<?php

namespace Vn\Db;

require_once ('vn/sql/sql.php');
require_once ('vn/db/exception.php');

use Vn\Sql\Render;

class Conn
{
	private $conn = NULL;
	private $isOpen = FALSE;

	/**
	 * Opens a new connection to the database.
	 *
	 * @param string $host The host name
	 * @param string $user The user name to authenticate
	 * @param string $pass The user password
	 * @param string $name The default schema name
	 *
	 * @return boolean %TRUE on success, %FALSE otherwise
	 **/
	function open ($host, $user, $pass, $name)
	{
		$conn = $this->conn = mysqli_init ();
		$conn->options (MYSQLI_READ_DEFAULT_FILE, __DIR__.'/my.cnf');
		@$conn->real_connect ($host, $user, $pass, $name);

		if (mysqli_connect_errno ())
		{
			sleep (1);
			throw new Exception  (mysqli_connect_errno (), mysqli_connect_error ());
			return FALSE;
		}

		$this->isOpen = TRUE;
		$this->query ('SET CHARACTER SET utf8');
		return TRUE;
	}

	/**
	 * Closes the current connection, if it's closed does nothing.
	 **/
	function close ()
	{
		if ($this->isOpen)
			$this->conn->close ();
			
		$this->isOpen = FALSE;
	}
	
	/**
	 * Checks whether the connection is open.
	 *
	 * @return boolean %TRUE if connection is open, %FALSE otherwise
	 **/
	function isOpen ()
	{
		return $this->isOpen;
	}
	
	/**
	 * Executes the query and gets it's first row.
	 *
	 * @param string $query The SQL query
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed[] An associative array with the first row, %NULL if error
	 **/
	function getRow ($query, $params = NULL)
	{
		$result = $this->query ($query, $params);

		if ($result && ($row = $result->fetch_assoc ()))
			return $row;

		return NULL;
	}
	
	/**
	 * Executes the query and gets the first value of the first row.
	 *
	 * @param string $query The SQL query
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function getValue ($query, $params = NULL)
	{
		$result = $this->query ($query, $params);

		if ($result && ($row = $result->fetch_row ()))
			return $row[0];

		return NULL;			
	}
	
	/**
	 * Executes the query stored in the specified file and gets the result.
	 *
	 * @param string $query The SQL query
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function queryFromFile ($file, $params = NULL)
	{
		$query = file_get_contents ($file);
		
		if ($query)
			return $this->query ($query, $params);
			
		return NULL;
	}
	
	/**
	 * Executes the query and gets the result.
	 *
	 * @param string $query The SQL query
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function query ($query, $params = NULL)
	{
		$result = $this->conn->query (Render::toString ($query, $params));
		
		if (!$result)
			$this->checkError ();
		else
		while ($this->moreResults ())
			$this->nextResult ();

		return $result;	
	}

	/**
	 * Execute multiple queries separated by semicolons.
	 *
	 * @param string $query The SQL query
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function multiQuery ($query, $params = NULL)
	{
		$success = $this->conn->multi_query (Render::toString ($query, $params));
		
		if (!$success)
			$this->checkError ();

		return $success;
	}
	
	function storeResult ()
	{
		$result = $this->conn->store_result ();
		
		if (!$result)
			$this->checkError ();

		return $result;
	}
	
	function moreResults ()
	{
		return $this->conn->more_results ();
	}
	
	function nextResult ()
	{
		return $this->conn->next_result ();
	}

	private function checkError ()
	{
		if ($this->conn->errno)
		{
			$code = $this->conn->errno;
			$message = $this->conn->error;
		
			$sql = 'SELECT es_es message, 2000 + id AS id '.
				'FROM sql_error WHERE code = @err';
		
			if ($code == 1305 && ($row = $this->getRow ($sql)))
				throw new Exception  ($row['id'], $row['message']);
			else
				throw new Exception  ($code, $message);
		}
	}
	
	function checkWarnings ()
	{
		if ($this->conn->warning_count > 0)
		if ($result = $this->conn->query ('SHOW WARNINGS'))
		{
			$warnings = [];
			$sql = 'SELECT es_es message, 3000 + id AS id '.
				'FROM sql_warning WHERE code = @warn';

			while ($row = $result->fetch_assoc ())
			{
				if ($row['Code'] == 1265
				&& ($warning = $this->getRow ($sql)))
				{
					$row['Code'] = $warning['id'];
					$row['Message'] = $warning['message'];
				}
			
				$warnings[] = $row;
			}
			
			return $warnings;
		}
		
		return NULL;
	}
}

?>