<?php
    class ConnectionSettings{
        const Host = "localhost";
        const DBName = "";

        const ReadOnlyUser = "";
        const ReadOnlyPassword = "";

        const ReadWriteUser = "";
        const ReadWritePassword ="";
    }

    class SQLParameter{
        public $parameter;
        public $value;
        public $dataType;

        public function __construct($parameter, $value, $dataType="string")
        {
            $this->parameter = $parameter;
            $this->value = $value;
            switch($dataType){
                case "string":
                    $this->dataType = PDO::PARAM_STR;
                    break;
                case "int":
                    $this->dataType = PDO::PARAM_INT;
                    break;
                case "bool":
                    $this->dataType = PDO::PARAM_BOOL;
                    break;
                case "null":
                    $this->dataType = PDO::PARAM_NULL;
                    break;
                default:
                    $this->dataType = PDO::PARAM_STR;
            }
        }
    }

    class DBConnection{
        public $readOnly;
        public $readWrite;

        public function __construct($readOnly, $readWrite)
        {
            $this->readOnly = $readOnly;
            $this->readWrite = $readWrite;
        }
    }

    class DB extends ConnectionSettings{
        private static $dbConnection;

        function EstablishConnections(){
            //Establish Read Only Connection
            if(!isset($mysql) || $mysql==null){
                $mysqlReader =  new PDO("mysql:host=" . self::Host . ";dbname=".self::DBName, self::ReadOnlyUser, self::ReadOnlyPassword);
            }

            //Establish Read Write Connection
            if(!isset($mysql) || $mysql==null){
                $mysqlAdmin =  new PDO("mysql:host=" . self::Host . ";dbname=".self::DBName, self::ReadWriteUser, self::ReadWritePassword);
            }

            self::$dbConnection = new DBConnection($mysqlReader, $mysqlAdmin);
        }

        function Query($sqlCommand,$sqlParameters=null){
            try {
                $readOnly = self::$dbConnection->readOnly;
                $readOnly->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                if($sqlParameters!=null){
                    $sqlQuery = $readOnly->prepare($sqlCommand);
                    foreach($sqlParameters as $sqlParameter){
                        $sqlQuery->bindParam($sqlParameter->parameter, $sqlParameter->value, $sqlParameter->dataType);
                    }
                    $sqlQuery->execute();
                    return $sqlQuery->fetchAll();
                }else{
                    $sqlResponse = $readOnly->query($sqlCommand);
                    return $sqlResponse;
                }
            } catch (PDOException $e) {
                echo 'Connection failed: ' . $e->getMessage();
            }
        }
        function QueryCount($sqlCommand,$sqlParameters=null){
            try {
                $readOnly = self::$dbConnection->readOnly;
                $readOnly->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                if($sqlParameters!=null){
                    $sqlQuery = $readOnly->prepare($sqlCommand);
                    $sqlQuery->execute($sqlParameters);
                    return sizeof($sqlQuery->fetchAll());
                }else{
                    $readOnly->query($sqlCommand);
                    $foundRows = $readOnly->query("SELECT FOUND_ROWS()")->fetchColumn();
                    return $foundRows;
                }
            } catch (PDOException $e) {
                echo 'Connection failed: ' . $e->getMessage();
            }
        }
    }

    DB::EstablishConnections();
?>