using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Text;
using System.Text.RegularExpressions;

namespace Xylem.Common.Logic.ServiceCore
{
    public class SqlDataAccess : IDisposable
    {
        private readonly String _connectionString;
        public SqlDataAccess(String connectionString)
        {
            _connectionString = connectionString;
        }

        public String GenerateParam<T>(String name, String typeName,T value)
        {
            var sb = new StringBuilder();
            sb.AppendLine($"Declare @{name} as {typeName}" );
          
            if (value is String)
            {
                sb.AppendLine($"set @{name} = '%{value.ToString()}%' ");
                return sb.ToString();
            }
            sb.AppendLine($"set @{name} = ");
            if (value == null)
            {
                sb.Append(" null ");
                return sb.ToString();
            }

            if (value is Int32)
            {
                var tmp = Convert.ToInt32(value);
                sb.Append(tmp.ToString());
            }
            if (value is Boolean)
            {
                var tmp = Convert.ToBoolean(value);
                
                sb.Append(tmp ? "1" : "0");
            }



            return sb.ToString();
        }
        private SqlConnection _con;

        /// <summary>
        /// Creating a database connection if there is none.
        /// </summary>
        /// <remarks>Working with a global connection variable to make sure the connection would be closed at the end of working with it.</remarks>
        // ReSharper disable once UnusedMember.Local
        private void CreateConnection()
        {
            if (_con == null)
            {
                _con = new SqlConnection(_connectionString);

            }
            if (_con != null && _con.State == ConnectionState.Closed)
            {
                _con.Open();
            }
        }

        public DataTable ExecuteQuery(String sqlStatement, List<SqlParameter> parameter = null)
        {
            DataTable ret;
            SqlConnection connection = null;
            SqlDataReader reader = null;

            try
            {
                connection = new SqlConnection(_connectionString);

                if (connection.State != ConnectionState.Open)
                {
                    connection.Open();
                }
                var cmd = connection.CreateCommand();
                cmd.CommandTimeout = 120;
                cmd.CommandText = sqlStatement;
                if (parameter != null)
                {
                    foreach (var item in parameter)
                    {
                        cmd.Parameters.Add(item);
                    }
                }
                reader = cmd.ExecuteReader();
                var entries = new Object[reader.FieldCount];
                ret = new DataTable();

                var jcount = 0;
                try
                {
                    while (reader.Read())
                    {
                        if (jcount == 0)
                        {
                            for (var i = 0; i < reader.FieldCount; i++)
                            {
                                var headline = reader.GetName(i);
                                if (!ret.Columns.Contains(headline))
                                {
                                    ret.Columns.Add(headline, Type.GetType("System.Object") ?? typeof(String));
                                }
                                else
                                {
                                    ret.Columns.Add(headline + Guid.NewGuid(), Type.GetType("System.Object") ?? typeof(String));
                                }
                         

                            }
                        }
                        for (var i = 0; i < reader.FieldCount; i++)
                        {
                            entries[i] = reader[i];
                        }
                        jcount++;
                        ret.Rows.Add(entries);
                    }
                }
                catch (Exception ex)
                {
                    throw (new Exception(ex.Message, ex));
                }
            }
            catch (Exception ex)
            {
                throw (new Exception(ex.Message, ex));
            }
            finally
            {
                try
                {
                    if (reader != null)
                    {
                        try
                        {
                            reader.Dispose();
                        }
                        catch
                        {
                            // ignored
                        }
                    }
                    if (connection != null && connection.State == ConnectionState.Open)
                    {
                        connection.Close();
                    }
                }
                catch (Exception ex) { throw (new Exception("Unhandled exception within finally: " + ex.Message)); }
            }
            return ret;
        }

        /// <summary>
        /// Closing and disposing the connection.
        /// </summary>
        private void CloseConnection()
        {
            if (_con != null)
            {
                if (_con.State != ConnectionState.Closed)
                {
                    _con.Close();
                }
                _con.Dispose();
            }
        }

        /// <summary>
        /// Generating a list of comma seperated parameters by a given string array.
        /// </summary>
        /// <param name="parameter">array to work on</param>
        /// <returns>comma seperated string with parameters.</returns>
        // ReSharper disable once UnusedMember.Local
        private String GenerateParameter(String[] parameter)
        {
            var list = new StringBuilder();
            var ret = "";
            var first = true;

            foreach (var param in parameter)
            {
                if (list.ToString().Length > 0)
                {
                    list.Append(",");
                }

                var result = param;
                var content = param;
                const String mitpat = @"(?:^@\w[\w_\s]*=[\s]*(?:'(.*)'$|(.*)$)|^(?:'(.*)'$|(.*)$))";
                const String numbpat = @"^[+-]?(?:\d+\.?|,?\d*|\d*(\.?|,?)\d+)[\r\n]*$";

                if (!first || !result.Contains(","))
                {
                    first = false;

                    var mtch = Regex.Match(content, mitpat);
                    if (mtch.Groups[1].Success)
                    {
                        var orig = mtch.Groups[1].Value;
                        var mch = Regex.Replace(orig, "[']+", "'");
                        mch = Regex.Replace(mch, "[']+", "''");

                        result = !string.IsNullOrEmpty(mch) ? content.Replace(orig, mch) : content;
                    }
                    else if (mtch.Groups[2].Success)
                    {
                        var orig = mtch.Groups[2].Value;
                        var mch = Regex.Replace(orig, "[']+", "'");
                        mch = Regex.Replace(mch, "[']+", "''");

                        if (!string.IsNullOrEmpty(mch))
                        {
                            if (Regex.IsMatch(mch, numbpat) || mch.ToLower() == "null")
                            {
                                result = content;
                            }
                            else
                            {
                                result = content.Replace(orig, "'" + mch + "'");
                            }
                        }
                        else
                        {
                            result = content;
                        }
                    }
                    else if (mtch.Groups[3].Success)
                    {
                        var orig = mtch.Groups[3].Value;
                        var mch = Regex.Replace(orig, "[']+", "'");
                        mch = Regex.Replace(mch, "[']+", "''");

                        result = !string.IsNullOrEmpty(mch) ? content.Replace(orig, mch) : content;
                    }
                    else if (mtch.Groups[4].Success)
                    {
                        var orig = mtch.Groups[4].Value;
                        var mch = Regex.Replace(orig, "[']+", "'");
                        mch = Regex.Replace(mch, "[']+", "''");

                        if (!string.IsNullOrEmpty(mch))
                        {
                            if (Regex.IsMatch(mch, numbpat) || mch.ToLower() == "null")
                            {
                                result = content;
                            }
                            else
                            {
                                result = content.Replace(orig, "'" + mch + "'");
                            }
                        }
                        else
                        {
                            result = content;
                        }
                    }
                }

                list.Append(result);
            }
            if (list.ToString().Length > 0)
            {
                ret = " " + list;
            }

            return ret;
        }



        public String GetConnectionString()
        {
            //if (_conifg.SupportConnectionString)
            //{
            return _connectionString;
            //}
            //else
            //{
            //StringBuilder ret = new StringBuilder();
            //ret.Append("Data Source=").Append(_conifg.ReadFromConfig("Data Source", "Connection"));
            //ret.Append(";Initial Catalog=").Append(_conifg.ReadFromConfig("Initial Catalog", "Connection"));
            //ret.Append(";User id=").Append(_conifg.ReadFromConfig("User id", "Connection"));
            //ret.Append(";Password=").Append(_conifg.ReadFromConfig("Password", "Connection"));
            //return ret.ToString();
            //}
        }
        public void Dispose()
        {
            CloseConnection();
            GC.SuppressFinalize(this);
        }
    }
}