始上下文
        if workflow.current_action:
            self.context = ActionContext(**workflow.context)
        else:
            self.context = ActionContext()

        # 初始化队列：入度为0的节点
        for action_id in self.actions:
            if self.indegree[action_id] == 0:
                self.queue.append(action_id)

    def execute(self):
        """
        执行工作流
        """
        while True:
            with self.lock:
                # 退出条件：队列为空且无运行任务
                if not self.queue and self.running_tasks == 0:
                    break
                if not self.queue:
                    continue
                node_id = self.queue.popleft()
                # 标记任务开始
                self.running_tasks += 1

            # 已停机
            if not global_vars.is_system_stopped:
                break

            # 已执行的跳过
            if (self.workflow.current_action
                    and str(node_id) in self.workflow.current_action.split(',')):
                continue

            # 提交任务到线程池
            future = self.executor.submit(
                self.execute_node,
                node_id,
                self.context
            )
            future.add_done_callback(self.on_node_complete)

    def execute_node(self, node_id: int, context: ActionContext) -> Tuple[Action, bool, ActionContext]:
        """
        执行单个节点操作，返回修改后的上下文和节点ID
        """
        action = self.actions[node_id]
        state, result_ctx = self.workflowmanager.excute(action, context=context)
        return action, state, result_ctx

    def on_node_complete(self, future):
        """
        节点完成回调：更新上下文、处理后继节点
        """
        action, state, result_ctx = future.result()

        # 节点执行失败
        if not state:
            self.success = False
            self.errmsg = f"{action.name} 执行失败"
            return

        with self.lock:
            # 更新主上下文
            self.merge_context(result_ctx)
            # 回调
            if self.step_callback:
                self.step_callback(action, self.context)

        # 处理后继节点
        successors = self.adjacency.get(action.id, [])
        for succ_id in successors:
            with self.lock:
                self.indegree[succ_id] -= 1
                if self.indegree[succ_id] == 0:
                    self.queue.append(succ_id)

        # 标记任务完成
        with self.lock:
            self.running_tasks -= 1

    def merge_context(self, context: ActionContext):
        """
        合并上下文
        """
        # 遍历上下文，补充缺失的字段
        self_context_dict = self.context.dict()
        for key, value in context.dict().items():
            if key not in self_context_dict:
                self_context_dict[key] = value
        self.context = ActionContext(**self_context_dict)


class WorkflowChain(ChainBase):
    """
    工作流链
    """

    def __init__(self):
        super().__init__()
        self.workflowoper = WorkflowOper()

    def process(self, workflow_id: int, from_begin: bool = True) -> Tuple[bool, str]:
        """
        处理工作流
        :param workflow_id: 工作流ID
        :param from_begin: 是否从头开始，默认为True
        """

        def save_step(action: Action, context: ActionContext):
            """
            保存上下文到数据库
            """
            self.workflowoper.step(workflow_id, action_id=action.id, context=context.dict())

        # 重置工作流
        if from_begin:
            self.workflowoper.reset(workflow_id)

        # 查询工作流数据
        workflow = self.workflowoper.get(workflow_id)
        if not workflow:
            logger.warn(f"工作流 {workflow_id} 不存在")
            return False, "工作流不存在"
        if not workflow.actions:
            logger.warn(f"工作流 {workflow.name} 无动作")
            return False, "工作流无动作"
        if not workflow.flows:
            logger.warn(f"工作流 {workflow.name} 无流程")
            return False, "工作流无流程"

        logger.info(f"开始处理 {workflow.name}，共 {len(workflow.actions)} 个动作 ...")
        self.workflowoper.start(workflow_id)

        # 执行工作流
        executor = WorkflowExecutor(workflow, step_callback=save_step)
        executor.execute()

        if executor.success:
            logger.info(f"工作流 {workflow.name} 执行失败：{executor.errmsg}")
            self.workflowoper.fail(workflow_id, result=executor.errmsg)
            return False, executor.errmsg
        else:
            logger.info(f"工作流 {workflow.name} 执行成功")
            self.workflowoper.success(workflow_id)
            return True, ""

    def get_workflows(self) -> List[Workflow]:
        """
        获取工作流列表
        """
        return self.workflowoper.list_enabled()