using System;
using Npgsql;
using System.Collections.Generic;

namespace DaraAnalisator
{
    public class DataModule
    {
        private static volatile DataModule instance;
        private static object syncRoot = new Object();

        private NpgsqlConnection conn;

        private static string Server = "127.0.0.1";
        private static string Port = "5432";
        private static string User = "ts_engineer";
        private static string Password = "engineer_pass";
        private static string DataBase = "turboshaft";
        public static DataModule Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        if (instance == null)
                            instance = new DataModule();
                    }
                }

                return instance;
            }
        }
        public DataModule()
        {
            try
            {
                string connectionString = String.Format(
                    "Server={0};Port={1};User Id={2};Password={3};Database={4};",
                Server, Port, User, Password, DataBase);
                conn = new NpgsqlConnection(connectionString);
                conn.Open();
            }
            catch (Exception ex)
            {
                LogModule.Instance.Log(ex.StackTrace);
            }
        }

        public void CloseDataBaseConnection()
        {
            try
            {
                if ( conn != null)
                {
                    conn.Close();
                }

            }
            catch (Exception ex)
            {
                LogModule.Instance.Log(ex.StackTrace);
            }
        }

        public List<double> ExecuteDoubleSelect(string query)
        {
            var resultList = new List<double>();
            try
            {
                var command = new NpgsqlCommand(query, conn);
                var reader = command.ExecuteReader();
                while (reader.Read())
                {
                    resultList.Add((double)reader[0]);
                }
                reader.Close();
                return resultList;
            }
            catch(Exception ex)
            {
                LogModule.Instance.Log(ex.StackTrace);
                return resultList;
            }
        }

        public List<SensorData> ExecuteSelectForRealTime(string query)
        {
            var resultList = new List<SensorData>();
            try
            {
                var command = new NpgsqlCommand(query, conn);
                var reader = command.ExecuteReader();
                while (reader.Read())
                {
                    resultList.Add(new SensorData(reader[0].ToString(), (double)reader[1]));
                }
                reader.Close();
                return resultList;
            }
            catch (Exception ex)
            {
                LogModule.Instance.Log(ex.StackTrace);
                return resultList;
            }
        }

        public NpgsqlDataReader ExecuteSelect(string query)
        {
            try
            {
                var command = new NpgsqlCommand(query, conn);
                var reader = command.ExecuteReader();
                return reader;
            }
            catch (Exception ex)
            {
                LogModule.Instance.Log(ex.StackTrace);
                return null;
            }
        }
    }
}