using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Claims;
using System.Security.Principal;
using System.Text;
using System.Threading.Tasks;

namespace CloudBuilder.Core.Extensions
{
    /// <summary>
    /// <see cref="ClaimsIdentity"/>扩展操作类
    /// </summary>
    public static class ClaimsIdentityExtensions
    {
        /// <summary>
        /// 获取指定类型的Claim值
        /// </summary>
        public static string GetClaimValueFirstOrDefault(this IIdentity identity, string type)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.FindFirst(type)?.Value;
        }

        /// <summary>
        /// 获取指定类型的所有Claim值
        /// </summary>
        public static string[] GetClaimValues(this IIdentity identity, string type)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.Claims.Where(m => m.Type == type).Select(m => m.Value).ToArray();
        }

        /// <summary>
        /// 获取用户ID
        /// </summary>
        public static T GetUserId<T>(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return default(T);
            }
            string value = claimsIdentity.FindFirst(ClaimTypes.NameIdentifier)?.Value;
            if (value == null)
            {
                return default(T);
            }
            return value.CastTo<T>();
        }

        /// <summary>
        /// 获取用户ID
        /// </summary>
        public static string GetUserId(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.FindFirst(ClaimTypes.NameIdentifier)?.Value;
        }

        /// <summary>
        /// 获取用户名
        /// </summary>
        public static string GetUserName(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.FindFirst(ClaimTypes.Name)?.Value;
        }

        /// <summary>
        /// 获取Email
        /// </summary>
        public static string GetEmail(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.FindFirst(ClaimTypes.Email)?.Value;
        }

        /// <summary>
        /// 获取昵称
        /// </summary>
        public static string GetNickName(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return null;
            }
            return claimsIdentity.FindFirst(ClaimTypes.GivenName)?.Value;
        }

        /// <summary>
        /// 移除指定类型的声明
        /// </summary>
        public static void RemoveClaim(this IIdentity identity, string claimType)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return;
            }
            Claim claim = claimsIdentity.FindFirst(claimType);
            if (claim == null)
            {
                return;
            }
            claimsIdentity.RemoveClaim(claim);
        }

        /// <summary>
        /// 获取所有角色
        /// </summary>
        public static string[] GetRoles(this IIdentity identity)
        {
            if (!(identity is ClaimsIdentity claimsIdentity))
            {
                return new string[0];
            }
            return claimsIdentity.FindAll(ClaimTypes.Role).SelectMany(m =>
            {
                string[] roles = m.Value.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
                return roles;
            }).ToArray();
        }
    }
}