#!/usr/bin/env perl

if($#ARGV < 0){&Usage();exit;}

$pluginname = "__nada__";
foreach $arg (@ARGV){
	$pluginname = $arg;
}

if($pluginname eq "__nada__"){&Usage();exit;}

print "\n";
print "Generating files for plugin $pluginname ....\n";

# Create directory to hold source
mkdir($pluginname);

# Create C++ Header File
$dhfile = $fname = "DEventProcessor_${pluginname}.h";
open(FILE,">$pluginname/$dhfile");
&PrintFileHeader();
&PrintClass();
close(FILE);
print " - $dhfile\n";

# Create C++ Implementation file
$ccfile = $fname = "DEventProcessor_${pluginname}.cc";
open(FILE,">$pluginname/$ccfile");
&PrintFileHeader();
&PrintMethods();
close(FILE);
print " - $ccfile\n";

# Create Makefile
open(FILE,">$pluginname/Makefile");
&PrintMakefile();
close(FILE);
print " - Makefile\n";

###############
# PrintFileHeader
###############
sub PrintFileHeader()
{
	# print a few lines at the very top of the file
	$uname = `uname -nprs`;
	chomp($uname);
	print FILE "// \$Id\$\n";
	print FILE "//\n";
	print FILE "//    File: $fname\n";
	print FILE "// Created: ".`date`;
	print FILE "// Creator: ".$ENV{"USER"}." (on $uname)\n";
	print FILE "//\n";
}


###############
# PrintClass
###############
sub PrintClass()
{
	$content = "
\#ifndef _DEventProcessor_${pluginname}_
\#define _DEventProcessor_${pluginname}_

\#include <JANA/JEventProcessor.h>

class DEventProcessor_${pluginname}:public jana::JEventProcessor{
	public:
		DEventProcessor_${pluginname}();
		~DEventProcessor_${pluginname}();
		const char* className(void){return \"DEventProcessor_${pluginname}\";}

	private:
		jerror_t init(void);						///< Called once at program start.
		jerror_t brun(jana::JEventLoop *eventLoop, int runnumber);	///< Called everytime a new run number is detected.
		jerror_t evnt(jana::JEventLoop *eventLoop, int eventnumber);	///< Called every event.
		jerror_t erun(void);						///< Called everytime run number changes, provided brun has been called.
		jerror_t fini(void);						///< Called after last event of last event source has been processed.
};

\#endif // _DEventProcessor_${pluginname}_

";
	print FILE $content;
	
}

###############
# PrintMethods
###############
sub PrintMethods
{
	$content = "
\#include \"DEventProcessor_${pluginname}.h\"
using namespace jana;


// Routine used to create our DEventProcessor
\#include \<JANA/JApplication.h\>
extern \"C\"{
void InitPlugin(JApplication *app){
	InitJANAPlugin(app);
	app->AddProcessor(new DEventProcessor_${pluginname}());
}
} // \"C\"


//------------------
// DEventProcessor_${pluginname} (Constructor)
//------------------
DEventProcessor_${pluginname}::DEventProcessor_${pluginname}()
{

}

//------------------
// ~DEventProcessor_${pluginname} (Destructor)
//------------------
DEventProcessor_${pluginname}::~DEventProcessor_${pluginname}()
{

}

//------------------
// init
//------------------
jerror_t DEventProcessor_${pluginname}::init(void)
{
	// Create histograms here
	return NOERROR;
}

//------------------
// brun
//------------------
jerror_t DEventProcessor_${pluginname}::brun(JEventLoop *eventLoop, int runnumber)
{
	return NOERROR;
}

//------------------
// evnt
//------------------
jerror_t DEventProcessor_${pluginname}::evnt(JEventLoop *loop, int eventnumber)
{
	// Fill histograms here

	return NOERROR;
}

//------------------
// erun
//------------------
jerror_t DEventProcessor_${pluginname}::erun(void)
{
	// Any final calculations on histograms (like dividing them)
	// should be done here. This may get called more than once.
	return NOERROR;
}

//------------------
// fini
//------------------
jerror_t DEventProcessor_${pluginname}::fini(void)
{
	// Called at very end. This will be called only once

	return NOERROR;
}

";
	print FILE $content;
	
}

###############
# PrintMakefile
###############
sub PrintMakefile()
{
	# Contents of default Makefile for plugins
	print FILE "\n";
	print FILE "PACKAGES = ROOT:JANA\n";
	print FILE "\n";
	print FILE "include \$(HALLD_HOME)/src/BMS/Makefile.shlib\n";
	print FILE "\n";
}

###############
# Usage
###############
sub Usage()
{
	print "\n";
	print "Usage:\n\t mkplugin name\n";
	print "\n";
	print "Generate the C++ source and header files to implement a new\n";
	print "plugin for use with the Hall-D analysis framework.\n";
	print "\n";
	print "This script superceeds some similar functionality in the mkprocessor\n";
	print "script. Unlike mkprocessor, the mkplugin script will create a directory\n";
	print "for the files and write the files to it. In addition, it will create\n";
	print "a default Makefile so that one can immediately compile the new plugin.\n";
	print "\n";
	print "The C++ files generated will define a class based on JEventProcessor.\n";
	print "The \"name\" parameter specifies a unique name for the class.\n";
	print "The class will, by default, be called DEventProcessor_name.\n";
	print "This can lead to long names, but at least it is clear.\n";
	print "what they are.\n";
	print "\n";
	print "Event processors are starting (or end) points in the analysis\n";
	print "chain. They are typically used for creating histograms and trees.\n";
	print "Only one (of each type) of event processor object is created\n";
	print "in a program which is then used by all threads. This is in\n";
	print "contrast to factories which are created for each thread.\n";
	print "If you wish to generate data visible by other factories and\n";
	print "event processors, then see mkfactory.\n";
	print "\n";
	print "It should be noted that plugins do not require and are not limited\n";
	print "to implementing JEventProcessor objects. This is just forseen as the\n";
	print "most common use and so a skeleton implementation is provided here.\n";
	print "\n";
	print "\n";
	print "\n";
}