ScadaBridge/tests/ScadaLink.TemplateEngine.Tests/Flattening/DiffServiceTests.cs

using ScadaLink.Commons.Types.Flattening;
using ScadaLink.TemplateEngine.Flattening;

namespace ScadaLink.TemplateEngine.Tests.Flattening;

public class DiffServiceTests
{
    private readonly DiffService _sut = new();

    [Fact]
    public void ComputeDiff_NullOldConfig_AllAdded()
    {
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" },
                new ResolvedAttribute { CanonicalName = "Status", Value = "OK", DataType = "String" }
            ],
            Alarms =
            [
                new ResolvedAlarm { CanonicalName = "HighTemp", TriggerType = "RangeViolation" }
            ],
            Scripts =
            [
                new ResolvedScript { CanonicalName = "Monitor", Code = "// code" }
            ]
        };

        var diff = _sut.ComputeDiff(null, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Equal(2, diff.AttributeChanges.Count);
        Assert.All(diff.AttributeChanges, c => Assert.Equal(DiffChangeType.Added, c.ChangeType));
        Assert.Single(diff.AlarmChanges);
        Assert.Single(diff.ScriptChanges);
    }

    [Fact]
    public void ComputeDiff_IdenticalConfigs_NoChanges()
    {
        var config = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes = [new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" }],
            Alarms = [],
            Scripts = []
        };

        var diff = _sut.ComputeDiff(config, config);

        Assert.False(diff.HasChanges);
        Assert.Empty(diff.AttributeChanges);
    }

    [Fact]
    public void ComputeDiff_AttributeRemoved_DetectedAsRemoved()
    {
        var oldConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" },
                new ResolvedAttribute { CanonicalName = "Removed", Value = "x", DataType = "String" }
            ]
        };
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes = [new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" }]
        };

        var diff = _sut.ComputeDiff(oldConfig, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Single(diff.AttributeChanges);
        Assert.Equal(DiffChangeType.Removed, diff.AttributeChanges[0].ChangeType);
        Assert.Equal("Removed", diff.AttributeChanges[0].CanonicalName);
    }

    [Fact]
    public void ComputeDiff_AttributeChanged_DetectedAsChanged()
    {
        var oldConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes = [new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double" }]
        };
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes = [new ResolvedAttribute { CanonicalName = "Temp", Value = "50", DataType = "Double" }]
        };

        var diff = _sut.ComputeDiff(oldConfig, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Single(diff.AttributeChanges);
        Assert.Equal(DiffChangeType.Changed, diff.AttributeChanges[0].ChangeType);
        Assert.Equal("25", diff.AttributeChanges[0].OldValue?.Value);
        Assert.Equal("50", diff.AttributeChanges[0].NewValue?.Value);
    }

    [Fact]
    public void ComputeDiff_RevisionHashes_Included()
    {
        var config = new FlattenedConfiguration { InstanceUniqueName = "Instance1" };
        var diff = _sut.ComputeDiff(config, config, "sha256:old", "sha256:new");

        Assert.Equal("sha256:old", diff.OldRevisionHash);
        Assert.Equal("sha256:new", diff.NewRevisionHash);
    }

    [Fact]
    public void ComputeDiff_ScriptCodeChange_Detected()
    {
        var oldConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Scripts = [new ResolvedScript { CanonicalName = "Script1", Code = "// v1" }]
        };
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Scripts = [new ResolvedScript { CanonicalName = "Script1", Code = "// v2" }]
        };

        var diff = _sut.ComputeDiff(oldConfig, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Single(diff.ScriptChanges);
        Assert.Equal(DiffChangeType.Changed, diff.ScriptChanges[0].ChangeType);
    }

    [Fact]
    public void ComputeDiff_AttributeDescriptionChange_DetectedAsChanged()
    {
        // TemplateEngine-017: AttributesEqual must compare Description.
        var oldConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double", Description = "Original" }
            ]
        };
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "Temp", Value = "25", DataType = "Double", Description = "Updated" }
            ]
        };

        var diff = _sut.ComputeDiff(oldConfig, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Single(diff.AttributeChanges);
        Assert.Equal(DiffChangeType.Changed, diff.AttributeChanges[0].ChangeType);
    }

    [Fact]
    public void ComputeDiff_AlarmDescriptionChange_DetectedAsChanged()
    {
        // TemplateEngine-017: AlarmsEqual must compare Description.
        var oldConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Alarms =
            [
                new ResolvedAlarm { CanonicalName = "HighTemp", TriggerType = "RangeViolation", Description = "Original" }
            ]
        };
        var newConfig = new FlattenedConfiguration
        {
            InstanceUniqueName = "Instance1",
            Alarms =
            [
                new ResolvedAlarm { CanonicalName = "HighTemp", TriggerType = "RangeViolation", Description = "Updated" }
            ]
        };

        var diff = _sut.ComputeDiff(oldConfig, newConfig);

        Assert.True(diff.HasChanges);
        Assert.Single(diff.AlarmChanges);
        Assert.Equal(DiffChangeType.Changed, diff.AlarmChanges[0].ChangeType);
    }

    [Fact]
    public void ConnectionsEqual_IdenticalConfigs_ReturnsTrue()
    {
        // TemplateEngine-017: ConnectionsEqual is the comparator callers use
        // to detect connection-endpoint drift (the diff-view extension that
        // surfaces this in the UI is tracked under TemplateEngine-018).
        var a = new ConnectionConfig
        {
            Protocol = "OpcUa",
            ConfigurationJson = "{\"endpoint\":\"opc.tcp://host-a\"}",
            BackupConfigurationJson = "{\"endpoint\":\"opc.tcp://host-b\"}",
            FailoverRetryCount = 3
        };
        var b = a with { };

        Assert.True(DiffService.ConnectionsEqual(a, b));
    }

    [Fact]
    public void ConnectionsEqual_EndpointEdit_ReturnsFalse()
    {
        // TemplateEngine-017: primary endpoint JSON edit must surface as a
        // change. Without this, deployment redeploys ship a different
        // ConnectionConfig with no visible drift signal.
        var a = new ConnectionConfig
        {
            Protocol = "OpcUa",
            ConfigurationJson = "{\"endpoint\":\"opc.tcp://host-a:4840\"}",
            FailoverRetryCount = 3
        };
        var b = a with { ConfigurationJson = "{\"endpoint\":\"opc.tcp://host-b:4840\"}" };

        Assert.False(DiffService.ConnectionsEqual(a, b));
    }

    [Fact]
    public void ConnectionsEqual_BackupConfigurationEdit_ReturnsFalse()
    {
        var a = new ConnectionConfig { Protocol = "OpcUa", ConfigurationJson = "{}", BackupConfigurationJson = null, FailoverRetryCount = 3 };
        var b = a with { BackupConfigurationJson = "{\"endpoint\":\"opc.tcp://backup\"}" };

        Assert.False(DiffService.ConnectionsEqual(a, b));
    }

    [Fact]
    public void ConnectionsEqual_FailoverRetryCountEdit_ReturnsFalse()
    {
        var a = new ConnectionConfig { Protocol = "OpcUa", ConfigurationJson = "{}", FailoverRetryCount = 3 };
        var b = a with { FailoverRetryCount = 5 };

        Assert.False(DiffService.ConnectionsEqual(a, b));
    }

    [Fact]
    public void ConnectionsEqual_ProtocolEdit_ReturnsFalse()
    {
        var a = new ConnectionConfig { Protocol = "OpcUa", ConfigurationJson = "{}", FailoverRetryCount = 3 };
        var b = a with { Protocol = "Modbus" };

        Assert.False(DiffService.ConnectionsEqual(a, b));
    }
}