// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

using SixLabors.ImageSharp.Memory;

namespace SixLabors.ImageSharp.Tests.Memory.DiscontiguousBuffers;

public partial class MemoryGroupTests
{
    public class CopyTo : MemoryGroupTestsBase
    {
        public static readonly TheoryData<int, int, int, int> WhenSourceBufferIsShorterOrEqual_Data =
            CopyAndTransformData;

        [Theory]
        [MemberData(nameof(WhenSourceBufferIsShorterOrEqual_Data))]
        public void WhenSourceBufferIsShorterOrEqual(int srcTotal, int srcBufLen, int trgTotal, int trgBufLen)
        {
            using MemoryGroup<int> src = this.CreateTestGroup(srcTotal, srcBufLen, true);
            using MemoryGroup<int> trg = this.CreateTestGroup(trgTotal, trgBufLen, false);

            src.CopyTo(trg);

            int pos = 0;
            MemoryGroupIndex i = src.MinIndex();
            MemoryGroupIndex j = trg.MinIndex();
            for (; i < src.MaxIndex(); i += 1, j += 1, pos++)
            {
                int a = src.GetElementAt(i);
                int b = trg.GetElementAt(j);

                Assert.True(a == b, $"Mismatch @ {pos} Expected: {a} Actual: {b}");
            }
        }

        [Fact]
        public void WhenTargetBufferTooShort_Throws()
        {
            using MemoryGroup<int> src = this.CreateTestGroup(10, 20, true);
            using MemoryGroup<int> trg = this.CreateTestGroup(5, 20, false);

            Assert.Throws<ArgumentOutOfRangeException>(() => src.CopyTo(trg));
        }

        [Theory]
        [InlineData(30, 10, 40)]
        [InlineData(42, 23, 42)]
        [InlineData(1, 3, 10)]
        [InlineData(0, 4, 0)]
        public void GroupToSpan_Success(long totalLength, int bufferLength, int spanLength)
        {
            using MemoryGroup<int> src = this.CreateTestGroup(totalLength, bufferLength, true);
            int[] trg = new int[spanLength];
            src.CopyTo(trg);

            int expected = 1;
            foreach (int val in trg.AsSpan().Slice(0, (int)totalLength))
            {
                Assert.Equal(expected, val);
                expected++;
            }
        }

        [Theory]
        [InlineData(20, 7, 19)]
        [InlineData(2, 1, 1)]
        public void GroupToSpan_OutOfRange(long totalLength, int bufferLength, int spanLength)
        {
            using MemoryGroup<int> src = this.CreateTestGroup(totalLength, bufferLength, true);
            int[] trg = new int[spanLength];
            Assert.ThrowsAny<ArgumentOutOfRangeException>(() => src.CopyTo(trg));
        }

        [Theory]
        [InlineData(30, 35, 10)]
        [InlineData(42, 23, 42)]
        [InlineData(10, 3, 1)]
        [InlineData(0, 3, 0)]
        public void SpanToGroup_Success(long totalLength, int bufferLength, int spanLength)
        {
            int[] src = new int[spanLength];
            for (int i = 0; i < src.Length; i++)
            {
                src[i] = i + 1;
            }

            using MemoryGroup<int> trg = this.CreateTestGroup(totalLength, bufferLength);
            src.AsSpan().CopyTo(trg);

            int position = 0;
            for (MemoryGroupIndex i = trg.MinIndex(); position < spanLength; i += 1, position++)
            {
                int expected = position + 1;
                Assert.Equal(expected, trg.GetElementAt(i));
            }
        }

        [Theory]
        [InlineData(10, 3, 11)]
        [InlineData(0, 3, 1)]
        public void SpanToGroup_OutOfRange(long totalLength, int bufferLength, int spanLength)
        {
            int[] src = new int[spanLength];
            using MemoryGroup<int> trg = this.CreateTestGroup(totalLength, bufferLength, true);
            Assert.ThrowsAny<ArgumentOutOfRangeException>(() => src.AsSpan().CopyTo(trg));
        }
    }
}