#
# Copyright (C) 2002 Motorola. All Rights Reserved

use strict;

# =========================
package TWiki::Plugins::QuizPlugin; 	# change the package name!!!

# =========================
use vars qw(
        $web $topic $user $installWeb $VERSION $debug
	$quizNumber
    );

$VERSION = '1.000';

# =========================
sub initPlugin
{
    ( $topic, $web, $user, $installWeb ) = @_;

    # check for Plugins.pm versions
    if( $TWiki::Plugins::VERSION < 1 ) {
        &TWiki::Func::writeWarning( "Version mismatch between QuizPlugin and Plugins.pm" );
        return 0;
    }

    # Get plugin debug flag
    $debug = &TWiki::Func::getPreferencesFlag( "QUIZPLUGIN_DEBUG" );

    # Plugin correctly initialized
    &TWiki::Func::writeDebug( "- TWiki::Plugins::QuizPlugin::initPlugin( $web.$topic ) is OK" ) if $debug;
    $quizNumber = 1;
    return 1;
}

# =========================
sub DISABLE_commonTagsHandler
{
### my ( $text, $topic, $web ) = @_;   # do not uncomment, use $_[0], $_[1]... instead

    &TWiki::Func::writeDebug( "- QuizPlugin::commonTagsHandler( $_[2].$_[1] )" ) if $debug;

}

# =========================
sub DISABLE_startRenderingHandler
{
### my ( $text, $web ) = @_;   # do not uncomment, use $_[0], $_[1] instead

    &TWiki::Func::writeDebug( "- QuizPlugin::startRenderingHandler( $_[1].$topic )" ) if $debug;

    # This handler is called by getRenderedVersion just before the line loop

    # do custom extension rule, like for example:
    # $_[0] =~ s/old/new/go;
}

# =========================
sub DISABLE_outsidePREHandler
{
### my ( $text ) = @_;   # do not uncomment, use $_[0] instead

#   &TWiki::Func::writeDebug( "- QuizPlugin::outsidePREHandler( $web.$topic )" ) if $debug;

    # This handler is called by getRenderedVersion, in loop outside of <PRE> tag.
    # This is the place to define customized rendering rules.
    # Note: This is an expensive function to comment out.
    # Consider startRenderingHandler instead
}

# =========================
sub DISABLE_insidePREHandler
{
### my ( $text ) = @_;   # do not uncomment, use $_[0] instead

#   &TWiki::Func::writeDebug( "- QuizPlugin::insidePREHandler( $web.$topic )" ) if $debug;

    # This handler is called by getRenderedVersion, in loop inside of <PRE> tag.
    # This is the place to define customized rendering rules.
    # Note: This is an expensive function to comment out.
    # Consider startRenderingHandler instead
}

# =========================
sub endRenderingHandler
{
### my ( $text ) = @_;   # do not uncomment, use $_[0] instead

    &TWiki::Func::writeDebug( "- QuizPlugin::endRenderingHandler( $web.$topic )" ) if $debug;

    # This handler is called by getRenderedVersion just after the line loop

    $_[0] =~ s/%QUIZ{(.*?)}%/&handleQuiz($1)/geo;
}

# =========================

sub handleQuiz {
    my $attrs = shift;
    my $name = TWiki::Func::extractNameValuePair($attrs);
    my $correct = TWiki::Func::extractNameValuePair($attrs, "correct");
    my $jumptopic = TWiki::Func::extractNameValuePair($attrs, "jump");

    if (!defined($correct)) {
	return "<font color=red>Invalid quiz $attrs - need correct answer(s)</font><br>";
    }

    my $result = "<form name=quiz$quizNumber>" .
	"<table bgcolor=mistyrose width=100% border=0 cellspacing=0 cellpadding=0>" .
	"<tr><td valign=top width=25%>Q$quizNumber: $name:</td>\n";

    if ($attrs =~ /\bstring\b/o) {
	my $length = length($correct);
	$result = stringScript($quizNumber, $correct, $jumptopic) . $result;
	$result .= "<td valign=center width=100%><input name=field" .
	    " size=$length maxlength=$length";
    } elsif (TWiki::Func::extractNameValuePair($attrs, "someof")) {
	my $answers = TWiki::Func::extractNameValuePair($attrs, "someof");
	$result = someOfScript($quizNumber, $answers, $correct, $jumptopic) .
	    $result . "<td width=100%>\n";
	my @corrects = split(/;/, $correct);
	my $type = "radio";
	if ($correct =~ /;/) {
	    $type = "checkbox";
	}
	my @anslist = split(/;/, $answers);
	foreach my $answer (@anslist) {
	    $result .= "<input type=$type name=\"field";
	    $result .= "\" value=\"$answer\"> $answer <br>\n";
	}
    } else {
	return "<font color=red>Invalid quiz $attrs - need someof " .
	    "or string</font><br>";
    }

    $result .= "</td></tr></table>";
    $result .= "<input type=button value=\"Submit\" onClick=\"Submit${quizNumber}()\">";
    $result .= "<input type=button value=\"Show Solutions\" onClick=\"Cheat${quizNumber}()\">";
    $quizNumber++;
    return $result . "</form>";
}

my $scriptHeader = "<script language=\"JavaScript\"> <!--HIDE\n";
my $scriptFooter = "//STOP HIDING-->\n</script>\n";

sub cheatScript {
    my ($quizNumber,$set) = @_;
    return "var first$quizNumber=1; function Cheat${quizNumber}() {
	if (first$quizNumber==1) {
		alert(\"You should try at least once before clicking on 'Show Solutions'!\");
	} else { $set }}";
}

sub submitScript{
    my ($quizNumber, $check, $jumpTopic) = @_;
    my $result = "function Submit${quizNumber}() { first$quizNumber=0;
	if ( $check ) {if (confirm(\"Correct!!! Click on OK to continue\"))";
    if ($jumpTopic ne "") {
	$result .= "window.location.replace(\"$jumpTopic\")";
    }
    return $result . ";} else {alert(\"Wrong! Try again...\\n\");}}";
}

# Generate script for someOf
sub someOfScript {
    my ($quizNumber, $legalAnswers, $correctAnswers, $jumpTopic) = @_;

    my @possibles = split(/;/, $legalAnswers);
    my %nameMap;
    my @corrects = split(/;/, $correctAnswers);

    my $n = 0;
    foreach my $poss (@possibles) {
	$nameMap{$poss} = "window.document.quiz${quizNumber}.field[$n].checked";
	$n++;
    }
    
    my $set = "";
    my $check = "";
    foreach my $poss (@possibles) {
	if ($check ne "") {
	    $check .= "&&";
	}
	$set .= $nameMap{$poss};
	if ($correctAnswers !~ /\b$poss\b/) {
	    $set .= "=false;";
	    $check .= "!";
	} else {
	    $set .= "=true;";
	}
	$check .= $nameMap{$poss};
    }

    return $scriptHeader .
	cheatScript($quizNumber, $set) .
	    submitScript($quizNumber, $check, $jumpTopic) .
		$scriptFooter;
}

# Generate script for string
sub stringScript {
    my ($quizNumber, $correctAnswer, $jumpTopic) = @_;

    return $scriptHeader .
	cheatScript($quizNumber,
		    "window.document.quiz" . $quizNumber .
		    ".field.value=\"$correctAnswer\";") .
	submitScript($quizNumber,
		     "window.document.quiz$quizNumber" . 
		     ".field.value==\"$correctAnswer\"", $jumpTopic) .
	$scriptFooter;
}

1;