using System.Text.Json;
using Fleet.Core;
using Fleet.Rpc;
using Microsoft.Extensions.DependencyInjection;
using MoShiro.Backend.Application;
using MoShiro.TestSupport;

namespace MoShiro.Backend.Tests;

public sealed class VersionRequirementTests : IClassFixture<BackendFixture>
{
    private readonly BackendFixture _backend;

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

    [Fact]
    public async Task AnAgentBelowTheRequiredVersion_IsRejectedAtHello_AndGetsInOnceTheRequirementIsMet()
    {
        BackendOptions options = _backend.App.Services.GetRequiredService<BackendOptions>();
        options.MinAgentVersion = "9.0.0"; // 模拟器的版本是 0.0.1-sim
        try
        {
            await using AgentSimulator old = await _backend.ConnectAgentAsync(hello: false);
            var hello = new HelloParams { NodeVersion = "0.0.1-sim", NowUtcMs = TimeProvider.System.GetUtcNow().ToUnixTimeMilliseconds() };
            RpcMessage reply = await old.RequestRawAsync(FleetMethods.Hello, JsonSerializer.SerializeToElement(hello, FleetRpcContext.Default.HelloParams));
            Assert.Equal(FleetErrors.VersionRequired.Value, reply.Error!.Data!.Code);
            Assert.Contains("9.0.0", reply.Error.Message);
        }
        finally
        {
            options.MinAgentVersion = null; // 共用的后端：恢复，别影响别的测试
        }

        await using AgentSimulator ok = await _backend.ConnectAgentAsync();
        Assert.True(_backend.App.Services.GetRequiredService<MoShiro.Backend.Application.IAgentGateway>().IsOnline(ok.NodeId));
    }

    [Fact]
    [Trait("Category", "Slow")]
    public async Task AnAgentTheBackendRejectedForItsVersion_TriesAgainEveryFiveSeconds_AndComesOnlineWhenAccepted()
    {
        BackendOptions options = _backend.App.Services.GetRequiredService<BackendOptions>();
        IAgentGateway gateway = _backend.App.Services.GetRequiredService<IAgentGateway>();
        options.MinAgentVersion = "999.0.0";
        try
        {
            await using AgentHarness agent = await AgentHarness.StartAsync(_backend, waitForConnection: false);
            await Task.Delay(TimeSpan.FromSeconds(2));
            Assert.False(gateway.IsOnline(agent.NodeId));

            options.MinAgentVersion = null; // 通过了：下一次握手（最迟 5 秒）就上线
            await BackendFixture.EventuallyAsync(() => Task.FromResult(gateway.IsOnline(agent.NodeId)), TimeSpan.FromSeconds(12));
        }
        finally
        {
            options.MinAgentVersion = null;
        }
    }

    [Fact]
    [Trait("Category", "Slow")]
    public async Task AnAgentThatRequiresANewerBackend_DoesNotGoOnline_AndKeepsChecking()
    {
        IAgentGateway gateway = _backend.App.Services.GetRequiredService<IAgentGateway>();
        await using AgentHarness agent = await AgentHarness.StartAsync(_backend, config => config.Fleet.MinServerVersion = "999.0.0", waitForConnection: false);
        await Task.Delay(TimeSpan.FromSeconds(7)); // 至少重试过一次
        Assert.False(gateway.IsOnline(agent.NodeId));
    }
}