#!/usr/bin/env bash

# i3-get-window-criteria - Get criteria for use with i3 config commands

# To use, run this script, then click on a window.
# Output is in the format: [<name>=<value> <name>=<value> ...]

# Known problem: when WM_NAME is used as fallback for the 'title="<string>"' criterion,
# quotes in "<string>" are not escaped properly. This is a problem with the output of `xprop`,
# reported upstream: https://bugs.freedesktop.org/show_bug.cgi?id=66807

match_int='[0-9][0-9]*'
match_string='".*"'
match_qstring='"[^"\\]*(\\.[^"\\]*)*"' # NOTE: Adds 1 backreference

{
    # Run xwininfo, get window id
    window_id=$(xwininfo -int | sed -nre "s/^xwininfo: Window id: ($match_int) .*$/\1/p")
    echo "id=$window_id"

    # Run xprop, transform its output into i3 criteria. Handle fallback to
    # WM_NAME when _NET_WM_NAME isn't set
    xprop -id "$window_id" |
        sed -nr \
            -e "s/^WM_CLASS\(STRING\) = ($match_qstring), ($match_qstring)$/instance=\1\nclass=\3/p" \
            -e "s/^WM_WINDOW_ROLE\(STRING\) = ($match_qstring)$/window_role=\1/p" \
            -e "/^WM_NAME\(STRING\) = ($match_string)$/ {s//title=\1/; h}" \
            -e "/^_NET_WM_NAME\(UTF8_STRING\) = ($match_qstring)$/ {s//title=\1/; h}" \
            -e '$ {g; p}'
} | sort | tr "\n" " " | sed -r 's/^ *(.*) $/[\1]\n/'