# -*-eselect-*-
# Copyright 2005-2014 Gentoo Foundation
# Distributed under the terms of the GNU GPL version 2 or later
#
# DOCUMENTATION
# Following actions possible
# * show		do_show()
# * list		do_list()
# * set			do_set()
# * update		do_update()
#
# Behaviour:
# do_show():
#	Checks if /usr/bin/gnuclient is a link and if the target exists,
#	if yes, it outputs the currently linked gnuclient implementation.
#	If it is no symlink, the user is told so, the same if there is
#	no /usr/bin/gnuclient or the target does not exist.
# do_list(): List all available gnuclient implementations.
# do_set(): Set a version to be target of the symlink.
# do_update(): Set the target to the "best" available version.

DESCRIPTION="Manage /usr/bin/gnuclient implementations"
MAINTAINER="emacs@gentoo.org"
VERSION="1.17"

BINARYLIST="gnuclient gnudoit gnuattach"
MANPAGELIST="gnuclient gnudoit gnuattach gnuserv"

find_targets() {
	# Return the list of available gnuclient implementations
	local j
	for j in gnuclient-{emacs,xemacs}; do
		[[ -f ${EROOT}/usr/bin/${j} ]] && echo ${j}
	done
}

remove_symlinks() {
	# Remove existing symlinks to binaries and man pages
	local f
	for f in ${BINARYLIST}; do
		rm -f "${EROOT}/usr/bin/${f}"
	done
	for f in ${MANPAGELIST}; do
		rm -f "${EROOT}"/usr/share/man/man1/${f}.1*
	done
}

set_bin_symlinks() {
	# Set symlinks to binaries
	local target=${1#gnuclient-} f
	for f in ${BINARYLIST}; do
		# set symlink only if target binary actually exists
		if [[ -f ${EROOT}/usr/bin/${f}-${target} ]]; then
			ln -s "${f}-${target}" "${EROOT}/usr/bin/${f}" || die \
				"Couldn't set ${f}-${target} ${EROOT}/usr/bin/${f} symlink"
		fi
	done
}

set_man_symlinks() {
	# Set symlinks to man pages
	local target=${1#gnuclient-} suffix f i
	for f in ${MANPAGELIST}; do
		for i in "${EROOT}/usr/share/man/man1/${f}-${target}.1"*; do
			if [[ -f ${i} ]]; then
				# target file exists; determine compression suffix
				suffix=${i##*/"${f}-${target}.1"}
				ln -s "${f}-${target}.1${suffix}" \
					"${EROOT}/usr/share/man/man1/${f}.1${suffix}"
			fi
		done
	done
}

set_symlinks() {
	# Set symlinks to binaries and man pages
	local target=$1 targets
	# target may be specified by its name or its index
	if is_number "${target}"; then
		# numeric index, find the target's name
		targets=( $(find_targets) )
		[[ ${target} -ge 1 && ${target} -le ${#targets[@]} ]] \
			|| die -q "Number out of range: $1"
		target=${targets[target-1]}
	fi

	# is the target valid, i.e. does a gnuclient binary with this name exist?
	[[ -f ${EROOT}/usr/bin/${target} ]] \
		|| die -q "Target \"$1\" doesn't appear to be valid!"

	echo "Switching gnuclient to ${target} ..."
	remove_symlinks || die -q "Couldn't remove existing symlink"
	set_bin_symlinks "${target}"
	set_man_symlinks "${target}"
	return 0
}

test_for_root() {
	# checks if the user has rights to modify /usr/bin/
	[[ -w ${EROOT}/usr/bin ]] || die -q "You need root privileges!"
}

### show action ###

describe_show() {
	echo "Show the current target of the gnuclient symlink"
}

do_show() {
	[[ $# -gt 0 ]] && die -q "Too many parameters"

	write_list_start "Current target of gnuclient symlink:"
	if [[ -L ${EROOT}/usr/bin/gnuclient && -e ${EROOT}/usr/bin/gnuclient ]]
	then
		write_kv_list_entry \
			"$(basename "$(readlink "${EROOT}/usr/bin/gnuclient")")" ""
	elif [[ -e ${EROOT}/usr/bin/gnuclient ]]; then
		write_kv_list_entry \
			"(not a symlink or target of symlink does not exist)" ""
	else
		write_kv_list_entry "(unset)" ""
	fi
}

### list action ###

describe_list() {
	echo "List available gnuclient symlink targets"
}

do_list() {
	[[ $# -gt 0 ]] && die -q "Too many parameters"

	local i targets
	targets=( $(find_targets) )

	for (( i = 0; i < ${#targets[@]}; i++ )); do
		# Highlight the currently chosen version
		[[ ${targets[i]} = \
			"$(basename "$(readlink "${EROOT}/usr/bin/gnuclient")")" ]] \
			&& targets[i]=$(highlight_marker "${targets[i]}")
	done
	write_list_start "Available gnuclient symlink targets:"
	write_numbered_list -m "(none found)" "${targets[@]}"
}

### set action ###

describe_set() {
	echo "Set a new gnuclient symlink"
}

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

describe_set_parameters() {
	echo "<target>"
}

do_set() {
	[[ -z $1 ]] && die -q "You didn't tell me what to set the symlink to"
	[[ $# -gt 1 ]] && die -q "Too many parameters"
	test_for_root

	if [[ -e ${EROOT}/usr/bin/gnuclient && ! -L ${EROOT}/usr/bin/gnuclient ]]
	then
		die -q "${EROOT}/usr/bin/gnuclient exists but is not a symlink"
	fi

	set_symlinks "$1" || die -q "Couldn't set a new symlink"
}

### update action ###

describe_update() {
	echo "Automatically update the gnuclient symlink"
}

describe_update_options() {
	echo "ifunset : Do not override currently set version"
}

do_update() {
	[[ -z $1 || $1 = ifunset || $1 = --if-unset ]] || die -q "Usage error"
	[[ $# -gt 1 ]] && die -q "Too many parameters"
	test_for_root

	if [[ -L ${EROOT}/usr/bin/gnuclient ]]; then
		if [[ $1 == *if*unset && -e ${EROOT}/usr/bin/gnuclient ]]; then
			return 0
		fi
		remove_symlinks || die -q "Couldn't remove existing symlink"
	elif [[ -e ${EROOT}/usr/bin/gnuclient ]]; then
		die -q "${EROOT}/usr/bin/gnuclient exists but is not a symlink"
	fi

	local targets=( $(find_targets) )
	if [[ ${#targets[@]} -gt 0 ]]; then
		set_symlinks "${targets[0]}" || die -q "Couldn't set a new symlink"
	fi
}