################################################################################
# WeBWorK Online Homework Delivery System
# Copyright © 2000-2003 The WeBWorK Project, http://openwebwork.sf.net/
# $CVSHeader$
# 
# This program is free software; you can redistribute it and/or modify it under
# the terms of either: (a) the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any later
# version, or (b) the "Artistic License" which comes with this package.
# 
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See either the GNU General Public License or the
# Artistic License for more details.
################################################################################

package WeBWorK::ContentGenerator::Instructor::PGProblemEditor;
use base qw(WeBWorK::ContentGenerator::Instructor);


=head1 NAME

WeBWorK::ContentGenerator::Instructor::ProblemSetEditor - Edit a set definition list

=cut

use strict;
use warnings;
use CGI qw();
use WeBWorK::Utils qw(readFile);
use Apache::Constants qw(:common REDIRECT);


our $libraryName;
our $rowheight;

sub title {
	my $self = shift;
	#FIXME  don't need the entire path  ??
	return "Instructor Tools - PG Problem Editor ";
}
sub go {
	my $self 			= shift;
	my ($setName, $problemNumber) = @_;
	my $r 				= 	$self->{r};
	my $ce				=	$self->{ce};
	my $submit_button 	= $r->param('submit');  # obtain submit command from form

	# various actions depending on state.
	if (     defined($submit_button) and ($submit_button eq 'Save' or $submit_button eq 'Refresh')    ) {
	
		$self->initialize($setName,$problemNumber);  # write the necessary files
													 # return file path for viewing problem
													 # in $self->{currentSourceFilePath}
		#redirect to view the problem
		
		my $hostname 		= 	$r->hostname();
		my $port     		= 	$r->get_server_port();
		my $uri		 		= 	$r->uri;
		my $courseName		=	$self->{ce}->{courseName};
		my $problemSeed		= 	($r->param('problemSeed')) ? $r->param('problemSeed') : '';
		my $displayMode		=	($r->param('displayMode')) ? $r->param('displayMode') : '';
        my $viewURL         =   '';
        if ($self->{file_type} eq 'problem') {
        	# redirect to have problem read by Problem.pm
			$viewURL  		= 	"http://$hostname:$port";
			$viewURL		   .= 	$ce->{webworkURLs}->{root}."/$courseName/$setName/$problemNumber/?";
			$viewURL		   .=	$self->url_authen_args;
			$viewURL		   .=   "&displayMode=$displayMode&problemSeed=$problemSeed";   # optional displayMode and problemSeed overrides
			if ($submit_button eq 'Save') {
				$viewURL		   .=	"&editMode=savedFile";
			} else {		
				$viewURL		   .=	"&editMode=temporaryFile";
			}
			$viewURL		   .=	'&sourceFilePath='. $self->{currentSourceFilePath}; # path to pg text for viewing
			                                                                            # allows Problem.pg to recognize state
	                                                                                    # of problem being viewed.
	    } elsif ($self->{file_type} eq 'set_header') {
	    	# redirect set headers to ProblemList page
	    	$viewURL  		= 	"http://$hostname:$port";
			$viewURL		   .= 	$ce->{webworkURLs}->{root}."/$courseName/$setName/?";
			$viewURL		   .=	$self->url_authen_args;
			$viewURL		   .=   "&displayMode=$displayMode&problemSeed=$problemSeed";   # optional displayMode and problemSeed overrides
			if ($submit_button eq 'Save') {
				$viewURL		   .=	"&editMode=savedFile";
			}
		}
		$r->header_out(Location => $viewURL );
		return REDIRECT;
	} else {
		# initialize and 
		# display the editing window
		
		$self->SUPER::go(@_);
	}

}

sub initialize {
	
	my ($self, $setName, $problemNumber) = @_;
	my $ce 						= 	$self->{ce};
	my $r						=	$self->{r};
	my $path_info 				= 	$r->path_info || "";
	my $db						=	$self->{db};
	my $user					=	$r->param('user');
	my $effectiveUserName		=	$r->param('effectiveUser');
	my $courseName				=	$ce->{courseName};

	
	# Find URL for viewing problem
	
	# find path to pg file for the problem
	
	my $templateDirectory		=	$ce->{courseDirs}->{templates};
	my $problemPath             =   $templateDirectory;
	my $problem_record          =   undef;
		# FIXME  there is a discrepancy in the way that the problems are found.
		# FIXME  more error checking is needed in case the problem doesn't exist.
	if (defined($problemNumber) and $problemNumber) {
		$problem_record		=	$db->getMergedProblem($effectiveUserName, $setName, $problemNumber);
		# If there is no global_user defined problem, (i.e. the sets haven't been assigned yet), 
		# look for a global version of the problem.
		$problem_record			=	$db->getGlobalProblem($setName, $problemNumber) unless defined($problem_record);
		# bail if no problem is found
		die "Cannot find a problem record for set $setName / problem $problemNumber" 
			unless defined($problem_record);
		$problemPath           .=   '/'.$problem_record->source_file;
		$self->{file_type}      =   'problem';
	} elsif (defined($problemNumber) and $problemNumber==0) { # we are editing a header file
		my $set_record          =   $db->getMergedSet($effectiveUserName, $setName);
		die "Cannot find a set record for set $setName" unless defined($set_record);	
		$problemPath           .=   '/'.$set_record->set_header;
		$self->{file_type}      =   'set_header';
	}
	
	my $editFileSuffix			=	$user.'.tmp';
	my $submit_button			= 	$r->param('submit');

	my $displayMode	  			= 	( defined($r->param('displayMode')) 	) ? $r->param('displayMode') : $ce->{pg}->{options}->{displayMode};
	# try to get problem seed from the input parameter, or from the problem record
	my $problemSeed;
	if ( defined($r->param('problemSeed'))	) {
		$problemSeed            =   $r->param('problemSeed');	
	} elsif (defined($problem_record) and  $problem_record->can('problem_seed')) {
		$problemSeed            =   $problem_record->problem_seed;
	}
	# make absolutely sure that the problem seed is defined, if it hasn't been.
	$problemSeed				=	'123456' unless defined($problemSeed) and $problemSeed =~/\S/;
	
	my $problemContents	= '';
	my $currentSourceFilePath	=	'';
	my $editErrors = '';	
	
	# update the .pg and .pg.tmp files in the directory
	# if a .tmp file already exists use that, unless the revert button has been pressed.
	# These .tmp files are
	# removed when the file is finally saved.
	my $inputFilePath           =  (-r "$problemPath.$editFileSuffix")?"$problemPath.$editFileSuffix" : $problemPath;
	$inputFilePath              =   $problemPath  if defined($submit_button) and $submit_button eq 'Revert';
	
	if (not defined($submit_button) or $submit_button eq 'Revert' ) {
		# this is a fresh editing job
		# copy the pg file to a new file with the same name with .tmp added
		# store this name in the $self->currentSourceFilePath for use in body 
		eval { $problemContents			=	WeBWorK::Utils::readFile($inputFilePath)    };  
		# try to read file
		$problemContents = $@ if $@;
		$editErrors .= $problemContents;
		$currentSourceFilePath			=	"$problemPath.$editFileSuffix"; 
		$self->{currentSourceFilePath}	=	$currentSourceFilePath; 
	} elsif ($submit_button	eq 'Refresh' ) {
		# grab the problemContents from the form in order to save it to the tmp file
		# store tmp file name in the $self->currentSourceFilePath for use in body 
		
		$problemContents				=	$r->param('problemContents');
		$currentSourceFilePath			=	"$problemPath.$editFileSuffix";	
		$self->{currentSourceFilePath}	=	$currentSourceFilePath;
	} elsif ($submit_button eq 'Save') {
		# grab the problemContents from the form in order to save it to the permanent file
		# later we will unlink (delete) the temporary file
	 	# store permanent file name in the $self->currentSourceFilePath for use in body 
		
		$problemContents				=	$r->param('problemContents');
		$currentSourceFilePath			=	"$problemPath"; 		
		$self->{currentSourceFilePath}	=	$currentSourceFilePath;	
	} else {
		# give a warning
		die "Unrecognized submit command $submit_button";
	}
	
	# Handle the problem of line endings.  Make sure that all of the line endings.  Convert \r\n to \n
	$problemContents    =~    s/\r\n/\n/g;
	$problemContents    =~    s/\r/\n/g;
	
	# print changed pg files
	# FIXME  make sure that the permissions are set correctly!!!
	# Make sure that the warning is being transmitted properly.
	
	eval {
		local *OUTPUTFILE;
		open OUTPUTFILE, ">", $currentSourceFilePath
				or die "Failed to write to $currentSourceFilePath.  
				It is likely that the permissions in the template directory have not been set correctly.".
				"The web server must be able to create and write to files in the directory containing the problem. 
				$!";
		print OUTPUTFILE $problemContents;
		close OUTPUTFILE;
	};
	# record an error string for later use if there was a difficulty in writing to the file
	# FIXME is this string every inspected?
	
	my $openTempFileErrors = $@ if $@;
	
	if (  $openTempFileErrors)   {
	    
		$self->{openTempFileErrors}	= "Unable to write to $currentSourceFilePath: $openTempFileErrors";
		#diagnose errors:
		warn "Editing errors: $openTempFileErrors\n";
		warn "The file $currentSourceFilePath exists. \n " if -e $currentSourceFilePath; #FIXME 
		warn "The file $currentSourceFilePath cannot be found. \n " unless -e $currentSourceFilePath;
		warn "The file $currentSourceFilePath does not have write permissions. \n"
		                 if -e $currentSourceFilePath and not -w $currentSourceFilePath;
		
		
		
	} else {	
		# unlink the temporary file if there are no errors and the save button has been pushed
	    
		$self->{openTempFileErrors}	=	'';
		unlink("$problemPath.$editFileSuffix") if defined($submit_button) and $submit_button eq 'Save';		
	};
	
		
	# return values for use in the body subroutine
	$self->{problemPath}              =   $problemPath;
	$self->{inputFilePath}            =   $inputFilePath;
	$self->{displayMode}              =   $displayMode;
	$self->{problemSeed}              =   $problemSeed;
	$self->{r_problemContents}        =   \$problemContents;
	# FIXME  there is no way to edit in a temporary file -- all editing takes place on disk!!!

	
	
}

sub path {
	my $self          = shift;
	my $set_id        = shift;
	my $problem_id    = shift;
	my $args          = $_[-1];
	
	my $ce = $self->{ce};
	my $root = $ce->{webworkURLs}->{root};
	my $courseName = $ce->{courseName};
	return $self->pathMacro($args,
		"Home"          => "$root",
		$courseName     => "$root/$courseName",
		'instructor'    => "$root/$courseName/instructor",
		'sets'          => "$root/$courseName/instructor/sets/",
		"$set_id"       => "$root/$courseName/instructor/sets/$set_id/",
		"problems"      => "$root/$courseName/instructor/sets/$set_id/problems",
		"$problem_id"   => ''
	);
}
sub body {
	my $self = shift;
	
	# test area
	my $r       =   $self->{r};
	my $db      =   $self->{db};
	my $ce      =   $self->{ce};
	my $user    =   $r->param('user');
	my $key     =   $db->getKey($user)->key();
	
	
	################
	# Gathering info
	# What is needed
	#     $problemPath  -- 
	#     $formURL -- given by $r->uri
	#     $tmpProblemPath 
	my $problemPath 	         =   $self->{problemPath};
	my $inputFilePath            =   $self->{inputFilePath};
	
	

	
	

	my $header = CGI::i("Editing problem:  $inputFilePath");

	#########################################################################
	# Find the text for the problem, either in the tmp file, if it exists
	# or in the original file in the template directory
	#########################################################################
	my $problemContents = ${$self->{r_problemContents}};

#	eval { $problemContents	=	WeBWorK::Utils::readFile($problemPath)  };  # try to read file
#	$problemContents = $@ if $@;
	
			
			
	#########################################################################
	# Format the page
	#########################################################################
	# Define parameters for textarea
	# FIXME 
	# Should the seed be set from some particular user instance??
	# The mode list should be obtained from global.conf ultimately
	my $rows 		= 	20;
	my $columns		= 	80;
	my $mode_list 	= 	['plainText','formattedText','images'];
	my $displayMode	= 	$self->{displayMode};
	my $problemSeed	=	$self->{problemSeed};	
	my $uri			=	$r->uri;
	########################################################################
	# Define a link to view the problem
	#FIXME
	
	#########################################################################

	
	warn "Errors in the problem ".CGI::br().$self->{editErrors} if $self->{editErrors};

			   
	return CGI::p($header),
		#CGI::start_form("POST",$r->uri,-target=>'_problem'),  doesn't pass on the target parameter???
		qq!<form method="POST" action="$uri" enctype="application/x-www-form-urlencoded", target="_problem">!,
		$self->hidden_authen_fields,
		CGI::hidden(-name=>'file_type',-default=>$self->{file_type}),
		CGI::div(
		'Seed: ',
		CGI::textfield(-name=>'problemSeed',-value=>$problemSeed),
		'Mode: ',
		CGI::popup_menu(-name=>'displayMode', -'values'=>$mode_list,
													 -default=>$displayMode),
		CGI::a(
			{-href=>'http://webwork.math.rochester.edu/docs/docs/pglanguage/manpages/',-target=>"manpage_window"},
			'Manpages',
			)
		),
		CGI::p(
			CGI::textarea(-name => 'problemContents', -default => $problemContents,
						  -rows => $rows, -columns => $columns, -override => 1,
			),
		),
		CGI::p(
			( ($self->{file_type} eq 'problem') ? CGI::submit(-value=>'Refresh',-name=>'submit') : ''   ),
			CGI::submit(-value=>'Save',-name=>'submit'),
			CGI::submit(-value=>'Revert',-name=>'submit'),
		),	
		CGI::end_form(),


}



1;