using MAX.Core.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace MAX.Framework.Interfaces
{
	/// <summary>
	/// 模块上下文：模块在「服务注册阶段」能拿到的全部宿主信息。
	/// 之所以包成一个对象，是为了以后要再补宿主的其他东西（日志、配置节、HostApplicationBuilder 等）时不用改接口签名。
	/// </summary>
	public sealed class ModuleContext
	{
		public ModuleContext(
			IServiceCollection services,
			IServiceRegistrar registrar,
			IConfiguration configuration,
			IHostEnvironment? environment = null)
		{
			Services = services;
			Registrar = registrar;
			Configuration = configuration;
			Environment = environment;
		}

		/// <summary>
		/// 服务集合（Microsoft.Extensions.DependencyInjection），等价于宿主里的 <c>builder.Services</c>
		/// </summary>
		public IServiceCollection Services { get; }

		/// <summary>
		/// 容器无关的注册器，等价于 <see cref="IStartup.Register"/> 里拿到的那个，便于以后换容器
		/// </summary>
		public IServiceRegistrar Registrar { get; }

		/// <summary>
		/// 应用配置，等价于宿主的 <c>builder.Configuration</c>（永不为 null；走旧的无参入口时是空配置）
		/// </summary>
		public IConfiguration Configuration { get; }

		/// <summary>
		/// 宿主环境，等价于宿主的 <c>builder.Environment</c>；走旧的无参入口时为 null
		/// </summary>
		public IHostEnvironment? Environment { get; }
	}
}