# 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 the ld symlink"
MAINTAINER="Martin Matouš <m@matous.dev>"
VERSION="1.0.0"

BIN_DIR="${EROOT%/}/usr/bin"

find_targets() {
	local linker
	# get all ld.* files
	for linker in "${BIN_DIR}/"ld.*; do
		[[ -f ${linker} ]] && basename "${linker}"
	done
}

remove_symlink() {
	[[ ! -e "${BIN_DIR}/ld" ]] && return
	[[ -L "${BIN_DIR}/ld" ]] || die -q "${BIN_DIR}/ld is not a symlink!"
	rm -f "${BIN_DIR}/ld"
}

set_symlink() {
	local target="$1"
	if is_number "${target}"; then
		local -r targets=( $(find_targets) )
		[[ ${target} -ge 1 && ${target} -le ${#targets[@]} ]] \
			|| die -q "Number out of range: $1"
		target=${targets[target-1]}
	elif [[ ! "$target" == "ld."* ]]; then
		target="ld.$target"
	fi

	if [[ ! -L "${BIN_DIR}/${target}" ]]; then
		die -q "Target \"${1}\" (${BIN_DIR}/${target}) doesn't appear to be valid!"
	fi

	remove_symlink || die -q "Couldn't remove existing symlink"
	ln -s "${target}" "${BIN_DIR}/ld"
}

### show action ###

describe_show() {
	echo "Show the current linker symlink"
}

do_show() {
	write_list_start "Current linker symlink:"
	if [[ -L "${BIN_DIR}/ld" ]]; then
		# "dereference" only 1 layer od symlinking, unlike readlink/canonicalize
		local -r linker=$(find "${BIN_DIR}/ld" -printf %l)
		write_kv_list_entry "${linker}" ""
	else
		write_kv_list_entry "(unset)" ""
	fi
}

### list action ###

describe_list() {
	echo "List available linkers"
}

do_list() {
	local i
	local targets=( $(find_targets) )

	write_list_start "Available linker symlink targets:"
	for (( i = 0; i < ${#targets[@]}; i++ )); do
		[[ ${targets[i]} = $(find "${BIN_DIR}/ld" -printf %l) ]] \
			&& targets[i]=$(highlight_marker "${targets[i]}")
	done
	write_numbered_list -m "(none found)" "${targets[@]}"
}

### set action ###

describe_set() {
	echo "Set a new linker symlink target"
}

describe_set_parameters() {
	echo "<target>"
}

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

do_set() {
	local -r linker="$1"
	[[ -z "$linker" ]] && die -q "You didn't tell me what to set the symlink to"
	[[ $# -gt 1 ]] && die -q "Too many parameters"
	set_symlink "$linker" || die -q "Couldn't set a new symlink"
}