//-----------------------------------------------------------------------
// <copyright file="HashMgr.cs" company="Origtek">
//     HashMgr belongs to Copyright (c) Origtek. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------

namespace OT.COM.Encryption
{
    using System;
    using System.Security.Cryptography;

    /// <summary>
    /// Manager of Hash function
    /// </summary>
    public partial class HashMgr
    {
        /// <summary>
        /// For choose hash type
        /// </summary>
        public enum HashType
        {
            /// <summary>
            /// MD5 algorithm
            /// </summary>
            HT_MD5 = 0,

            /// <summary>
            /// SHA1 algorithm
            /// </summary>
            HT_SHA1 = 1,

            /// <summary>
            /// SHA256 algorithm
            /// </summary>
            HT_SHA256 = 2,

            /// <summary>
            /// SHA384 algorithm
            /// </summary>
            HT_SHA384 = 3,

            /// <summary>
            /// SHA512 algorithm
            /// </summary>
            HT_SHA512 = 4,
        }

        /// <summary>
        /// Generate hash function
        /// </summary>
        /// <param name="i_htType">
        /// Hash type
        /// </param>
        /// <param name="i_sData">
        /// string data
        /// </param>
        /// <returns>
        /// Result string
        /// </returns>
        public string Generate(HashType i_htType, string i_sData)
        {
            return System.Text.Encoding.Unicode.GetString(
                this.Gernerate(
                    i_htType,
                    System.Text.Encoding.Unicode.GetBytes(i_sData)));
        }

        /// <summary>
        /// Base function of Generate
        /// </summary>
        /// <param name="i_htType">
        /// Hash type
        /// </param>
        /// <param name="i_byData">
        /// Byte array data
        /// </param>
        /// <returns>
        /// Result byte array
        /// </returns>
        public byte[] Gernerate(HashType i_htType, byte[] i_byData)
        {
            // This is one implementation of the abstract class MD5.
            string sName = Enum.GetName(typeof(HashType), i_htType);
            byte[] result = null;
            object oRes = null;

            string s = string.Format("System.Security.Cryptography.{0}CryptoServiceProvider", sName.Substring(3));

            switch (i_htType)
            {
                case HashType.HT_SHA256:
                    {
                        oRes = new SHA256CryptoServiceProvider();
                    }

                    break;
                case HashType.HT_SHA384:
                    {
                        oRes = new SHA384CryptoServiceProvider();
                    }

                    break;
                case HashType.HT_SHA512:
                    {
                        oRes = new SHA512CryptoServiceProvider();
                    }

                    break;
                default:
                    {
                    }

                    break;
            }

            if (oRes != null && oRes is HashAlgorithm)
            {
                result = (oRes as HashAlgorithm).ComputeHash(i_byData);
            }

            return result;
        }
    }
}