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

/*
Generate exercises based on wiki content and its structure
 
exercises idea to implement (cf http://fabien.benetou.fr/Cookbook/Cognition#DailyExercisesFeed )
 	random type is not implemented properly enough for score tracking
		e.g. highest score from random appear as other exercise
		after 1 random exercise, going back to the same type of the last picked exercise
	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
		extend type=pagehasexpression
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)
	see the hall of fame to see which exercise are the easiest
do a graph traversal rather than random jumps
	i.e. if pick randomly from the linked pages or from the group or from the the whole wiki of the previous page
	consider https://research.cc.gatech.edu/inc/game-forge 
improve parsing
	discard more pages
		structuring e.g. PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
		page with just one line, especially markups, typically redirections
support other interfaces
	e.g. http://www.cs.cmu.edu/~listen/ listed in Content/Education#SeeAlso
	Vimperator with predictable link numbers to go faster
track time require for answering each question
	display a clock
	could improve excitment, e.g. answer the maximum number of questions correctly in X minutes
	

implemented
	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 page corresponds the updates visualization V, A, B or C? (type=historyvisualization)
	is page A linked to page B? (type=pagelink)
*/

$RecipeInfo['Exercises']['Version'] = '2015-16-08';

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

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

	$availableexercisetypes = array("pagelink", "expressioninpage", "pagehasexpression");
	if (file_exists($FarmD."/pub/visualization/edits_per_page/" ))
		//the pim_functions.php generated the PJS has been loaded before
		$availableexercisetypes[] = "historyvisualization";

	if ($type=="random" || $type=="") {
		$type= $availableexercisetypes[array_rand($availableexercisetypes)];
		$random=true;
	}

	$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

	$minlinelength = 20;
	// this could also be consider a difficulty, the shorter the harder
	// it can be overwritten per each exercise

	// tracking the current score
	$counterparam = "";
	if ( $counter > 0) {
		$counterparam = "counter=$counter&";
	}

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

	}

	//randomly pick a page in the possible pages
	$sourcepage = $pages[array_rand($pages)];
	unset($pages[array_search($sourcepage,$pages)]);

	switch ($type){
		case "pagelink":
			$content = ReadPage($sourcepage,READPAGE_CURRENT);
			$links = $content["targets"];
			$links_array = explode(",",$links);
			//note that count($links_array)<1) was not used since explode returned an array with en empty value
			while (($links_array[0]=="") && (count($pages)>0)) {
				$sourcepage = $pages[array_rand($pages)];
				unset($pages[array_search($sourcepage,$pages)]);
				$content = ReadPage($sourcepage,READPAGE_CURRENT);
				$links = $content["targets"];
				$links_array = explode(",",$links);
			}
			if ($links_array[0]=="") {
				$result .= "Unfortunately it seems no suitable page has been found for this game. ";
				$result .= "Try in another group or [[AllPages/AllPages?action=Exercises&type=$type&counter=$counter|in the entire wiki]].";
				break;
			}

			//randomly pick a page amongst the linked pages
			$answers[] = $links_array[array_rand($links_array)];
			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[] = $pages[array_rand($pages)];
				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 ( $i == count($answers) -1 )
					$result .= " or ";
				$currentpage = $answers[$i];
				//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."]], ";
			}
			$result .="? ";
			$result .="\n\nClick on the answer.";
			break;
		case "historyvisualization":
			$processingpath = "$ScriptUrl/pub/libraries/processing.js";
			$processinglib = "<script src=\"$processingpath\" type=\"text/javascript\"></script>";
			$processingfile = "$ScriptUrl/pub/visualization/edits_per_page/$sourcepage.pjs";
			// TODO if it does not exist, pick another page, adapt code above

			$answers[] = $sourcepage;

			//randomly pick n-1 others pages which may not be amongst the list of linked page
			for ($i=1;$i<$n;$i++) {
				$answers[] = $pages[array_rand($pages)];
				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:";

			// note that there might be more than 1 correct answer but this is not a problem as long as the question is stated clearly.
			shuffle($answers);

			for ($i=0;$i<count($answers);$i++) {
				if ( $i == count($answers) -1 )
					$result .= " or ";
				//display the groupname everytime only if using AllPages
				$currentpage = $answers[$i];
				if ($group != "AllPages") 
					list($currentgroup,$currentpage) = explode(".",$answers[$i]);
				$result .="[[$pagename?action=ExercisesCheck&".$counterparam
					."type=$type&source=$sourcepage&answer=".md5($answers[$i])."|".$currentpage."]], ";
			}
			$result .="? ";
			$result .="\n\nClick on the answer.";
			break;
		case "pagehasexpression":
			$content = ReadPage($sourcepage,READPAGE_CURRENT);
			$text = $content["text"];
			$lines = explode("\n",$text);

			$pickedline = $lines[array_rand($lines)];
			unset($lines[array_search($pickedline,$lines)]);
			//should be better parsed! e.g. remove markups
			//pregreplace("/(:.*:)/","",$pickedline);
			while (( strlen($pickedline) < $minlinelength ) && ( count($lines) > 0 ) ) {
				$pickedline = $lines[array_rand($lines)];
				//pregreplace("/(:.*:)/","",$pickedline);
				unset($lines[array_search($pickedline,$lines)]);
			}
			$actualanswer = $pickedline;
			$answers[] = $pickedline;

			for ($i=1;$i<$n;$i++) {
				$otherpage = $pages[array_rand($lines)];
				$otherpage = $pages[array_rand($pages)];
				unset($pages[array_search($otherpage,$pages)]);
				$content = ReadPage($otherpage,READPAGE_CURRENT);
				$text = $content["text"];
				$lines = explode("\n",$text);
				$pickedline = $lines[array_rand($lines)];
				unset($lines[array_search($pickedline,$lines)]);
				while (( strlen($pickedline) < $minlinelength ) && ( count($lines) > 0 ) ) {
					$pickedline = $lines[array_rand($lines)];
					unset($lines[array_search($pickedline,$lines)]);
				}
				$answers[] = $pickedline;
			}

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

			shuffle($answers);

			for ($i=0;$i<$n;$i++) {
				if ($answers[$i]==$actualanswer)
					$hashedanswer = md5($sourcepage);
				else
					$hashedanswer = md5($answers[$i]);
				// hashing the answer, NOT the page, but only used to hide so should not be problematic
				$result .="\n* [[$pagename?action=ExercisesCheck&".$counterparam
					."type=$type&source=$sourcepage&answer=$hashedanswer|$i]] [@".$answers[$i]."@] ";
			}
			$result .="\n\nClick on the answer.";
			
			break;
		case "expressioninpage":
			$content = ReadPage($sourcepage,READPAGE_CURRENT);
			$text = $content["text"];
			$lines = explode("\n",$text);

			$pickedline = $lines[array_rand($lines)];
			unset($lines[array_search($pickedline,$lines)]);
			while (( strlen($pickedline) < $minlinelength ) && ( count($lines) > 0 ) ) {
				$pickedline = $lines[array_rand($lines)];
				unset($lines[array_search($pickedline,$lines)]);
			}
			$answers[] = $sourcepage;

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

			//display
			$result .= "Does the page expression \n* [@$pickedline@] \n\nbelongs 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<$n;$i++) {
				$hashedanswer = md5($answers[$i]);
				if ( $i == count($answers) -1 )
					$result .= " or ";
				$result .="[[$pagename?action=ExercisesCheck&".$counterparam
					."type=$type&source=$sourcepage&answer=$hashedanswer|".$answers[$i]."]], ";
			}
			$result .="?\n\nClick on the answer.";
			
			// explode content by line "%0a" or word " "
			break;
		default:
			$result .= "Exercise type unknown.";
	}

        unset($availableexercisetypes[array_search($type,$availableexercisetypes)]);
	if (count($availableexercisetypes) > 0) {
		$result .= "\n\nTry other types of exercises:";
		foreach ($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){
	global $ScriptUrl, $FarmD, $Author;

	$activityfile = $FarmD."/wiki.d/.exercisesscores";

	$type = $_GET["type"];
	$sourcepage = $_GET["source"];
	$answer = $_GET["answer"];
	$counter = 0;
	if ( isset($_GET["counter"]) )
		$counter = (int) $_GET["counter"];

	$score_lower_threshold = 3;
	// this could also be a value relative to the top score if there is one

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

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

	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.";
					// $halloffame = ExercisesResults();
					// to add to $verbatimresult to motivate playing again
				}
				$result .="\n\nTry to redeem yourself by [[$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=$type|trying another time]]. ";
			}
			break;
		case "pagehasexpression":
		// XXX does not work
			if ( md5($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 {
				$result .="No, it was the expression of [[$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=$type|trying another time]]. ";
			}
			break;
		case "expressioninpage":
			if ( md5($sourcepage) === $answer ) {
				$result .="Excellent! that expression did come from [[$sourcepage]].";
				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]] was the page that expression came from.";
				// 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 $renderedresult.$verbatimresult;
	if ( ( isset($Author) ) && ( $counter > $score_lower_threshold ) ) {
		$score = "$counter,$Author,$type,".time()."\n";
		$write_result = file_put_contents($activityfile,$score, FILE_APPEND | LOCK_EX);
		if ($write_result < 1)
			print "There seems to be an error updating the score file, please check that $activityfile has write permission for httpd.";
	}
}

Markup("exercisesresults", "directives", "/\(:exercisesresults:\)/", ExercisesResults());
# markup to display results
#	default to all participant, not just the currently logged in user
#		hall of fame could be useful in collaborative learning wikis
#	consider first sparklines for visuals
#	remove failed before top score, try to group sessions and avoid results for the same
function ExercisesResults(){
	global $ScriptUrl, $FarmD, $Author;
	$availableexercisetypes = array("pagelink", "expressioninpage", "pagehasexpression", "historyvisualization");
	$activityfile = $FarmD."/wiki.d/.exercisesscores";
        if (file_exists($activityfile)) {
		$raw_scores = file_get_contents($activityfile);
		$allscores = explode("\n",$raw_scores);
		rsort($allscores,SORT_NUMERIC);
		//dirty, but array_filter with an lambda to test for current exercise didn't work 
		foreach ($allscores as $score ) {
			list($counter,$author,$type,$time) = explode(",",$score);
			if ($counter.$author.$type.$time != "")
				$structuredanswers[] = array("counter"=>$counter,"author"=>$author,"type"=>$type,"time"=>$time);
		}
		// could instead filter by exercise and sort by highest score, listing the top3 score per per exercise
		$past_scores .= "<table><tr>";
		foreach ($availableexercisetypes as $exercisetype){
			$past_scores .= "<td><a href=\"AllPages/AllPages?action=Exercises&type=$exercisetype\">$exercisetype</a></td>";
		}
		$past_scores .= "</tr><tr>";
		foreach ($availableexercisetypes as $exercisetype){
			$past_scores .= "<td valign=\"top\">";
			$answers_added = 1;
			foreach ($structuredanswers as $sa){
				if ($sa["type"]==$exercisetype && $answers_added<4){
					$past_scores .= "".$sa["counter"]." done by ".$sa["author"]." (".date("H:m m/d/y",$sa["time"]).")<br/>";
					$answers_added++;
				}
			}
			$past_scores .= "</td>";
		}
		$past_scores .= "</tr></table>";
	} else {
		$past_scores = "Currently no scores have been recorded. Consider starting an exercise first";
		// print "Go above the minimum threshold of good answers while being logged in.";
		// removed for now since the threshold is at 1
	}
	return $past_scores;
}

?>