using MediatR;
using Microsoft.Extensions.Logging;
using X1.Application.Features.TaskExecution.Events.NodeExecutionEvents;
using X1.Domain.Events;
using X1.Domain.Entities.TestCase;

namespace X1.Application.Features.TaskExecution.Events.ControllerHandlers;

/// <summary>
/// 启动流程控制器处理器
/// 处理测试流程启动相关的节点执行事件
/// </summary>
public class StartFlowControllerHandler : INotificationHandler<StartFlowExecutionEvent>
{
    private readonly IMediator _mediator;
    private readonly ILogger<StartFlowControllerHandler> _logger;

    /// <summary>
    /// 初始化启动流程控制器处理器
    /// </summary>
    /// <param name="mediator">MediatR 中介者</param>
    /// <param name="logger">日志记录器</param>
    public StartFlowControllerHandler(IMediator mediator, ILogger<StartFlowControllerHandler> logger)
    {
        _mediator = mediator;
        _logger = logger;
    }

    /// <summary>
    /// 处理启动流程节点执行事件
    /// </summary>
    /// <param name="notification">节点执行事件</param>
    /// <param name="cancellationToken">取消令牌</param>
    /// <returns>处理任务</returns>
    public async Task Handle(StartFlowExecutionEvent notification, CancellationToken cancellationToken)
    {
        _logger.LogInformation("开始执行启动流程，任务执行ID: {TaskExecutionId}, 节点ID: {NodeId}, 运行时编码: {RuntimeCode}",
            notification.TaskExecutionId, notification.NodeId, notification.RuntimeCode);

        try
        {
            // 1. 更新节点状态为运行中
            await UpdateNodeStatusAsync(notification.NodeId, NodeExecutionStatus.Running);

            // 2. 执行启动流程业务逻辑
            var result = await ExecuteStartFlowAsync(notification, cancellationToken);

            // 3. 创建执行结果
            var executionResult = new NodeExecutionResult
            {
                TaskExecutionId = notification.TaskExecutionId,
                NodeId = notification.NodeId,
                StepMapping = StepMapping.StartFlow,
                Status = NodeExecutionStatus.Completed,
                IsSuccess = true,
                ResultData = result,
                ExecutorId = notification.ExecutorId,
                RuntimeCode = notification.RuntimeCode,
                CreatedAt = DateTime.UtcNow
            };

            // 4. 发布完成事件
            await PublishCompletedEventAsync(notification, executionResult, cancellationToken);

            _logger.LogInformation("启动流程执行成功，任务执行ID: {TaskExecutionId}, 节点ID: {NodeId}",
                notification.TaskExecutionId, notification.NodeId);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "启动流程执行失败，任务执行ID: {TaskExecutionId}, 节点ID: {NodeId}",
                notification.TaskExecutionId, notification.NodeId);

            // 发布失败事件
            await PublishFailedEventAsync(notification, ex.Message, cancellationToken);
        }
    }

    /// <summary>
    /// 执行启动流程业务逻辑
    /// </summary>
    /// <param name="notification">事件通知</param>
    /// <param name="cancellationToken">取消令牌</param>
    /// <returns>执行结果</returns>
    private async Task<string> ExecuteStartFlowAsync(StartFlowExecutionEvent notification, CancellationToken cancellationToken)
    {
        // TODO: 实现具体的启动流程逻辑
        // 这里应该调用实际的启动流程服务
        
        _logger.LogInformation("正在执行启动流程，运行时编码: {RuntimeCode}", notification.RuntimeCode);
        
        // 模拟异步操作
        await Task.Delay(500, cancellationToken);
        
        // 模拟成功结果
        var result = new
        {
            Status = "Success",
            Message = "测试流程启动成功",
            Timestamp = DateTime.UtcNow,
            RuntimeCode = notification.RuntimeCode,
            FlowInitialized = true
        };

        return System.Text.Json.JsonSerializer.Serialize(result);
    }

    /// <summary>
    /// 更新节点状态
    /// </summary>
    /// <param name="nodeId">节点ID</param>
    /// <param name="status">新状态</param>
    /// <returns>更新任务</returns>
    private async Task UpdateNodeStatusAsync(string nodeId, NodeExecutionStatus status)
    {
        // TODO: 实现节点状态更新逻辑
        // 这里应该更新数据库中的节点状态
        
        _logger.LogInformation("更新节点状态，节点ID: {NodeId}, 新状态: {Status}", nodeId, status);
        
        // 模拟异步操作
        await Task.CompletedTask;
    }

    /// <summary>
    /// 发布完成事件
    /// </summary>
    /// <param name="notification">原始事件</param>
    /// <param name="result">执行结果</param>
    /// <param name="cancellationToken">取消令牌</param>
    /// <returns>发布任务</returns>
    private async Task PublishCompletedEventAsync(StartFlowExecutionEvent notification, NodeExecutionResult result, CancellationToken cancellationToken)
    {
        var completedEvent = new NodeExecutionCompletedEvent
        {
            TaskExecutionId = notification.TaskExecutionId,
            NodeId = notification.NodeId,
            StepMapping = StepMapping.StartFlow,
            ExecutorId = notification.ExecutorId,
            RuntimeCode = notification.RuntimeCode,
            ScenarioCode = notification.ScenarioCode,
            ScenarioId = notification.ScenarioId,
            FlowName = notification.FlowName,
            FlowId = notification.FlowId,
            Result = result,
            Timestamp = DateTime.UtcNow
        };

        await _mediator.Publish(completedEvent, cancellationToken);
    }

    /// <summary>
    /// 发布失败事件
    /// </summary>
    /// <param name="notification">原始事件</param>
    /// <param name="errorMessage">错误消息</param>
    /// <param name="cancellationToken">取消令牌</param>
    /// <returns>发布任务</returns>
    private async Task PublishFailedEventAsync(StartFlowExecutionEvent notification, string errorMessage, CancellationToken cancellationToken)
    {
        var failedEvent = new NodeExecutionFailedEvent
        {
            TaskExecutionId = notification.TaskExecutionId,
            NodeId = notification.NodeId,
            StepMapping = StepMapping.StartFlow,
            ExecutorId = notification.ExecutorId,
            RuntimeCode = notification.RuntimeCode,
            ScenarioCode = notification.ScenarioCode,
            ScenarioId = notification.ScenarioId,
            FlowName = notification.FlowName,
            FlowId = notification.FlowId,
            ErrorMessage = errorMessage,
            ErrorCode = "START_FLOW_ERROR",
            Timestamp = DateTime.UtcNow
        };

        await _mediator.Publish(failedEvent, cancellationToken);
    }
}