using Fleet.Core;
using Microsoft.Extensions.Time.Testing;
using MoShiro.Protocol;

namespace MoShiro.Measurement.Tests;

public sealed class RestartUpdaterTests
{
    private readonly List<string> _restarts = [];

    private RestartUpdater Create(string tag = "dev-aaa", string commit = "aaa", long builtAt = 1_000) =>
        new("agent", _restarts.Add, TimeProvider.System, NullNodeLog.Instance, tag, commit, builtAt);

    private static UpdateOfferParams Offer(string tag, long seq, string component = "agent", string commit = "bbb") =>
        new() { Manifest = $"{{\"component\":\"{component}\",\"tag\":\"{tag}\",\"version\":\"0.4.0\",\"commit\":\"{commit}\",\"digest\":\"sha256:{new string('a', 64)}\",\"seq\":{seq}}}", Signature = "ignored" };

    [Fact]
    public void ANewerRelease_IsAvailable_AndOnlyARequestRestartsTheNode()
    {
        RestartUpdater updater = Create();
        updater.Offer(Offer("dev-bbb", 2_000));
        UpdateStatus status = updater.Status();
        Assert.Equal("available", status.State);
        Assert.Equal("dev-bbb", status.Available!.Tag);
        Assert.Equal(2_000, status.Available.Seq);
        Assert.Empty(_restarts);

        Assert.True(updater.RequestApply());
        Assert.Equal(["update"], _restarts);
        Assert.Equal("applying", updater.Status().State);
    }

    [Fact]
    public void TheReleaseThatIsAlreadyRunning_IsUpToDate_ByTagOrByCommit()
    {
        RestartUpdater updater = Create();
        updater.Offer(Offer("dev-aaa", 2_000));
        Assert.Equal("up_to_date", updater.Status().State);
        updater.Offer(Offer("dev-other-tag", 2_000, commit: "aaa"));
        Assert.Equal("up_to_date", updater.Status().State);
        Assert.False(updater.RequestApply());
        Assert.Empty(_restarts);
    }

    [Fact]
    public void AnOfferOlderThanThisBuild_OrForAnotherComponent_IsNotAnUpdate()
    {
        RestartUpdater updater = Create(builtAt: 5_000);
        updater.Offer(Offer("dev-bbb", 2_000));
        Assert.Equal("up_to_date", updater.Status().State);
        updater.Offer(Offer("dev-ccc", 9_000, component: "probe"));
        Assert.Equal("up_to_date", updater.Status().State);
        Assert.False(updater.RequestApply());
    }

    [Fact]
    public void GarbageOffers_AreIgnored()
    {
        RestartUpdater updater = Create();
        updater.Offer(new UpdateOfferParams { Manifest = "not json", Signature = "x" });
        updater.Offer(new UpdateOfferParams { Manifest = new string('x', 5000), Signature = "x" });
        updater.Offer(new UpdateOfferParams { Manifest = "{\"component\":\"agent\"}", Signature = "x" });
        Assert.Equal("up_to_date", updater.Status().State);
        Assert.False(updater.RequestApply());
    }

    [Fact]
    public async Task TheAutoPolicy_RestartsByItself_ButNotBeforeTheMinimumUptime()
    {
        var time = new FakeTimeProvider(DateTimeOffset.FromUnixTimeSeconds(2_000_000_000));
        var updater = new RestartUpdater("agent", _restarts.Add, time, NullNodeLog.Instance, "dev-aaa", "aaa", 1_000, auto: true);
        updater.Offer(Offer("dev-bbb", 2_000));
        updater.Offer(Offer("dev-bbb", 2_000)); // 重连时面板会再发一次：不能排两个
        Assert.Empty(_restarts);
        time.Advance(TimeSpan.FromMinutes(9));
        await Task.Delay(50);
        Assert.Empty(_restarts);
        time.Advance(TimeSpan.FromMinutes(2));
        await WaitAsync(() => _restarts.Count == 1);
        Assert.Equal("applying", updater.Status().State);
        await Task.Delay(50);
        Assert.Single(_restarts);
    }

    [Fact]
    public async Task TheManualPolicy_NeverRestartsByItself()
    {
        var time = new FakeTimeProvider(DateTimeOffset.FromUnixTimeSeconds(2_000_000_000));
        var updater = new RestartUpdater("agent", _restarts.Add, time, NullNodeLog.Instance, "dev-aaa", "aaa", 1_000, auto: false);
        updater.Offer(Offer("dev-bbb", 2_000));
        time.Advance(TimeSpan.FromHours(1));
        await Task.Delay(50);
        Assert.Empty(_restarts);
        Assert.Equal("available", updater.Status().State);
    }

    private static async Task WaitAsync(Func<bool> condition)
    {
        for (int i = 0; i < 100 && !condition(); i++)
        {
            await Task.Delay(20);
        }

        Assert.True(condition());
    }

    [Fact]
    public void WithoutTheEnvironmentVariable_ThereIsNoUpdater()
    {
        Assert.Null(Environment.GetEnvironmentVariable(RestartUpdater.EnvironmentVariable));
        Assert.Null(RestartUpdater.FromEnvironment("agent", _restarts.Add, TimeProvider.System, NullNodeLog.Instance));
    }
}