using ScadaLink.Commons.Types.Enums;

namespace ScadaLink.DeploymentManager.Tests;

/// <summary>
/// WP-4: Tests for instance state transition matrix.
/// </summary>
public class StateTransitionValidatorTests
{
    // ── Deploy transitions ──

    [Theory]
    [InlineData(InstanceState.NotDeployed)]
    [InlineData(InstanceState.Enabled)]
    [InlineData(InstanceState.Disabled)]
    public void CanDeploy_AllStates_ReturnsTrue(InstanceState state)
    {
        Assert.True(StateTransitionValidator.CanDeploy(state));
    }

    // ── Disable transitions ──

    [Fact]
    public void CanDisable_WhenEnabled_ReturnsTrue()
    {
        Assert.True(StateTransitionValidator.CanDisable(InstanceState.Enabled));
    }

    [Fact]
    public void CanDisable_WhenDisabled_ReturnsFalse()
    {
        Assert.False(StateTransitionValidator.CanDisable(InstanceState.Disabled));
    }

    [Fact]
    public void CanDisable_WhenNotDeployed_ReturnsFalse()
    {
        Assert.False(StateTransitionValidator.CanDisable(InstanceState.NotDeployed));
    }

    // ── Enable transitions ──

    [Fact]
    public void CanEnable_WhenDisabled_ReturnsTrue()
    {
        Assert.True(StateTransitionValidator.CanEnable(InstanceState.Disabled));
    }

    [Fact]
    public void CanEnable_WhenEnabled_ReturnsFalse()
    {
        Assert.False(StateTransitionValidator.CanEnable(InstanceState.Enabled));
    }

    [Fact]
    public void CanEnable_WhenNotDeployed_ReturnsFalse()
    {
        Assert.False(StateTransitionValidator.CanEnable(InstanceState.NotDeployed));
    }

    // ── Delete transitions ──

    [Fact]
    public void CanDelete_WhenEnabled_ReturnsTrue()
    {
        Assert.True(StateTransitionValidator.CanDelete(InstanceState.Enabled));
    }

    [Fact]
    public void CanDelete_WhenDisabled_ReturnsTrue()
    {
        Assert.True(StateTransitionValidator.CanDelete(InstanceState.Disabled));
    }

    [Fact]
    public void CanDelete_WhenNotDeployed_ReturnsFalse()
    {
        Assert.False(StateTransitionValidator.CanDelete(InstanceState.NotDeployed));
    }

    // ── ValidateTransition ──

    [Fact]
    public void ValidateTransition_ValidDeploy_ReturnsNull()
    {
        var error = StateTransitionValidator.ValidateTransition(InstanceState.NotDeployed, "deploy");
        Assert.Null(error);
    }

    [Fact]
    public void ValidateTransition_InvalidEnable_ReturnsError()
    {
        var error = StateTransitionValidator.ValidateTransition(InstanceState.Enabled, "enable");
        Assert.NotNull(error);
        Assert.Contains("not allowed", error);
    }

    [Fact]
    public void ValidateTransition_InvalidDisable_ReturnsError()
    {
        var error = StateTransitionValidator.ValidateTransition(InstanceState.Disabled, "disable");
        Assert.NotNull(error);
    }

    [Fact]
    public void ValidateTransition_InvalidDeleteOnNotDeployed_ReturnsError()
    {
        var error = StateTransitionValidator.ValidateTransition(InstanceState.NotDeployed, "delete");
        Assert.NotNull(error);
    }

    [Fact]
    public void ValidateTransition_UnknownOperation_ReturnsError()
    {
        var error = StateTransitionValidator.ValidateTransition(InstanceState.Enabled, "unknown");
        Assert.NotNull(error);
    }
}