using Fleet.Core;
using Fleet.Rpc;
using Fleet.Server;
using Microsoft.Extensions.DependencyInjection;
using MoShiro.Backend.Application;
using MoShiro.Protocol;

namespace MoShiro.Backend.Gateway;

public static class GatewayServiceCollectionExtensions
{
    /// <summary>
    /// 在 Fleet.Server 之上接入 MoShiro：期望状态（TaskSet、DialTargets）、RawChunk 收件箱、<c>moshiro.*</c> 方法、注册挂钩和节点事件。
    /// 需要事先注册 <see cref="IFleetStore"/> 和 <see cref="TimeProvider"/>，并在 <c>AddMoShiroApplication</c> 之后调用。
    /// </summary>
    public static IServiceCollection AddMoShiroGateway(this IServiceCollection services)
    {
        services.AddSingleton<IAgentGateway, FleetGateway>();
        services.AddSingleton<IFleetVersionPolicy, BackendVersionPolicy>();
        services.AddHostedService<ConnectionShutdown>();
        services.AddFleetEnrollment();
        services.AddFleetServer(options => options.NodeIdPrefix = AgentIds.Prefix)
            .AddState<TaskSetStateProvider>()
            .AddState<DialTargetsStateProvider>()
            .AddInbox<RawChunkInbox>()
            .WithMethods(MoShiroMethodTable.Table)
            .MapMethods(MapMoShiroMethods);
        return services;
    }

    private static void MapMoShiroMethods(RpcRouter<NodeCallContext> router, IServiceProvider services)
    {
        router
            .OnNotify(
                MoShiroMethods.Event,
                MoShiroJsonContext.Default.AgentEventParams,
                (context, parameters, ct) => services.GetRequiredService<AgentEventService>().OnEventAsync(context.Node.Id, parameters, ct))
            .OnNotify(
                MoShiroMethods.Host,
                MoShiroJsonContext.Default.HostSnapshot,
                (context, snapshot, ct) => services.GetRequiredService<HostStatusService>().OnHostAsync(context.Node.Id, snapshot, ct))
            .OnNotify(
                MoShiroMethods.TestStatus,
                MoShiroJsonContext.Default.TestStatusParams,
                (context, parameters, ct) => services.GetRequiredService<TestService>().OnStatusAsync(context.Node.Id, parameters, ct));
    }
}

/// <summary>握手时的版本要求：告诉 Agent 面板的版本，并要求 Agent 不低于配置的最低版本。</summary>
internal sealed class BackendVersionPolicy(BackendOptions options) : IFleetVersionPolicy
{
    public string? ServerVersion => BuildInfo.Version;

    public string? MinNodeVersion => string.IsNullOrWhiteSpace(options.MinAgentVersion) ? null : options.MinAgentVersion;
}