<?php

namespace Empik\Marketplace\Utils;

class DbUtils
{
    public static function safeAddColumn($table, $column, $def)
    {
        if (!self::columnExists($table, $column))
            return \Db::getInstance()->execute('ALTER TABLE `' . _DB_PREFIX_ . $table . '` ADD `' . $column . '` ' . $def);

        return true;
    }

    public static function columnExists($table, $column)
    {
        $query = 'SELECT COUNT(*) 
              FROM information_schema.COLUMNS 
              WHERE TABLE_SCHEMA = DATABASE() 
              AND COLUMN_NAME = \'' . pSQL($column) . '\' 
              AND TABLE_NAME = \'' . _DB_PREFIX_ . pSQL($table) . '\'';

        return (bool)\Db::getInstance()->getValue($query);
    }

    public static function safeDropColumn($table, $column)
    {
        if (self::columnExists($table, $column)) {
            \Db::getInstance()->execute('ALTER TABLE `' . _DB_PREFIX_ . $table . '` DROP `' . $column . '` ');
        }

        return true;
    }
}