#!/usr/bin/env ruby

# $Id$
# $URL$

require 'fileutils'
require 'thread'
require 'open3'

JOBSDIR = "jobs"
PARKDIR = "park"
PROCDIR = "processors"
RESULTDIR = "results"
FAILDIR = "failure"
MONITORDIR = "monitor"
RUNMODE = 0755
CONFIG = "config"
@config = { "waittime" => 3, "maxproc" => 3 }
@processor_threads = []
@jobclaimlock = Mutex.new

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}"
	FileUtils.cp(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 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
	}
	return nil
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
	@processor_threads << Thread.new do
		begin
			# gebruik een mutex voor het claimen van een job!
			runjob = nil
			@jobclaimlock.synchronize {
				runjob = getjob
			}

			if ! runjob.nil?
				starttime = Time.now
				puts "Starting job: #{runjob}"
				owd = Dir.pwd
#				puts "#{@basedir}/#{PROCDIR}/#{runjob}"
				Dir.chdir("#{@basedir}/#{PROCDIR}/#{runjob}")
				begin
					output = File.open("#{@basedir}/#{PROCDIR}/#{runjob}/output", "w")
					Open3.popen3("#{@basedir}/#{PROCDIR}/#{runjob}/job", "r+"){ |stdin, stdout, stderr|
						# dit moet netter kunnen, nu wordt de volgorde van de diverse outputs veranderd
						while !stdout.eof and ! stderr.eof do
							#output.print "XXX ERR #{stderr.gets}"
							#output.print "XXX OUT #{stdout.gets}"
							output.print stderr.gets
							output.print stdout.gets
						end
					}
					output.close
					finishjob runjob
					puts "Finished job: #{runjob} [runtime: #{Time.now-starttime}]"
				rescue
					failjob runjob
					puts "Failed job: #{runjob} [runtime: #{Time.now-starttime}]"
					puts $!
				end
				Dir.chdir(owd)
			end
		rescue
			puts "failure in thread"
			puts $!
		end
	end
end

def stop
	puts "unimplemented"
end

def stopall
	puts "unimplemented"
end

def master
	if Process.euid != 0
		puts "If your jobs need root privileges you want to run this as root"
	end

	while true
		sleep @config["waittime"]
#		puts "Number of threads: #{@processor_threads.length}"
		# dode threads moeten opgeruimd worden
		(0...@processor_threads.length).to_a.reverse.each{|thr|
#			puts "thr: #{thr}"
#			puts @processor_threads[thr].status
			if @processor_threads[thr].status == false
#				puts "deleting thread #{thr}"
				@processor_threads.delete_at(thr)
			end
		}
		if @processor_threads.length < @config["maxproc"]
			# nog testen op aanwezig zijn van nieuwe jobs in queue?
			runprocessor
		end
		readconfig
	end

#        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