<?php if (!defined('PmWiki')) exit();

# generate exercises based on wiki content and its structure
# 
# still to implement (cf http://fabien.benetou.fr/Cookbook/Cognition#DailyExercisesFeed )
#	is word X from page A, B, C or D?
#	does page A contains word X, Y or Z?
#	what is the correct order for pages A, B and C on descending criteria i A>B>C? A>C>B? B>C>A? B>A>C? C>B>A? C>A>B?
#		e.g. size, frequency update, last edition, ... 
#	which of those page corresponds the updates visualization V, A, B or C? 
#	keyword or URL in pages
# implemented
#	is page A linked to page B? (type=pagelink)
# consider a difficulty parameter
#	should be linked to the counter
#	e.g. increasing the number of possibilities (at least 1 out of 5 pages instead of at least 1 out of 3)


$RecipeInfo['Exercises']['Version'] = '2011-12-08';

SDV($HandleActions['Exercises'], 'Exercises');
SDV($HandleAuth['Exercises'],'read');

function Exercises($pagename, $auth){

	$exercisetype="pagelink";
	list($group,$page) = explode(".",$pagename);
	// the pattern should be improve, e.g. remove PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
	if ($group == "AllPages"){
		// equivalent to getting ALL pages
	        $pages = ListPages();
	} else {
	        $pages = ListPages("/$group\./e");

	}

	//randomly pick a page in the possible pages
	$sourcepage = $pages[rand(0,count($pages))];
	// -1?

	$content = ReadPage($sourcepage,READPAGE_CURRENT);
	//$text = $content["text"];
	// to use later on for expression exercises
	$links = $content["targets"];
	$links_array = explode(",",$links);

	//$answers = array();
	//consider pilling up potential in $answers[]

	//randomly pick a page amongst the linked pages
	$pageA = $links_array[rand(0,count($links_array)-1)];

        unset($pages[array_search($pageA,$links_array)]);
        unset($pages[array_search($pageA,$pages)]);
	//randomly pick 2 others pages which are not amongst the list of linked page
	$pageB = $pages[rand(0,count($pages)-1)];
        unset($pages[array_search($pageB,$pages)]);
	$pageC = $pages[rand(0,count($pages)-1)];
        unset($pages[array_search($pageC,$pages)]);

	//display
	$result .="Is page [[$sourcepage]] linked to ";
	$counter = (int) $_GET["counter"];

	$counterparam = "";
	if ( $counter > 0) {
		$counterparam = "counter=$counter&";
	}

	$answers = array ($pageA,$pageB,$pageC);
	shuffle($answers);
	for ($i=0;$i<count($answers);$i++) {
		if ($answers[$i] != "") {
			if ( $i == count($answers) -1 )
				$result .= " or ";
			//display the groupname everytime only if using AllPages
			if ($group != "AllPages") {
				list($currentgroup,$currentpage) = explode(".",$answers[$i]);
				$result .="[[$pagename?action=ExercisesCheck&".$counterparam
					."type=$exercisetype&source=$sourcepage&answer=".$answers[$i]."|".$currentpage."]], ";
			} else {
				$result .="[[$pagename?action=ExercisesCheck&".$counterparam
					."type=$exercisetype&source=$sourcepage&answer=".$answers[$i]."|".$answers[$i]."]], ";
			}
		}
	}
	$result .="? ";
	$result .="\n\nClick on the answer.";

	$result .= "\n\nGenerated by [[http://fabien.benetou.fr/MemoryRecalls/ImprovingPIM#PIMBasedExercises|PIM Based Exercises]]";
	$renderedresult = MarkupToHTML($pagename, $result);
	print $renderedresult;
	
	//$text = RetrieveAuthSection($pagename,$auth);
	//$content = MarkupToHTML($pagename, $text);
	//print $content;
}

SDV($HandleActions['ExercisesCheck'], 'ExercisesCheck');
SDV($HandleAuth['ExercisesCheck'],'read');

function ExercisesCheck($pagename, $auth){
	$type = $_GET["type"];
	$sourcepage = $_GET["source"];
	$answer = $_GET["answer"];
	$counter = (int) $_GET["counter"];

	list($group,$page) = explode(".",$pagename);
	if ($group == "AllPages"){
		// equivalent to getting ALL pages
	        $pages = ListPages();
	} else {
	        $pages = ListPages("/$group\./e");
	}

	switch ($type) {
		case "pagelink":
			$content = ReadPage($sourcepage,READPAGE_CURRENT);
			$links = $content["targets"];
			$links_array = explode(",",$links);
			$formattedlinks = implode(", ",$links_array);

			if ( in_array($answer,$links_array) ) {
				$result .="Excellent! [[$sourcepage]] is indeed linked to [[$answer]]. ";
				$result .="Note that $formattedlinks also are. ";
				if ( $counter > 0) {
					$counter++;
					$result .="\n\nSee if you can [[$pagename?action=Exercises&counter=$counter|solve yet another one]]. ";
				} else {
					$result .="\n\nSee if you can [[$pagename?action=Exercises&counter=1|solve yet another one]]. ";
				}
			} else {
				$result .="No, [[$sourcepage]] is not linked to [[$answer]] ";
				$result .="but $formattedlinks are. ";
				$result .="\n\nTry to redeem yourself by [[$pagename?action=Exercises|trying another time]]. ";
			}
			break;
	}
	$result .= "\n\nGenerated by [[http://fabien.benetou.fr/MemoryRecalls/ImprovingPIM#PIMBasedExercises|PIM Based Exercises]]";
	$renderedresult = MarkupToHTML($pagename, $result);
	print $renderedresult;
}

?>