using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Avalonia_Services.Core
{
    /// <summary>
    /// 单个端点定义。
    /// </summary>
    public class ServiceEndpoint
    {
        /// <summary>路由路径，如 "api/wData"</summary>
        public string Pattern { get; init; } = string.Empty;

        /// <summary>HTTP 方法（GET/POST/PUT/DELETE）</summary>
        public string HttpMethod { get; init; } = "GET";

        /// <summary>端点名称（用于 OpenAPI / 日志）</summary>
        public string? Name { get; set; }

        /// <summary>端点处理器</summary>
        public Func<ServiceEndpointContext, Task<object?>> Handler { get; init; } = _ => Task.FromResult<object?>(null);

        /// <summary>该端点专属的过滤器（按顺序执行）</summary>
        public List<IEndpointFilter> Filters { get; init; } = new();

        /// <summary>是否需要鉴权</summary>
        public bool RequireAuthorization { get; set; }

        /// <summary>鉴权策略名</summary>
        public string? Policy { get; set; }

        /// <summary>
        /// 设置端点名称（Fluent API）。
        /// </summary>
        public ServiceEndpoint WithName(string name)
        {
            Name = name;
            return this;
        }
    }

    /// <summary>
    /// 端点集合 —— 所有端点的注册中心。在 Avalonia-Services 中统一配置。
    /// </summary>
    public class ServiceEndpointCollection
    {
        /// <summary>所有已注册的端点</summary>
        public List<ServiceEndpoint> Endpoints { get; } = new();

        /// <summary>作用于所有端点的全局过滤器</summary>
        public List<IEndpointFilter> GlobalFilters { get; } = new();

        /// <summary>
        /// 注册一个端点。
        /// </summary>
        public ServiceEndpoint MapGet(string pattern, Func<ServiceEndpointContext, Task<object?>> handler)
        {
            return AddEndpoint(pattern, "GET", handler);
        }

        /// <summary>
        /// 注册一个 POST 端点。
        /// </summary>
        public ServiceEndpoint MapPost(string pattern, Func<ServiceEndpointContext, Task<object?>> handler)
        {
            return AddEndpoint(pattern, "POST", handler);
        }

        /// <summary>
        /// 注册一个 PUT 端点。
        /// </summary>
        public ServiceEndpoint MapPut(string pattern, Func<ServiceEndpointContext, Task<object?>> handler)
        {
            return AddEndpoint(pattern, "PUT", handler);
        }

        /// <summary>
        /// 注册一个 DELETE 端点。
        /// </summary>
        public ServiceEndpoint MapDelete(string pattern, Func<ServiceEndpointContext, Task<object?>> handler)
        {
            return AddEndpoint(pattern, "DELETE", handler);
        }

        /// <summary>
        /// 添加全局过滤器（作用于所有端点）。
        /// </summary>
        public ServiceEndpointCollection AddGlobalFilter(IEndpointFilter filter)
        {
            GlobalFilters.Add(filter);
            return this;
        }

        /// <summary>
        /// 通过匿名函数添加全局过滤器。
        /// </summary>
        public ServiceEndpointCollection AddGlobalFilter(Func<ServiceEndpointContext, EndpointFilterDelegate, Task> filter)
        {
            GlobalFilters.Add(new AnonymousEndpointFilter(filter));
            return this;
        }

        private ServiceEndpoint AddEndpoint(string pattern, string method, Func<ServiceEndpointContext, Task<object?>> handler)
        {
            var endpoint = new ServiceEndpoint
            {
                Pattern = pattern,
                HttpMethod = method,
                Handler = handler,
            };
            Endpoints.Add(endpoint);
            return endpoint;
        }
    }

    /// <summary>
    /// 构建器 —— 提供 Fluent API 来配置所有端点。
    /// </summary>
    public class ServiceEndpointBuilder
    {
        /// <summary>
        /// 端点集合
        /// </summary>
        public ServiceEndpointCollection Endpoints { get; } = new();

        /// <summary>
        /// 鉴权服务（默认匿名）
        /// </summary>
        public IAuthService AuthService { get; set; } = new AnonymousAuthService();

        /// <summary>
        /// 配置端点（在此方法中调用 endpoints.MapGet 等）。
        /// </summary>
        public ServiceEndpointBuilder ConfigureEndpoints(Action<ServiceEndpointCollection> configure)
        {
            configure(Endpoints);
            return this;
        }

        /// <summary>
        /// 设置鉴权服务。
        /// </summary>
        public ServiceEndpointBuilder UseAuthService(IAuthService authService)
        {
            AuthService = authService;
            return this;
        }

        /// <summary>
        /// 构建最终的端点集合。
        /// </summary>
        public ServiceEndpointCollection Build()
        {
            return Endpoints;
        }
    }
}