using Google.Protobuf.WellKnownTypes;
using Grpc.Core;
using ZB.MOM.WW.MxGateway.Contracts.Proto;
using ZB.MOM.WW.MxGateway.Server.Sessions;

namespace ZB.MOM.WW.MxGateway.Tests.Gateway.Sessions;

public sealed class SparseArrayExpanderTests
{
    private static MxValue SparseValue(
        MxDataType elementType,
        uint totalLength,
        params (uint Index, MxValue Value)[] elements)
    {
        MxSparseArray sparse = new()
        {
            ElementDataType = elementType,
            TotalLength = totalLength,
        };

        foreach ((uint index, MxValue value) in elements)
        {
            sparse.Elements.Add(new MxSparseElement { Index = index, Value = value });
        }

        return new MxValue { SparseArrayValue = sparse };
    }

    [Fact]
    public void Expand_Int32_FillsDefaultsAndSetsElement()
    {
        MxValue value = SparseValue(
            MxDataType.Integer,
            4,
            (1, new MxValue { Int32Value = 7 }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxValue.KindOneofCase.ArrayValue, value.KindCase);
        Assert.Equal(MxDataType.Integer, value.ArrayValue.ElementDataType);
        Assert.Equal(new uint[] { 4 }, value.ArrayValue.Dimensions);
        Assert.Equal(MxArray.ValuesOneofCase.Int32Values, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { 0, 7, 0, 0 }, value.ArrayValue.Int32Values.Values);
    }

    [Fact]
    public void Expand_Boolean_EmptyElements_AllDefaultFalse()
    {
        MxValue value = SparseValue(MxDataType.Boolean, 3);

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.BoolValues, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { false, false, false }, value.ArrayValue.BoolValues.Values);
    }

    [Fact]
    public void Expand_ZeroTotalLength_Throws()
    {
        MxValue value = SparseValue(MxDataType.Integer, 0);

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public void Expand_IndexOutOfRange_Throws()
    {
        MxValue value = SparseValue(
            MxDataType.Integer,
            2,
            (5, new MxValue { Int32Value = 1 }));

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public void Expand_DuplicateIndex_Throws()
    {
        MxValue value = SparseValue(
            MxDataType.Integer,
            4,
            (1, new MxValue { Int32Value = 1 }),
            (1, new MxValue { Int32Value = 2 }));

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public void Expand_UnsupportedElementType_Throws()
    {
        MxValue value = SparseValue(MxDataType.Unspecified, 2);

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public void Expand_ElementValueKindMismatch_Throws()
    {
        MxValue value = SparseValue(
            MxDataType.Integer,
            2,
            (0, new MxValue { StringValue = "nope" }));

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }

    [Fact]
    public void Expand_String_FillsEmptyStringDefault()
    {
        MxValue value = SparseValue(
            MxDataType.String,
            2,
            (0, new MxValue { StringValue = "a" }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.StringValues, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { "a", string.Empty }, value.ArrayValue.StringValues.Values);
    }

    [Fact]
    public void Expand_Time_FillsEpochDefault()
    {
        MxValue value = SparseValue(
            MxDataType.Time,
            2,
            (1, new MxValue { TimestampValue = new Timestamp { Seconds = 5 } }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.TimestampValues, value.ArrayValue.ValuesCase);
        Assert.Equal(2, value.ArrayValue.TimestampValues.Values.Count);
        Assert.Equal(0, value.ArrayValue.TimestampValues.Values[0].Seconds);
        Assert.Equal(0, value.ArrayValue.TimestampValues.Values[0].Nanos);
        Assert.Equal(5, value.ArrayValue.TimestampValues.Values[1].Seconds);
    }

    [Fact]
    public void Expand_Double_HappyPath()
    {
        MxValue value = SparseValue(
            MxDataType.Double,
            3,
            (2, new MxValue { DoubleValue = 1.5 }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.DoubleValues, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { 0d, 0d, 1.5 }, value.ArrayValue.DoubleValues.Values);
    }

    [Fact]
    public void Expand_Float_HappyPath()
    {
        MxValue value = SparseValue(
            MxDataType.Float,
            2,
            (0, new MxValue { FloatValue = 2.5f }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.FloatValues, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { 2.5f, 0f }, value.ArrayValue.FloatValues.Values);
    }

    [Fact]
    public void Expand_Int64_WhenElementIsInt64()
    {
        MxValue value = SparseValue(
            MxDataType.Integer,
            3,
            (2, new MxValue { Int64Value = 9_000_000_000L }));

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxArray.ValuesOneofCase.Int64Values, value.ArrayValue.ValuesCase);
        Assert.Equal(new[] { 0L, 0L, 9_000_000_000L }, value.ArrayValue.Int64Values.Values);
    }

    [Fact]
    public void Expand_NonSparseValue_NoOps()
    {
        MxValue value = new() { Int32Value = 42 };

        SparseArrayExpander.Expand(value);

        Assert.Equal(MxValue.KindOneofCase.Int32Value, value.KindCase);
        Assert.Equal(42, value.Int32Value);
    }

    [Fact]
    public void Expand_NullValue_ThrowsArgumentNull()
    {
        Assert.Throws<ArgumentNullException>(() => SparseArrayExpander.Expand(null!));
    }

    [Fact]
    public void Expand_TotalLengthExceedsMaxArrayLength_Throws()
    {
        MxValue value = SparseValue(MxDataType.Integer, 2_147_483_648u);

        RpcException ex = Assert.Throws<RpcException>(() => SparseArrayExpander.Expand(value));
        Assert.Equal(StatusCode.InvalidArgument, ex.StatusCode);
    }
}