#!/bin/sh
#description: control keyboard layouts
#usage: shift-keyboard-layout
#change keyboard layout to the next configured one

default_layouts="latam,us,ru" #see /usr/share/X11/xkb/rules/base.lst
progname="$(expr "${0}" : '.*/\([^/]*\)')"

_str2lower() {
    [ -z "${1}" ] && return 1
    printf "%s\\n" "${@}" | tr 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' 'abcdefghijklmnopqrstuvwxyz'
}

_notify() {
    [ -z "${1}" ] && return 1
    if [ X"${TERM}" = X"linux" ] || [ -z "${TERM}" ]; then
        kill -9 $(pgrep notify-osd) >/dev/null 2>&1
        if ! DISPLAY=:0 notify-send -t 1000 "${1}"  "${2}"; then
            if command -v "gxmessage" 2>/dev/null; then
                font="Monaco 9"
                gxmessage "${font:+-fn "$font"}" "${1} ${2}" "ok"
            else
                font="fixed"
                xmessage "${font:+-fn "$font"}" "${1} ${2}" "ok"
            fi
        fi
    else
        if [ -z "${2}" ]; then
            printf "%s\\n" "${1}"
        else
            printf "%s: %s" "${1}" "${2}"; printf "\\n"
        fi
    fi
}

_return_valid_layouts() {
    [ -z "${1}" ] && { printf "%s" "${default_layouts}"; return; } || _return_valid_layouts__arg="${1}"
    _return_valid_layouts__reference=$(awk '/! layout/,/! variant/ {if ($0 !~ "^$" && $1 !~ "!") print $1}' /usr/share/X11/xkb/rules/base.lst 2>&1)
    _return_valid_layouts__arg="$(_str2lower "${_return_valid_layouts__arg}")"
    _return_valid_layouts__arg="$(printf "%s" "${_return_valid_layouts__arg}" | sed 's: :,:g')"
    _return_valid_layouts__cp="${_return_valid_layouts__arg}"

    while [ "${_return_valid_layouts__arg}" ]; do
        _return_valid_layouts__option="${_return_valid_layouts__arg%%,*}"
        if [ -z "$(printf "%s" "${_return_valid_layouts__reference}" | grep "${_return_valid_layouts__option}")" ]; then
             printf "%s" "${default_layouts}"; return;
        fi
        [ X"${_return_valid_layouts__arg}" = X"${_return_valid_layouts__option}" ] \
            && _return_valid_layouts__arg="" \
            || _return_valid_layouts__arg="${_return_valid_layouts__arg#*,}"
    done
     printf "%s" "${_return_valid_layouts__cp}"; return;
}

if [ ! -t 0 ]; then
    #there is input comming from pipe or file, add to the end of $@
    set -- "${@}" $(cat)
fi

for arg; do #parse options
    case "${arg}" in
        --) shift; break ;;
        -h|--help) {
            printf "Usage: %b\\n" "${progname}\\nChange keyboard layout (see minos-config)."
            exit; } ;;
        -*) printf "%s\\n" "${progname}: unrecognized option '${arg}'" >&2
            printf "Usage: %b\\n" "${progname}\\nChange keyboard layout (see minos-config)." >&2
            exit 1
            ;;
    esac
done

if ! command -v "setxkbmap" >/dev/null; then
    _notify "Error" "install setxkbmap to run this program"
fi

current_layout="$(setxkbmap -query | awk '/layout/ {print $2}')"
layouts="$(minos-config keyboard-layouts 2>/dev/null)"
[ -z "${layouts}" ] && layouts="${default_layouts}" || layouts="$(_return_valid_layouts "${layouts}")"
d_layouts="${layouts}"
c_layouts="${layouts}"
c="0";d="0"

while [ "${d_layouts}" ]; do
    option="${d_layouts%%,*}"
    d="$((${d} + 1))"
    [ X"${d_layouts}" = X"${option}" ] && d_layouts="" || d_layouts="${d_layouts#*,}"
done

while [ "${c_layouts}" ]; do #in what position is the current_layout with respect to the array?
    option="${c_layouts%%,*}"
    c="$((${c} + 1))"
    [ X"${current_layout}" = X"${option}" ] && break
    [ X"${c_layouts}" = X"${option}" ] && c_layouts="" || c_layouts="${c_layouts#*,}"
done

[ -z "${c_layouts}" ] && exit 1 #invalid layout format

e="$((${c} + 1))"
[ "${d}" -eq "${c}" ] && e="1" #return to first element if we're in the last item

c="0"; while [ "${layouts}" ]; do #set next keyboard layout
    option="${layouts%%,*}"
    c="$((${c} + 1))"
    if [ "${c}" -eq "${e}" ]; then
        setxkbmap "${option}"
        _notify "Keyboard layout: $(printf "%s\\n" "${option}" | \
            tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')"
    fi
    [ X"${layouts}" = X"${option}" ] && layouts="" || layouts="${layouts#*,}"
done