using Fleet.Server;
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using MoShiro.Backend.Api;
using MoShiro.Backend.Application;
using MoShiro.Backend.Gateway;
using MoShiro.Backend.Storage.Sqlite;

namespace MoShiro.Backend;

/// <summary>
/// 组合根：在这里显式注册所有层。配置来自 <c>appsettings.json</c>、环境变量（<c>MoShiro__DataDirectory</c> 等）和命令行。
/// 测试用 <see cref="Build"/> 在真实端口上启动整个后端。
/// </summary>
public static class BackendHost
{
    public const string ConfigurationSection = "MoShiro";
    public const int MaxRequestBodyBytes = 64 * 1024;

    public static WebApplication Build(string[] args, Action<BackendOptions>? configureOptions = null, TimeProvider? time = null)
    {
        WebApplicationBuilder builder = WebApplication.CreateSlimBuilder(args);

        var options = new BackendOptions();
        builder.Configuration.GetSection(ConfigurationSection).Bind(options);
        configureOptions?.Invoke(options);

        builder.WebHost.ConfigureKestrel(kestrel => kestrel.Limits.MaxRequestBodySize = MaxRequestBodyBytes);
        builder.Logging.AddSimpleConsole(console =>
        {
            console.SingleLine = true;
            console.UseUtcTimestamp = true;
            console.TimestampFormat = "yyyy-MM-ddTHH:mm:ss.fffZ ";
        });

        IServiceCollection services = builder.Services;
        services.AddSingleton(time ?? TimeProvider.System);
        services.AddMoShiroSqlite(options.DataDirectory);
        // 国家和运营商：Backend 用节点的来源地址查一次（Probe、Agent 不访问任何外部服务）；地址留空就不查
        if (string.IsNullOrWhiteSpace(options.GeoLookupUrl))
        {
            services.AddSingleton<IGeoLookup, NoGeoLookup>();
        }
        else
        {
            services.AddSingleton<IGeoLookup>(new HttpGeoLookup(options.GeoLookupUrl));
        }

        services.AddMoShiroApplication(options);
        services.AddMoShiroGateway();
        services.AddMoShiroApi();

        WebApplication app = builder.Build();
        // 静默死亡的 Agent（断电、断网）不会关闭连接：15 秒一个 Ping，20 秒没有 Pong 就关闭，这样面板上的在线状态才可信
        app.UseWebSockets(new WebSocketOptions { KeepAliveInterval = TimeSpan.FromSeconds(15), KeepAliveTimeout = TimeSpan.FromSeconds(20) });
        app.UseMoShiroCors(options.CorsOrigins);
        app.UseMoShiroApi();
        app.MapMoShiroApi();
        app.MapFleetEnrollment("/api/agent/v1/enroll");
        app.MapFleetLink("/api/agent/v1/rpc");
        return app;
    }
}