using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Formats.Asn1;
using VoiceCat.Crypto;

namespace VoiceCat.Tests;

public class IdentityTests
{
    [Fact]
    public void CredentialsSurviveRestartAndBindIdentityIntoCertificate()
    {
        string directory = Path.Combine(Path.GetTempPath(), "voicecat-credentials-" + Guid.NewGuid());
        try
        {
            string identityFingerprint, certificateFingerprint;
            using (var credentials = ServerCredentials.LoadOrCreate(directory, "Server, with punctuation"))
            {
                identityFingerprint = credentials.Identity.Fingerprint;
                certificateFingerprint = credentials.CertificateFingerprint;
                using var tls = credentials.CreateTlsSession();
                Assert.False(tls.IsReady);
                byte[] identity = File.ReadAllBytes(Path.Combine(directory, "identity.key"));
                Assert.Equal(96, identity.Length);
                Assert.Equal(identity[..32], identity[64..]);
                using var certificate = X509Certificate2.CreateFromPem(File.ReadAllText(Path.Combine(directory, "server.crt")));
                var san = new AsnReader(certificate.Extensions["2.5.29.17"]!.RawData, AsnEncodingRules.DER).ReadSequence();
                Assert.Equal("urn:voicecat:identity:ed25519:" + Convert.ToHexString(credentials.Identity.PublicKey).ToLowerInvariant(),
                    san.ReadCharacterString(UniversalTagNumber.IA5String, new Asn1Tag(TagClass.ContextSpecific, 6)));
                Assert.False(san.HasData);
            }
            using var restored = ServerCredentials.LoadOrCreate(directory, "ignored after creation");
            Assert.Equal(identityFingerprint, restored.Identity.Fingerprint);
            Assert.Equal(certificateFingerprint, restored.CertificateFingerprint);
            File.Delete(Path.Combine(directory, "server.key"));
            Assert.Throws<InvalidDataException>(() => ServerCredentials.LoadOrCreate(directory, "unchanged"));
            using var stillPresent = ServerIdentity.Load(Path.Combine(directory, "identity.key"));
            Assert.Equal(identityFingerprint, stillPresent.Fingerprint);
        }
        finally { if (Directory.Exists(directory)) Directory.Delete(directory, true); }
    }

    [Fact]
    public void TofuRequiresExplicitPinAndPreservesCppFileFormat()
    {
        string directory = Path.Combine(Path.GetTempPath(), "voicecat-pins-" + Guid.NewGuid());
        Directory.CreateDirectory(directory);
        string path = Path.Combine(directory, "pins.txt");
        string fingerprint = Convert.ToHexString(RandomNumberGenerator.GetBytes(32));
        try
        {
            var store = new TofuStore(path);
            Assert.Equal(TofuStatus.FirstConnect, store.Check("localhost", 9987, fingerprint));
            Assert.False(File.Exists(path));
            store.Pin("localhost", 9987, fingerprint);
            Assert.Equal($"localhost:9987 {fingerprint.ToLowerInvariant()}\n", File.ReadAllText(path));
            store = new(path);
            Assert.Equal(TofuStatus.Matched, store.Check("localhost", 9987, fingerprint));
            Assert.Equal(TofuStatus.Mismatch, store.Check("localhost", 9987, new string('0', 64)));
            Assert.Equal(TofuStatus.Matched, new TofuStore(path).Check("localhost", 9987, fingerprint));
            store.Remove("localhost", 9987);
            Assert.Equal(TofuStatus.FirstConnect, new TofuStore(path).Check("localhost", 9987, fingerprint));
            File.WriteAllText(path, "localhost:9987 " + new string('g', 64));
            Assert.Throws<InvalidDataException>(() => new TofuStore(path));
        }
        finally { Directory.Delete(directory, true); }
    }
}