#!/usr/bin/env bash

WALLFILE="$HOME/Pictures/wallconfig"
WALLLINK="$HOME/Pictures/current_wall"
BINNAME="setwall"

function unsetwalls() {
	for wall in $@; do
        echo unsetting $wall
        pat=$(echo $wall | sed 's/\//\\\//g')
		sed -i.bak "/$pat/d" $WALLFILE
	done
}
function unsetcur() {
    if [ -f "${WALLLINK}" ]; then
        unsetwalls $(realpath --relative-to=$HOME $WALLLINK)
    else
        echo "could not resolve current wallpaper"
        exit 1
    fi
}
function delete() {
	echo deleting wallfile
	rm $WALLFILE
}
function unsetall() {
	echo clearing wallfile
	echo -n > $WALLFILE
}

function setwalls() {
	for wall in $@; do
		if grep -q $wall "$WALLFILE"; then
			echo $wall already set
		else
			echo setting $wall
			echo $wall >> $WALLFILE
		fi
	done
}

function runsetwall() {
	feh --bg-tile $1
    # wal --saturate 0.9 -i $1
}

function applywall() {
	echo applying wallpaper $1
	rm $WALLLINK
	ln -s $(pwd)/$1 $WALLLINK
	runsetwall $1
}

function reapply() {
	echo reapplying linked wallpaper
	# feh --bg-fill $WALLLINK
    runsetwall $WALLLINK
}

function help() {
	echo "Wallpaper mangement script"
	echo
	echo "Syntax: ${BINNAME} OPTIONS"
	echo "options:"
	echo "  -A, --apply [OPTIONS]           applies a random wallpaper"
	echo "  -S, --set FILES                 sets new wallpapers"
	echo "  -U, --unset [OPTIONS] [FILES]   unsets new wallpapers"
	echo "  -P, --preview FILE              temporarily sets a wallpaper"
	echo "  -h, --help                      this message"
	echo
	echo "unset options:"
	echo "  -a, --all                       clears wallconfig file"
	echo "  -d, --delete                    deleted wallconfig file"
	echo "  -c, --current                   unset currently applied wallpaper"
	echo
	echo "apply options:"
	echo "  -r, --reapply                   reapply last applied wallpaper"
}

function unknown() {
	echo "${BINNAME}: unknown option $1" 1>&2
	exit 1
}

if [[ $# -eq 0 ]]; then
	echo "${BINNAME}: no arguments given" 1>&2
	help
	exit 1
fi

mode="N"
pos=""

while [[ $# -gt 0 ]]; do
	keys="$1"
	# If $1 does is single - argument
	if [[ $1 == '-'* ]] && [[ ! $1 == '--'* ]] ; then
		# Remove first -
		keys=${keys#?}
		# Place space between each character
		keys=$(echo $keys | sed 's/./-& /g')
	fi

	for key in $keys; do
		case $mode in 
			U)
				case $key in
					-a|--all)
						unsetall
						exit 0
						;;
					-d|--delete)
						delete
						exit 0
						;;
                    -c|--current)
                        unsetcur
                        exit 0
                        ;;
					'-'*|'--'*)
						unknown $key
						;;
					*)
						pos="$pos $key"
						shift
						;;
				esac
				;;
			A)
				case $key in
					-r|--reapply)
						reapply
						exit 0
						;;
					'-'*|'--'*)
						unknown $key
						;;
					*)
						echo Unexpected argument
						help
						exit 0
						;;
				esac
				;;
			S)
				pos="$pos $key"
				shift
				;;

			*)
				case $key in
					-A|--apply)
						mode="A"
						shift
						;;
					-U|--unset)
						mode="U"
						shift
						;;
					-S|--set)
						mode="S"
						shift
						;;
					-P|--preview)
						applywall $2
						exit 0
						;;
					-h|--help)
						help
						shift
						exit 0
						;;
					*)
						unknown $key
						;;
				esac
				;;
		esac
	done
done

case $mode in
	U)
		unsetwalls $pos
		;;
	S)
		setwalls $pos
		;;
	A)
		applywall $(shuf -n 1 $WALLFILE)
		;;
esac