<?php
class mysql
{
	/**
	 * Object instance of PHP PDO
	 * @var PDO
	 */
	private $pdo;

	/**
	 * Database host
	 * @var string
	 */
	private $host;

	/**
	 * Database name
	 * @var string
	 */
	private $dbname;

	/**
	 * Database username
	 * @var string
	 */
	private $username;

	/**
	 * Database password
	 * @var string
	 */
	private $password;

	/**
	 * Database tables prefix
	 * @var string
	 */
	private $table;

	/**
	 * Save database informations
	 *
	 * @param string $host     127.0.0.1
	 * @param string $dbname   Database name
	 * @param string $username Database username
	 * @param string $password Database password
	 */
	public function __construct($host, $dbname, $username, $password)
	{
		$this->host = $host;
		$this->dbname = $dbname;
		$this->username = $username;
		$this->password = $password;
	}

	/**
	 * Return an instance of PDO
	 *
	 * @return PDO
	 */
	public function getDB()
	{
		if ($this->pdo === null)
		{
			$this->pdo = new PDO('mysql:dbname=' . $this->dbname . ';host=' . $this->host . '', $this->username, $this->password, [
				PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
				PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"
			]);
		}

		return $this->pdo;
	}

	/**
	 * Set a table name for database requests
	 *
	 * @param string $name
	 */
	public function table($name)
	{
		$this->table = $name;
		return $this;
	}

	/**
	 * Set a table prefix when we use function table()
	 * @param string $prefix
	 */
	public function setTablePrefix($prefix)
	{
		$this->tablePrefix = $prefix;
	}

	/**
	 * Insert data in database
	 *
	 * @param  array $data - Possible data
	 * Single insertion $data value :
	 * ['value1', 'value2', 'value3',    ... ]
	 *
	 * Multiple insertions $data value :
	 * [ ['value1', 'value2', 'value3'], ['value4', 'value5', 'value6'],    ... ]
	 *
	 * @return int rowCount - Return numbers of inserted rows of the request
	 */
	public function insert($data)
	{
		$columns = $reqFilledValues = "";
		foreach ($this->getDB()->query('DESCRIBE ' . $this->tablePrefix . $this->table)->fetchAll(PDO::FETCH_ASSOC) as $i => $columnInfo)
			if ($columnInfo['Extra'] != "auto_increment" && $columnInfo['Default'] === NULL)
			{
				if ($columns != "")
				{
					$columns .= ", ";
					$reqFilledValues .= ", ";
				}
				$columns .= $columnInfo['Field'];
				$reqFilledValues .= "?";
			}

		$sql = 'INSERT INTO ' . $this->tablePrefix . $this->table . ' (' . $columns . ') VALUES (' . $reqFilledValues . ')';

		if (count($data) > 1 && is_array($data[0]))
			for ($i = 0; $i < count($data); $i++)
				$sql .= ', (' . $reqFilledValues . ')';

		$req = $this->getDB()->prepare($sql);

		for ($i = 1; $i < count($data[0]) + 1; $i++)
			$req->bindParam($i, $data[0][$i - 1]);

		if (count($data) > 1 && is_array($data[0]))
			for ($j = 0; $j < count($data); $j++)
				foreach ($data[$j] as $value)
				{
					$req->bindParam($i, $value);
					$i++;
				}

		$req->execute();
		return $req->rowCount();
	}
}