using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MySql.Data.MySqlClient;


namespace dbApp
{
    class CDBInfo
    {
        private MySqlConnection spoj = null;  // pro pripojeni k MySQL.
        private MySqlCommand prikaz = null;   // pro SQL prikaz.
        private MySqlDataAdapter res = null;  // pro cteni z dtb.
        private System.Data.DataTable tab = null;  // ??
        string host, user, pass, dBase;

        /// <summary>
        ///Ddatova tabulka ziskana aplikaci metody ApplSelect
        /// </summary>
        public System.Data.DataTable GetData
        {
            get
            {
                return tab;
            }
        }
        /// <summary>
        /// zjisti, zda je objekt pripojen k MySQL serveru
        /// </summary>
        private bool isConnect
        {
            get
            {
                return (spoj.State != System.Data.ConnectionState.Open) ? false : true;
            }
        }

        int ApplVector(string sqlQuery)
        {
            prikaz.CommandText = sqlQuery;
            return Convert.ToInt32(prikaz.ExecuteScalar());


        }
        /// <summary>
        /// Konstruktor pro pocatecni inicializaci promennych a vnitrnich objektu
        /// </summary>
        public CDBInfo()
        {
            spoj = new MySqlConnection();
            prikaz = new MySqlCommand();
            tab = new System.Data.DataTable();
            host = user = pass = dBase = "";
            prikaz.Connection = spoj;
         }
        /// <summary>
        /// Nastaveni parametru pro pripojeni
        /// </summary>
        /// <param name="host">IP nebo DNS jmeno MySQL serveru</param>
        /// <param name="user">Uzivatelske jmeno</param>
        /// <param name="pass">Uzivatelske heslo</param>
        /// <param name="dBase">Jmeno database</param>
        public void Config(string host, string user, string pass, string dBase) // metoda bez navratove hodnoty se 4 vstupnimy parametry
        {
                this.host = host; // nastavi promennou host v instanci tridy na hodnotu lokalni promenne host
                this.user = user;
                this.pass = pass;
                this.dBase = dBase;
        }
        /// <summary>
        /// Pripojeni k serveru ma zaklade udaju predanych metodou void Config()
        /// </summary>
        /// <returns>true v pripade zdaru, jinak false</returns>
        public bool Connect() //metoda s navratovym typem bool, bez vstupniho parametru.
        {
            string cs = String.Format("Persist Security Info=False;database={0};server={1};user id={2};Password={3}",dBase,host,user,pass); // vytvori string
            spoj.ConnectionString = cs; //pripoji connectionstring
            spoj.Open(); //otevre spojeni
            return isConnect; //vrati jestli se podarilo pripojit k serveru
        }
        /// <summary>
        /// Odpojeni od MySQL serveru
        /// </summary>
        public void Disconnect() // metoda bez navratove hodnoty, bez parametru
        {
            if (isConnect)  //uzavre pripjeni, pokud isConnect je true.
                spoj.Close();
        }
        /// <summary>
        /// Aplikuje vkladaci dotaz
        /// </summary>
        /// <param name="sqlQuery">sql dotaz vkladaci</param>
        /// <returns></returns>
        public int ApplInsert(string sqlQuery) // metoda s navratovou hodnotou int a vstupni string
        {
            prikaz.CommandText = sqlQuery; //nahraje SQL prikaz ze vstupni promenne sqlQuery
            return prikaz.ExecuteNonQuery(); // provede prikaz a vrati cislo kolik bylo provedeno zmen
        }
        /// <summary>
        /// Aplikuje vyberovy dotaz
        /// </summary>
        /// <param name="sqlQuery">sql dotaz</param>
        /// <returns></returns>
        public int ApplSelect(string sqlQuery) // metoda s navratovou hodnotou int a vstupni string
        {
            res = new MySqlDataAdapter(sqlQuery, spoj); // vytvori instanci tridy s paramety sqlQuery a spoj.
            res.Fill(tab); // naplni tabulku
            return tab.Rows.Count; //vrati pocet radku v tabulce
        }



    }
}