#!/bin/bash
#
#   Author:         Twily                                                     2015
#   Description:    Cut window in half and spawn a terminal in its remaining space
#   Requires:       wmctrl, xdotool, xwininfo, urxvt
#   Usage:          $ sh ./split.grid {H,V,Q,<none>}
#                       (See below for keybind alternative.
#                        Keybinds can be set in your WM)
#

ACT=$(xdotool getactivewindow)

G=24                # Gap between windows
D=0                 # Decoration height
M=0                 # Border width

let M=$M*2
if [ "$D" -gt "0" ]; then D=$(( $D + ( $M / 2 ) )); fi

function getAct {
    unset X Y W H
    eval $(xwininfo -id $ACT | 
        sed -n -e "s/^ \+Absolute upper-left X: \+\([0-9]\+\).*/X=\1/p" \
               -e "s/^ \+Absolute upper-left Y: \+\([0-9]\+\).*/Y=\1/p" \
               -e "s/^ \+Width: \+\([0-9]\+\).*/W=\1/p" \
               -e "s/^ \+Height: \+\([0-9]\+\).*/H=\1/p" )

        X=$(( $X - ( $M / 2 ) ))
        Y=$(( $Y - ( $M / 2 ) - $D ))
}
getAct

function splitH {
    # Spawn below
    aH=$(( $H / 2 - ( $G / 2 ) - ( $M / 2 ) - $D ))

    wmctrl -i -r $ACT -e 0,$X,$Y,$W,$aH

    Y=$(( $Y + $aH + $G + $D + $M ))
    H=$(( $H - $aH - $G - $D - $M ))
}

function splitV {
    # Spawn right
    aW=$(( $W / 2 - ( $G / 2 ) - $M ))

    wmctrl -i -r $ACT -e 0,$X,$Y,$aW,$H

    X=$(( $X + $aW + $G + $M ))
    W=$(( $W - $aW - $G - $M ))
}

quad=false                                                  # [Keybind alternative]
case $1 in
    'H') splitH                                             # [W-A-h]
         ;;
    'V') splitV                                             # [W-A-v]
         ;;
    'Q') splitH && quad=true                                # [W-A-b]
         ;;
      *) if [ "$W" -gt "$H" ]; then splitV; else splitH; fi # [W-s]
         ;;
esac

urxvt -g "1x1+"$X"+"$Y &

function relocate {
    for i in {0..49}; do # timeout
        if ps -p $! >/dev/null; then
            sleep .1

            wmctrl -r :ACTIVE: -e 0,$X,$Y,$W,$H
            break
        fi
    done
}
relocate

if $quad; then
    TMP=$(xdotool getactivewindow)
    getAct
    splitV

    urxvt -g "1x1+"$X"+"$Y &
    relocate

    ACT=$TMP
    getAct
    splitV

    urxvt -g "1x1+"$X"+"$Y &
    relocate
fi

exit 0