#!/bin/bash

LAYOUTS_DIR="$HOME/.screenlayout"


_die() {
    echo "$0: $1" >&2
    exit $2
}

test -d "$LAYOUTS_DIR" || (mkdir "$LAYOUTS_DIR" && touch "$LAYOUTS_DIR/default.sh")


die_if_invalid_path() {
    if [[ "$1" =~ ".." ]]; then
        die "Path can\`t contains '..'" 3
    fi

    if [[ "$1" = /* ]]; then
        die "Path can\`t start from '/'" 3
    fi
}


cmd_list() {
    ls "$LAYOUTS_DIR"
}

cmd_edit() {
    die_if_invalid_path "$1"
    $EDITOR "$LAYOUTS_DIR/$1.sh"
    chmod u+x "$LAYOUTS_DIR/$1.sh"
}

cmd_wallpaper() {
    local wallpapers="$HOME/.wallpaper"
    feh --no-fehbg --bg-scale "$wallpapers/$(ls "$wallpapers" | shuf -n 1)"
}

cmd_load() {
    if [ -z "$1" ]; then
        "$LAYOUTS_DIR/default.sh"
    else
        "$LAYOUTS_DIR/$1.sh"
    fi
    cmd_wallpaper
}

cmd_help () {
    echo "slm (ls|add|load|wallpaper)" >&2
}


case "$1" in
    ls) shift;         cmd_list       "$@" ;;
    add|edit) shift;   cmd_edit       "$@" ;;
    load) shift;       cmd_load       "$@" ;;
    wallpaper) shift;  cmd_wallpaper  "$@" ;;
    *) shift;          cmd_help       "$@" ;;
esac
exit 0