using SuiteLink.Client.Protocol;

namespace SuiteLink.Client.Tests.Protocol;

public sealed class SuiteLinkFrameReaderTests
{
    [Fact]
    public void ParseFrame_WithValidFrame_ParsesMessageTypeAndPayload()
    {
        var bytes = new byte[]
        {
            0x05, 0x00,
            0x00, 0x09,
            0x01, 0x02,
            0xA5
        };

        var frame = SuiteLinkFrameReader.ParseFrame(bytes);

        Assert.Equal((ushort)0x0900, frame.MessageType);
        Assert.Equal(new byte[] { 0x01, 0x02 }, frame.Payload.ToArray());
        Assert.Equal((ushort)5, frame.RemainingLength);
    }

    [Fact]
    public void ParseFrame_WithInvalidMarker_ThrowsFormatException()
    {
        var bytes = new byte[]
        {
            0x03, 0x00,
            0x40, 0x24,
            0x00
        };

        var exception = Assert.Throws<FormatException>(() => SuiteLinkFrameReader.ParseFrame(bytes));

        Assert.Contains("marker", exception.Message, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void ParseFrame_WithTooShortInput_ThrowsFormatException()
    {
        var bytes = new byte[] { 0x03, 0x00, 0x40, 0x24 };

        Assert.Throws<FormatException>(() => SuiteLinkFrameReader.ParseFrame(bytes));
    }

    [Fact]
    public void ParseFrame_WithRemainingLengthBelowMinimum_ThrowsFormatException()
    {
        var bytes = new byte[]
        {
            0x02, 0x00,
            0x40, 0x24
        };

        Assert.Throws<FormatException>(() => SuiteLinkFrameReader.ParseFrame(bytes));
    }

    [Fact]
    public void ParseFrame_WithTruncatedInput_ThrowsFormatException()
    {
        var bytes = new byte[]
        {
            0x05, 0x00,
            0x40, 0x24,
            0x01,
            0xA5
        };

        Assert.Throws<FormatException>(() => SuiteLinkFrameReader.ParseFrame(bytes));
    }

    [Fact]
    public void TryParseFrame_WithExtraBytes_ReturnsFrameAndConsumedLength()
    {
        var bytes = new byte[]
        {
            0x03, 0x00,
            0x40, 0x24,
            0xA5,
            0xFF, 0xEE
        };

        var parsed = SuiteLinkFrameReader.TryParseFrame(bytes, out var frame, out var consumed);

        Assert.True(parsed);
        Assert.Equal(5, consumed);
        Assert.Equal((ushort)0x2440, frame.MessageType);
        Assert.True(frame.Payload.IsEmpty);
    }

    [Fact]
    public void ParseFrame_WithExtraBytes_ThrowsFormatException()
    {
        var bytes = new byte[]
        {
            0x03, 0x00,
            0x40, 0x24,
            0xA5,
            0xFF
        };

        Assert.Throws<FormatException>(() => SuiteLinkFrameReader.ParseFrame(bytes));
    }

    [Fact]
    public void TryParseFrame_WithIncompleteBuffer_ReturnsFalse()
    {
        var bytes = new byte[]
        {
            0x05, 0x00,
            0x00, 0x09,
            0x01
        };

        var parsed = SuiteLinkFrameReader.TryParseFrame(bytes, out _, out var consumed);

        Assert.False(parsed);
        Assert.Equal(0, consumed);
    }
}