using System.Data;
using JdeScoping.DataSync.Etl.Transformers;
using NSubstitute;

namespace JdeScoping.DataSync.Tests.Etl.Transformers;

public class JdeDateTransformerTests
{
    [Fact]
    public void FieldCount_ReducedByOne()
    {
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, 124001m, 120000m, "Test" });
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        Assert.Equal(3, reader.FieldCount);
    }

    [Fact]
    public void GetName_DateColumnRenamed_TimeColumnRemoved()
    {
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, 124001m, 120000m, "Test" });
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        Assert.Equal("Id", reader.GetName(0));
        Assert.Equal("UpdatedAt", reader.GetName(1));
        Assert.Equal("Name", reader.GetName(2));
    }

    [Fact]
    public void GetValue_ParsesJulianDateAndTime()
    {
        // Julian date 124001 = Jan 1, 2024 (century digit 1 = 2000s, year 24, day 001)
        // Time 120000 = 12:00:00
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, 124001m, 120000m, "Test" });
        source.Read().Returns(true);
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        reader.Read();
        var expectedDate = new DateTime(2024, 1, 1, 12, 0, 0);
        Assert.Equal(expectedDate, reader.GetValue(1));
    }

    [Fact]
    public void GetValue_NullDate_ReturnsDbNull()
    {
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, DBNull.Value, DBNull.Value, "Test" });
        source.Read().Returns(true);
        source.IsDBNull(1).Returns(true);
        source.IsDBNull(2).Returns(true);
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        reader.Read();
        Assert.Equal(DBNull.Value, reader.GetValue(1));
    }

    [Fact]
    public void GetFieldType_DateColumn_ReturnsDateTime()
    {
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, 124001m, 120000m, "Test" });
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        Assert.Equal(typeof(DateTime), reader.GetFieldType(1));
    }

    [Fact]
    public void GetOrdinal_NewDateColumn_ReturnsCorrectOrdinal()
    {
        var source = CreateMockReader(new[] { "Id", "UPMJ", "TDAY", "Name" }, new object[] { 1, 124001m, 120000m, "Test" });
        var transformer = new JdeDateTransformer("UPMJ", "TDAY", "UpdatedAt");
        var reader = transformer.Transform(source);
        Assert.Equal(1, reader.GetOrdinal("UpdatedAt"));
    }

    [Fact]
    public void ParseJdeDateTime_VariousDates()
    {
        // Test the static parsing method
        Assert.Equal(new DateTime(2024, 1, 1, 12, 0, 0), JdeDateTransformer.ParseJdeDateTime(124001m, 120000m));
        Assert.Equal(new DateTime(2023, 12, 31, 23, 59, 59), JdeDateTransformer.ParseJdeDateTime(123365m, 235959m));
        Assert.Equal(new DateTime(1999, 6, 15, 0, 0, 0), JdeDateTransformer.ParseJdeDateTime(99166m, 0m));
    }

    private static IDataReader CreateMockReader(string[] columns, object[] values)
    {
        var reader = Substitute.For<IDataReader>();
        reader.FieldCount.Returns(columns.Length);
        for (int i = 0; i < columns.Length; i++)
        {
            var index = i;
            reader.GetName(index).Returns(columns[index]);
            reader.GetOrdinal(columns[index]).Returns(index);
            reader.GetValue(index).Returns(values[index]);
            reader.IsDBNull(index).Returns(values[index] == DBNull.Value);
            reader.GetFieldType(index).Returns(values[index]?.GetType() ?? typeof(object));
        }
        return reader;
    }
}