# Copyright (C) 2022 Martin Matouš

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

DESCRIPTION="Manage XDG autostart applications"
MAINTAINER="Martin Matouš <m@matous.dev>"
VERSION="1.0.0"

AUTOSTART_DIR="${XDG_CONFIG_HOME%/}/autostart"

get_entry_dirs() {
	echo "${XDG_DATA_HOME%/}/applications"
	local xdg_data
	IFS=':' read -ra xdg_data <<< "${XDG_DATA_DIRS}"
	for dir in "${xdg_data[@]}"; do
		echo "${dir%/}/applications"
	done
}

find_targets() {
	mapfile -t entry_dirs < <(get_entry_dirs)
	local dir
	for dir in "${entry_dirs[@]}"; do
		for desktop_file in "${dir%/}"/*.desktop; do
			[[ -f ${desktop_file} ]] && echo "${desktop_file}"
		done
	done
}

remove_symlink() {
	if [[ ! -L "${symlink}" ]]; then
		die -q "${symlink} does not exist or is not a symlink!"
	fi
	rm -f "${symlink}"
}

### list action ###

is_enabled() {
	local -r entry="${1}"
	mapfile -t autostarted_list < <(find "${AUTOSTART_DIR}" -type l)
	local autostarted
	IFS=""
	for autostarted in ${autostarted_list[@]}; do
	 	autostarted="$(canonicalise "${autostarted}")"
	 	[[ "${entry}" = "${autostarted}" ]] && return 0
	done
	return 1
}

describe_list() {
	echo "List available XDG .desktop files"
}

do_list() {
	local i
	mapfile -t targets < <(find_targets)
	if [[ ! -d ${AUTOSTART_DIR} ]]; then
		write_warning_msg "Autostart dir not found. Maybe you are running eselect autostart as root?"
	fi

	write_list_start "Available autostart symlink targets:"
	for (( i = 0; i < ${#targets[@]}; i++ )); do
		is_enabled "${targets[i]}" && targets[i]=$(highlight_marker "${targets[i]}")
	done
	write_numbered_list -m "(none found)" "${targets[@]}"
}

### enable action ###

describe_enable() {
	echo "Enable specified XDG .desktop file(s)"
}

describe_enable_parameters() {
	echo "<target>"
}

describe_enable_options() {
	echo "<target> : Target name or number (from 'list' action)"
}

deduce_path() {
	mapfile -t entry_dirs < <(get_entry_dirs)
	local dir
	local -r entry_relative_path="${1}"
	for dir in "${entry_dirs[@]}"; do
		if [[ -f ${dir%/}/${entry_relative_path} ]]; then
			echo "${dir%/}/${entry_relative_path}"
		fi
	done
}

activate_entry() {
	local entry=${1}
	shift
	local -r targets=("${@}")

	if is_number "${entry}"; then
		[[ ${entry} -ge 1 && ${entry} -le ${#targets[@]} ]] \
			|| die -q "Number out of range: ${entry}"
		entry=${targets[entry-1]}
	fi

	if [[ ! "${entry}" == *".desktop" ]]; then
		entry="${entry}.desktop"
	fi

	# if only file specified (no / in arg)
	if [[ ! "${entry}" == *"/"* ]]; then
		entry=$(deduce_path "${entry}")
	fi

	if [[ ! -f ${entry} ]]; then
		write_error_msg "Entry ${entry} doesn't exist!"
		return
	fi

	local -r symlink="${AUTOSTART_DIR}/$(basename "${entry}")"
	# entry with that name is already activated
	if [[ -L ${symlink} ]]; then
		local -r active=$(find "${symlink}" -printf %l)
		if [[ "${active}" = "${entry}" ]]; then
			write_warning_msg "${active} is already activated"
			return
		else
			remove_symlink "${symlink}" \
				|| die -q "Couldn't deactivate previous entry"
		fi
		return
	fi

	ln -s "${entry}" "${symlink}" || \
		write_error_msg "Failed to create symlink '${symlink}' -> '${entry}'"
}

do_enable() {
	[[ -z ${1} ]] && die -q "You didn't specify any .desktop file to enable"

	# create directory if necessary
	if [[ ! -d ${AUTOSTART_DIR} ]]; then
		mkdir -p "${AUTOSTART_DIR}" || die -q "Failed to create ${AUTOSTART_DIR}"
	fi

	# make sure we have proper permissions
	if [[ ! -w ${AUTOSTART_DIR} ]]; then
		die -q "You don't have permission to write to ${AUTOSTART_DIR}"
	fi

	mapfile -t targets < <(find_targets)
	for entry in "$@"; do
		activate_entry "${entry}" "${targets[@]}"
	done
}

### disable action ###

describe_disable() {
	echo "Disable specified XDG .desktop file(s)"
}

describe_disable_parameters() {
	echo "<target>"
}

describe_disable_options() {
	echo "<target> : Target name or number (from 'list' action)"
}


do_disable() {
	[[ -z ${1} ]] && die -q "You didn't specify any XDG .desktop files to disable"

	local symlink_name symlink entry
	mapfile -t targets < <(find_targets)
	for entry in "$@"; do
		if is_number "${entry}"; then
			[[ ${entry} -ge 1 && ${entry} -le ${#targets[@]} ]] \
				|| die -q "Number out of range: ${entry}"
			entry="${targets[entry-1]}"
		fi

		if [[ ! "${entry}" == *".desktop" ]]; then
			entry="${entry}.desktop"
		fi

		symlink_name=$(basename "${entry}")
 		symlink="${AUTOSTART_DIR}/${symlink_name}"
		remove_symlink "${symlink}"
	done
}