<?php
/*
	Contain the common functions 
	required in shop and admin pages
*/
require_once 'config.php';
require_once 'database.php';

/*
	Make sure each key name in $requiredField exist
	in $_POST and the value is not empty
*/
function checkRequiredPost($requiredField) {
	$numRequired = count($requiredField);
	$keys        = array_keys($_POST);
	
	$allFieldExist  = true;
	for ($i = 0; $i < $numRequired && $allFieldExist; $i++) {
		if (!in_array($requiredField[$i], $keys) || $_POST[$requiredField[$i]] == '') {
			$allFieldExist = false;
		}
	}
	
	return $allFieldExist;
}




/*
	Join up the key value pairs in $_GET
	into a single query string
*/
function queryString()
{
	$qString = array();
	
	foreach($_GET as $key => $value) {
		if (trim($value) != '') {
			$qString[] = $key. '=' . trim($value);
		} else {
			$qString[] = $key;
		}
	}
	
	$qString = implode('&', $qString);
	
	return $qString;
}

/*
	Put an error message on session 
*/
function setError($errorMessage)
{
	if (!isset($_SESSION['plaincart_error'])) {
		$_SESSION['plaincart_error'] = array();
	}
	
	$_SESSION['plaincart_error'][] = $errorMessage;

}

/*
	print the error message
*/
function displayError()
{
	if (isset($_SESSION['plaincart_error']) && count($_SESSION['plaincart_error'])) {
		$numError = count($_SESSION['plaincart_error']);
		
		echo '<table id="errorMessage" width="550" align="center" cellpadding="20" cellspacing="0"><tr><td>';
		for ($i = 0; $i < $numError; $i++) {
			echo '&#8226; ' . $_SESSION['plaincart_error'][$i] . "<br>\r\n";
		}
		echo '</td></tr></table>';
		
		// remove all error messages from session
		$_SESSION['plaincart_error'] = array();
	}
}

/**************************
	Paging Functions
***************************/

function getPagingQuery($sql, $itemPerPage = 10)
{
	if (isset($_GET['page']) && (int)$_GET['page'] > 0) {
		$page = (int)$_GET['page'];
	} else {
		$page = 1;
	}
	
	// start fetching from this row number
	$offset = ($page - 1) * $itemPerPage;
	
	return $sql . " LIMIT $offset, $itemPerPage";
}

/*
	Get the links to navigate between one result page to another.
	Supply a value for $strGet if the page url already contain some
	GET values for example if the original page url is like this :
	
	http://www.phpwebcommerce.com/plaincart/index.php?c=12
	
	use "c=12" as the value for $strGet. But if the url is like this :
	
	http://www.phpwebcommerce.com/plaincart/index.php
	
	then there's no need to set a value for $strGet
	
	
*/
function getPagingLink($sql, $itemPerPage = 10, $strGet = '')
{
	$result        = dbQuery($sql);
	$pagingLink    = '';
	$totalResults  = dbNumRows($result);
	$totalPages    = ceil($totalResults / $itemPerPage);
	
	// how many link pages to show
	$numLinks      = 10;

		
	// create the paging links only if we have more than one page of results
	if ($totalPages > 1) {
	
		$self = 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'] ;
		

		if (isset($_GET['page']) && (int)$_GET['page'] > 0) {
			$pageNumber = (int)$_GET['page'];
		} else {
			$pageNumber = 1;
		}
		
		// print 'previous' link only if we're not
		// on page one
		if ($pageNumber > 1) {
			$page = $pageNumber - 1;
			if ($page > 1) {
				$prev = " <a href=\"$self?page=$page&$strGet/\">[Prev]</a> ";
			} else {
				$prev = " <a href=\"$self?$strGet\">[Prev]</a> ";
			}	
				
			$first = " <a href=\"$self?$strGet\" class=\"pagBox\" >[First]</a> ";
		} else {
			$prev  = ''; // we're on page one, don't show 'previous' link
			$first = ''; // nor 'first page' link
		}
	
		// print 'next' link only if we're not
		// on the last page
		if ($pageNumber < $totalPages) {
			$page = $pageNumber + 1;
			$next = " <a href=\"$self?page=$page&$strGet\" class=\"pagBox\">[Next]</a> ";
			$last = " <a href=\"$self?page=$totalPages&$strGet\" class=\"pagBox\">[Last]</a> ";
		} else {
			$next = ''; // we're on the last page, don't show 'next' link
			$last = ''; // nor 'last page' link
		}

		$start = $pageNumber - ($pageNumber % $numLinks) + 1;
		$end   = $start + $numLinks - 1;		
		
		$end   = min($totalPages, $end);
		
		$pagingLink = array();
		for($page = $start; $page <= $end; $page++)	{
			if ($page == $pageNumber) {
				$pagingLink[] = " $page ";   // no need to create a link to current page
			} else {
				if ($page == 1) {
					$pagingLink[] = " <a href=\"$self?$strGet\" class=\"pagBox\">$page</a> ";
				} else {	
					$pagingLink[] = " <a href=\"$self?page=$page&$strGet\" class=\"pagBox\">$page</a> ";
				}	
			}
	
		}
		
		$pagingLink = implode(' | ', $pagingLink);
		
		// return the page navigation link
		$pagingLink = $first . $prev . $pagingLink . $next . $last;
	}
	
	return $pagingLink;
}
?>