From 14b917b5779e350a10db2397ff4da788a0945dcc Mon Sep 17 00:00:00 2001
From: Sean Whitton <spwhitton@spwhitton.name>
Date: Sun, 14 Jan 2024 19:38:39 +0000
Subject: i3status-wrapper: improve & simplify normalising the number of cols

---
 scripts/desktop/i3status-wrapper | 206 +++++++++++++++++++--------------------
 1 file changed, 101 insertions(+), 105 deletions(-)

diff --git a/scripts/desktop/i3status-wrapper b/scripts/desktop/i3status-wrapper
index 7b6087b4..7fe552a9 100755
--- a/scripts/desktop/i3status-wrapper
+++ b/scripts/desktop/i3status-wrapper
@@ -71,37 +71,31 @@ unless (fork // warn "couldn't fork monitoring loop") {
 	$wmipc->cmd(map("[con_id=$_] move container workspace current", @old_ids),
 		    "focus child");
     }
-    update_paper_ws_cols();
-
-    # Now loop forever reading events, assuming no exceptions.
-
-    sub new_container {
-	# New window on one of our monitored workspaces.
-	# Push a window off the workspace to accommodate new one.
-	# Leave it to a later loop iteration to update the focus.
-	my $ws = $info{paper_ws}{$info{focused_ws}};
-	my $cols = $ws->{cols};
-	if ($ws->{cols}->@*) {
-	    my $i = first { $cols->[$_] == $ws->{focused_col} } 0..$#$cols;
-	    splice $cols->@*, $i+1, 0, shift->{container}{id};
-	    if ($ws->{monocle} || $cols->@* > $ws->{ncols}) {
-		with_ignored_events {
-		    my $pushed = shift $cols->@*;
-		    $wmipc->cmd(hide_con($pushed));
-		    push $ws->{off_left}->@*, $pushed;
-		};
+    my @trees = $wmipc->get_tree;
+    while (@trees) {
+	foreach my $node ((shift @trees)->{nodes}->@*) {
+	    if ($node->{type} eq "workspace"
+		&& grep $_ eq $node->{name}, @all_workspaces) {
+		my $entry = $info{paper_ws}{$node->{id}}
+		  //= { off_left => [], off_right => [] };
+		sync_cols($node => $entry);
+		$entry->{ncols} = max 2, scalar $entry->{cols}->@*;
+	    } elsif (grep $_ eq "caffeinated", $node->{marks}->@*) {
+		register_caffeinated($node);
 	    }
-	} else {
-	    push $ws->{cols}->@*, shift->{container}{id};
+	    unshift @trees, $node;
 	}
     }
+
+    # Now loop forever reading events, assuming no exceptions.
+
     eval {
 	while (my $e = <$events>) {
 	    state $last_e;
 
 	    # New containers
 	    if ($last_e && $last_e->{change} && $last_e->{change} eq "new") {
-		new_container($last_e)
+		normalise_ws_cols()
 		  unless $e->{change} && $e->{change} eq "floating";
 		undef $last_e;
 	    } elsif ($e->{change} && $e->{change} eq "new"
@@ -113,67 +107,24 @@ unless (fork // warn "couldn't fork monitoring loop") {
 		     && $e->{change} eq "floating"
 		     && $e->{container}{type} ne "floating_con") {
 		# A container stopped floating -- it's as though it's new.
-		new_container($e);
-		$info{paper_ws}{$info{focused_ws}}{focused_col}
-		  = $e->{container}{id};
-	    }
-
-	    # Closing containers
-	    elsif (($e->{change} && $e->{change} eq "close"
-		    || $e->{change} && $e->{change} eq "floating"
-		    && $e->{container}{type} eq "floating_con")
-		   && exists $info{paper_ws}{$info{focused_ws}}) {
-		# We just drop the column here.  When the focus change event
-		# comes in, that part of the loop is responsible for pulling
-		# in another container as a replacement, if necessary.
-		my $cols = $info{paper_ws}{$info{focused_ws}}{cols};
-		my $i = first { $cols->[$_] == $e->{container}{id} }
-		  0..$#$cols;
-		splice $cols->@*, $i, 1;
+		normalise_ws_cols();
 	    }
 
 	    # Other container changes
-	    elsif ($e->{change} && $e->{change} eq "focus"
-		   && $e->{container} && $e->{container}{type} eq "con"
-		   && exists $info{paper_ws}{$info{focused_ws}}
-		   && !$info{paper_ws}{$info{focused_ws}}{monocle}) {
-		# Change of window focus on one of our monitored workspaces.
-		# Update which column we think is focused.
-		my $ws = $info{paper_ws}{$info{focused_ws}};
-		$ws->{focused_col} = $e->{container}{id};
-
-		# If the change of focus was triggered by a container closing,
-		# we might need to pull in a container.
-		if ($ws->{ncols} > $ws->{cols}->@*
-		    && ($ws->{off_left}->@* || $ws->{off_right}->@*)) {
-		    my $cols = $ws->{cols};
-		    my $i = first { $cols->[$_] eq $e->{container}{id} }
-		      0..$#$cols;
-		    my $mid_i = floor @$cols/2;
-		    if ($ws->{off_left}->@*
-			&& ($i < $mid_i || !$ws->{off_right}->@*)) {
-			with_ignored_events {
-			    my $pulled = pop $ws->{off_left}->@*;
-			    $wmipc->cmd(("focus left")x$i,
-					show_con($pulled), "move left",
-					("focus right")x$i);
-			    unshift @$cols, $pulled;
-			    $ws->{focused_col} = $cols->[$i];
-			};
-		    } elsif ($ws->{off_right}->@*
-			     && ($i >= $mid_i || !$ws->{off_left}->@*)) {
-			with_ignored_events {
-			    my $j = $#$cols - $i;
-			    my $pulled = pop $ws->{off_right}->@*;
-			    $wmipc->cmd(("focus right")x$j,
-					show_con($pulled), ("focus left")x$j);
-			    push @$cols, $pulled;
-			    $ws->{focused_col} = $cols->[$i+1];
-			};
-		    }
-		}
-	    } elsif ($e->{change} && $e->{change} eq "move") {
-		update_paper_ws_cols();
+	    elsif ($e->{change} && exists $info{paper_ws}{$info{focused_ws}}
+		   && ($e->{change} eq "close"
+		       || $e->{change} eq "focus"
+		       && $e->{container} && $e->{container}{type} eq "con"
+		       || $e->{change} eq "floating"
+		       && $e->{container}{type} eq "floating_con")) {
+		# Generally we seek to update $info{paper_ws} with the
+		# information we receive by subscription, but in some cases we
+		# can't be sure of what has happened.
+		# For example, as we don't maintain a representation of the
+		# whole tree, on a change=move event, we don't know where the
+		# container has gone.  Or a focus change might be due to a new
+		# container, in which case we might need to push one off.
+		normalise_ws_cols();
 	    }
 
 	    # Ticks
@@ -190,6 +141,10 @@ unless (fork // warn "couldn't fork monitoring loop") {
 	    # Workspace changes
 	    elsif ($e->{change} && $e->{change} eq "focus" && $e->{current}) {
 		$info{focused_ws} = $e->{current}{id};
+		# Must normalise in case containers have moved to or from here
+		# in our absence.
+		normalise_ws_cols()
+		  if exists $info{paper_ws}{$info{focused_ws}};
 	    } elsif ($e->{change} && $e->{change} eq "init" && $e->{current}
 		     && grep $_ eq $e->{current}{name}, @all_workspaces) {
 		$info{paper_ws}{$e->{current}{id}}
@@ -338,36 +293,77 @@ sub clear_caffeinated {
     kill USR1 => $i3status;
 }
 
-sub update_paper_ws_cols {
-    my @trees = $wmipc->get_tree;
-    while (@trees) {
-	foreach my $node ((shift @trees)->{nodes}->@*) {
-	    if ($node->{type} eq "workspace"
-		&& grep $_ eq $node->{name}, @all_workspaces) {
-		my $entry = $info{paper_ws}{$node->{id}}
-		  //= { off_left => [], off_right => [] };
+sub sync_cols {
+    my ($node, $entry) = @_;
 
-		# Here we assume that the containers for the columns are
-		# directly below the type=workspace node.  That won't be true
-		# if workspace_layout is not configured to 'default'.
-		foreach my $child_id ($node->{focus}->@*) {
-		    my $child_node
-		      = first { $_->{id} == $child_id } $node->{nodes}->@*;
-		    $entry->{focused_col} = $child_id, last
-		      if $child_node->{type} eq "con";
-		}
+    # Here we assume that the containers for the columns are directly below
+    # the type=workspace node.  That won't be true if workspace_layout is not
+    # configured to 'default'.
+    foreach my $child_id ($node->{focus}->@*) {
+	my $child_node = first { $_->{id} == $child_id } $node->{nodes}->@*;
+	$entry->{focused_col} = $child_id, last
+	  if $child_node->{type} eq "con";
+    }
+    $entry->{cols} = [];
+    foreach my $child_node ($node->{nodes}->@*) {
+	push $entry->{cols}->@*, $child_node->{id}
+	  if $child_node->{type} eq "con";
+    }
+}
 
-		$entry->{cols} = [];
-		foreach my $child_node ($node->{nodes}->@*) {
-		    push $entry->{cols}->@*, $child_node->{id}
-		      if $child_node->{type} eq "con";
+sub normalise_ws_cols {
+    my $ws = $info{paper_ws}{$info{focused_ws}};
+    my $floating_focus;
+    my @trees = $wmipc->get_tree;
+    while (@trees) {
+	for ((shift @trees)->{nodes}->@*) {
+	    if ($_->{id} == $info{focused_ws}) {
+		sync_cols($_ => $ws);
+		my $first_focus = $_->{focus}->[0];
+		$floating_focus = ! grep $_ == $first_focus, $ws->{cols}->@*;
+		last;
+	    }
+	    unshift @trees, $_
+	}
+    }
+    my $cols = $ws->{cols};
+    with_ignored_events {
+	$wmipc->cmd("focus tiling");
+	while (1) {
+	    my $i = first { $cols->[$_] eq $ws->{focused_col} } 0..$#$cols;
+	    my $mid_i = floor @$cols/2;
+	    # Pull column in if there are too few columns but some available.
+	    if ($ws->{ncols} > @$cols
+		&& ($ws->{off_left}->@* || $ws->{off_right}->@*)) {
+		if ($ws->{off_left}->@*
+		    && ($i < $mid_i || !$ws->{off_right}->@*)) {
+		    my $pulled = pop $ws->{off_left}->@*;
+		    $wmipc->cmd(("focus left")x$i,
+				show_con($pulled), "move left",
+				("focus right")x$i);
+		    unshift @$cols, $pulled;
+		    $ws->{focused_col} = $cols->[$i];
+		} elsif ($ws->{off_right}->@*
+			 && ($i >= $mid_i || !$ws->{off_left}->@*)) {
+		    my $j = $#$cols - $i;
+		    my $pulled = pop $ws->{off_right}->@*;
+		    $wmipc->cmd(("focus right")x$j,
+				show_con($pulled), ("focus left")x$j);
+		    push @$cols, $pulled;
+		    $ws->{focused_col} = $cols->[$i+1];
 		}
-		$entry->{ncols} = max 2, scalar $entry->{cols}->@*;
-	    } elsif (grep $_ eq "caffeinated", $node->{marks}->@*) {
-		register_caffeinated($node);
 	    }
-	    unshift @trees, $node;
+	    # Push a column off if there are too many columns.
+	    elsif (@$cols > $ws->{ncols}) {
+		my $pushed = $i < $mid_i ? pop @$cols : shift @$cols;
+		$wmipc->cmd(hide_con($pushed));
+		push $ws->{$i < $mid_i ? "off_right" : "off_left"}->@*,
+		  $pushed;
+	    }
+	    # Number of columns is correct.
+	    else { last }
 	}
+	$wmipc->cmd("focus floating") if $floating_focus;
     }
 }
 
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