# Copyright 1999-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
# Based on postgresql.eselect

inherit config multilib

DESCRIPTION="Utility to select the default Electron slot"
VERSION="0.2"

# We do a lot of things in /usr and it's a bit of a pain to write this
# constantly.
USR_PATH="${EROOT%/}/usr"

active_slot() {
    # ${USR_PATH}/bin/electron is a symlink to the active
    # slot. See if it's there, then find out where it links to.
	if [[ -h "${USR_PATH}/bin/electron" ]] ; then
		canonicalise -m "${USR_PATH}/bin/electron" | \
			sed -re 's#.*-([1-9][0-9]?)/electron$#\1#'
	else
		echo "(none)"
	fi
}

lib_dir() {
	local lib_list=$(list_libdirs)
	if [[ ${lib_list} =~ .*lib64.* && \
		-n $(ls -d ${USR_PATH}/lib64/electron-* 2> /dev/null) ]] ; then
		echo "lib64"
	elif [[ ${lib_list} =~ .*lib32.* && \
		-n $(ls -d ${USR_PATH}/lib32/electron-* 2> /dev/null) ]] ; then
		echo "lib32"
	elif [[ ${lib_list} =~ .*libx32.* && \
		-n $(ls -d ${USR_PATH}/libx32/electron-* 2> /dev/null) ]] ; then
		echo "libx32"
	else
		echo "lib"
	fi
}

### Get Slots Function ###
# Find all available slots in the preferred lib_dir() and return them.
get_slots() {
	local slot
	local found_slots

	for slot in $(find "${USR_PATH}/$(lib_dir)/" \
					   -mindepth 1 -maxdepth 1 -type d -name 'electron-*' | \
						 sed -re 's#.*-([1-9][0-9]?)$#\1#' | sort -n)
	do
		found_slots+=( ${slot} )
	done

	echo ${found_slots[@]}
}

### List Action ###
describe_list() {
	echo "List available Electron slots."
}

do_list() {
	if $(is_output_mode brief) ; then
		echo $(get_slots)
	else
		write_list_start "Available Electron slots"

		local slot
		for slot in $(get_slots) ; do
			case "${slot}" in
				"$(active_slot)" )
					write_kv_list_entry \
						"$(highlight_marker ${slot})";;
				* )
					write_kv_list_entry "${slot}";;
			esac
		done

		[[ -z "$(get_slots)" ]] && write_warning_msg "No slots available."
	fi
}

### Show Action ###
describe_show() {
	echo "Show which slot is currently active."
}

do_show() {
	echo $(active_slot)
}

### Set Action ###
describe_set() {
	echo "Create symbolic link for Electron."
}

do_set() {
	local slot=$1

	if [[ ! -d ${USR_PATH}/$(lib_dir)/electron-${slot} ]] ; then
		die -q "Not a valid slot."
	fi

	# If there's an active slot, unset that one first
	local active_slot=$(active_slot)
	if [[ "${active_slot}" != "(none)" ]] ; then
		echo -ne "Unsetting ${active_slot} as default..."
		do_unset ${active_slot}
		echo "done."
	fi

	echo -ne "Setting ${slot} as the default..."

	# Link modules to /usr/lib{,32,64}/
	local x
	for x in $(list_libdirs) ; do
		if [[ -d "${USR_PATH}/${x}/electron-${slot}" ]] ; then
			ln -sf "${USR_PATH}/${x}/electron-${slot}" "${USR_PATH}/${x}/electron" || \
				die -q "SYMLINK FAILED: ${USR_PATH}/${x}/electron-${slot} -> ${USR_PATH}/${x}/electron"
		fi
	done

	# Link binaries to /usr/bin/
	if [[ -f "${USR_PATH}/bin/electron-${slot}" ]] ; then
	        ln -sf "${USR_PATH}/bin/electron-${slot}" "${USR_PATH}/bin/electron" || \
			die -q "SYMLINK FAILED: ${USR_PATH}/bin/electron-${slot} -> ${USR_PATH}/bin/electron"
	else
		die -q "${USR_PATH}/bin/electron-${slot} does not exist"
	fi

	echo "success!"
}

### Unset Action ###
describe_unset() {
	echo "Remove symbolic links."
}

# Undo everything done by do_set().
do_unset() {
	local slot=$1
	if [[ ${slot} != $(active_slot) ]] ; then
		echo "Slot already inactive; no work to do."
		return 0
	fi

	# Get the file path that the link is pointing to. If it has the string
	# "electron-${slot}" somewhere in it, then it's a link that this module is
	# handling.
	is_active_slot_link() {
		if [[ $(canonicalise -m "$1") == *electron-${slot}* ]] ; then
			return 0 # yes
		else
			return 1 # no
		fi
    }

	# Start with some known locations that are, or will contain, symlinks.
	local paths=(
		"${USR_PATH}/bin/electron"
	)

	local lib
	for lib in $(list_libdirs) ; do
		# If $libdir is a symlink, it will point to a real lib directory that
		# will be or has been added in this loop.
		[[ -h "${USR_PATH}/${lib}" ]] && continue

		# If the $libdir/electron symlink exists, then there are certainly
		# others within that same directory that must be cleaned up.
		if [[ -h "${USR_PATH}/${lib}/electron" ]] ; then
			paths+=( "${USR_PATH}/${lib}/electron" )
		fi
	done

	local l path
	for path in "${paths[@]}" ; do
		# If $path is a link that belongs to the active slot, it can be removed
		# without invoking find.
		if [[ -h "${path}" ]] && is_active_slot_link "${path}" ; then
			rm "${path}" || write_warning_msg "Couldn't remove: ${path}"
			continue
		fi
	done
}

### Update Action ###
describe_update() {
	echo "Refreshes all symbolic links managed by this module"
}

do_update() {
	local active_slot=$(active_slot)
	local slots=($(get_slots))

	if [[ ${slots[@]} =~ ${active_slot} ]] ; then
		# If active_slot is in the slots list, set it again as the installation
		# may have changed.
		do_set ${active_slot}
	elif [[ ${#slots[@]} -ne 0 ]] ; then
		# If $slots is not empty and active_slot is not in the list, set the
		# highest slot available.
		do_set ${slots[-1]}
	elif [[ ${active_slot} != "(none)" ]] ; then
		# If slots is empty, but active_slot still has a value, an unset must
		# happen as the links are now pointing to nothing.
		do_unset ${active_slot}
	else
		echo "Apparently, I have nothing to do."
	fi
}