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

error_reporting(0);
// for demo

# 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? (type=expressioninpage)
#	does page A contains word X, Y or Z? (type=pagehasexpression)
#	which of those group corresponds the graph visualization V, A, B or C? 
#		using groupnetworkvisualization.php
#	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, ... 
#	what is the color hashing used in RevertedPIM for this group, color A, B or C?
#		might require JS
#	keyword or URL in pages
#	definition of word and vice versa
#		limited to pages with definitions (e.g. some languages)
#			list lines with "* word = definition"
#			split word and definition
#			pick one and display the other with alternatives
# implemented
#	which of those page corresponds the updates visualization V, A, B or C? (type=historyvisualization)
#	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)
# XXX
# 	picking a random page seems to fail from time to time
#		some (very few) indices are not used, resulting in picked an empty string
#		http://php.net/manual/en/function.array-rand.php seems to fix it


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

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

function Exercises($pagename, $auth){
	global $ScriptUrl;
	$type = $_GET["type"];
	$counter = (int) $_GET["counter"];
	$difficulty = (int) $_GET["difficulty"];
	list($group,$page) = explode(".",$pagename);

	$availableexercisetypes = array("pagelink", "expressioninpage", "pagehasexpression", "historyvisualization");
	//should also test if the pim_functions.php generated the PJS has been loaded, else not make historyvisualization available

	if ($type=="random")
		$type= $availableexercisetypes[rand(0,count($availableexercisetypes)-1)];

	$result = "";
	$verbatimresult = "";

	$n=3;
	// n should be based on $difficulty, e.g. n=2+$difficulty or n=2^$difficulty
	// it used to determine the number of false answers
	// it can be overwritten per each exercise

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

	switch ($type){
		case "pagelink":
			// the pattern should be improve, e.g. remove PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
			if ($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);
			$links = $content["targets"];
			$links_array = explode(",",$links);

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

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

			unset($pages[array_search($answers[0],$links_array)]);
			unset($pages[array_search($answers[0],$pages)]);

			//randomly pick n-1 others pages which may not be amongst the list of linked page
			for ($i=1;$i<$n;$i++) {
				$answers[] = $pages[rand(0,count($pages)-1)];
				unset($pages[array_search($answers[$i],$pages)]);
			}

			//display
			$result .="Is page [[$sourcepage]] linked to ";

			// there should now be at least 1 needle in the haystack, the first one
			// note that there might be more but this is not a problem as long as the question is stated clearly.
			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&".$counterparam
							."type=$type&source=$sourcepage&answer=".$answers[$i]."|".$currentpage."]], ";
					} else {
						$result .="[[$pagename?action=ExercisesCheck&".$counterparam
							."type=$type&source=$sourcepage&answer=".$answers[$i]."|".$answers[$i]."]], ";
					}
				}
			}
			$result .="? ";
			$result .="\n\nClick on the answer.";
			break;
		case "historyvisualization":
			$processingpath = '/mirrors/fabien/pub/libraries/processing.js';
			$processingpath = "$ScriptUrl/pub/libraries/processing.js";
			$processinglib = "<script src=\"$processingpath\" type=\"text/javascript\"></script>";
			// 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)];
			$processingfile = "/mirrors/fabien/pub/visualization/edits_per_page/$sourcepage.pjs";
			$processingfile = "$ScriptUrl/pub/visualization/edits_per_page/$sourcepage.pjs";

			//randomly pick a page amongst the linked pages
			$answers[] = $sourcepage;

			unset($pages[array_search($answers[0],$pages)]);

			//randomly pick n-1 others pages which may not be amongst the list of linked page
			for ($i=1;$i<$n;$i++) {
				$answers[] = $pages[rand(0,count($pages)-1)];
				unset($pages[array_search($answers[$i],$pages)]);
			}

			//display
			$historyvisualization = $processinglib.'<canvas data-src="'.$processingfile.'"></canvas>';
			$verbatimresult = $historyvisualization;
			$result .="Which of those page corresponds the updates visualization:";

			// there should now be at least 1 needle in the haystack, the first one
			// note that there might be more but this is not a problem as long as the question is stated clearly.
			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&".$counterparam
							."type=$type&source=$sourcepage&answer=".md5($answers[$i])."|".$currentpage."]], ";
					} else {
						$result .="[[$pagename?action=ExercisesCheck&".$counterparam
							."type=$type&source=$sourcepage&answer=".md5($answers[$i])."|".$answers[$i]."]], ";
					}
				}
			}
			$result .="? ";
			$result .="\n\nClick on the answer.";
			// XXX checking of the result is not yet done, might have to hide (e.g. via hash) the answer and the source
			break;
		case "pagehasexpression":
			// the pattern should be improve, e.g. remove PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
			if ($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)];
			$sourcepage = $pages[array_rand($pages)];
			unset($pages[array_search($sourcepage,$pages)]);
			$content = ReadPage($sourcepage,READPAGE_CURRENT);
			$text = $content["text"];
			$lines = explode("\n",$text);

			// $links = $content["targets"];		
			// $links_array = explode(",",$links);
			// could be use for increase difficulty, e.g. pick content from related pages

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

			$minlinelength = 20;
			// this could also be consider a difficulty, the shorter the harder

			//$answers[]["source"] = $sourcepage;
			$pickedline = $lines[rand(0,count($lines)-1)];
			unset($lines[array_search($pickedline,$lines)]);
			while (( strlen($pickedline) < $minlinelength ) && ( count($lines) > 0 ) ) {
				$pickedline = $lines[rand(0,count($lines)-1)];
				unset($lines[array_search($pickedline,$lines)]);
			}
			//$answers[]["line"] = $pickedline;
			$actualanswer = $pickedline;
			$answers[] = $pickedline;

			//randomly pick n-1 others pages which may not be amongst the list of linked page
			for ($i=1;$i<$n;$i++) {
				$otherpage = $pages[rand(0,count($pages)-1)];
				$otherpage = $pages[array_rand($pages)];
				unset($pages[array_search($otherpage,$pages)]);
				$content = ReadPage($otherpage,READPAGE_CURRENT);
				$text = $content["text"];
				$lines = explode("\n",$text);
				//$answers[]["source"] = $otherpage;
				$pickedline = $lines[rand(0,count($lines)-1)];
				unset($lines[array_search($pickedline,$lines)]);
				while (( strlen($pickedline) < $minlinelength ) && ( count($lines) > 0 ) ) {
					$pickedline = $lines[rand(0,count($lines)-1)];
					unset($lines[array_search($pickedline,$lines)]);
				}
				//$answers[]["line"] = $pickedline;
				$answers[] = $pickedline;
			}

			//display
			$result .= "Does the page [[$sourcepage]] has expression ";


			// there should now be at least 1 needle in the haystack, the first one
			// note that there might be more but this is not a problem as long as the question is stated clearly.
			shuffle($answers);

			for ($i=0;$i<$n;$i++) {
				if ($answers[$i]==$actualanswer)
					$hashedanswer = md5($sourcepage);
				else
					$hashedanswer = md5($answers[$i]);
				$result .="\n* [[$pagename?action=ExercisesCheck&".$counterparam
					."type=$type&source=$sourcepage&answer=$hashedanswer|$i]] [@".$answers[$i]."@] ";
				//should be better parsed!
			}
			$result .="\n\nClick on the answer.";
			
			break;
		case "expressioninpage":
			// explode content by line "%0a" or word " "
			$result .= "Does the expression 'EXPRESSION' come from PAGEA, PAGEB or PAGEC?";
			break;
		default:
			$result .= "Exercise type unknown.";
	}

        unset($availableexercisetypes[array_search($type,$availableexercisetypes)]);
	if (count($availableexercisetypes) > 0) {
		$result .= " Try other types of exercises:";
		foreach ($availableexercisetypes as $e) {
			$result	.= " [[$pagename?action=Exercises&type=$e|$e]],";
		}
		$result .= " or a [[$pagename?action=Exercises&type=random|random]] one.";
		if ( $counter > 0) {
			$result .= " (note that it resets the counter)";
		}
	}
	$result .= "\n\n%center%[-Generated by [[http://fabien.benetou.fr/MemoryRecalls/ImprovingPIM#PIMBasedExercises|PIM Based Exercises]].-]%%";
	$renderedresult = MarkupToHTML($pagename, $result);
	print "<html>".$verbatimresult.$renderedresult."</html>";
	
	//$text = RetrieveAuthSection($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&type=$type&counter=$counter|solve yet another one]]. ";
				} else {
					$result .="\n\nSee if you can [[$pagename?action=Exercises&type=$type&counter=1|solve yet another one]]. ";
				}
			} else {
				$result .="No, [[$sourcepage]] is not linked to [[$answer]] ";
				$result .="but $formattedlinks are. ";
				if ($counter > 0) $result .="\nIt means you are losing your $counter points.";
				$result .="\n\nTry to redeem yourself by [[$pagename?action=Exercises&type=$type|trying another time]]. ";
			}
			break;
		case "historyvisualization":
			if ( md5($sourcepage) === $answer ) {
				$result .="Excellent! [[$sourcepage]] indeed has that history of editions.";
				if ( $counter > 0) {
					$counter++;
					$result .="\n\nSee if you can [[$pagename?action=Exercises&type=$type&counter=$counter|solve yet another one]]. ";
				} else {
					$result .="\n\nSee if you can [[$pagename?action=Exercises&type=$type&counter=1|solve yet another one]]. ";
				}
			} else {
				$result .="No, it was the visualization of [[$sourcepage]] history of editions.";
				// display it again
				if ($counter > 0) $result .="\nIt means you are losing your $counter points.";
				$result .="\n\nTry to redeem yourself by [[$pagename?action=Exercises&type=$type|trying another time]]. ";
			}
			break;
		case "pagehasexpression":
			if ( md5($sourcepage) === $answer ) {
				$result .="Excellent! [[$sourcepage]] indeed has that expression.";
				if ( $counter > 0) {
					$counter++;
					$result .="\n\nSee if you can [[$pagename?action=Exercises&type=$type&counter=$counter|solve yet another one]]. ";
				} else {
					$result .="\n\nSee if you can [[$pagename?action=Exercises&type=$type&counter=1|solve yet another one]]. ";
				}
			} else {
				$result .="No, it was the expressoin of [[$sourcepage]].";
				// display it again
				if ($counter > 0) $result .="\nIt means you are losing your $counter points.";
				$result .="\n\nTry to redeem yourself by [[$pagename?action=Exercises&type=$type|trying another time]]. ";
			}
			break;
		default:
			$result .= "Exercise type unknown, this most likely indicate that the checking for the solution has not yet been implemented, please consider notifying the author. For now try [[$pagename?action=Exercises&type=random|a random type of exercise]].";
	}
	$result .= "\n\n%center%[-Generated by [[http://fabien.benetou.fr/MemoryRecalls/ImprovingPIM#PIMBasedExercises|PIM Based Exercises]].-]%%";
	$renderedresult = MarkupToHTML($pagename, $result);
	print $renderedresult;
}

?>