using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Net.Http;
using System.Security.Claims;
using System.Text;
using YLErp;

namespace YLErp.Helpers
{
    /// <summary>
    /// 用户认证帮助类
    /// </summary>
    public class AuthHelper
    {
        public const string CookieAuthType = "yc_identity";

        public const string JwtAuthType = "yc_mapi";

        /// <summary>
        /// 登录Token过期时间（秒）
        /// </summary>
        public static int ExpireInSeconds => PS.Config?.ErpElement?.LoginTokenExpireSeconds ?? 3600 * 10; // 默认10小时

        public const string JwtIssuer = "yilian";
        
        public const string JwtAudience = "yilian";

        public const string JwtSecretKey = "GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrkzI1NiJ9eyJjbGFTT";

        public const string JwtUserToken = "###jwt###";

        public static string CreateJwtToken(ClaimsIdentity identity)
        {
            var key = new SymmetricSecurityKey(Convert.FromBase64String(JwtSecretKey));

            var claims = new ClaimsIdentity(identity);
            if (!claims.HasClaim(c => c.Type == "jti"))
            {
                claims.AddClaim(new Claim("jti", Guid.NewGuid().ToString("N")));
            }

            var tokenDescriptor = new SecurityTokenDescriptor
            {
                Subject = claims,
                Expires = DateTime.UtcNow.AddSeconds(ExpireInSeconds),
                Issuer = JwtIssuer,
                Audience = JwtAudience,
                SigningCredentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha512)
            };

            var tokenHandler = new JwtSecurityTokenHandler();

            var token = tokenHandler.CreateToken(tokenDescriptor);

            return tokenHandler.WriteToken(token);
        }

        /// <summary>
        /// 解析JWT token
        /// </summary>
        /// <param name="token">JWT token字符串</param>
        /// <returns>解析后的JWT token对象</returns>
        public static JwtSecurityToken ParseJwtToken(string token)
        {
            var tokenHandler = new JwtSecurityTokenHandler();
            return tokenHandler.ReadJwtToken(token);
        }

        /// <summary>
        /// 检查token是否需要续期
        /// </summary>
        /// <param name="token">JWT token对象</param>
        /// <param name="thresholdSeconds">续期阈值（秒）</param>
        /// <returns>是否需要续期</returns>
        public static bool NeedRefreshToken(JwtSecurityToken token, int thresholdSeconds = 3600)
        {
            var timeUntilExpiry = token.ValidTo - DateTime.UtcNow;
            return timeUntilExpiry.TotalSeconds < thresholdSeconds;
        }
    }
}