using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using Infrastructure.Extensions;
using Microsoft.Extensions.Configuration;
using Newtonsoft.Json;

namespace Infrastructure.Security
{
    public class EncryptionService : IEncryptionService
    {
        private readonly string _key;
        private readonly string _iv;

        public EncryptionService(IConfiguration configuration)
        {
            this._key = configuration.GetSection("security").GetValue<string>("key");
            this._iv = configuration.GetSection("security").GetValue<string>("iv");
        }

        public string CreatePasswordHash(string password, string saltkey)
        {
            var saltAndPassword = String.Concat(password, saltkey);
            var algorithm = SHA1.Create();
            var bytes = algorithm.ComputeHash(Encoding.UTF8.GetBytes(saltAndPassword));
            var result = string.Empty;
            var builder = new StringBuilder();
            builder.Append(result);
            foreach (var item in bytes)
            {
                builder.Append($"{item:x2}");
            }
            result = builder.ToString();
            return result;
        }

        public string CreateSalt()
        {
            var code = string.Empty;
            var builder = new StringBuilder();
            builder.Append(code);
            for (int i = 0; i < 6; i++)
            {
                var random = new byte[1];
                RandomNumberGenerator.Create().GetBytes(random);
                builder.Append(new Random(Convert.ToInt32(random[0])).Next(0, 9));
            }
            code = builder.ToString();
            return code;
        }

        public string EncryptObject(object obj)
        {
            var data = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(obj));
            var key = Encoding.UTF8.GetBytes(this._key);
            var iv = Encoding.UTF8.GetBytes(this._iv);
            using (var ms = new MemoryStream())
            {
                using (var cs = new CryptoStream(ms, TripleDES.Create().CreateEncryptor(key, iv), CryptoStreamMode.Write))
                {
                    cs.Write(data, 0, data.Length);
                    cs.FlushFinalBlock();
                }
                return ms.ToArray().BytesToHex();
            }
        }

        public T DecryptObject<T>(string value)
        {
            var data = value.HexToBytes();
            var key = Encoding.UTF8.GetBytes(this._key);
            var iv = Encoding.UTF8.GetBytes(this._iv);
            using (var ms = new MemoryStream(data))
            {
                using (var cs = new CryptoStream(ms, TripleDES.Create().CreateDecryptor(key, iv), CryptoStreamMode.Read))
                {
                    using (var sr = new StreamReader(cs, Encoding.UTF8))
                    {
                        return JsonConvert.DeserializeObject<T>(sr.ReadToEnd());
                    }
                }
            }
        }
    }
}