# -*-eselect-*-  vim: ft=eselect
# Copyright 1999-2024 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

inherit config

DESCRIPTION="Manage D symlinks"
MAINTAINER="marco.leise@gmx.de"
VERSION="20241230"

ETC_PATH="${EROOT}/etc"
COMPILER_PATH="${EROOT}/usr/bin"
MAN1_PATH="${EROOT}/usr/share/man/man1"
MAN5_PATH="${EROOT}/usr/share/man/man5"
INC_PATH="${EROOT}/usr/include/dlang"
CONFIG_FILE="${EROOT}/var/lib/dlang"
declare -A COMPILER_NAMES=([dmd]="Digital Mars D (dmd)"
                           [ldc2]="LLVM D2 (ldc2)")


### list action ###

describe_list() {
	echo "List installed D compilers by vendor (or all installed compilers)"
}

describe_list_options() {
	for compiler in ${!COMPILER_NAMES[@]}; do
		printf "% -11s : List installed %s compilers\n" $compiler "${COMPILER_NAMES[$compiler]}"
	done
}

describe_list_parameters() {
	echo "[<vendor>]"
}

do_list() {
	[[ $# -eq 1 ]] && has "$1" ${!COMPILER_NAMES[@]} || [[ $# -eq 0 ]] \
		|| die -q "Syntax: eselect dlang list [$(compiler_options)]"

	for compiler in ${!COMPILER_NAMES[@]}; do
		if [[ $# -eq 0 ]] || [[ $compiler == $1 ]]; then
			write_list_start "Available ${COMPILER_NAMES[$compiler]} compilers:"
			local targets=($(find_targets $compiler))
			local active="$(do_show $compiler)"
			local mode="$(load_config "$CONFIG_FILE" $compiler)"
			for ((i = 0; i < ${#targets[@]}; i++)); do
				if [[ "${targets[$i]}" == "$active" ]]; then
					if [[ "${mode:-auto}" == "auto" ]]; then
						targets[$i]="$(highlight_marker "${targets[$i]}" auto)"
					else
						targets[$i]="$(highlight_marker "${targets[$i]}" manual)"
					fi
				fi
			done
			write_numbered_list -m "(none found)" "${targets[@]}"
			echo
		fi
	done
}


### set action ###

describe_set() {
	echo "Set active version of D compilers"
}

describe_set_options() {
	for compiler in ${!COMPILER_NAMES[@]}; do
		printf "% -11s : Set active %s compiler\n" $compiler "${COMPILER_NAMES[$compiler]}"
	done
}

describe_set_parameters() {
	echo "<vendor>"
}

do_set() {
	[[ $# -eq 2 ]] && has "$1" ${!COMPILER_NAMES[@]} \
		|| die -q "2 arguments required: eselect dlang set $(compiler_options) <version|index|\"auto\">"

	local targets=($(find_targets $1))
	local target="$2"
	if [[ "$target" == "auto" ]]; then
		local autoTarget="${targets[$((${#targets[@]} - 1))]}"
		if [[ -n "${targets[$(($target - 1))]}" ]]; then
			target="$autoTarget"
		fi
	elif is_number "$2" && [[ $2 -ge 1 ]]; then
		local idxToTarget="${targets[$(($target - 1))]}"
		if [[ -n "${targets[$(($target - 1))]}" ]]; then
			target="$idxToTarget"
		fi
	fi

	has "$target" "${targets[@]}" || die -q "Invalid or unavailable target"
	if [[ "$2" == "auto" ]]; then
		echo -n "Switching $1 to always latest version, currently $target..."
	else
		echo -n "Switching $1 to $target..."
	fi

	case $1 in
		dmd)
			clean_dmd_symlinks
			symlink_helper "/usr/lib/dmd/${target}/bin/dmd"      "${COMPILER_PATH}/dmd"
			symlink_helper "/usr/lib/dmd/${target}/bin/dmd.conf" "${ETC_PATH}/dmd.conf"
			symlink_helper "/usr/lib/dmd/${target}/import"       "${INC_PATH}/dmd"
			[[ -d ${MAN1_PATH} ]] && symlink_helper "/usr/lib/dmd/${target}/man/man1/dmd.1"      "${MAN1_PATH}/dmd.1"
			[[ -d ${MAN5_PATH} ]] && symlink_helper "/usr/lib/dmd/${target}/man/man5/dmd.conf.5" "${MAN5_PATH}/dmd.conf.5"
			;;
		ldc2)
			clean_ldc_symlinks
			# Since ldc2-1.40 the package is split into dev-lang/ldc2 and
			# dev-libs/ldc2-runtime. Because we can't control the order in which
			# they are merged we will try to update as many symlinks as
			# possible.
			symlink_helper "/usr/lib/ldc2/${target}/bin/ldc2" "${COMPILER_PATH}/ldc2"
			symlink_helper "/usr/lib/ldc2/${target}/bin/ldmd2" "${COMPILER_PATH}/ldmd2"
			symlink_helper "/usr/lib/ldc2/${target}/include/d" "${INC_PATH}/ldc"
			symlink_helper "/usr/lib/ldc2/${target}/etc/ldc2.conf" "${ETC_PATH}/ldc2.conf"
			symlink_helper "/usr/lib/ldc2/${target}/usr/share/bash-completion/completions/ldc2" "${EROOT}/usr/share/bash-completion/completions/ldc2"

			# Added in LDC 1.32.0 (2023-03-12)
			symlink_helper "/usr/lib/ldc2/${target}/bin/timetrace2txt" "${COMPILER_PATH}/timetrace2txt"
			;;
	esac
	store_config "$CONFIG_FILE" $1 "$2"

	echo " done"
}

clean_dmd_symlinks() {
	rm -f "${COMPILER_PATH}/dmd"
	rm -f "${ETC_PATH}/dmd.conf"
	rm -f "${INC_PATH}/dmd"
	rm -f "${MAN1_PATH}/dmd.1"
	rm -f "${MAN5_PATH}/dmd.conf.5"
}

clean_ldc_symlinks() {
	# Keep in sync with do_set
	rm -f "${COMPILER_PATH}/ldc2"
	rm -f "${COMPILER_PATH}/ldmd2"
	rm -f "${INC_PATH}/ldc"
	rm -f "${ETC_PATH}/ldc2.conf"
	rm -f "${EROOT}/usr/share/bash-completion/completions/ldc2"
	rm -f "${COMPILER_PATH}/timetrace2txt"
}

### show action ###

describe_show() {
	echo "Show active D compiler by vendor"
}

describe_show_options() {
	for compiler in ${!COMPILER_NAMES[@]}; do
		printf "% -11s : Show active %s compiler\n" $compiler "${COMPILER_NAMES[$compiler]}"
	done
}

describe_show_parameters() {
	echo "<vendor>"
}

do_show() {
	[[ $# -eq 1 ]] && has "$1" ${!COMPILER_NAMES[@]} \
		|| die -q "1 argument required: eselect dlang show $(compiler_options)"

	local interpreter
	case "${1}" in
		dmd)
			get_dmd_interpreter
			;;
		ldc2)
			get_ldc_interpreter
			;;
		*)
			die -q "Unknown compiler: '${1}'"
			;;
	esac

	[[ -n "$interpreter" ]] && echo "$interpreter"
}


### update action ###

describe_update() {
	echo "Update active D compilers to the latest installed version in absense of a manually set version"
}

describe_update_options() {
	for compiler in ${!COMPILER_NAMES[@]}; do
		printf "% -11s : Update active %s compiler\n" $compiler "${COMPILER_NAMES[$compiler]}"
	done
}

describe_update_parameters() {
	echo "<vendor>"
}

do_update() {
	[[ $# -eq 1 ]] && has "$1" ${!COMPILER_NAMES[@]} \
		|| die -q "1 argument required: eselect dlang update $(compiler_options)"

	local targets=($(find_targets $1))
	if [[ ${#targets[@]} -eq 0 ]]; then
		# No compiler available, remove symlinks
		echo "No installed ${COMPILER_NAMES[$1]} compilers. Removing any existing symlinks."
		case $1 in
			# Keep this in sync with `do_set`
			dmd)
				clean_dmd_symlinks
				;;
			ldc2)
				clean_ldc_symlinks
				;;
		esac
	else
		# Check if the active compiler is actually available, update otherwise
		local compiler=$1
		local active="$(do_show $compiler)"
		local latest="${targets[$((${#targets[@]} - 1))]}"
		local mode="$(load_config "$CONFIG_FILE" $compiler)"
		: "${mode:=auto}"
		if [[ "$active" == "" ]]; then
			# First installation of a compiler
			do_set $compiler auto
		elif ! has "$active" "${targets[@]}"; then
			# Active compiler is no longer valid (uninstalled), switch to "auto"
			echo "Switching $1 from uninstalled version '$active' to '$latest'"
			do_set $compiler auto
		elif [[ "${mode}" == "auto" ]] && [[ "$active" != "$latest" ]]; then
			# Active compiler was set to auto and we have a more recent version
			echo "Updating active $1 version from '$active' to '$latest'"
			do_set $compiler auto
		else
			# The active compiler is the latest
			if [[ ${compiler} == ldc2 ]]; then
				# It's possible that only one of dev-lang/ldc2 and
				# dev-libs/ldc2-runtime is currently merged => we need
				# to take care of possible broken symlinks.

				local component link expected_file arr=(
					"compiler:${COMPILER_PATH}/ldc2:${EROOT}/usr/lib/ldc2/${active}/bin/ldc2"
					"runtime:${ETC_PATH}/ldc2.conf:${EROOT}/usr/lib/ldc2/${active}/etc/ldc2.conf"
				)
				local x msg=""
				for x in "${arr[@]}"; do
					IFS=: read -r component link expected_file <<<"${x}"
					if [[ -L "${link}" && ! -f "${expected_file}" ]]; then
						msg="Updating active ${compiler} version '${active}' because its ${component} has just been removed"
						break
					fi

					if [[ ! -L "${link}" && -f "${expected_file}" ]]; then
						msg="Updating active ${compiler} version '${active}' because its ${component} has just been merged"
						break
					fi
				done

				if [[ ${msg} ]]; then
					echo "${msg}"
					do_set "${compiler}" "${mode}"
				fi
			fi
		fi
	fi
}


### helper functions ###

# Find a list of D versions
find_targets() {
	local cmd
	case "$1" in
		dmd)
			cmd=(
				find "${EROOT}/usr/lib/dmd"
				-mindepth 1 -maxdepth 1
				# Directories are named after a dmd SLOT like `2.109' or `9999'
				-name "*"
				# check for an actual compiler installation, not an empty folder
				-exec test -x "{}/bin/dmd" \;
				# Output one directory per line
				-printf '%f\n'
			)
			;;
		ldc2)
			cmd=(
				find "${EROOT}/usr/lib/ldc2"
				-mindepth 1 -maxdepth 1
				# Find directories with the format `1.39' or `9999'
				-name "*"
				# Check for the existence of either dev-lang/ldc2
				# or dev-libs/ldc2-runtime.
				"-(" -exec test -x "{}/bin/ldc2" \;
				     -o -exec test -f "{}/etc/ldc2.conf" \;
				"-)"
				-printf '%f\n'
			)
			;;
		*)
			die "Unknown compiler '$1'"
	esac

	"${cmd[@]}" 2> /dev/null | LC_ALL=C sort -t. -k2 -g
}

# Creates a symlink or prints a message and quits on error
symlink_helper() {
	[[ -e ${EROOT}/${1} ]] || return
	local link="$(canonicalise "${EROOT}/$1")"
	ln -nfs "$link" "$2" || die -q "Couldn't symlink '$link' as '$2'!"
}

# Prints compilers as argument options <comp1|comp2|...>
compiler_options() {
	local additional=0
	echo -n "<"
	for compiler in ${!COMPILER_NAMES[@]}; do
		[[ $additional -eq 1 ]] && echo -n "|"
		echo -n $compiler
		additional=1
	done
	echo -n ">"
}

# Get the SLOT of a D compiler path
# The paths are expected to belong under /usr/lib/dmd or /usr/lib/ldc2
get_slot_from_path() {
	local path="${1}"
	if [[ ${path} =~ ^"${EROOT}"/usr/lib/(dmd|ldc2)/([^/]*)/ ]]; then
		echo "${BASH_REMATCH[2]}"
	fi
}

# Get the SLOT of the eselect'ed dmd
get_dmd_interpreter() {
	interpreter=$(get_slot_from_path "$(readlink "${COMPILER_PATH}/dmd")")
}

# Get the SLOT of the eselect'ed ldc2
get_ldc_interpreter() {
	local try
	# A link created by dev-lang/ldc2 or dev-libs/ldc2-runtime
	for try in "${COMPILER_PATH}"/ldc2 "${ETC_PATH}"/ldc2.conf; do
		if [[ -L ${try} ]]; then
			interpreter=$(get_slot_from_path "$(readlink "${try}")")
			return
		fi
	done
}