#!/usr/bin/xotclsh
# $Id: MC.xotcl,v 1.1 2004/05/23 22:50:39 neumann Exp $
#
# A simple multiple choice test application
#
array set opts {-pkgdir .}; array set opts $argv
lappend auto_path $opts(-pkgdir)

package require XOTcl 1 1; namespace import -force xotcl::*
#package require xotcl::package; package verbose 1
package require xotcl::actiweb::htmlPlace
package require xotcl::actiweb::pageTemplate

HtmlPlace ::receiver -port 8092 -allowExit exit

# Define a pool of questions: Question and their alternatives
# are defined as classes and all questions are stored in the pool
#
Class Pool
Class Pool::Question -parameter {text {altcounter 1}}
Class Pool::Question::Alternative -parameter {text correct}

Pool::Question instproc alternatives {pairs} {
  my instvar altcounter
  foreach {alt correct} $pairs {
    incr altcounter
    [self class]::Alternative [self]::$altcounter \
	-text $alt -correct $correct
  }
}

#
# An Exam has a name and is a selection of questions from a pool.
# "requiredCorrect" defines the minimal number of correct answers
# to pass the test.

Class Exam -parameter {name requiredCorrect pool questions}

#
# For every candidate we create an individual exam. We scramble
# the questions and alternatives and use the studentID as a seed.
#

Class IndividualExam -superclass Agent -parameter {ID exam}

IndividualExam instproc random modulo {            ;### random number generator
  my instvar seed
  set seed [expr {($seed*12731+34197) % 21473}]
  return [expr {$seed % $modulo}]
}
IndividualExam instproc permute {list} {           ;### permute random permutation
  set permuted {}
  for {set nr [llength $list]} {$nr>0} {incr nr -1} {
    set select [my random $nr]
    lappend permuted [lindex $list $select]
    set list [lreplace $list $select $select]
  }
  return $permuted
}
IndividualExam instproc init args {
  my instvar seed ID exam individualTest alternatives
  set questions [$exam set questions]
  set seed $ID
  ### compute order of individual tests and alternatives
  foreach index [my permute [$exam set questions]] {
    set questionObj [$exam set pool]::$index
    lappend individualTest $index
    set alts [my permute [lsort [$questionObj info children]]]
    lappend alternatives $alts
  }
  #puts stderr "Individual test [self] has $individualTest"
}

#
# Define a web facade using a page template
# "testObject" is the individual test that is shielded by the web facade
#
Class WebExam -superclass WebObject \
  -instmixin PageTemplateHtml -parameter {testObject}
WebExam instproc default {} {     ;### This method creates the HTML Test
  my instvar testObject       ;### import var that stores shielded test object
  ### import vars from the test
  $testObject instvar individualTest alternatives exam
  set action [my selfAction result]
  ### create Test page
  set htmlText "
\n
\n"
  ### iterate over the set of questions/alternatives
  ### and add them to the HTML text
  foreach question $individualTest alts $alternatives {
    append htmlText "
-  [[$exam pool]::$question text]\n
\n"
    foreach a $alts {
      append htmlText "
-   \
	[$a text] ([$a correct])\n"
    }
    append htmlText "
<p>\n"
  }
  ### we have to add a hidden form field, otherwise we get no result, 
  ### if nothing is tagged
  append htmlText ""
  ### the submit button lets us send the result back
  append htmlText "

\n"
  ### create simple HTML Page
  my simplePage [$exam name] \
       "Exam [$exam name] for [string trimleft $testObject :] \
	(Exam: $exam)" $htmlText
}
WebExam instproc result {} {      ;# This method analyses the results of the test
  my instvar testObject       ;### import var that stores shielded test
  set exam [$testObject exam]
  $testObject instvar individualTest alternatives
  foreach question $individualTest alts $alternatives {
    foreach a $alts {set ca($a) 0}
  }
  foreach a [my getFormData] {set ca([$a set content]) 1}
  set htmlText "You have answered:
"
  array set answerText  {0 " -- answered no\n"  1 " -- answered yes\n"}
  array set correctText {0 "\n -- Wrong.
\n" 1 "\n -- Correct.
\n"}
  set correctAnswers 0
  foreach q $individualTest {
    set correct 1
    append htmlText "
-  [[$exam pool]::$q text]: 
\n"
    foreach alternative [[$exam pool]::$q info children] {
      set altCorrect [expr {$ca($alternative) == [$alternative correct]}]
      append htmlText [$alternative text]\n \
	  $answerText($ca($alternative)) \
	  $correctText($altCorrect)
      set correct [expr {$correct && $altCorrect}]
    }
    if {$correct} {incr correctAnswers}
  }
  append htmlText 
\n
  if {$correctAnswers < [$exam requiredCorrect]} {
    my simplePage [self] "Sorry" "$htmlText\
	Only $correctAnswers question were answered correctly. You have not succeeded :("
  } else {
    my simplePage [self] "Congratulations" "$htmlText\
	$correctAnswers questions were answered correctly. You have succeeded :-)"
  }
}
WebExam instproc init args {
  next
  [my place] exportObjs [self]     ;# export object
  my exportProcs result            ;# export methods
}

# Create a Pool P with 6 example questions with 3 alternatives for each.

Pool p
Pool::Question p::1 \
    -text "When was the first XOTcl Version released?" -alternatives {
	"1998" 0
	"1999" 1
	"2000" 0
    }
Pool::Question p::2 -text "Who is author of XOTcl?" -alternatives {
    "Gustaf Neumann" 1
    "Mika Haekinnen" 0
    "Uwe Zdun" 1
}
Pool::Question p::3 -text "Which of the systems are other OO extensions of Tcl?" \
    -alternatives {
	"XTCL" 0
	"ITCL" 1
	"OTCL" 1
    }
Pool::Question p::4 \
    -text "Which methods are provided by the Object class?" -alternatives {
	"set" 1
	"instvar" 0
	"filter" 1
    }
Pool::Question p::5 \
    -text  "Which methods are provided by the Object class?" -alternatives {
	"unset" 1
	"instproc" 0
	"mixin" 1
    }
Pool::Question p::6 \
    -text "Which methods are provided by the Class class?" -alternatives {
	"proc" 0
	"instproc" 1
	"mixin" 0
    }

### Define an exam

Exam xotclTest \
    -pool p \
    -name "XOTcl Test" \
    -questions {1 2 3 4 5} \
    -requiredCorrect 4

### Define two Student tests with the XOTcl Test

foreach {Student ID} {
    Uwe 7850247
    Gustaf 7850248
} {
    ## Define the individual exams
    IndividualExam $Student -exam xotclTest -ID $ID
    ### Define a web facade for each student
    WebExam $Student.html -testObject $Student

}
receiver startEventLoop
