--- iselect.pl	2007/10/25 11:22:18	1
+++ iselect.pl	2007/10/25 15:12:43	10
@@ -2,141 +2,200 @@
 
 use strict;
 use Term::Screen;
+use Carp qw/cluck/;
 use Data::Dump qw/dump/;
 
 my $data = <<'EOF';
  First line
 
-+first selectable
-+ second selectable
+{s}first selectable
+{s}second selectable
 
  a space....
 
                                     ...infinity and beyond
 
 
-+foo
-+bar
+{s}foo
+{s}bar
 
  bum
+
 EOF
 
 open(my $ps, "ps ax |") || die "can't do ps ax: $!";
 while(<$ps>) {
-	$data .= '+'.$_;
-	$data .= ' '.$_;
+	$data .= '{s}'.$_;
+	$data .= $_;
 }
 close($ps);
 
+$data .= "\n--EOF--";
 
-my @lines = split(/\n/, $data);
+my $scr;
 
-my $scr = new Term::Screen || die "can't init Term::Screen";
-$scr->clrscr()->noecho();
+# leave sane terminal if script dies
+$SIG{__DIE__} = sub {
+    eval { system('stty sane'); };
+};
+
+
+my @lines = split(/\n/, $data);
 
-my $o = 0;	# offset in original text
+my $top_screen_line = 0;	# offset in original text
 my $pos = 0;
 
+# default: select first line
+my $sel_pos = 0;
+my $status_text = '';
+my $error_text = '';
+
+my $status_lines = 3;
+
 # find which lines are selectable in input file
 my $selectable_line;
 
 for my $l (0 .. $#lines) {
-	next if (length($lines[$l]) < 2);
-	my $foo = ' ';
-	if ($lines[$l] !~ m/^\s/o) {
+	if ($lines[$l] =~ s/^{s}//) {
 		$selectable_line->{$l}++;
-		$foo = '*';
 	}
-	warn "$l: $foo $lines[$l]\n";
+}
+
+# select first selectable line
+
+if ( $selectable_line ) {
+	$pos = $sel_pos = (sort { $a <=> $b } keys %$selectable_line)[0];
+	warn "selected first selectable line $sel_pos";
 }
 
 sub full_line {
 	my $t = shift;
-	my $l = length($t);
+	$t = '' unless defined $t;
 	return $t . (" " x ($scr->cols - length($t)));
 }
 
 sub chunk {
 	my $t = shift;
-	my $o = '';
-	$o = substr($t,1,$scr->cols) if length($t) > 1;
-	return $o . ( ' ' x ( $scr->cols - length($o) - 1 ) );
+	cluck "expected line" unless defined $t;
+	return substr($t,0,$scr->cols);
+}
+
+sub redraw_line {
+	my ($l,$line) = @_;
+
+	if ( defined $selectable_line->{ $l + $top_screen_line } ) {
+		$scr->at($l,0)->bold()->puts( full_line( chunk($line) ) )->normal();
+	} else {
+		$scr->at($l,0)->puts( full_line( chunk($line) ) );
+	}
 }
 
 sub redraw {
-	for my $l (0 .. $scr->rows) {
-		my $line = $lines[ $l + $o ] || '';
-		next if (length($line) < 2);
-		if (substr($line,0,1) !~ m/^\s/o) {
-			$scr->at($l,0)->bold()->puts( full_line( chunk($line) ) )->normal();
-		} else {
-			$scr->at($l,0)->puts( full_line( chunk($line) ) );
-		}
+	for my $l (0 .. $scr->rows - $status_lines) {
+		my $line = $lines[ $l + $top_screen_line ];
+		redraw_line( $l, $line );
 		last if ($l == $#lines);
 	}
+	selected(0);
 }
 
-# default: select first line
-my $sel_pos = 0;
-my $status_text = '';
-my $error_text = '';
-$pos = 0;
-
 sub status {
 	my $pcnt = int(($pos || 0) * 100 / ($#lines || 1));
 	my $pos_txt = sprintf('%d, %d%% ',$pos,$pcnt);
 	
-	$scr->at($scr->rows - 2,0)->reverse()->puts(
+	$scr->at($scr->rows - $status_lines + 1,0)->reverse()->puts(
 		sprintf(' %-'.($scr->cols - length($pos_txt) - 2).'s ',$status_text)
 	.$pos_txt)->normal();
-	$scr->at($scr->rows - 1,0)->puts(
+	$scr->at($scr->rows - $status_lines + 2,0)->puts(
 		sprintf('%-'.$scr->cols.'s', $error_text)
 	);
 }
 
 sub selected {
-	my $d = shift || return;
+	my $d = shift || 0;
 
-	if ( $selectable_line->{ $pos } ) {
-		$scr->at($pos-$o,0)->bold()->puts( chunk($lines[$pos]) )->normal();
-	} else {
-		$scr->at($pos-$o,0)->puts( chunk($lines[$pos]) )->normal();
-	}
-	$pos += $d;
+	my $screen_line = $pos - $top_screen_line;
 
-	my $max_row = $scr->rows - 3;
+	redraw_line( $screen_line, $lines[$pos] );
 
-	if ($pos < 1) {
-		$error_text = "Already at Begin.";
-		$pos = 0;
+	my $last_screen_line = $scr->rows - $status_lines;
+
+	if ( $d < 0 && $screen_line == 0 ) {
+		if ( $pos > 0 ) {
+			$top_screen_line--;
+			$pos--;
+		} else {
+			$error_text = "Already at Begin.";
+		}
 		redraw;
-	} elsif ($pos > $max_row) {
-		$o = $pos - $max_row;	# put selected line on last
-		$error_text = "Already at End.";
+	} elsif ( $d > 0 && $screen_line == $last_screen_line ) {
+		if ( $pos < $#lines ) {
+			$top_screen_line++;
+			$pos++;
+		} else {
+			$error_text = "Already at End.";
+		}
 		redraw;
+	} else {
+		$pos += $d;
 	}
 
-	$scr->at($pos-$o,0)->reverse()->puts(chunk($lines[$pos]))->normal();
+	my $line = $lines[$pos];
+	if ( defined $selectable_line->{ $pos } ) {
+		$scr->at($pos - $top_screen_line,0)->reverse->bold()->puts( full_line( chunk($line) ) )->normal();
+		$sel_pos = $pos;
+	} else {
+		$scr->at($pos - $top_screen_line,0)->reverse->puts( full_line( chunk($line) ) );
+		$sel_pos = -1;
+	}
 	status;
 }
 
-$status_text = "let's see does it work?";
+$scr = new Term::Screen || die "can't init Term::Screen";
+$scr->clrscr()->noecho();
 redraw;
 selected;
 
 while(my $key = $scr->getch()) {
 
-	$status_text = "key: $key pos: $pos sel_pos: $sel_pos";
 	$error_text = "";
 
+	my $lines_on_screen = $scr->rows - $status_lines;
+
 	if ($key eq 'ku') {
 		selected( -1 );
 	} elsif ($key eq 'kd') {
 		selected( +1 );
+	} elsif ($key eq 'pgup' ) {
+		# first line on screen?
+		if ( $pos == $top_screen_line ) {
+			$top_screen_line -= $lines_on_screen;
+			$top_screen_line = 0 if $top_screen_line < 0;
+			redraw;
+		}
+		selected( -( $pos - $top_screen_line ) );
+	} elsif ($key eq 'pgdn' ) {
+		# last line on screen?
+		if ( $pos - $top_screen_line == $lines_on_screen ) {
+			$top_screen_line += $lines_on_screen;
+			$top_screen_line = $#lines - $lines_on_screen if $top_screen_line >= $#lines - $lines_on_screen;
+			redraw;
+		}
+		selected( $top_screen_line + $lines_on_screen - $pos );
+	}
+
+	$status_text = sprintf("pos: %-3d sel_pos: %-3d top_screen_line: %-3d", $pos, $sel_pos, $top_screen_line );
+	if ( length($key) > 1 ) {
+		$status_text .= " key: $key";
+	} else {
+		$status_text .= sprintf("key: %s [%03d][%02x]", $key =~ m/\w/ ? $key : '?' , ord($key), ord($key) );
 	}
 
 	status;
 
+	# CTRL+L
+	redraw if ord($key) eq 0x0c;
+
 	exit if (lc($key) eq 'q');
 }