<?php

namespace Vn\Db;

require_once ('vn/lib/type.php');
require_once ('vn/db/exception.php');

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

	function __construct ()
	{
		$this->initHandler ();
	}

	/**
	 * 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, $port = NULL)
	{
		$conn = $this->initHandler ();
		$conn->options (MYSQLI_OPT_LOCAL_INFILE, TRUE);
		$conn->options (MYSQLI_READ_DEFAULT_FILE, __DIR__.'/my.cnf');
		$conn->real_connect ($host, $user, $pass, $name, $port);
	
		if (mysqli_connect_errno ())
		{
			sleep (3);
			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->conn = NULL;
		}

		$this->isOpen = FALSE;
	}

	/**
	 * Initializes the internal database connection handler.
	 *
	 * @return Objetct The connection handler
	 **/
	function initHandler ()
	{
		if (!$this->conn)
			$this->conn = new \mysqli ();
			
		return $this->conn;
	}
	
	/**
	 * Returns the internal database connection handler. This function shoud be
	 * used to set options for specific databases that could not be set using 
	 * the Db\Conn class methods.
	 *
	 * @return Objetct The connection handler
	 **/
	function getHandler ()
	{
		return $this->conn;
	}

	/**
	 * Changes the default schema for the current connection.
	 *
	 * @param string $schema The schema name
	 * @return boolean %TRUE if success, %FALSE otherwise
	 **/
	function selectDb ($dbName)
	{
		return $this->conn->select_db ($dbName);
	}
	
	/**
	 * 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 = $this->conn->query ($this->render ($query, $params));
		
		if (!$result)
			$this->checkError ();
		else
		while ($this->moreResults ())
			$this->nextResult ();

		return $result;	
	}
	
	/**
	 * Checks whether the connection is open.
	 *
	 * @return boolean %TRUE if connection is open, %FALSE otherwise
	 **/
	function isOpen ()
	{
		return $this->isOpen;
	}
	
	/**
	 * Gets the first row value of the first column from a result.
	 *
	 * @param resource $result The database result
	 *
	 * @return mixed[] An associative array with the first row, %NULL if error
	 **/
	function getRowFromResult ($result)
	{
		if ($result)
		{
			$row = $result->fetch_assoc ();
			$result->free ();
			return $row;
		}

		return NULL;
	}

	/**
	 * Gets the first row value of the first column from a result.
	 *
	 * @param resource $result The database result
	 *
	 * @return mixed  The value or %NULL if error
	 **/
	function getValueFromResult ($result)
	{
		$value = NULL;

		if ($result)
		{
			$row = $result->fetch_row ();
		
			if ($row && count ($row) > 0)
				$value = $row[0];
			
			$result->free ();
		}

		return $value;	
	}
	
	/**
	 * 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);
		return $this->getRowFromResult ($result);
	}
	
	/**
	 * 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);
		return $this->getValueFromResult ($result);
	}
	
	/**
	 * Loads a query from a file and renders it.
	 *
	 * @param string $file The file path
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The query string
	 **/
	function loadFromFile ($file, $params = NULL)
	{
		$query = file_get_contents ($file .'.sql');
		
		if ($query === FALSE)
			throw new Exception  (NULL, 'Can not load query from file');
		
		return $this->render ($query, $params);
	}
	
	/**
	 * Executes the query stored in the specified file and gets the result.
	 *
	 * @param string $file The file path
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function queryFromFile ($file, $params = NULL)
	{
		$query = $this->loadFromFile ($file, $params);
		
		if ($query)
			return $this->query ($query);
			
		return NULL;
	}
	
	/**
	 * Executes the file query and gets it's first row.
	 *
	 * @param string $file The file path
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed[] An associative array with the first row, %NULL if error
	 **/
	function getRowFromFile ($file, $params = NULL)
	{
		$result = $this->queryFromFile ($file, $params);
		return $this->getRowFromResult ($result);
	}
	
	/**
	 * Executes the file query and gets the first value of the first row.
	 *
	 * @param string $file The file path
	 * @param mixed[] $params The query parameters
	 *
	 * @return mixed The value or %NULL if error
	 **/
	function getValueFromFile ($file, $params = NULL)
	{
		$result = $this->queryFromFile ($file, $params);
		return $this->getValueFromResult ($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 = $this->conn->multi_query ($this->render ($query, $params));
		
		if (!$success)
			$this->checkError ();

		return $success;
	}
	
	/**
	 * Prepare an SQL statement for execution.
	 *
	 * @param string $query The SQL query
	 *
	 * @return mixed The statement object or %FALSE if an error occurred
	 **/
	function prepare ($query)
	{
		return $this->conn->prepare ($query);
	}
	
	function storeResult ()
	{
		$result = $this->conn->store_result ();
		
		if (!$result)
			$this->checkError ();

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

	/**
	 * Check if there has been an error in the last query or multiquery,
	 * throwing a @Db\Exception exception if any.
	 **/
	function checkError ()
	{
		if ($this->conn->errno)
			throw new Exception ($this->conn->errno, $this->conn->error);
	}
	
	/**
	 * Check if there have been warnings in the last query.
	 *
	 * @return boolean %TRUE if there have been warnings %FALSE otherwise
	 **/
	function checkWarnings ()
	{
		return $this->conn->warning_count > 0;
	}

	/**
	 * Renders an SQL string using the given parameters.
	 *
	 * @param string $query The SQL string
	 * @param mixed[] $paramsMap The query parameters
	 *
	 * @return string The rendered SQL string
	 **/
	function render ($query, $paramsMap = NULL)
	{
		if (isset ($paramsMap) && is_array ($paramsMap) && count ($paramsMap) > 0)
		{
			$i = 0;
			$params = [];
	
			foreach ($paramsMap as $key => $value)
				$params[$key] = $this->renderValue ($value);
				
			$replaceFunc = function ($matches) use (&$params, &$i)
			{
				$key = substr ($matches[0], 1);
				
				if (strlen ($key) == 0)
					$key = $i++;	
				if (isset ($params[$key]))
					return $params[$key];
			
				return '#'. $key;
			};

			return preg_replace_callback ('/#\w*/', $replaceFunc, $query);
		}
		else
			return $query;
	}
	
	/**
	 * Gets an SQL respresentation from a PHP value.
	 *
	 * @param mixed $value The value
	 *
	 * @return string The SQL value
	 **/
	function renderValue ($value)
	{
		if ($value !== NULL)
		switch (get_type ($value))
		{
			case TYPE_BOOLEAN:
				return ($value) ? 'TRUE' : 'FALSE';
			case TYPE_STRING:
				return '\'' . $this->conn->escape_string ($value) . '\'';
			case TYPE_DATE:
				return strftime ('\'%Y-%m-%d\'', $value->getTimestamp ());
			case TYPE_TIME:
				return strftime ('\'%T\'', $value->getTimestamp ());
			case TYPE_DATE_TIME:
				return strftime ('\'%Y-%m-%d %T\'', $value->getTimestamp ());
			default:
				return '\'' . $this->conn->escape_string ($value) . '\'';
		}
		else
			return 'NULL';
	}
}

?>