#!/usr/bin/perl

# catalog.cgi - a simple library catalog based on the content of a MyLibrary instance

# Eric Lease Morgan <emorgan@nd.edu>
# August 21, 2007 - added about page
# July 19, 2007 - added "borrowing" and reading of reviews; i should call it "cooked"
# July 18, 2007 - added paging of SRU results; started adding check-out features
# July  5, 2007 - first investigations


# require/use
use CGI;
use CGI::Carp qw(fatalsToBrowser);
use LWP::UserAgent;
use MyLibrary::Core;
use MyLibrary::Patron;
use MyLibrary::Auth::Basic;
use MARC::Batch;
use MARC::File::XML ( BinaryEncoding => 'utf8', RecordFormat => 'USMARC' );
use strict;
use XML::LibXML;
use XML::LibXSLT;

# define constants
use constant TEMPLATE    => 'etc/template.txt';
use constant HOME        => 'etc/home.txt';
use constant RESULTS     => 'etc/results.txt';
use constant ABOUT       => 'etc/about.txt';
use constant TAGGED      => 'etc/tagged.txt';
use constant SRUXSLT     => 'etc/style.xsl';
use constant MARC2MODS   => 'etc/marc2mods.xsl';
use constant PAGESIZE    => 25;
use constant SRUROOT     => 'http://dewey.library.nd.edu/mylibrary/demos/catalog/sru/server.cgi?operation=searchRetrieve&version=1.1&startRecord=##START##&maximumRecords=##PAGESIZE##&query=';  
use constant FILENAME    => 'Local file';
use constant ISBN        => 'ISBN';
use constant LCCN        => 'LCCN';
use constant NOART       => 'etc/no-art.jpeg';
use constant CMDTERM     => 'term';
use constant FORMSMALL   => 'etc/form-small.txt';
use constant AMAZON      => 'http://webservices.amazon.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=xyzzy&Operation=ItemLookup&ResponseGroup=Images,Reviews&ItemId=';
use constant AMAZON2PICT => 'etc/amazon2pict.xsl';
use constant AMAZON2REVW => 'etc/amazon2reviews.xsl';
use constant CREATE      => 'etc/create.txt';
use constant SIGNIN      => 'etc/signin.txt';
use constant COOKIENAME  => 'catalog';
use constant EXPIRE      => '60m';
use constant CHOICES_A   => 'etc/choices-authenticated.txt';
use constant CHOICES_N   => 'etc/choices-not.txt';
use constant ERROR       => 'etc/error.txt';

# initialize
my $cgi = CGI->new;
my $html;
MyLibrary::Config->instance( 'catalog' );

# authenticate, if there is a cookie
my ( $auth, $session_id, $status, $username );
if ( $cgi->cookie( COOKIENAME )) {

	$session_id = $cgi->cookie( COOKIENAME );
	$auth       = MyLibrary::Auth::Basic->new( sessid => $session_id, session_expire => EXPIRE );
	$status     = $auth->status;
	$username   = $auth->username;
	
}

# get the command
my $cmd = $cgi->param( 'cmd' );

# branch accordingly
if (! $cmd ) {

	# display the home page
	$html = &slurp( TEMPLATE );
	$html =~ s/##CONTENT##/&slurp( HOME )/e;
	$html =~ s/##FORMSMALL##//e;
		
}

elsif ( $cmd eq 'about' ) {

	# display the home page
	$html = &slurp( TEMPLATE );
	$html =~ s/##CONTENT##/&slurp( ABOUT )/e;
	$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
	$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

}


elsif ( $cmd eq 'reviews' ) {

	# get the input
	my $id = $cgi->param( 'id' );

	# make sure there is input
	if ( ! $id ) {
	
		# display an error
		my $title   = $cgi->h1( 'Software error' );
		my $message = $cgi->p( 'No id was supplied. Call Eric.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# sanity check
	elsif ( ! MyLibrary::Resource->new( id => $id )) {
	
		# display an error
		my $title   = $cgi->h1( 'Software error' );
		my $message = $cgi->p( "The supplied resource ID ($id) does not exist. Call Eric." );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# do the work
	else {
	
		# get the resource and isbn
		my $resource = MyLibrary::Resource->new( id => $id );
		my $isbn = &get_location( $resource, ISBN );
		my $reviews;
		
		if ( ! $isbn ) {
		
			# display an error
			my $title   = $cgi->h1( 'Bummer' );
			my $message = $cgi->p( "The supplied resource ID ($id) does not have an ISBN number and therefore I can't get a review." );
			$html = &slurp( TEMPLATE );
			$html =~ s/##CONTENT##/&slurp( ERROR )/e;
			$html =~ s/##TITLE##/$title/e;
			$html =~ s/##MESSAGE##/$message/e;
			$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
			$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
			
		}

		else {
		
			my $ua = LWP::UserAgent->new( agent => 'AMAZON-Images-Client/0.1 ' );
			my $request = HTTP::Request->new( GET => AMAZON . $isbn );
			my $response = $ua->request( $request );
	
			# create parser and process input
			if ($response->is_success) {
	
				my $parser     = XML::LibXML->new;
				my $xslt       = XML::LibXSLT->new;
				my $source     = $parser->parse_string( $response->content );
				my $style      = $parser->parse_file( AMAZON2REVW );
				my $stylesheet = $xslt->parse_stylesheet( $style );
				my $results    = $stylesheet->transform( $source );
				$reviews    = $cgi->ol( $stylesheet->output_string( $results )) unless ( ! $stylesheet->output_string( $results ));
				$reviews =~ s/&lt;/</g;
				$reviews =~ s/&gt;/>/g;
				
			}
			
			# done
			$html = &slurp( TEMPLATE );
			$html =~ s/##CONTENT##/&slurp( ERROR )/e;
			$html =~ s/##TITLE##/$cgi->h1('Reviews for ' . $resource->name)/e;
			$html =~ s/##MESSAGE##/$reviews/e;
			$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
			$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
			
		}
		

	}


}

elsif ( $cmd eq 'checkout' ) {

	# get the input
	my $id = $cgi->param( 'id' );
	
	# make sure they are authenticated
	if ( $status ne 'authenticated' ) {

		# display an error
		my $title   = $cgi->h1( 'Something went wrong' );
		my $message = $cgi->p( 'You need to be authenticated in order to check out an item. Please ' . 
		              $cgi->a({ href => './?cmd=signin' }, 'sign in' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# make sure there is input
	elsif ( ! $id ) {
	
		# display an error
		my $title   = $cgi->h1( 'Software error' );
		my $message = $cgi->p( 'No id was supplied. Call Eric.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# sanity check
	elsif ( ! MyLibrary::Resource->new( id => $id )) {
	
		# display an error
		my $title   = $cgi->h1( 'Software error' );
		my $message = $cgi->p( "The supplied resource ID ($id) does not exist. Call Eric." );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# do the work
	else {
	
		# get this patron and add this item to their pile
		my $patron   = MyLibrary::Patron->new( username => $username );
		my $resource = MyLibrary::Resource->new( id => $id );
		my $name     = $resource->name;
		$patron->patron_resources( new => [ $id ]);
		$patron->commit;
			
		# display the result
		my $username = $auth->username;
		my $title    = $cgi->h1( 'Success!' );
		my $message  = $cgi->p( "Your item has been identified. A student has retrieved the item ($name) and finished delivering it to your door. You might want to now view " .
		               $cgi->a({ href => './?cmd=my' }, 'your borrowed items' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
}


elsif ( $cmd eq 'return' ) {

	# get the input
	my $id      = $cgi->param( 'id' );
	my $confirm = $cgi->param( 'confirm' );
	
	# check for id
	if ( ! $id ) {
	
		# display an error
		my $title    = $cgi->h1( 'Software error' );
		my $message  = $cgi->p( 'This function requires a resource ID as input. Call Eric.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
	
	}
	
	# make sure they are authenticatead
	elsif ( $status ne 'authenticated' ) {

		# display an error
		my $title   = $cgi->h1( 'Something went wrong' );
		my $message = $cgi->p( 'You need to be authenticated in order to return something from your bookshelf. Please ' . 
		              $cgi->a({ href => './?cmd=signin' }, 'sign in' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# make sure the passed id is valid
	elsif ( ! MyLibrary::Resource->new( id => $id )) {

		# display an error
		my $title   = $cgi->h1( 'Software error' );
		my $message = $cgi->p( "The supplied resource ID ($id) does not point to a valid resource. Call Eric." );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# confirm the deletion
	elsif ( ! $confirm ) {
	
		# return a confirmation
		my $resource = MyLibrary::Resource->new( id => $id );
		my $name     = $resource->name;
		my $title    = $cgi->h1( 'Are you sure?' );
		my $message  = $cgi->p( "Are you sure you want to return <b>$name</b> to the library? " . 
		               $cgi->a({ href => './?cmd=return&id=' . $resource->id . '&confirm=yes' }, 'Yes') . ', return it. ' . 
		               $cgi->a({ href => './?cmd=my' },  'No' ) . ', never mind.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# do the work
	elsif ( $confirm eq 'yes' ) {
	
		# get this patron and update their resource list
		my $patron = MyLibrary::Patron->new( username => $username );
		$patron->patron_resources( del => [ $id ]);
		$patron->commit;

		# display the results
		my $title    = $cgi->h1( 'Done' );
		my $message  = $cgi->p( "The title has been returned to the library. Now, wasn't that easy? You might now want to view " . 
		               $cgi->a({ href => './?cmd=my' }, 'your list' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
	
	}

}


elsif ( $cmd eq 'my' ) {
	
	# make sure they are authenticated
	if ( $status ne 'authenticated' ) {

		# display an error
		my $title    = $cgi->h1( 'Bummer' );
		my $message  = $cgi->p( 'You need to be signed in to use this function. ' . 
		               $cgi->a({ href => './?cmd=signin' }, 'Sign in' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
		
	# do the work
	else {
	
		# create the patron
		my $patron = MyLibrary::Patron->new( username => $username );
		my $reading_list;
		foreach ( $patron->patron_resources( sort => 'name' )) {
		
			my $resource = MyLibrary::Resource->new( id => $_ );
			$reading_list .= $cgi->li( $resource->name . ' <span style="color: gray">(' . $cgi->a({ href => './?cmd=return&id=' . $resource->id }, 'return' ) . ')</span>'  );
			
		}
		
		# sanity check
		if ( $reading_list ) { $reading_list = $cgi->ol( $reading_list )}
		else { $reading_list = $cgi->p( '(Your bookshelf is empty.)' )}
			
		# display the list, or lack thereof
		my $title    = $cgi->h1( "Bookshelf for $username" );
		my $message  = $cgi->p( 'Here is a list of things checked out to you:' );
		$message    .= $reading_list;
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
	
	}

}


elsif ( $cmd eq 'create' ) {

	# get the input
	my $username = $cgi->param( 'username' );
	my $password = $cgi->param( 'password' );
	my $echo     = $cgi->param( 'echo' );
	
	# sanity check
	if ( ! $username or ! $password  ) {
	
		# display an error
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( CREATE )/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
		
	}
	
	# more sanity checking
	elsif ( ! $username or ! $password or ! $echo ) {
	
		# display an error
		my $title   = $cgi->h1( 'Something went wrong' );
		my $message = $cgi->p( 'Alas, you need to complete all three fields. Please go back and try again.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# even more checking
	elsif ( $password ne $echo ) {

		# display an error
		my $title   = $cgi->h1( 'Something went wrong' );
		my $message = $cgi->p( 'Bummer, your password and echoed password do not match. Please go back and try again.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# make sure the name isn't already taken
	elsif ( MyLibrary::Patron->new( username => $username )) {

		# display an error
		my $title   = $cgi->h1( 'Something went wrong' );
		my $message = $cgi->p( 'Hmmm, that username has already been take. Please try another.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# whew!
	else {
	
		# do the work
		my $patron = MyLibrary::Patron->new;
		$patron->patron_username( $username );
		$patron->patron_password( $password );
		$patron->patron_stylesheet_id( 1 );
		$patron->commit;
		
		# display the result
		my $title   = $cgi->h1( 'Congrats!' );
		my $message = $cgi->p( "The account named $username has been created. Now, please " . 
		              $cgi->a({ href => './?cmd=signin' }, 'sign in' ) . '.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}

}


elsif ( $cmd eq 'signin' ) {

	# get the input
	my $username = $cgi->param( 'username' );
	my $password = $cgi->param( 'password' );
	
	# make sure they aren't already logged in
	if ( $status eq 'authenticated' ) {
	
		# display an error
		my $username = $auth->username;
		my $title    = $cgi->h1( 'Oops!' );
		my $message  = $cgi->p( "It seems as if you are already signed in as <b>$username</b>. If this is not you, then please " . $cgi->a({ href => './?cmd=signout' }, 'sign out' ) . ' and sign in again.' );
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( ERROR )/e;
		$html =~ s/##TITLE##/$title/e;
		$html =~ s/##MESSAGE##/$message/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
		
	}
	
	# display the form
	elsif ( ! $username or ! $password ) {
	
		# display form
		$html = &slurp( TEMPLATE );
		$html =~ s/##CONTENT##/&slurp( SIGNIN )/e;
		$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
		$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;

	}
	
	# do the work
	else {
	
		# authenticate; 
		my $auth = MyLibrary::Auth::Basic->new( session_expire => EXPIRE );
		my $return_code = $auth->authenticate( username => $username, password => $password );
		
		# cool
		if ( $return_code eq 'success' ) {
		
			# set the cookie
			$session_id = $auth->sessid;
			$status     = $auth->status;
			$username   = $auth->username;
			my $cookie  = $cgi->cookie( -name => COOKIENAME, -value => $session_id );
			my $header  = $cgi->header( -cookie => $cookie, -type => 'text/html', -charset => 'utf-8' );
			
			# set up the result
			my $title = $cgi->h1( "Hello, $username" );
			my $message = $cgi->p( 'You have sucessfully signed in. Welcome.' );
			$html = &slurp( TEMPLATE );
			$html =~ s/##CONTENT##/&slurp( ERROR )/e;
			$html =~ s/##TITLE##/$title/e;
			$html =~ s/##MESSAGE##/$message/e;
			$html =~ s/##STATUS##/$status/ge;
			$html =~ s/##USERNAME##/$username/ge;
			$html =~ s/##SESSIONID##/$session_id/ge;
			$html =~ s/##CHOICES##/&choices/ge;
			$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
			$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
			
			# send the cookie, the html, and quit
			print $header;
			print $html;
			exit;

		}
		
		# bad input
		elsif ( $return_code eq 'password failure' or $return_code eq 'username failure' ) {
		
			# display an error
			my $title   = $cgi->h1( 'Username/password problem' );
			my $message = $cgi->p( 'That username/password combination is invalid. Please try again.' );
			$html = &slurp( TEMPLATE );
			$html =~ s/##CONTENT##/&slurp( ERROR )/e;
			$html =~ s/##TITLE##/$title/e;
			$html =~ s/##MESSAGE##/$message/e;
			$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
			$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
			
		}
		
		# unknown error
		else {
		
			# display an error
			my $title   = $cgi->h1( 'Software error' );
			my $message = $cgi->p( "Unknown value for return_code ($return_code). Call Eric." );
			$html = &slurp( TEMPLATE );
			$html =~ s/##CONTENT##/&slurp( ERROR )/e;
			$html =~ s/##TITLE##/$title/e;
			$html =~ s/##MESSAGE##/$message/e;
			$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
			$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
		
		}
		
	}

}


elsif ( $cmd eq 'signout' ) {

	# do the work, immediately
	my $cookie = $cgi->cookie( -name => COOKIENAME, -value => '', -expires => '-1h' );
	my $header = $cgi->header( -cookie => $cookie, -type => 'text/html', -charset => 'utf-8' );
	$auth->close_session;
	
	# re-define
	$session_id = '';
	$status     = '';
	$username   = '';

	# set up the result
	my $title    = $cgi->h1( 'Sign out' );
	my $message  = $cgi->p( 'You have successfully signed out. Thank you for being with us. ' . 
	               $cgi->a({ href => './?cmd=signin' } , 'Sign in' ) . ' again.' );
	$html = &slurp( TEMPLATE );
	$html =~ s/##CONTENT##/&slurp( ERROR )/e;
	$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
	$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
	$html =~ s/##TITLE##/$title/e;
	$html =~ s/##MESSAGE##/$message/e;
	$html =~ s/##STATUS##/$status/ge;
	$html =~ s/##USERNAME##/$username/ge;
	$html =~ s/##SESSIONID##/$session_id/ge;
	$html =~ s/##CHOICES##/&choices/ge;
	
	# reset the cookie, send the html, and quit, immediately
	print $header;
	print $html;
	exit;

}


elsif ( $cmd eq 'tagged' ) {

	# get the resource
	my $resource = MyLibrary::Resource->new( id => $cgi->param( 'id' ));
				
	# get this record; not done elegantly
	my $batch = MARC::Batch->new( 'USMARC', &get_location( $resource, FILENAME ) );
	my $marc = $batch->next;
	
	# display the results page
	$html = &slurp( TEMPLATE );
	$html =~ s/##CONTENT##/&slurp( TAGGED )/e;
	$html =~ s/##TAGGED##/$marc->as_formatted/e;

}

elsif ( $cmd eq 'marcxml' ) {

	# get the resource
	my $resource = MyLibrary::Resource->new( id => $cgi->param( 'id' ));
				
	# get this record; not done elegantly
	my $batch = MARC::Batch->new( 'USMARC', &get_location( $resource, FILENAME ) );
	my $marc  = $batch->next;

	# display & done
	print $cgi->header( -type => 'text/xml', -charset => 'utf-8' );
	print MARC::File::XML::record( $marc );
	exit;
	
}


elsif ( $cmd eq 'mods' ) {

	# get the resource
	my $resource = MyLibrary::Resource->new( id => $cgi->param( 'id' ));
				
	# get this record; not done elegantly
	my $batch = MARC::Batch->new( 'USMARC', &get_location( $resource, FILENAME ) );
	my $marc  = $batch->next;
	
	# transform marcxml into mods
	my $parser     = XML::LibXML->new;
	my $xslt       = XML::LibXSLT->new;
	my $source     = $parser->parse_string( MARC::File::XML::record( $marc )) or croak $!;
	my $style      = $parser->parse_file( MARC2MODS )                         or croak $!;
	my $stylesheet = $xslt->parse_stylesheet( $style )                        or croak $!;
	my $results    = $stylesheet->transform( $source )                        or croak $!;

	# display & done
	print $cgi->header( -type => 'text/xml', -charset => 'utf-8' );
	print $stylesheet->output_string( $results );
	exit;
	
}


elsif ( $cmd eq 'search' ) {

	# get the input
	my $query = $cgi->param( 'query' );
	my $start = $cgi->param( 'start' );
	
	# sanity check
	if ( ! $start ) { $start = 0 }
	
	# munge the query into cql
	while ( $query =~ /^ / ) { $query =~ s/^ // }
	while ( $query =~ / $/ ) { $query =~ s/ $// }
	while ( $query =~ /  / ) { $query =~ s/  / / }
	if ($query =~ /\s/) {
	
		if (( $query =~ / and / ) | ( $query =~ / or / ) | ( $query =~ / not / )) { }
		elsif ( $query =~ /=/ ) { }
		elsif ( $query !~ /"/ ) {
		
			# try to make queries with no syntactical sugar a bit "smarter"
			my @terms = split / /, $query;
			my $enhancement;
			for ( my $i; $i <= $#terms; $i++ ) {
			
				if ( $i < $#terms ) { $enhancement .= $terms[$i] . ' and ' }
				else { $enhancement .= $terms[$i] }
			
			}
			
			$query = '"' . $query . '"' . " or ($enhancement)";
			
		}
		
	}

	# create an SRU URL
	my $url = SRUROOT . "$query";
	$url =~ s/##PAGESIZE##/PAGESIZE/e;
	$url =~ s/##START##/$start/e;

	# create a user agent, create a request, send it, and get a response
	my $ua = LWP::UserAgent->new( agent => 'SRU-Client/0.1 ' );
  	my $request = HTTP::Request->new( GET => $url );
	my $response = $ua->request( $request );

	# transform the response into a snippet of html
	my $parser     = XML::LibXML->new;
	my $xslt       = XML::LibXSLT->new;
	my $source     = $parser->parse_string( $response->content ) or croak $!;
	my $style      = $parser->parse_file( SRUXSLT )              or croak $!;
	my $stylesheet = $xslt->parse_stylesheet( $style )           or croak $!;
	my $results    = $stylesheet->transform( $source )           or croak $!;
	
	# create a list of integers from the xslt; note, the first integer is the total number of records
	my $ids = $stylesheet->output_string( $results );
	chop $ids;
	my @ids = split /\t/, $ids;
	my $number_of_hits = splice @ids, 0, 1;
	
	# build the hit list
	my $hit_list;
	if ( $number_of_hits ) {
	
		for ( my $i = 0; $i <= $#ids; $i++ ) {
		
			$hit_list .= &list_one_resource( $ids[ $i ]);
			last if ( $i == $number_of_hits );
			
		}
		
		$hit_list = $cgi->ol({ -start => $start + 1 }, $hit_list );
		
	}
	
	# display the results page
	$html = &slurp( TEMPLATE );
	$html =~ s/##CONTENT##/&slurp( RESULTS )/e;
	$html =~ s/##FORMSMALL##/&slurp( FORMSMALL )/e;
	$html =~ s/##QUERY##/$cgi->param( 'query' )/ge;
	$html =~ s/##NUMBEROFHITS##/&commify( $number_of_hits )/e;
	$html =~ s/##HITLIST##/$hit_list/e;
	$html =~ s/##PAGER##/&pager( '?cmd=search&query=' . $cgi->param( 'query' ) . '&start=', $start, $number_of_hits )/e;

}

		
else {

	# error
	$html  = $cgi->start_html( -title => 'MyLibrary' );
	$html .= $cgi->h1( 'MyLibrary' );
	$html .= $cgi->p( "Unknown value for cmd ($cmd). Call Eric." );
	$html .= $cgi->end_html;

}

# done
$html =~ s/##STATUS##/$status/ge;
$html =~ s/##USERNAME##/$username/ge;
$html =~ s/##SESSIONID##/$session_id/ge;
$html =~ s/##CHOICES##/&choices/ge;
print $cgi->header( -type => 'text/html', -charset => 'utf-8' );
print $html;
exit;


#############
# subroutines


sub slurp {

	# open a file named by the input and return its contents
	my $f = @_[0];
	my $r;
	open (F, "< $f");
	while (<F>) { $r .= $_ }
	close F;
	return $r;

}


sub list_one_resource {

	# get this resouce
	my $resource = MyLibrary::Resource->new( id => shift );
	
	# initialize
	my $cells;
	my $rows;
	my $details;
	
	# get the isbn
	my $isbn = &get_location( $resource, ISBN );
	
	# initialize cover art and rating
	my $image_source = NOART;
	my $rating = '';
	if ( $isbn ) {
	
		my $ua = LWP::UserAgent->new( agent => 'AMAZON-Images-Client/0.1 ' );
		my $request = HTTP::Request->new( GET => AMAZON . $isbn );
		my $response = $ua->request( $request );

		# create parser and process input
		if ($response->is_success) {

			my $parser     = XML::LibXML->new;
			my $xslt       = XML::LibXSLT->new;
			my $source     = $parser->parse_string( $response->content );
			my $style      = $parser->parse_file( AMAZON2PICT );
			my $stylesheet = $xslt->parse_stylesheet( $style );
			my $results    = $stylesheet->transform( $source );
			my $amazon     = $stylesheet->output_string( $results ) unless ( ! $stylesheet->output_string( $results ));

			my @amazon = split /\t/, $amazon;
			$image_source = @amazon[0] unless ( ! @amazon[0] );
			$rating = @amazon[1] . ' stars out of ' . @amazon[2] . ' reviews ' . $cgi->a({ href => './?cmd=reviews&id=' . $resource->id }, 'Read reviews') unless ( ! @amazon[1] );
		
		}
		
	}

	# add rating
	if ( $rating ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'rating: ' );
		$cells .= $cgi->td( $rating );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}


	# add isbn to output
	if ( $isbn ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'ISBN: ' );
		$cells .= $cgi->td( $isbn );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# view as
	$cells  = $cgi->td({ -class => 'label' }, 'view as: ' );
	$cells .= $cgi->td( $cgi->a({ -href => './?cmd=tagged&id=' . $resource->id }, 'tagged' )   . '; ' . 
	                    $cgi->a({ -href => './?cmd=marcxml&id='    . $resource->id }, 'MARCXML' )  . '; ' . 
	                    $cgi->a({ -href => './?cmd=mods&id='   . $resource->id }, 'MODS' )
	                  );
	$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	# call number
	my $lccn = &get_location( $resource, LCCN );
	if ( $lccn ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'location: ' );
		$cells .= $cgi->td( $lccn );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}
	
	# status
	$cells  = $cgi->td({ -class => 'label' }, 'status: ' );
	$cells .= $cgi->td( 'available ' . $cgi->a({ href => './?cmd=checkout&id=' . $resource->id }, 'Get it for me!') );
	$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	# creator
	if ( $resource->creator ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'creator(s): ' );
		$cells .= $cgi->td( $resource->creator );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# description
	if ( $resource->note ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'note(s): ' );
		$cells .= $cgi->td( $resource->note );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}
	
	# subjects
	if ( $resource->subject ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'subject(s): ' );
		$cells .= $cgi->td( $resource->subject );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# format
	if ( $resource->format ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'format: ' );
		$cells .= $cgi->td( $resource->format );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# source
	if ( $resource->source ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'source: ' );
		$cells .= $cgi->td( $resource->source );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# type
	if ( $resource->type ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'type: ' );
		$cells .= $cgi->td( $resource->type );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# language
	if ( $resource->language ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'language: ' );
		$cells .= $cgi->td( $resource->language );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# coverage
	if ( $resource->coverage ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'coverage: ' );
		$cells .= $cgi->td( $resource->coverage );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# relation
	if ( $resource->relation ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'relation: ' );
		$cells .= $cgi->td( $resource->relation );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# publisher
	if ( $resource->publisher ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'publisher: ' );
		$cells .= $cgi->td( $resource->publisher );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# rights
	if ( $resource->rights ) {
	
		$cells  = $cgi->td({ -class => 'label' }, 'rights: ' );
		$cells .= $cgi->td( $resource->rights );
		$rows  .= $cgi->Tr( { -valign => 'top' }, $cells );

	}

	# wrap the details in a table
	$details = $cgi->table({ -border => 0, -class => 'detail' }, $rows );
	
	# add cover art
	$cells  = $cgi->td({ -class => 'label' }, $cgi->img({ -src => $image_source, -height => 60, -width => 44 }));
	$cells .= $cgi->td( $details );
	$rows   = $cgi->Tr( { -valign => 'top' }, $cells );
	
	# wrap the whole thing in a table as well as a div
	$details = $cgi->table({ -border => 0 }, $rows );
	$details = $cgi->div({ -id => 'd' . $resource->id, -style => 'display: block' }, $details );
	
	# done; complete with cool show/hide javascript
	#return $cgi->li({ -class => 'citation' }, $resource->name . ' ' . $cgi->a( { -href => "javascript:expand('d" . $resource->id . "')", -style => 'color: grey; text-decoration: none' }, 'more...' ) . $details );
	return $cgi->li({ -class => 'citation' }, $resource->name . $details );

}


sub commify {

	# cool hack; http://www.unix.org.ua/orelly/perl/cookbook/ch02_18.htm
    my $text = reverse $_[0];
    $text =~ s/(\d\d\d)(?=\d)(?!\d*\.)/$1,/g;
    return scalar reverse $text;
    
}


sub pager {

	# get the input
	my $link  = shift;
	my $start = shift;
	my $size  = shift;
	
	# create the links
	my $previous = $cgi->a({ -href => $link . ( $start - PAGESIZE ) }, 'Previous' ) . '&#xA0;&#xA0;';
	my $next     = '&#xA0;&#xA0;' . $cgi->a({ -href => $link . ( $start + PAGESIZE ) }, 'Next' );
	
	# build the pager
	my $pager;
	if ( $start - PAGESIZE >= 0 ) { $pager = $previous }
	if ( $start + PAGESIZE < $size ) { $pager .= $next }
	
	# done
	return $pager;

}


sub get_location {
	
	# get the input
	my $resource      = shift;
	my $location_type = shift;
	
	# initialize
	my $location;
	
	# process each location
	foreach ( $resource->resource_locations ) {
	
		my $type = MyLibrary::Resource::Location::Type->new( id => $_->resource_location_type );
		if ( $type->name eq $location_type ) {
		
			$location = $_->location;
			last;
		
		}
	
	}

	# done
	return $location

}


sub facet_term_combinations {

	# get the input
	my @facets = @_;
	
	# initialize
	my $terms;
	foreach ( @facets ) {
			
		# create a list of terms associated with each facet
		foreach my $id ($_->related_terms(sort => 'name')) {
		
			my $term = MyLibrary::Term->new( id => $id );
			$terms .= '<li><a href="?cmd=' . CMDTERM . '&id=' . $id .  '">' . $term->term_name . '</a> <span style="color: gray"> (' . &commify( scalar( $term->related_resources )) . ' items)</span></li>';
		
		}
				
	}
	
	# done
	return $cgi->ol( $terms );
	
}

sub choices {
	
	# return a set of menu options
	if ( $status eq 'authenticated' ) { return &slurp( CHOICES_A )}
	else { return &slurp( CHOICES_N )}
	
}