using Admin.Core.Common;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.IdentityModel.Tokens;
using System;
using System.Collections.Generic;
using System.Security.Claims;
using System.Text;

namespace Admin.Core.Extensions
{
    /// <summary>
    /// 系统 授权服务 配置
    /// </summary>
    public static class AuthorizationSetup
    {
        public static void AddAuthorizationSetup(this IServiceCollection services)
        {
            if (services == null) throw new ArgumentNullException(nameof(services));

            // 以下四种常见的授权方式。

            // 1、这个很简单，其他什么都不用做， 只需要在API层的controller上边，增加特性即可
            // [Authorize(Roles = "Admin,System")]


            // 2、这个和上边的异曲同工，好处就是不用在controller中，写多个 roles 。
            // 然后这么写 [Authorize(Policy = "Admin")]
            services.AddAuthorization(options =>
            {
                options.AddPolicy("Client", policy => policy.RequireRole("Client").Build());
                options.AddPolicy("Admin", policy => policy.RequireRole("Admin").Build());
                options.AddPolicy("SystemOrAdmin", policy => policy.RequireRole("Admin", "System"));
                options.AddPolicy("A_S_O", policy => policy.RequireRole("Admin", "System", "Others"));
            });




            #region 参数
            //读取配置文件
            var symmetricKeyAsBase64 = AppSecretConfig.Audience_Secret_String;
            var keyByteArray = Encoding.ASCII.GetBytes(symmetricKeyAsBase64);
            var signingKey = new SymmetricSecurityKey(keyByteArray);
            var Issuer = Appsettings.app(new string[] { "Audience", "Issuer" });
            var Audience = Appsettings.app(new string[] { "Audience", "Audience" });
            var Expiration = Appsettings.app(new string[] { "Audience", "Expiration" });

            var signingCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256);

            // 如果要数据库动态绑定，这里先留个空，后边处理器里动态赋值
            var permission = new List<PermissionItem>();

            // 角色与接口的权限要求参数
            var permissionRequirement = new PermissionRequirement(
                "/api/denied",// 拒绝授权的跳转地址（目前无用）
                permission,
                ClaimTypes.Role,//基于角色的授权
                Issuer,//发行人
                Audience,//听众
                signingCredentials,//签名凭据
                expiration: TimeSpan.FromSeconds(double.Parse(Expiration))//接口的过期时间
                );
            #endregion
            // 3、自定义复杂的策略授权
            services.AddAuthorization(options =>
            {
                options.AddPolicy(Permissions.Name,
                         policy => policy.Requirements.Add(permissionRequirement));
            });


            // 4、基于Scope策略授权
            //services.AddAuthorization(options =>
            //{
            //    options.AddPolicy("Scope_AdminModule_Policy", builder =>
            //    {
            //        //客户端Scope中包含Admin.core.api.AdminModule才能访问
            //        // 同时引用nuget包：IdentityServer4.AccessTokenValidation
            //        builder.RequireScope("Admin.core.api.AdminModule");
            //    });

            //    // 其他 Scope 策略
            //    // ...

            //});

            // 这里冗余写了一次,因为很多人看不到
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            // 注入权限处理器
            services.AddScoped<IAuthorizationHandler, PermissionHandler>();
            services.AddSingleton(permissionRequirement);
        }
    }
}