# -*-eselect-*-  vim: ft=eselect
# Copyright 1999-2020 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

DESCRIPTION="Manage /usr/bin/vi implementations"
MAINTAINER="vim@gentoo.org"
VERSION="1.2"

# find a list of vi symlink targets, best first
find_targets() {
	local f
	for f in \
			"${EROOT}"/usr/bin/vim \
			"${EROOT}"/usr/bin/nvim \
			"${EROOT}"/usr/bin/nvi \
			"${EROOT}"/usr/bin/elvis \
			"${EROOT}"/usr/bin/vile \
			"${EROOT}"/usr/bin/gvim \
			"${EROOT}"/usr/bin/qvim \
			"${EROOT}"/usr/bin/xvile \
			"${EROOT}"/usr/bin/vis \
			"${EROOT}"/usr/bin/pyvim \
			"${EROOT}"/bin/busybox \
		; do
		if [[ -f "${f}" ]] ; then
			echo $(basename "${f}" )
		fi
	done
}

# try to remove the vi, ex, view and man vi symlinks
remove_symlinks() {
	rm -f "${EROOT}"/usr/bin/{vi,ex,view} &>/dev/null && \
	rm -f "${EROOT}"/usr/share/man/man1/{vi,ex,view}.1{,.Z,.gz,.bz2,.lzma,.lz,.lzo,.lz4,.xz,.zst} &> /dev/null
}

# set a man page symlink
set_man_symlink() {
	local target="${1}" link_name="${2}" x extension

	for x in '' .Z .gz .bz2 .lzma .lz .lzo .lz4 .xz .zst; do
		if [[ -e ${EROOT}/usr/share/man/man1/${target}.1${x} ]]; then
			extension=".1${x}"
			break
		fi
	done

	if [[ -z "${extension}" ]]; then
		echo "Couldn't find a man page for ${target}; skipping." 1>&2
		return 1
	fi

	ln -s "${target}${extension}" \
		"${EROOT}/usr/share/man/man1/${link_name}${extension}"
}

# set the vi, ex, view, and man vi symlinks
set_symlinks() {
	local target="${1}" targets
	if is_number "${target}" && [[ ${target} -ge 1 ]]; then
		targets=( $(find_targets ) )
		target=${targets[target-1]}
	fi

	local dir
	if [[ ${target} == "busybox" ]]; then
		dir="${EROOT}/bin"
	else
		dir="${EROOT}/usr/bin"
	fi

	if [[ -f "${dir}/${target}" ]] ; then
		remove_symlinks

		# it's okay if these fail
		set_man_symlink "${target}" "vi"
		set_man_symlink "${target}" "ex"
		set_man_symlink "${target}" "view"

		# it's not okay if these fail
		target=$(relative_name "${dir}/${target}" "${EROOT}/usr/bin")
		ln -s "${target}" "${EROOT}/usr/bin/vi" \
			|| die "Couldn't set ${target} /usr/bin/vi symlink"
		ln -s "${target}" "${EROOT}/usr/bin/ex" \
			|| die "Couldn't set ${target} /usr/bin/ex symlink"
		ln -s "${target}" "${EROOT}/usr/bin/view" \
			|| die "Couldn't set ${target} /usr/bin/view symlink"
	else
		die -q  "Target \"${1}\" doesn't appear to be valid!"
	fi
}

### show action ###

describe_show() {
	echo "Show the current vi implementation"
}

do_show() {
	[[ -z "${@}" ]] || die -q "Too many parameters"

	write_list_start "Current vi implementation:"
	if [[ -L "${EROOT}/usr/bin/vi" ]] ; then
		write_kv_list_entry "$(basename $(canonicalise ${EROOT}/usr/bin/vi ) )" ""
	elif [[ -e "${EROOT}/usr/bin/vi" ]] ; then
		write_kv_list_entry "(not a symlink)" ""
	else
		write_kv_list_entry "(unset)" ""
	fi
}

### list action ###

describe_list() {
	echo "List available vi implementations"
}

do_list() {
	[[ -z "${@}" ]] || die -q "Too many parameters"

	local i targets
	targets=( $(find_targets ) )
	for (( i = 0; i < ${#targets[@]}; i++ )); do
		[[ ${targets[i]} = \
			$(basename "$(canonicalise "${EROOT}/usr/bin/vi")") ]] \
			&& targets[i]=$(highlight_marker "${targets[i]}")
	done
	write_list_start "Available vi implementations:"
	write_numbered_list -m "(none found)" "${targets[@]}"
}

### set action ###

describe_set() {
	echo "Set a new vi implementation provider"
}

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

describe_set_parameters() {
	echo "<target>"
}

do_set() {
	if [[ -z "${1}" ]] ; then
		die -q "You didn't give me a provider name"

	elif [[ -n "${2}" ]] ; then
		die -q "Too many parameters"

	elif [[ -L "${EROOT}/usr/bin/vi" ]] ; then
		if ! remove_symlinks ; then
			die -q "Can't remove existing provider"
		elif ! set_symlinks "${1}" ; then
			die -q "Can't set new provider"
		fi

	elif [[ -e "${EROOT}/usr/bin/vi" ]] ; then
		die -q "Sorry, ${EROOT}/usr/bin/vi confuses me"

	else
		set_symlinks "${1}" || die -q "Can't set a new provider"
	fi
}

### update action ###

describe_update() {
	echo "Automatically update the vi provider"
}

describe_update_options() {
	echo "--if-unset : Do not override existing implementation"
}

do_update() {
	[[ -z "${1}" ]] || ( [[ -z "${2}" ]] && [[ "${1}" == "--if-unset" ]] ) || \
		die -q "Usage error"

	if [[ -L "${EROOT}/usr/bin/vi" ]]; then
		[[ ${1} == "--if-unset" ]] && return
		remove_symlinks || die -q "Can't remove existing link"
	fi
	if [[ -e "${EROOT}/usr/bin/vi" ]]; then
		die -q "Can't set a new provider"
	elif ! [[ -z $(find_targets ) ]]; then
		set_symlinks 1 || die -q "Can't set a new provider"
	fi
}