#!/usr/bin/env ruby

# $Id$
# $URL$

require 'fileutils'

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
	if FileTest.exists?("#{@basedir}/#{CONFIG}")
		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
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).flock(File::LOCK_UN)
	else
		# XXX wellicht eerst een touch ofzo doen en dan locken voor de schrijf loop
		# geopend wordt
		FileUtils.touch(COUNTERFILE)
		File.new(COUNTERFILE).flock(File::LOCK_EX)
		File.open(COUNTERFILE, "w"){|file|
			jobscounter = 1
			file.puts jobscounter
		}
		File.new(COUNTERFILE).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}", "w"){|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.open("#{@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 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
		FileUtils.mv("#{@basedir}/#{JOBSDIR}/#{file}", "#{@basedir}/#{PARKDIR}")
	}
end

def unparkjobs
	Dir.entries("#{@basedir}/#{PARKDIR}").each{|file|
		if file == '.' or file == '..'
			next
		end
		FileUtils.mv("#{@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")
			FileUtils.mv("#{@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 incrementrunning
	# als ik threading ga gebruiken is dit niet meer nodig (want geen runningfile nodig)
	File.new(RUNNINGFILE).flock(File::LOCK_EX)
	File.open(RUNNINGFILE, "r+"){|file|
		running = file.read
		running = running.to_i + 1
		file.seek(0)
		file.trunc
		file.puts running
	}
	File.new(RUNNINGFILE).flock(File::LOCK_UN)
end

def decrementrunning
	# als ik threading ga gebruiken is dit niet meer nodig (want geen runningfile nodig)
	File.new(RUNNINGFILE).flock(File::LOCK_EX)
	File.open(RUNNINGFILE, "r+"){|file|
		running = file.read
		running = running.to_i - 1
		if running < 0
			running = 0
		end
		file.seek(0)
		file.trunc
		file.puts running
	}
	File.new(RUNNINGFILE).flock(File::LOCK_UN)
end

def getjob
	Dir.entries("#{@basedir}/#{JOBSDIR}").each{|file|
		if file == '.' or file == '..'
			next
		else
			if FileTest.file?("#{@basedir}/#{JOBSDIR}/#{file}")
				Dir.mkdir("#{@basedir}/#{PROCDIR}/#{file}")
				FileUtils.mv("#{@basedir}/#{JOBSDIR}/#{file}", "#{@basedir}/#{PROCDIR}/#{file}/job")
				return file
			end
		end
	}
end

def failjob(jobnumber)
	FileUtils.mv("#{@basedir}/#{PROCDIR}/#{jobnumber}", "#{@basedir}/#{FAILDIR}")
end

def finishjob(jobnumber)
	FileUtils.mv("#{@basedir}/#{PROCDIR}/#{jobnumber}", "#{@basedir}/#{RESULTDIR}")
end

def runprocessor
	incrementrunning
	sleep 1		# XXX niet nodig als locking echt werkt (of bij threading)
	runjob = getjob
	if ! runjob.nil?
		puts "Starting job: #{runjob}"
		owd = Dir.pwd
		Dir.cd("#{@basedir}/#{PROCDIR}/#{runjob}")
# XXX IPC nog even uitzoeken... popen3 ?
#                if "${basedir}/processors/${runjob}/job" 2>&1 > "${basedir}/processors/${runjob}/output" ;then
#                        finishjob ${runjob}
			puts "Finished job: #{runjob}"
#                else
#                        failjob ${runjob}
			puts "Failed job: #{runjob}"
#                fi
		Dir.cd(owd)
	end
	decrementrunning
end

def stop
	puts "unimplemented"
end

def stopall
	puts "unimplemented"
end

def master
	if Process.euid != 0
		puts "If your jobs need root priviledges (XXX spelling) you want to run this as root"
	end

	# als ik threading ga gebruiken is dit niet meer nodig (want geen runningfile nodig)
	if ! FileTest.file?(RUNNINGFILE)
		FileUtils.touch(RUNNINGFILE)
	end
	File.new(RUNNINGFILE).flock(File::LOCK_EX)
	File.open(RUNNINGFILE, "w"){|file|
		file.puts "0"
	}
	File.new(RUNNINGFILE).flock(File::LOCK_UN)

#        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

# XXX SIGHUP handler die config opnieuw inleest

@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