#!/bin/sh
#
# Rotate tiling of windows.
#
# This assumes windows are tiled like so, which is what window-vtile does:
#   +---------+---------+
#   | main    | second  |
#   | window  | window  |
#   | full    +---------+
#   | height  | third   |
#   |         | window  |
#   +---------+---------+
#
# This script will "rotate" the second window to the main window, the main
# window to the third window, and the third window to the main window:
#   +---------+---------+
#   | second  | third   |
#   |         |         |
#   |         +---------+
#   |         | main    |
#   |         |         |
#   +---------+---------+
#
# And pressing it again will rotate it once more in the same direction:
#   +---------+---------+
#   | third   | main    |
#   |         |         |
#   |         +---------+
#   |         | second  |
#   |         |         |
#   +---------+---------+
#
# And a third press will restore the original situation.

set -euC
IFS="
"

border=2
titlebar=16
#border=2
#if [ -f ~/.cwmrc ]; then
#	border=$(( 2 *
#		$( (grep ^borderwidth ~/.cwmrc || echo "1 1") | awk '{print $2}' )
#	))
#fi

# Find the main window by position.
all_windows=$(xdotool search --name --desktop $(xdotool get_desktop) '')
main_window=0
for win in $all_windows; do
	eval $(xdotool getwindowgeometry --shell $win)
	[ $X -le 0 ] && [ $Y -le 0 ] && main_window=$win
done

# No main window found; use the active window.
[ $main_window -eq 0 ] && main_window=$(xdotool getactivewindow)

# Sort all the other windows in an array by Y-position, which means they're the
# same order as on the screen
other_windows=""
for win in $all_windows; do
	[ $win -eq $main_window ] && continue

	eval $(xdotool getwindowgeometry --shell $win)
	other_windows=$(printf "$Y $win\n$other_windows")
done
sorted=$(echo "$other_windows" | sort -n)
other_windows=""
for w in $sorted; do
	other_windows=$(printf "$other_windows\n$(echo "$w" | cut -d ' ' -f 2)")
done
other_windows=$(echo "$other_windows" | tail -n+2)

# Put main window to the bottom of the others.
other_windows=$(printf "$other_windows\n$main_window")

# Top window is new "main" window.
main_window=$(echo "$other_windows" | head -n 1)
other_windows=$(echo "$other_windows" | tail -n+2)

# Now we can set the positions and resize!
n_wins=$(echo "$other_windows" | wc -l)
screen_width=$(xwininfo -root | grep Width | cut -d: -f2 | tr -d ' ')
screen_height=$(xwininfo -root | grep Height | cut -d: -f2 | tr -d ' ')
width=$(( $screen_width / 2 - $border ))
height=$(( $screen_height - $border - $titlebar ))

# Position and size the main window.
xdotool windowmove $main_window 0 0
xdotool windowsize $main_window $width $height

# ... and the other windows.
i=0
for win in $other_windows; do
	xdotool windowmove $win $(( $width + $border )) \
		$(( $height / $n_wins * $i ))
	xdotool windowsize $win $width $(( $height / $n_wins ))
	i=$(( $i + 1 ))
done