#!/usr/bin/perl -w
# 
# mob 2010-03-24
# The usual free license verbiage here. Make it better and send it back.
# 
# This code is cleaner than the others I have of this style, since some vars are
# passed into the stages.
# 
#
# perl program to mimic the display from metacat. I have discovered that this is a
# really clunky operation. It re-reads the EML doc for every "display module".
# I guess it needs to, since it is generating a new web page each time. (You
# could get on with that project to pull the entire EML only once,and hide 
# sections with tabs.
#
#
## NOTE on versions of XML-LibXML and XSLT which are available on Penguin:
# XML-LibXML
# Currently penguin is running  http://search.cpan.org/~pajas/XML-LibXML-1.69/ 
# which uses this syntax for parsing:
# my $source = $parser->parse_file( "${xml_dataset_query_url}${docid}" );

# But the current version as of march 2010 is 1.7 which has a different syntax:
# my $source = XML::LibXML->load_xml(location => 'test.xml');
# my $style_doc = XML::LibXML->load_xml(location=>'test_person.xsl', no_cdata=>1);

# XML-LibXSLT:
# per http://search.cpan.org/~msergeant/XML-LibXSLT-1.58/LibXSLT.pm
# print $stylesheet->output_string($results);
# The 1.7 version is
# print $stylesheet->output_as_bytes($results);



#--------------------------------------------------------------------------80c->

# load perl modules
use strict;       # turn on strict syntax checking.
use CGI;
use XML::LibXSLT;
use XML::LibXML;
use URI;          # for parsing URL syntax. not curently used
use LWP::Simple;  # for grabbing url. not currently used, but might need its "get" method for URIs
use File::Basename; # app must know its own name so stylesheets can create new URLs back

#--------------------------------------------------------------------------80c->
# Set up debug status
my $debug = 1;


#--------------------------------------------------------------------------80c->
# Set up pgm configuration - use template vars here.
# create a name for yourself!
my $referrer = 'showDataset.cgi';

my $xslt_root_path = '/var/www/sbc.lternet.edu/lib/xslt';

# configure which metacat to use. Use a timeout value to check the health of the
# primary Metacat.

# The Metacats we have available
# Use the long format, so you can add the sessionId param when you get logins running..
my $xml_dataset_query_url = 'http://metacat.lternet.edu/knb/metacat?action=read&qformat=xml&docid=';
my $alternate_query_url = 'http://knb.ecoinformatics.org/knb/metacat?action=read&qformat=xml&docid=';
my $xml_source_url = "";

# check the primary Metacat URL, and use alternate if there is a problem
my $ua = LWP::UserAgent->new;
 $ua->timeout(5);
 
my $response = $ua->get("$xml_dataset_query_url");
 if ($response->is_success) {
     $xml_source_url = "$xml_dataset_query_url";   
 }
 else {
    $xml_source_url = "$alternate_query_url"; 
 }

debug("XML source is: $xml_source_url");    



#--------------------------------------------------------------------------80c->
# instantiate common objects and variables
# create an object for the input params
my $query   = new CGI;
my $docid = $query->param('docid');

# these for reading XML and transforming
my $parser =  XML::LibXML->new();
my $xslt = XML::LibXSLT->new();

# set path for EML xslt stylesheets:
my $xslt_path = "${xslt_root_path}/eml";   


my $source="";
## parse 2 XML files: the eml dataset and the xslt, then create a styelsheet object
$source = $parser->parse_file( "${xml_source_url}${docid}" );
my $style_doc = $parser->parse_file("${xslt_path}/eml-2.0.0.xsl");

my $stylesheet = $xslt->parse_stylesheet($style_doc);

#--------------------------------------------------------------------------80c->
# Define the main program logic that calls subroutines to do the work
#--------------------------------------------------------------------------80c->


# The processing steps we are handling. A dataset summary view is the default.
# "displaymodule" is analogous to "stage" in other cgis, but consistent with
# existing wording in eml-*.xsl
my $displaymodule = $query->param('displaymodule') || 'dataset';

# define the possible stages
my %displaymodules = (
              'dataset'           => \&dataset,
              'entity'            => \&entity,
              'attribute'         => \&attribute,
              'attributedomain'   => \&attributeDomain,              
              'attributecoverage' => \&attributeCoverage,              
              'attributedetail'   => \&attributeDetail,   # not sure of use
              'attributemethod'   => \&attributeMethod,   # not yet tested           
              'inlinedata'        => \&inlineData,        # not yet tested     
              'additionalmetadata'=> \&additionalMetadata,             
              'responsibleparties'=> \&responsibleParties,
              'coverage'          => \&coverage,  # local coveral
              'coverageall'       => \&coverageall,
              'methodsall'        => \&methodsall,
              
               
             );
             
# call the appropriate routine based on the stage. 
# all stages use the vars for docid, source_xml and xsl_stylesheet
# 2010-05-04: referrer, too!
if ( $displaymodules{$displaymodule} ) {
  $displaymodules{ $displaymodule }->("$docid", "$source", "$stylesheet", "$referrer");
} else {
  &handleResponseMessage();
}


#--------------------------------------------------------------------------80c->
# Define the subroutines to do the work
#--------------------------------------------------------------------------80c->
#####
### Default stage, show a dataset
#
sub dataset {
# no other query params needed

# create HTML output from EML and stylesheet and send it back
my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  referrer => "$referrer",
    
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

}


#####
### stage to show all the people as a separate webpage
#
sub responsibleParties {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');

# create HTML output from EML and stylesheet and send it back
my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

}



#####
### stage to show all the coverage elements as a separate webpage
#
sub coverage {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');

# create HTML output from EML and stylesheet and send it back
my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

}

#####
### stage to show all the coverage elements as a separate webpage
#
sub coverageall {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');

# create HTML output from EML and stylesheet and send it back
my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

}

#####
### stage to show all the methods elements as a separate webpage
#
sub methodsall {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');

# create HTML output from EML and stylesheet and send it back
my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

}


#####
### 
#
# stage to show the data entity (dataTable tree)
sub entity {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }



#####
### 
# 
# stage showing attribute details
sub attribute {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }



# note that attributeDomain","attributeCoverage" "attributeMethod",  all use the same params,
# only the displaymodule changes [HAVE NOT YET TESTED attributeMethod ]
#####
### 
#
sub attributeDomain {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');
my $attributeindex = $query->param('attributeindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  attributeindex => "$attributeindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }


#####
### 
# 
sub attributeCoverage {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');
my $attributeindex = $query->param('attributeindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  attributeindex => "$attributeindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }


#####
### 
# 
sub attributeMethod {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');
my $attributeindex = $query->param('attributeindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  attributeindex => "$attributeindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }



#####
### 
# 
sub inlineData {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $entitytype = $query->param('entitytype');
my $entityindex = $query->param('entityindex');
my $distributionlevel = $query->param('distributionlevel');
my $physicalindex = $query->param('physicalindex');
my $distributionindex = $query->param('distributionindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  entitytype => "$entitytype",
  entityindex => "$entityindex",
  distributionlevel => "$distributionlevel",
  physicalindex => "$physicalindex",
  distributionindex => "$distributionindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }


#####
### 
#
sub additionalMetadata {
# get the other params from CGI
my $displaymodule = $query->param('displaymodule');
my $additionalmetadataindex = $query->param('additionalmetadataindex');

my $results = $stylesheet->transform($source, XML::LibXSLT::xpath_to_string( 
  docid => "$docid",
  displaymodule => "$displaymodule",
  additionalmetadataindex => "$additionalmetadataindex",
  referrer => "$referrer",
  
  ));

print "Content-type: text/html\n\n";
print $stylesheet->output_string($results);

 }


#####
### HandleResponseMssage
#
sub handleResponseMessage {
# user picked a stage that does not exist yet. send an error msg.

# user picked an EML docid that does not exist 
# (handled by returning the metacat error xslt)

# metacat is not returning data

}



#####
### Debug message
#
sub debug {
    my $msg = shift;
    
    if ($debug) {
        print STDERR "showDataset.cgi: $msg\n";
    }
}