using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ssgrestserver.request
{
    class DBManager
    {


        #region Singleton

        private volatile static DBManager mInstance = null;

        private static object mSingletonLocker = new object();

        private DBManager()
        {

            CONNECT_STRING = Program.mainForm.getStartupPath() + @"\ssgCRUD.db";
            DB_SOURCE = $@"Data Source={CONNECT_STRING}";


            try
            {

                using (var conn = new SQLiteConnection(DB_SOURCE))
                {
                    int result = 0;

                    conn.Open();
                    using (var command = new SQLiteCommand("select count(*) from sqlite_master WHERE Name = 'ssgCRUD'", conn))
                    {
                        result = Convert.ToInt32(command.ExecuteScalar());
                    }


                    if (result < 1)
                    {
                        string bufTableBuildQuery = @"create table ssgCRUD (seqGFrameNo TEXT PRIMARY KEY, vriNoticeNo TEXT UNIQUE, payload TEXT)";

                        using (var command = new SQLiteCommand(bufTableBuildQuery, conn))
                        {
                            command.ExecuteNonQuery();
                        }

                    }

                }

            }
            catch (Exception)
            {

                throw;
            }

        }

        string CONNECT_STRING = "";
        string DB_SOURCE = "";

        public static DBManager getInstance()
        {
            lock (mSingletonLocker)
            {
                if (mInstance == null)
                {
                    mInstance = new DBManager();
                }
            }

            return mInstance;
        }
        #endregion



        public DataSet sendSelectQuery(string query)
        {
            DataSet rtnValue = new DataSet();

            try
            {

                using (var adapter = new SQLiteDataAdapter(query, DB_SOURCE))
                {
                    adapter.Fill(rtnValue, "rtnTable");
                }

            }
            catch (Exception ex)
            {
                Program.mainForm.recvLog("SQLQUERY_SELECT", ex.ToString());
            }

            return rtnValue;
        }

        public bool sendInsertQuery(string query)
        {

            try
            {

                using (var conn = new SQLiteConnection(DB_SOURCE))
                {
                    conn.Open();
                    using (var command = new SQLiteCommand(query, conn))
                    {
                        command.ExecuteNonQuery();
                    }

                }

                return true;

            }
            catch (Exception ex)
            {
                Program.mainForm.recvLog("SQLQUERY_INSERT", ex.ToString());
                return false;

            }

        }

    }
}