using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;

namespace Core
{
    /// <summary>
    /// Init classe validatore
    /// </summary>
    public class MachineDataValidator
    {
        #region Public Constructors

        /// <summary>
        /// Init classe validatore
        /// </summary>
        /// <param name="currMachineData"></param>
        public MachineDataValidator(string rawData)
        {
            // inizializzo info di base
            Dictionary<string, string> currMachineData = new Dictionary<string, string>();
            if (!string.IsNullOrEmpty(rawData))
            {
                try
                {
                    currMachineData = JsonConvert.DeserializeObject<Dictionary<string, string>>(rawData);
                }
                catch(Exception exc)
                { }
            }
            machTestData = currMachineData;
        }

        #endregion Public Constructors

        #region Public Properties

        /// <summary>
        /// Restituisce HASH del codice impiego = payload utente
        /// </summary>
        /// <returns></returns>
        public string machineKeyHash
        {
            get => calcMachineHash();
        }

        #endregion Public Properties

        #region Private Fields

        /// <summary>
        /// Dati rispetto cui fare i calcoli di validazione
        /// </summary>
        private Dictionary<string, string> machTestData = new Dictionary<string, string>();

        #endregion Private Fields

        #region Private Methods

        /// <summary>
        /// Calcola HASH del codice impiego = payload utente
        /// </summary>
        /// <returns></returns>
        private string calcMachineHash()
        {
            string hash = "";
            string buffData = currBaseBuffer();
            if (!string.IsNullOrEmpty(buffData))
            {
                // hashing!

                using (var hAlgo = SHA512.Create())
                //using (var hAlgo = MD5.Create())
                {
                    byte[] InputBytes = Encoding.UTF8.GetBytes(buffData);
                    var byteHash = hAlgo.ComputeHash(InputBytes);
                    hash = BitConverter.ToString(byteHash).Replace("-", "").Replace("/", "").Replace("\\", "").ToLowerInvariant();
                }
            }
            return hash;
        }

        public bool hasValidData
        {
            get => machTestData != null && machTestData.Count > 0;
        }

        /// <summary>
        /// Calcola hash key da info PC
        /// </summary>
        /// <returns></returns>
        private string currBaseBuffer()
        {
            string answ = "????????????????????????????????????????????";
            StringBuilder sb = new StringBuilder();
            try
            {
                // calcolo hashKey da alcuni valori solamente
                sb.Append($"{getDictVal("SystemName")}|");
                sb.Append($"{getDictVal("ProcessorId")}|");
                sb.Append($"{getDictVal("PartNumber")}|");
                sb.Append($"{getDictVal("MACAddress")}|");
                sb.Append($"{getDictVal("SerialNumber")}|");
                sb.Append($"{getDictVal("Architecture")}|");
                sb.Append($"{getDictVal("SoftwareElementID")}|");
                sb.Append($"{getDictVal("SystemBiosMajorVersion")}|");
                sb.Append($"{getDictVal("SystemBiosMinorVersion")}|");
                if (sb.Length > 0)
                {
                    answ = sb.ToString();
                    // lo uso 2 volte dritto e reverse...
                    answ += ReverseString(sb.ToString());
                }
            }
            catch
            { }
            return answ;
        }

        /// <summary>
        /// Recupera info da dictionary
        /// </summary>
        /// <param name="keyName"></param>
        /// <returns></returns>
        private string getDictVal(string keyName)
        {
            string answ = $"{keyName}{keyName}";
            if (machTestData.ContainsKey(keyName))
            {
                answ = machTestData[keyName];
            }
            return answ;
        }

        /// <summary>
        /// Esegue reverse delal stringa
        /// </summary>
        /// <param name="myStr"></param>
        /// <returns></returns>
        private string ReverseString(string myStr)
        {
            char[] myArr = myStr.ToCharArray();
            Array.Reverse(myArr);
            return new string(myArr);
        }

        #endregion Private Methods
    }
}