using NUnit.Framework;
using System.IO;
using System.Linq;
using System.Numerics;

namespace MatFileHandler.Tests
{
    [TestFixture]
    public class MatFileReaderHdfTests
    {
        private const string TestDirectory = "test-data";

        /// <summary>
        /// Test reading an ASCII-encoded string.
        /// </summary>
        [Test]
        public void TestAscii()
        {
            var matFile = ReadHdfTestFile("ascii");
            var arrayAscii = matFile["s"].Value as ICharArray;
            Assert.That(arrayAscii, Is.Not.Null);
            Assert.That(arrayAscii.Dimensions, Is.EqualTo(new[] { 1, 3 }));
            Assert.That(arrayAscii.String, Is.EqualTo("abc"));
            Assert.That(arrayAscii[2], Is.EqualTo('c'));
        }

        /// <summary>
        /// Test reading a Unicode string.
        /// </summary>
        [Test]
        public void TestUnicode()
        {
            var matFile = ReadHdfTestFile("unicode");
            var arrayUnicode = matFile["s"].Value as ICharArray;
            Assert.That(arrayUnicode, Is.Not.Null);
            Assert.That(arrayUnicode.Dimensions, Is.EqualTo(new[] { 1, 2 }));
            Assert.That(arrayUnicode.String, Is.EqualTo("必フ"));
            Assert.That(arrayUnicode[0], Is.EqualTo('必'));
            Assert.That(arrayUnicode[1], Is.EqualTo('フ'));
        }

        /// <summary>
        /// Test reading a wide Unicode string.
        /// </summary>
        [Test]
        public void TestUnicodeWide()
        {
            var matFile = ReadHdfTestFile("unicode-wide");
            var arrayUnicodeWide = matFile["s"].Value as ICharArray;
            Assert.That(arrayUnicodeWide, Is.Not.Null);
            Assert.That(arrayUnicodeWide.Dimensions, Is.EqualTo(new[] { 1, 2 }));
            Assert.That(arrayUnicodeWide.String, Is.EqualTo("🍆"));
        }

        /// <summary>
        /// Test reading a two-dimensional double array.
        /// </summary>
        [Test]
        public void TestMatrix()
        {
            var matFile = ReadHdfTestFile("matrix");
            var matrix = matFile["matrix"].Value as IArrayOf<double>;
            Assert.That(matrix.Dimensions, Is.EqualTo(new[] { 3, 2 }));
            Assert.That(matrix.ConvertToDoubleArray(), Is.EqualTo(new[] { 1.0, 3.0, 5.0, 2.0, 4.0, 6.0 }));
            Assert.That(matrix[0, 0], Is.EqualTo(1.0));
            Assert.That(matrix[0, 1], Is.EqualTo(2.0));
            Assert.That(matrix[1, 0], Is.EqualTo(3.0));
            Assert.That(matrix[1, 1], Is.EqualTo(4.0));
            Assert.That(matrix[2, 0], Is.EqualTo(5.0));
            Assert.That(matrix[2, 1], Is.EqualTo(6.0));
        }

        /// <summary>
        /// Test reading a two-dimensional complex array.
        /// </summary>
        [Test]
        public void TestComplexMatrix()
        {
            var matFile = ReadHdfTestFile("matrix_complex");
            var matrix = matFile["matrix"].Value as IArrayOf<Complex>;
            Assert.That(matrix.Dimensions, Is.EqualTo(new[] { 3, 2 }));
            Assert.That(matrix.ConvertToComplexArray(), Is.EqualTo(new[]
            {
                new Complex(1.0, 4.0),
                new Complex(3.0, 1.0),
                new Complex(5.0, 0.25),
                new Complex(2.0, 2.0),
                new Complex(4.0, 0.5),
                new Complex(6.0, 0.125),
            }));
            Assert.That(matrix[0, 0], Is.EqualTo(new Complex(1.0, 4.0)));
            Assert.That(matrix[0, 1], Is.EqualTo(new Complex(2.0, 2.0)));
            Assert.That(matrix[1, 0], Is.EqualTo(new Complex(3.0, 1.0)));
            Assert.That(matrix[1, 1], Is.EqualTo(new Complex(4.0, 0.5)));
            Assert.That(matrix[2, 0], Is.EqualTo(new Complex(5.0, 0.25)));
            Assert.That(matrix[2, 1], Is.EqualTo(new Complex(6.0, 0.125)));
        }

        /// <summary>
        /// Test reading lower and upper limits of integer data types.
        /// </summary>
        [Test]
        public void TestLimits()
        {
            var matFile = ReadHdfTestFile("limits");
            IArray array;
            array = matFile["int8_"].Value;
            CheckLimits(array as IArrayOf<sbyte>, CommonData.Int8Limits);
            Assert.That(array.ConvertToDoubleArray(), Is.EqualTo(new[] { -128.0, 127.0 }));

            array = matFile["uint8_"].Value;
            CheckLimits(array as IArrayOf<byte>, CommonData.UInt8Limits);

            array = matFile["int16_"].Value;
            CheckLimits(array as IArrayOf<short>, CommonData.Int16Limits);

            array = matFile["uint16_"].Value;
            CheckLimits(array as IArrayOf<ushort>, CommonData.UInt16Limits);

            array = matFile["int32_"].Value;
            CheckLimits(array as IArrayOf<int>, CommonData.Int32Limits);

            array = matFile["uint32_"].Value;
            CheckLimits(array as IArrayOf<uint>, CommonData.UInt32Limits);

            array = matFile["int64_"].Value;
            CheckLimits(array as IArrayOf<long>, CommonData.Int64Limits);

            array = matFile["uint64_"].Value;
            CheckLimits(array as IArrayOf<ulong>, CommonData.UInt64Limits);
        }

        /// <summary>
        /// Test writing lower and upper limits of integer-based complex data types.
        /// </summary>
        [Test]
        public void TestComplexLimits()
        {
            var matFile = ReadHdfTestFile("limits_complex");
            IArray array;
            array = matFile["int8_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<sbyte>>, CommonData.Int8Limits);
            Assert.That(
                array.ConvertToComplexArray(),
                Is.EqualTo(new[] { -128.0 + (127.0 * Complex.ImaginaryOne), 127.0 - (128.0 * Complex.ImaginaryOne) }));

            array = matFile["uint8_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<byte>>, CommonData.UInt8Limits);

            array = matFile["int16_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<short>>, CommonData.Int16Limits);

            array = matFile["uint16_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<ushort>>, CommonData.UInt16Limits);

            array = matFile["int32_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<int>>, CommonData.Int32Limits);

            array = matFile["uint32_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<uint>>, CommonData.UInt32Limits);

            array = matFile["int64_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<long>>, CommonData.Int64Limits);

            array = matFile["uint64_complex"].Value;
            CheckComplexLimits(array as IArrayOf<ComplexOf<ulong>>, CommonData.UInt64Limits);
        }

        /// <summary>
        /// Test reading a structure array.
        /// </summary>
        [Test]
        public void TestStruct()
        {
            var matFile = ReadHdfTestFile("struct");
            var structure = matFile["struct_"].Value as IStructureArray;
            Assert.That(structure, Is.Not.Null);
            Assert.That(structure.FieldNames, Is.EquivalentTo(new[] { "x", "y" }));
            var element = structure[0, 0];
            Assert.That(element.ContainsKey("x"), Is.True);
            Assert.That(element.Count, Is.EqualTo(2));
            Assert.That(element.TryGetValue("x", out var _), Is.True);
            Assert.That(element.TryGetValue("z", out var _), Is.False);
            Assert.That(element.Keys, Has.Exactly(2).Items);
            Assert.That(element.Values, Has.Exactly(2).Items);
            var keys = element.Select(pair => pair.Key);
            Assert.That(keys, Is.EquivalentTo(new[] { "x", "y" }));

            Assert.That((element["x"] as IArrayOf<double>)?[0], Is.EqualTo(12.345));

            Assert.That((structure["x", 0, 0] as IArrayOf<double>)?[0], Is.EqualTo(12.345));
            Assert.That((structure["y", 0, 0] as ICharArray)?.String, Is.EqualTo("abc"));
            Assert.That((structure["x", 1, 0] as ICharArray)?.String, Is.EqualTo("xyz"));
            Assert.That(structure["y", 1, 0].IsEmpty, Is.True);
            Assert.That((structure["x", 0, 1] as IArrayOf<double>)?[0], Is.EqualTo(2.0));
            Assert.That((structure["y", 0, 1] as IArrayOf<double>)?[0], Is.EqualTo(13.0));
            Assert.That(structure["x", 1, 1].IsEmpty, Is.True);
            Assert.That((structure["y", 1, 1] as ICharArray)?[0, 0], Is.EqualTo('a'));
            Assert.That(((structure["x", 0, 2] as ICellArray)?[0] as ICharArray)?.String, Is.EqualTo("x"));
            Assert.That(((structure["x", 0, 2] as ICellArray)?[1] as ICharArray)?.String, Is.EqualTo("yz"));
            Assert.That((structure["y", 0, 2] as IArrayOf<double>)?.Dimensions, Is.EqualTo(new[] { 2, 3 }));
            Assert.That((structure["y", 0, 2] as IArrayOf<double>)?[0, 2], Is.EqualTo(3.0));
            Assert.That((structure["x", 1, 2] as IArrayOf<float>)?[0], Is.EqualTo(1.5f));
            Assert.That(structure["y", 1, 2].IsEmpty, Is.True);
        }

        /// <summary>
        /// Test reading a logical array.
        /// </summary>
        [Test]
        public void TestLogical()
        {
            var matFile = ReadHdfTestFile("logical");
            var array = matFile["logical_"].Value;
            var logicalArray = array as IArrayOf<bool>;
            Assert.That(logicalArray, Is.Not.Null);
            Assert.That(logicalArray[0, 0], Is.True);
            Assert.That(logicalArray[0, 1], Is.True);
            Assert.That(logicalArray[0, 2], Is.False);
            Assert.That(logicalArray[1, 0], Is.False);
            Assert.That(logicalArray[1, 1], Is.True);
            Assert.That(logicalArray[1, 2], Is.True);
        }

        private static void CheckComplexLimits<T>(IArrayOf<ComplexOf<T>> array, T[] limits)
            where T : struct
        {
            Assert.That(array, Is.Not.Null);
            Assert.That(array.Dimensions, Is.EqualTo(new[] { 1, 2 }));
            Assert.That(array[0], Is.EqualTo(new ComplexOf<T>(limits[0], limits[1])));
            Assert.That(array[1], Is.EqualTo(new ComplexOf<T>(limits[1], limits[0])));
        }

        private static void CheckLimits<T>(IArrayOf<T> array, T[] limits)
            where T : struct
        {
            Assert.That(array, Is.Not.Null);
            Assert.That(array.Dimensions, Is.EqualTo(new[] { 1, 2 }));
            Assert.That(array.Data, Is.EqualTo(limits));
        }

        private static AbstractTestDataFactory<IMatFile> GetTests(string factoryName) =>
            new MatTestDataFactory(Path.Combine(TestDirectory, factoryName));

        private IMatFile ReadHdfTestFile(string testName)
        {
            return GetTests("hdf")[testName];
        }
    }
}