using System.Net;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json.Nodes;
using MoShiro.Backend.Api;
using MoShiro.Backend.Application;

namespace MoShiro.Backend.Tests;

/// <summary>
/// CI 登记清单不需要令牌，但清单必须带 CI 发布密钥的有效签名：令牌存在面板的数据库里，清库、重装或还没有 passkey 的时候就拿不到，
/// 而清单本来就是签名的，面板直接验签更简单，也没有长期令牌可偷。
/// </summary>
public sealed class ReleaseOfferTests : IClassFixture<BackendFixture>
{
    // openssl 生成的测试密钥对和签名（`openssl dgst -sha256 -sign`，DER）：证明验签接受 CI 脚本实际产出的格式
    private const string TestKey = "-----BEGIN PUBLIC KEY-----\nMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEQwlE2KjYWszeaTsng6CfPxhOqeIV\n+7dm940f7XfHJr9A6/OTiZ2YnhFWWipZ4Z4poPtb6hMW04tIARO8+Km34w==\n-----END PUBLIC KEY-----";
    private const string Manifest = "{\"schema\":1,\"component\":\"agent\",\"seq\":7}";
    private const string OpenSslSignature = "MEUCIDrOloi3otWBiCFcXEsPg6kHCS7G09PrO3hW+3AKXAiZAiEAvXgt9K+iZXnWiEgKdanBKbEoL0LyT/xuaEW6dAG0jDY=";

    private readonly BackendFixture _backend;

    public ReleaseOfferTests(BackendFixture backend)
    {
        _backend = backend;
    }

    [Fact]
    public void ASignatureFromOpenSsl_Verifies_AndAnyChangeDoesNot()
    {
        Assert.True(ReleaseSignature.Verify(TestKey, Manifest, OpenSslSignature));

        Assert.False(ReleaseSignature.Verify(TestKey, Manifest.Replace("7", "8", StringComparison.Ordinal), OpenSslSignature));
        Assert.False(ReleaseSignature.Verify(TestKey, Manifest + " ", OpenSslSignature));

        byte[] tampered = Convert.FromBase64String(OpenSslSignature);
        tampered[10] ^= 1;
        Assert.False(ReleaseSignature.Verify(TestKey, Manifest, Convert.ToBase64String(tampered)));
    }

    [Fact]
    public void AnotherKey_GarbageAndEmptyInputs_AreRejected()
    {
        using var other = ECDsa.Create(ECCurve.NamedCurves.nistP256);
        string signature = Convert.ToBase64String(other.SignData(Encoding.UTF8.GetBytes(Manifest), HashAlgorithmName.SHA256, DSASignatureFormat.Rfc3279DerSequence));

        Assert.False(ReleaseSignature.Verify(TestKey, Manifest, signature));
        Assert.False(ReleaseSignature.Verify(TestKey, Manifest, "not base64!!"));
        Assert.False(ReleaseSignature.Verify(TestKey, Manifest, ""));
        Assert.False(ReleaseSignature.Verify("not a key", Manifest, OpenSslSignature));
        // P1363（节点和 WebAuthn 用的格式）不是 CI 签名的格式
        Assert.False(ReleaseSignature.Verify(TestKey, Manifest, Convert.ToBase64String(new byte[64])));
    }

    [Fact]
    public void TheEmbeddedReleaseKey_IsAUsableP256PublicKey()
    {
        using var key = ECDsa.Create();
        key.ImportFromPem(InstallScripts.ReleaseKey());

        Assert.Equal(256, key.KeySize);
    }

    [Theory]
    [InlineData("{\"component\":\"agent\",\"channel\":\"dev\",\"image\":\"r/a\",\"digest\":\"sha256:0000000000000000000000000000000000000000000000000000000000000000\",\"seq\":99999999999}", "AAAA")]
    [InlineData("", "")]
    [InlineData("not json", "MEUCIDrOloi3otWBiCFcXEsPg6kHCS7G09PrO3hW+3AKXAiZAiEAvXgt9K+iZXnWiEgKdanBKbEoL0LyT/xuaEW6dAG0jDY=")]
    public async Task OfferWithoutAValidCiSignature_IsForbidden_EvenWithoutAnyToken(string manifest, string signature)
    {
        using HttpClient anonymous = _backend.NewClient();
        using HttpResponseMessage response = await anonymous.PostAsync("/api/release/offer", BackendFixture.Json(new JsonObject { ["manifest"] = manifest, ["signature"] = signature }));

        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
    }

    [Fact]
    public async Task OfferWithAValidSignature_IsAccepted_WithoutAnyToken()
    {
        long seq = TimeProvider.System.GetUtcNow().ToUnixTimeSeconds() * 1000; // backend 的 release 通道：不和别的用例抢 agent 的 seq
        string manifest = $$"""{"schema":1,"component":"backend","channel":"release","image":"registry.example/moshiro/moshiro-backend","digest":"sha256:0000000000000000000000000000000000000000000000000000000000000000","tag":"dev-x","version":"0.1.1","seq":{{seq}}}""";
        using HttpClient anonymous = _backend.NewClient();

        using HttpResponseMessage offered = await anonymous.PostAsync("/api/release/offer", BackendFixture.Json(new JsonObject { ["manifest"] = manifest, ["signature"] = TestReleaseKey.Sign(manifest) }));
        Assert.Equal(HttpStatusCode.Created, offered.StatusCode);
    }
}