#!/bin/bash


# Most of the code taken from 
# https://unix.stackexchange.com/questions/48860/how-to-dump-the-icon-of-a-running-x-program


SIZE=16
COLOR="#00000000"

wid="$2"
# wid="$(xdotool selectwindow)"
# class="$(bspc query -T -n "$wid" | jq -r '.client.className')"
WM_CLASS="$(xprop -id "$wid" WM_CLASS | awk '{print $4}' | tr -d '"')"

name="$WM_CLASS"


CACHE="$1/$name"

if [ -f "$CACHE.jpg" ]; then
    exit 0
fi


# Check if there is an icon for us in xprop, 
# so it won't break the behavior of the script 
if [ -z "$(xprop -id "$wid" | grep "Icon")" ]; then
    exit 0
fi


# Resize it in advance, so icons will look better, but it's not necessary, so
# you can remove "-resize" flag if you prefer it the other way
cmd=(convert -resize "$SIZE"x"$SIZE" -set 'filename:w' '%w' - "${name}.png")

split_icons() {
    xprop -id "$wid" -notype 32c _NET_WM_ICON |
    awk -v RS=', | = ' '
        NR == 1         { h  = $1; i++; next }
        NR == i + 1     { x  = $1;        printf "%s = %s", h, x; next }
        NR == i + 2     { s  = x * $1 } { printf ", %s", $1 }
        NR == i + 2 + s { i += s + 2;     printf "\n" }
    '
}

to_pam() {
    perl -0777 -pe '@_=/\d+/g;
    printf "P7\nWIDTH %d\nHEIGHT %d\n", splice@_,0,2;
    printf "DEPTH 4\nMAXVAL 255\nTUPLTYPE RGB_ALPHA\nENDHDR\n";
    $_=pack "N*", @_;
    s/(.)(...)/$2$1/gs'
}



while read -r data; do to_pam <<< "$data" | "${cmd[@]}"; done < <(split_icons)

convert "$name.png" -background $COLOR -flatten -alpha off "$name.jpg"
mv "$name.jpg" "$CACHE.jpg" && rm "$name.png"