#!/usr/bin/env ruby

# $Id$
# $URL$


JOBSDIR = "jobs"
PARKDIR = "park"
PROCDIR = "processors"
RESULTDIR = "results"
FAILDIR = "failure"
MONITORDIR = "monitor"
RUNMODE = 0755
CONFIG = "config"
@config = { "waittime" => 3, "maxproc" => 3 }

COUNTERFILE="jobscounter"
RUNNINGFILE="runningcounter"

def usage
	puts <<ENDTXT
Usage: pb <option>

add <command>>-->-------Add the given command as a job.
addfile|af <file>>------Add the given file as a job.
createconfing>-->-------Write a default configuration file.
run>---->------->-------Start the master scheduler process.
del <jobnr>>---->-------Delete the given job from the queue.
help|-h>>------->-------Show this help.
park>--->------->-------Place all queued jobs in the parkinglot.
unpark>->------->-------Place all jobs from the parkinglot back in the queue.
retry <jobnr>>-->-------Reschedule a failed job. Destroys all output.
prio <h|n|l> <jobnr>>---Change the priority of the given job.>--[unimplemented]
status|st>------>-------Show the status of the current jobs.
stop <jobnr>>--->-------Stop the given job.>----[unimplemented]
stopall>>------->-------Stop all running jobs.>-[unimplemented]
ENDTXT
	exit
end

def readconfig
	File.open("#{@basedir}/#{CONFIG}").each_line {|line|
		line.sub!(/#.*/, "")
		line.sub!(/^\s*/, "")
		line.sub!(/\s*$/, "")
		if line.match(/^$/)
			next
		end
		line.match(/([^=]*?)\s*=\s*(.*)/)
		case $1
			when "maxproc"		then @config["maxproc"] = $2
			when "waittime"		then @config["waittime"] = $2
			else			puts "unknown option #{$1}"
		end
	}
end

def status
	readconfig
	# show which jobs are running
	puts "Running jobs (#{Dir.entries("#{@basedir}/#{PROCDIR}").size - 2}/#{@config["maxproc"]}):"
	# just call 'ls' instead of trying to figure out how to format it nicely for the screen
	system("ls" ,"#{@basedir}/#{PROCDIR}/")
	# show queues
	puts "Jobs queued (#{Dir.entries("#{@basedir}/#{JOBSDIR}").size - 2}):"
	system("ls", "#{@basedir}/#{JOBSDIR}/")
	puts "Jobs parked (#{Dir.entries("#{@basedir}/#{PARKDIR}").size - 2}):"
	puts "Jobs finished: #{Dir.entries("#{@basedir}/#{RESULTDIR}").size - 2}"
	puts "Jobs failed (#{Dir.entries("#{@basedir}/#{FAILDIR}").size - 2}):"
	system("ls", "#{@basedir}/#{FAILDIR}/")
end

def createdirs
	[ JOBSDIR, PARKDIR, PROCDIR, RESULTDIR, FAILDIR, MONITORDIR ].each{|dir|
		if ! FileTest.directory?("#{@basedir}/#{dir}")
			Dir.mkdir("#{@basedir}/#{dir}")
		end
	}
end

def increasejobscounter
	jobscounter = 0
	if FileTest.exists?(COUNTERFILE)
		File.new(COUNTERFILE).flock(File::LOCK_EX)
		File.open(COUNTERFILE, "r+"){|file|
			jobscounter = file.read
			if jobscounter.empty?
				jobscounter = 0
			end
			jobscounter = jobscounter.to_i
			jobscounter += 1
			file.seek(0)
			file.puts jobscounter
		}
		File.new(COUNTERFILE, "r+").flock(File::LOCK_UN)
	else
		File.open(COUNTERFILE, "w"){|file|
			File.new(COUNTERFILE).flock(File::LOCK_EX)
			jobscounter = 1
			file.puts jobscounter
		}
		File.new(COUNTERFILE, "r+").flock(File::LOCK_UN)
	end
	return jobscounter
end

def addjob
	jobnumber=sprintf("%06d", increasejobscounter)
	puts "New job: #{jobnumber}"
	if FileTest.exists?("#{@basedir}/#{JOBSDIR}/#{jobnumber}")
		puts "Job #{jobnumber} already scheduled. This should not happen."
		exit
	end
	File.open("#{@basedir}/#{JOBSDIR}/#{jobnumber}"){|file|
		file.puts ARGV.join(" ")
	}
	File.chmod(RUNMODE, "#{@basedir}/#{JOBSDIR}/#{jobnumber}")
end

def addjobfromfile
	filename = ARGV[0]
	if filename.nil?
		puts "Missing filename"
		usage
	else
		if ! FileTest.exists?(filename)
			puts "File #{filename} doesn't exist"
			usage
		end
	end
	jobnumber = sprintf("%06d", increasejobscounter)
	puts "New job: #{jobnumber}"
	File.copy(filename, "#{@basedir}/#{JOBSDIR}/#{jobnumber}")
	File.chmod(RUNMODE, "#{@basedir}/#{JOBSDIR}/#{jobnumber}")
end

def createconfig
	if ! FileTest.exists?("#{@basedir}/#{CONFIG}")
		File.new("#{@basedir}/#{CONFIG}", "w"){|file|
			file.puts <<EOT
# how many parallel processes?
maxproc=3
# take a break for how long between process end and starting a new one
waittime=3
EOT
		}
	end
end

def master
	# als ik threading ga gebruiken is deze dus niet nodig
	File.new(RUNNINGFILE, "w").flock(File::LOCK_EX){|file|
		file.puts "0"
	}

#        echo 0 >"${basedir}/$runningfile"
#
#        while sleep $waittime; do
#                if [ $(cat "${basedir}/${runningfile}") -lt $maxproc ]; then
#                        # via ls omdat anders de globbing klote is
#                        jl=$(ls ${basedir}/jobs/)
#                        if [ -n "$jl" ]; then
#                                ${pbcommand} process &
#                        fi
#                        readconfig
#                fi
#        done
end

def deljob
	jobnumber = ARGV[0]
	if jobnumber.nil?
		puts "Missing jobnumber"
		usage
	else
		jobnumber = sprintf("%06d", jobnumber.to_i)
		if FileTest.exists?("#{@basedir}/#{JOBSDIR}/#{jobnumber}")
			File.unlink("#{@basedir}/#{JOBSDIR}/#{jobnumber}")
		else
			puts "Job '#{jobnumber}' not in queue"
			exit
		end
	end
end

def parkjobs
	Dir.entries("#{@basedir}/#{JOBSDIR}").each{|file|
		if file == '.' or file == '..'
			next
		end
		File.move("#{@basedir}/#{JOBSDIR}/#{file}", "#{@basedir}/#{PARKDIR}")
	}
end

def unparkjobs
	Dir.entries("#{@basedir}/#{PARKDIR}").each{|file|
		if file == '.' or file == '..'
			next
		end
		File.move("#{@basedir}/#{PARKDIR}/#{file}", "#{@basedir}/#{JOBSDIR}")
	}
end

def unfail
	jobnumber = ARGV[0]
	if jobnumber.nil?
		puts "Missing jobnumber"
		usage
	else
		jobnumber = sprintf("%06d", jobnumber.to_i)
		if FileTest.exists?("#{@basedir}/#{FAILDIR}/#{jobnumber}/job")
			File.move("#{@basedir}/#{FAILDIR}/#{jobnumber}/job", "#{@basedir}/#{JOBSDIR}/#{jobnumber}")
			# XXX tja, lekker makkelijk even geen recursie implementeren
			system("rm", "-rf", "#{@basedir}/#{FAILDIR}/#{jobnumber}")
		else
			puts "Job '#{jobnumber}' not in failed dir"
			exit
		end
	end
end

def changeprio
	puts "unimplemented"
end

def runprocessor
#        incrementrunning
#        sleep 1
#        runjob=$(getjob)
#        if [ -n "${runjob}" ]; then
#                echo "Starting job: ${runjob}"
#                owd=$(pwd)
#                cd "${basedir}/processors/${runjob}"
#                if "${basedir}/processors/${runjob}/job" 2>&1 > "${basedir}/processors/${runjob}/output" ;then
#                        finishjob ${runjob}
#                        echo "Finished job: ${runjob}"
#                else
#                        failjob ${runjob}
#                        echo "Failed job: ${runjob}"
#                fi
#                cd $owd
#        fi
#        decrementrunning
end

def stop
	puts "unimplemented"
end

def stopall
	puts "unimplemented"
end

pbcommand = $0

command = ARGV.shift
@basedir = Dir.pwd

createdirs

case command
	when "add"		then addjob
	when "addfile", "af"	then addjobfromfile
	when "createconfig"	then createconfig
	when "run"		then master
	when "del"		then deljob
	when "help"		then usage
	when "-h"		then usage
	when "park"		then parkjobs
	when "unpark"		then unparkjobs
	when "retry"		then unfail
	when "prio"		then changeprio
	when "process"		then runprocessor
	when "status", "st"	then status
	when "stop"		then stop
	when "stopall"		then stopall
	else			usage
end