using Xunit;
using YZWater.Core.Services;

namespace YZWater.Core.Tests.Services;

/// <summary>
/// DeviceStateMachine 单元测试
/// </summary>
public class DeviceStateMachineTests
{
    [Fact]
    public void InitialState_ShouldBeStopped()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, sm.CurrentState);
    }

    [Fact]
    public void Start_ShouldTransitionToRunning()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.Start();
        Assert.Equal(DeviceStateMachine.DeviceState.Running, sm.CurrentState);
    }

    [Fact]
    public void Stop_FromRunning_ShouldTransitionToStopped()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.Start();
        sm.Stop();
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, sm.CurrentState);
    }

    [Fact]
    public void ReportFault_ShouldTransitionToFault()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.Start();
        sm.ReportFault();
        Assert.Equal(DeviceStateMachine.DeviceState.Fault, sm.CurrentState);
    }

    [Fact]
    public void Recover_FromFault_ShouldTransitionToStopped()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.Start();
        sm.ReportFault();
        sm.Recover();
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, sm.CurrentState);
    }

    [Fact]
    public void FaultCannotDirectlyTransitionToRunning()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.ReportFault();
        var canStart = sm.CanFire(DeviceStateMachine.DeviceTrigger.Start);
        Assert.False(canStart);
    }

    [Fact]
    public void TryFire_InvalidTransition_ShouldReturnFalse()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        // 从 Stopped 不能直接 Stop
        var result = sm.TryFire(DeviceStateMachine.DeviceTrigger.Stop);
        Assert.False(result);
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, sm.CurrentState);
    }

    [Fact]
    public void StateChanged_EventShouldFire()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        var eventFired = false;
        DeviceStateMachine.DeviceState? fromState = null;
        DeviceStateMachine.DeviceState? toState = null;

        sm.StateChanged += (id, from, to) =>
        {
            eventFired = true;
            fromState = from;
            toState = to;
        };

        sm.Start();

        Assert.True(eventFired);
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, fromState);
        Assert.Equal(DeviceStateMachine.DeviceState.Running, toState);
    }

    [Fact]
    public void BeginMaintenance_ShouldTransitionToMaintenance()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.BeginMaintenance();
        Assert.Equal(DeviceStateMachine.DeviceState.Maintenance, sm.CurrentState);
    }

    [Fact]
    public void CompleteMaintenance_ShouldTransitionToStopped()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        sm.BeginMaintenance();
        sm.CompleteMaintenance();
        Assert.Equal(DeviceStateMachine.DeviceState.Stopped, sm.CurrentState);
    }

    [Fact]
    public void ToDeviceStatus_ShouldConvertCorrectly()
    {
        var sm = new DeviceStateMachine("P001", "泵1");
        Assert.Equal(YZWater.Core.Models.DeviceStatus.Stopped, sm.ToDeviceStatus());

        sm.Start();
        Assert.Equal(YZWater.Core.Models.DeviceStatus.Running, sm.ToDeviceStatus());

        sm.ReportFault();
        Assert.Equal(YZWater.Core.Models.DeviceStatus.Fault, sm.ToDeviceStatus());
    }
}

/// <summary>
/// DeviceStateMachineManager 单元测试
/// </summary>
public class DeviceStateMachineManagerTests
{
    [Fact]
    public void GetOrCreate_ShouldCreateNewMachine()
    {
        var manager = new DeviceStateMachineManager();
        var sm = manager.GetOrCreate("P001", "泵1");
        Assert.NotNull(sm);
        Assert.Equal("P001", sm.DeviceId);
        Assert.Equal("泵1", sm.DeviceName);
    }

    [Fact]
    public void GetOrCreate_SameId_ShouldReturnSameInstance()
    {
        var manager = new DeviceStateMachineManager();
        var sm1 = manager.GetOrCreate("P001", "泵1");
        var sm2 = manager.GetOrCreate("P001", "泵1");
        Assert.Same(sm1, sm2);
    }

    [Fact]
    public void Get_ExistingMachine_ShouldReturnIt()
    {
        var manager = new DeviceStateMachineManager();
        manager.GetOrCreate("P001", "泵1");
        var sm = manager.Get("P001");
        Assert.NotNull(sm);
    }

    [Fact]
    public void Get_NonExistingMachine_ShouldReturnNull()
    {
        var manager = new DeviceStateMachineManager();
        var sm = manager.Get("P999");
        Assert.Null(sm);
    }

    [Fact]
    public void Clear_ShouldRemoveAllMachines()
    {
        var manager = new DeviceStateMachineManager();
        manager.GetOrCreate("P001", "泵1");
        manager.GetOrCreate("P002", "泵2");
        manager.Clear();
        Assert.Empty(manager.GetAll());
    }
}