using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace RoadFlow.Utility
{
    public static class GuidExtensions
    {
        /// <summary>
        /// 生成新的GUID（有的需要生成连续的Guid,所以统一调用这里的方法）
        /// </summary>
        /// <returns></returns>
        public static Guid NewGuid()
        {
            return Guid.NewGuid();
        }

        /// <summary>
        /// 判断为空GUID
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static bool IsEmptyGuid(this Guid guid)
        {
            return guid == Guid.Empty;
        }

        /// <summary>
        /// 判断为空GUID
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static bool IsEmptyGuid(this Guid? guid)
        {
            return !guid.HasValue || guid.Value == Guid.Empty;
        }
        /// <summary>
        /// 判断不为空GUID
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static bool IsNotEmptyGuid(this string guid)
        {
            if (guid.IsNullOrWhiteSpace())
                return false;
            return guid.ToGuid().IsNotEmptyGuid();
        }

        /// <summary>
        /// 判断不为空GUID
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static bool IsNotEmptyGuid(this Guid guid)
        {
            return guid != Guid.Empty;
        }

        /// <summary>
        /// 判断不为NULL和空GUID
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static bool IsNotEmptyGuid(this Guid? guid)
        {
            return guid.HasValue && guid.Value != Guid.Empty;
        }

        /// <summary>
        /// 将GUID转换为整数
        /// </summary>
        /// <param name="guid"></param>
        /// <returns>HashCode整数</returns>
        public static int ToInt(this Guid guid)
        {
            return Math.Abs(guid.GetHashCode());
            //byte[] buffer = guid.ToByteArray();
            //return BitConverter.ToInt32(buffer, 0);
        }

        /// <summary>
        /// 转换GUID为大写字符串
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static string ToUpperString(this Guid guid)
        {
            return guid.ToString().ToUpper();
        }
        /// <summary>
        /// 转换guid为小写字符串
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static string ToLowerString(this Guid guid)
        {
            return guid.ToString().ToLower();
        }

        /// <summary>
        /// 没有分隔线的字符串
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static string ToNString(this Guid guid)
        {
            return guid.ToString();
        }

        /// <summary>
        /// 没有分隔线的小写字符串
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static string ToLowerNString(this Guid guid)
        {
            return guid.ToString().ToLower();
        }

        /// <summary>
        /// 没有分隔线的大写字符串
        /// </summary>
        /// <param name="guid"></param>
        /// <returns></returns>
        public static string ToUpperNString(this Guid guid)
        {
            return guid.ToString().ToUpper();
        }

        /// <summary>
        /// 将int转换为GUID
        /// </summary>
        /// <param name="i">111</param>
        /// <returns>00000000-0000-0000-0000-000000000111</returns>
        public static Guid ToGuid(this int i)
        {
            return i.ToString().PadLeft(32, '0').ToGuid();
        }

        /// <summary>
        /// 将long转换为GUID
        /// </summary>
        /// <param name="i">111</param>
        /// <returns>00000000-0000-0000-0000-000000000111</returns>
        public static Guid ToGuid(this long i)
        {
            return i.ToString().PadLeft(32, '0').ToGuid();
        }

        /// <summary>
        /// 将GUID转换为int
        /// </summary>
        /// <param name="guid">00000000-0000-0000-0000-000000000111 的GUID</param>
        /// <returns>111</returns>
        public static int ToInteger(this Guid guid)
        {
            return guid.ToNString().TrimStart('0').ToInt();
        }

        /// <summary>
        /// 将GUID转换为long
        /// </summary>
        /// <param name="guid">00000000-0000-0000-0000-000000000111 的GUID</param>
        /// <returns>111</returns>
        public static long ToLong(this Guid guid)
        {
            return guid.ToNString().TrimStart('0').ToLong();
        }

        #region 生成顺序GUID
        //private static readonly RandomNumberGenerator Rng = RandomNumberGenerator.Create();

        ///// <summary>
        ///// 创建顺序GUID
        ///// </summary>
        ///// <returns></returns>
        //public static Guid NewSequentialGuid()
        //{
        //    SequentialGuidType sequentialGuidType;
        //    switch (Config.DatabaseType)
        //    {
        //        case "sqlserver":
        //            sequentialGuidType = SequentialGuidType.SequentialAtEnd;
        //            break;
        //        case "oracle":
        //            sequentialGuidType = SequentialGuidType.SequentialAsBinary;
        //            break;
        //        case "mySql":
        //            sequentialGuidType = SequentialGuidType.SequentialAsString;
        //            break;
        //        default:
        //            sequentialGuidType = SequentialGuidType.SequentialAsString;
        //            break;
        //    }

        //    var randomBytes = new byte[10];
        //    Rng.Locking(r => r.GetBytes(randomBytes));
        //    long timestamp = DateTime.UtcNow.Ticks / 10000L;
        //    byte[] timestampBytes = BitConverter.GetBytes(timestamp);
        //    if (BitConverter.IsLittleEndian)
        //    {
        //        Array.Reverse(timestampBytes);
        //    }
        //    byte[] guidBytes = new byte[16];
        //    switch (sequentialGuidType)
        //    {
        //        case SequentialGuidType.SequentialAsString:
        //        case SequentialGuidType.SequentialAsBinary:
        //            Buffer.BlockCopy(timestampBytes, 2, guidBytes, 0, 6);
        //            Buffer.BlockCopy(randomBytes, 0, guidBytes, 6, 10);
        //            if (sequentialGuidType == SequentialGuidType.SequentialAsString && BitConverter.IsLittleEndian)
        //            {
        //                Array.Reverse(guidBytes, 0, 4);
        //                Array.Reverse(guidBytes, 4, 2);
        //            }
        //            break;
        //        case SequentialGuidType.SequentialAtEnd:
        //            Buffer.BlockCopy(randomBytes, 0, guidBytes, 0, 10);
        //            Buffer.BlockCopy(timestampBytes, 2, guidBytes, 10, 6);
        //            break;
        //    }
        //    return new Guid(guidBytes);
        //}

        //private enum SequentialGuidType
        //{
        //    /// <summary>
        //    /// The GUID should be sequential when formatted using the
        //    /// <see cref="Guid.ToString()" /> method.
        //    /// </summary>
        //    SequentialAsString,

        //    /// <summary>
        //    /// The GUID should be sequential when formatted using the
        //    /// <see cref="Guid.ToByteArray" /> method.
        //    /// </summary>
        //    SequentialAsBinary,

        //    /// <summary>
        //    /// The sequential portion of the GUID should be located at the end
        //    /// of the Data4 block.
        //    /// </summary>
        //    SequentialAtEnd
        //}
        #endregion
    }
}