using FinalFactory.Rendezvous.Contracts;

namespace FinalFactory.Rendezvous.Tests.Contracts;

public sealed class NatPunchRequestTokenCodecTests
{
    [Theory]
    [InlineData(NatPunchPeerRole.HostPresence)]
    [InlineData(NatPunchPeerRole.Host)]
    [InlineData(NatPunchPeerRole.Client)]
    public void FixedSizeTokensRoundTripBelowLiteNetLibLimit(NatPunchPeerRole role)
    {
        MediationHandle handle = new(Guid.NewGuid());
        const string capability = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";

        string encoded = NatPunchRequestTokenCodec.Encode(role, handle, capability);

        Assert.Equal(NatPunchRequestTokenCodec.EncodedLength, encoded.Length);
        Assert.True(encoded.Length <= ContractLimits.LiteNetLibNatTokenMaxCharacters);
        Assert.True(NatPunchRequestTokenCodec.TryDecode(encoded, out NatPunchRequestToken? decoded));
        Assert.NotNull(decoded);
        Assert.Equal(role, decoded.Role);
        Assert.Equal(handle, decoded.MediationHandle);
        Assert.Equal(capability, decoded.Capability);
        Assert.DoesNotContain(capability, decoded.ToString(), StringComparison.Ordinal);
    }

    [Fact]
    public void MalformedAndNonCanonicalTokensAreRejected()
    {
        string valid = NatPunchRequestTokenCodec.Encode(
            NatPunchPeerRole.Client,
            new MediationHandle(Guid.Parse("00112233-4455-6677-8899-aabbccddeeff")),
            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA");
        string uppercaseHandle = valid[..6]
            + valid.Substring(6, 32).ToUpperInvariant()
            + valid[38..];

        Assert.False(NatPunchRequestTokenCodec.TryDecode(null, out _));
        Assert.False(NatPunchRequestTokenCodec.TryDecode(valid[..^1], out _));
        Assert.False(NatPunchRequestTokenCodec.TryDecode("x" + valid[1..], out _));
        Assert.False(NatPunchRequestTokenCodec.TryDecode(valid[..^1] + "x", out _));
        Assert.False(NatPunchRequestTokenCodec.TryDecode(uppercaseHandle, out _));
        Assert.Throws<ArgumentException>(() => NatPunchRequestTokenCodec.Encode(
            (NatPunchPeerRole)99,
            new MediationHandle(Guid.NewGuid()),
            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"));
    }

    [Fact]
    public void FixedWireLengthHasADedicatedLiteNetSafeContractLimit()
    {
        Assert.Equal(192, ContractLimits.NatPunchRequestTokenCharacters);
        Assert.Equal(
            ContractLimits.NatPunchRequestTokenCharacters,
            NatPunchRequestTokenCodec.EncodedLength);
        Assert.True(
            ContractLimits.NatPunchRequestTokenCharacters
            <= ContractLimits.LiteNetLibNatTokenMaxCharacters);
    }
}