#!/usr/bin/env perl
###################

$0="jobsel";
sub heply { $pos = tell DATA; print STDERR <DATA>; seek DATA,$pos,0 }
exit heply if $ARGV[0] eq '--help';
use Term::ReadKey;
ReadMode 4;
sub bye { print STDOUT "export JOBSEL_DISPLAY_MODE=$dispmode"; exit ReadMode 0 }
sub getkey { while(not defined ($k = ReadKey(-1))){} return $k }
$SIG{INT}=$SIG{STOP}=$SIG{STOP}=$SIG{TSTP}=$SIG{QUIT}='bye';
$dispmode = $ENV{JOBSEL_DISPLAY_MODE} eq "x" ? "x" : "c";

while(1){
	@o=@x=();
	for(split/[\r\n]+/,$ARGV[0]){ 
		($j,$p)=/(\d+)\]\S?\s+(\d+)/; 
		if (  open(P,"/proc/$p/stat") and ($c,$s)=(<P>=~/\s\((.+?)\)\s+(\S+)/)  ) {
			close P;
			push @o,[$j,$c,$p,$s];	# job number, command, pid, state
			
			s/(\S+\s+){3}//;
			push @x,sprintf "[%d] %5d         %s",$j,$p,$_;
		}
	}
	bye unless @o;

	$in=$#o if $in>$#o;
	$pos = tell STDERR;

	print STDERR "\033[s\033[1;0H";
	if($dispmode eq "x") {
		for(0..$#o) {
			printf STDERR "%s%s\033[m\n",($_==$in?"\033[44;1;36m":"\033[1;36m"),$x[$_];
		}
	}
	else {	
		print STDERR "\033[1;36mjobs: ";
		for(0..$#o) {
			printf STDERR "%s[%%%s %s(%s) %s]\033[m ",($_==$in?"\033[44;1;36m":"\033[1;36m"),@{$o[$_]};
		}
	}
	print STDERR "\033[u";

	$k=getkey;
	if($k eq chr(27)) {
		$k=getkey;
		if($k eq '[') {
			$k=getkey;
			if($k =~ /[DA]/) {	# arrow left/up
				$in-- if $in > 0
			}
			elsif($k =~ /[CB]/) {	# arrow right/down
				$in++ if $in < $#o
			}
			elsif($k =~ /[H5]/) {	# home/pg up
				$in=0
			}
			elsif($k =~ /[F6]/) {	# end/pg down
				$in=$#o
			}
			elsif($k eq chr(27)) { bye }
		}
		elsif($k eq chr(27)) { bye }
	}
	elsif($k =~ /[ts ]/i) {
		kill ${$o[$in]}[3] eq 'T' ? 18 : 20, ${$o[$in]}[2];	# CONT,TSTP
	}
	elsif($k =~ /k/i) {
		kill 9, ${$o[$in]}[2];	# KILL
	}
	elsif($k =~ /h/i) {
		kill 1, ${$o[$in]}[2];	# HUP
	}
	elsif($k =~ /i/i) {
		kill 2, ${$o[$in]}[2];	# INT
	}
	elsif($k =~ /d/i) {
		$/=undef;
		print STDERR "Commandline:\t";
		open A,"/proc/".${$o[$in]}[2]."/cmdline";
		print STDERR join(" ",split/\x0/,<A>)."\n";
		close A;
		print STDERR "Directory:\t";
		print STDERR readlink "/proc/".${$o[$in]}[2]."/cwd","\n";
		$/="\n";
		open A,"/proc/".${$o[$in]}[2]."/status";
		/^(ppid|uid|gid):/i and print STDERR $_ while<A>;
		close A;
	}
	elsif($k =~ /[xc]/i) {
		$dispmode=lc $k;
	}
	elsif($k eq '?') {
		heply
	}
	elsif($k =~ /[\r\n]/) {
		ReadMode 0;
		print STDOUT "export JOBSEL_DISPLAY_MODE=$dispmode; fg ".$o[$in][0];
		exit 0;
	}
	elsif($k =~ /q/i) { bye }
	
	# clear screen region
	print STDERR "\033[s\033[1;0H";
	if($dispmode eq "x") {
		print STDERR " " x ($ARGV[1] || `tput cols`), "\n" for @x
	}
	else {
		print STDERR " " x (-$pos+tell STDERR)
	}
	print STDERR "\033[u";
}

__END__

NAME		jobsel
SYNOPSIS	$ eval $(jobsel "$(jobs -l)" $COLUMNS)
DESCRIPTION	Improved job control frontend for bash
KEYS
   Left,Right	Select item
   Enter	Switch to job in forground
   H		Hangup selected process
   I		Interrupt process
   S,T,Space	Suspend, Resume job
   K		Kill process
   D		Process' details
   X,C		Expanded, collapsed display mode
   Q		Dismiss jobsel
   ?		Help
HINTS
   Define an alias!
     alias j='eval $(jobsel "$(jobs -l)" $COLUMNS)'
   Bind a function key for it!
     bind -x '"\204"':"eval \$(jobsel \"\$(jobs -l)\" \$COLUMNS)"
     bind '"\ej"':"\"\204\"" # ESC-J
     Where: 204 is an arbitrary free keyscan code