#!/usr/bin/env bash

# a i3-like scratchpad for arbitrary applications.
#
# this lets a new monitor called "scratchpad" appear in from the top into the
# current monitor. There the "scratchpad" will be shown (it will be created if
# it doesn't exist yet). If the monitor already exists it is scrolled out of
# the screen and removed again.
#
# Warning: this uses much resources because herbstclient is forked for each
# animation step.
#
# If a tag name is supplied, this is used instead of the scratchpad

tag="${1:-scratch}"
hc() { herbstclient "$@"; }

read -r x y w h <<EOF
$(hc monitor_rect)
EOF
rect=$((w/2))x$((h/2))+$((x+w/4))+$((y+h/4))
monitor=scratch

hc add "$tag"
if ! hc add_monitor "$rect" "$tag" $monitor 2>/dev/null; then
    hc substitute M monitors.by-name."$monitor".my_prev_focus \
        and + compare monitors.focus.name = "$monitor" \
            + focus_monitor M
    hc remove_monitor "$monitor"
else
    # remember which monitor was focused previously
    hc chain \
        , new_attr string monitors.by-name."$monitor".my_prev_focus \
        , substitute M monitors.focus.index \
            set_attr monitors.by-name."$monitor".my_prev_focus M
    hc chain , lock , raise_monitor "$monitor" , focus_monitor "$monitor" \
        , unlock , lock_tag "$monitor"
fi