# Copyright 1999-2017 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Id: $

inherit config multilib

DESCRIPTION="Manage active PostgreSQL client applications and libraries"
MAINTAINER="pgsql-bugs@gentoo.org"
VERSION="2.0"

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

# This list of files/directories are the symbolic link targets that need to be
# created when a slot is set.
#
# If you change this list, remember to change include_sources in do_set. And,
# they must be listed in the same order.
INCLUDE_TARGETS=(
	"${USR_PATH}"/include/postgresql
	"${USR_PATH}"/include/libpq-fe.h
	"${USR_PATH}"/include/pg_config_ext.h
	"${USR_PATH}"/include/pg_config_manual.h
	"${USR_PATH}"/include/libpq
	"${USR_PATH}"/include/postgres_ext.h
)

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

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

### Finder Function ###
# Takes two arguments:
#   - Absolute path to directory to search
#   - Pattern to search for
finder() {
	local source_dir=$1
	local pattern=$2

	# Prevent passed patterns from being globbed
	# If this module is run in /usr, '-name lib*' ends up globbing 'lib*',
	# passing to 'find' the pattern '-name lib lib32 lib64' and find interprets
	# those as path arguments causing failure.
	set -f
	find -L "${source_dir}" -maxdepth 1 -mindepth 1 ${pattern}
	set +f
}

### Linker Function ###
# Takes four arguments:
#   - Full source path (e.g. /usr/lib/postgresql-9.0/lib)
#   - Pattern to search for
#   - Full target directory path (e.g. /usr/bin)
#   - Suffix (Optional) (e.g 84 to make /usr/bin/psql84)
linker() {
	local source_dir=$1
	local pattern=$2
	local target_dir=$3
	local suffix=$4
	local link_source
	local findings
	local rel_source

	findings=$(finder "${source_dir}" "${pattern}")

	for link_source in ${findings} ; do
		local link_target="${target_dir%/}/$(basename ${link_source})${suffix}"

		# For good measure, remove target before creating the symlink
		[[ -h ${link_target} ]] && rm -f "${link_target}"
		[[ -e ${link_target} ]] && \
			die -q "The target '${link_target}' still exists and could not be removed!"

		# Create relative links so that they work both here and inside the new
		# root if $ROOT is not "/".
		rel_source=$(relative_name "${link_source}" "${target_dir}")
		ln -s "${rel_source}" "${link_target}" || die -q "Unable to create link!"
	done
}

### 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}/$(lib_dir)/" \
					   -mindepth 1 -maxdepth 1 -type d -name 'postgresql-*' | \
						 sed -re 's#.*([1-9][0-9.]+)$#\1#' | sort -n)
	do
		# Check that pg_config exists for this slot, otherwise we have
		# a false positive.
		[[ -x "${USR_PATH}/$(lib_dir)/postgresql-${slot}/bin/pg_config" ]] && \
			found_slots+=( ${slot} )
	done

	echo ${found_slots[@]}
}

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

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

		local provider
		local slot
		local bindir
		for slot in $(get_slots) ; do
			bindir="${USR_PATH}/$(lib_dir)/postgresql-${slot}/bin"

			# The output of `pg_config --version` also includes "PostgreSQL" in
			# the string, which is a bit redundant.
			provider=$("${bindir}"/pg_config --version | \
							  sed 's/[^0-9]*\(.*\)/\1/')

			# Unless a file exists that's controlled by the 'server' use flag,
			# report that it's client only.
			[[ -e "${bindir}/postmaster" ]] || provider+=' (Clients Only)'

			case "${slot}" in
				"$(active_slot)" )
					write_kv_list_entry \
						"$(highlight_marker ${slot})" "${provider}";;
				* )
					write_kv_list_entry "${slot}" "${provider}";;
			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)
}

### Show Service Action ###
# Here for backwards compatibility with ebuilds
describe_show-service()  {
	echo "Deprecated. For ebuild use; returns no useful information."
}

do_show-service() {
	echo 1
}

### Set Action ###
describe_set() {
	echo "Create symbolic links for PostgreSQL libraries and applications."
}

do_set() {
	local slot=$1

	if [[ ! -d ${USR_PATH}/$(lib_dir)/postgresql-${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 "Setting ${slot} as the default..."

	echo -ne "\tGenerating new links..."
	# Sources for header files
	# Targets are listed in the global variable INCLUDE_TARGETS.
	#
	# If you change this list, you must change the INCLUDE_TARGETS list,
	# too. And, they must be listed in the same order.
	local include_sources=(
		"${USR_PATH}"/include/postgresql-${slot}
		"${USR_PATH}"/include/postgresql-${slot}/libpq-fe.h
		"${USR_PATH}"/include/postgresql-${slot}/pg_config_ext.h
		"${USR_PATH}"/include/postgresql-${slot}/pg_config_manual.h
		"${USR_PATH}"/include/postgresql-${slot}/libpq
		"${USR_PATH}"/include/postgresql-${slot}/postgres_ext.h
	)

	# The linker function cannot accommodate this special purpose.
	local rel_source
	local i
	for (( i=0; $i < ${#include_sources[@]}; i++ )) ; do
		# Some headers are present only in specific versions of PostgreSQL
		[[ -e ${include_sources[$i]} ]] || continue

		# Create relative links so that they work both here and inside a new
		# root if $ROOT is not "/"
		rel_source=$(relative_name "${include_sources[$i]}" "$(dirname "${INCLUDE_TARGETS[$i]}")")

		ln -s "$rel_source" "${INCLUDE_TARGETS[$i]}" || \
			die -q "Unable to create link! $rel_source -> ${INCLUDE_TARGETS[$i]}"
	done

	# Link modules to /usr/lib{,32,64}/
	local x
	for x in $(list_libdirs) ; do
		if [[ -d "${USR_PATH}/${x}/postgresql-${slot}/${x}" ]] ; then
			# 'linker' function doesn't work for linking directories.
			# Default lib path - create a relative link
			ln -s "postgresql-${slot}/${x}" "${USR_PATH}/${x}/postgresql"

			# Linker works for files
			linker "${USR_PATH}/${x}/postgresql-${slot}/${x}/" \
				"-name lib*" "${USR_PATH}/${x}"
		fi
	done

	# Link binaries to /usr/bin/
	linker "${USR_PATH}/$(lib_dir)/postgresql-${slot}/bin/" \
		"" "${USR_PATH}/bin"

	# Link pkg-config metadata files
	linker "${USR_PATH}/$(lib_dir)/postgresql-${slot}/$(lib_dir)/pkgconfig/" \
		"" "${USR_PATH}/share/pkgconfig/"

	# Link man pages
	local mandir mansec
	for mandir in "${USR_PATH}"/share/postgresql-${slot}/man/man{1,3,7} ; do
		mansec=$(basename "${mandir}")
		linker "${mandir}" "" "${USR_PATH}/share/man/${mansec}"
	done

	# Default share path - use a relative link here by just specifying the
	# base name
	ln -s "postgresql-${slot}" "${USR_PATH}/share/postgresql"

	echo "done."
	echo "Setting ${slot} as default was successful!"
}

### 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

	# Start with some known locations that are, or will contain, symlinks.
	local paths=(
		"${INCLUDE_TARGETS[@]}"
		"${USR_PATH}"/share/man/man{1,3,7}
		"${USR_PATH}/share/postgresql"
		"${USR_PATH}/bin"
		"${USR_PATH}/share/pkgconfig"
	)

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

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

		# If path is a real directory, symlinks need to be found within it.
		for l in $(find "${path}" -mindepth 1 -maxdepth 1 -type l) ; do
			# Skip the slot specific links in /usr/bin (e.g., psql96) as they're
			# managed by their ebuilds
			[[ ${l} == ${USR_PATH}/bin/*${slot/.} ]] && continue

			# Get the file path that the link is pointing to. If it has the
			# string "postgresql-${slot}" somewhere in it, then it's a link that
			# needs to be removed.
			if [[ $(canonicalise "${l}") == *postgresql-${slot}* ]] ; then
				rm "${l}" || write_warning_msg "Couldn't remove: ${l}"
			fi
		done
	done
}

### Reset Action ###
describe_reset() {
	echo "Recreate symbolic links for currently active slot."
}

do_reset() {
	local slot=$(active_slot)
	[[ ${slot} == "(none)" ]] && die -q "No active slot to reset."
	do_unset ${slot}
	do_set ${slot}
}

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

do_update() {
	## ANTIQUITY CLEAN UP ##
	#
	# Older versions of this module generated state and environment files of
	# some sort or another. They're useless now and are just a waste of space.

	# Environment files that have been generated by older ebuilds and
	# previous versions of this module serve no purpose now.
	rm -f "${EROOT%/}"/etc/env.d/50postgresql*

	local etc_path="${EROOT%/}/etc/eselect/postgresql"
	if [[ -d ${etc_path} ]] ; then
		# Remove some files outright as they're entirely useless now.
		#   ${etc_path}/active: Contents was the active slot (e.g.,
		#       9.5), or it was a symlink to another file that was then
		#       canonicalised and parsed to get the active slot
		#   ${etc_path}/service: Told the initscript which slot to
		#       start. We now have separate scripts for each slot
		#   ${etc_path}/active.links*: Contained a list of symlinks
		#       created. We now search the known directories for the
		#       symlinks as only this module manage them.
		local f
		for f in "${etc_path}"/active* "${etc_path}/service" ; do
			if [[ -e "${f}" ]] ; then
				rm "${f}" || write_warning_msg "Can't remove: '${f}'"
			fi
		done

		local unused_files
		unused_file=( $(find "${etc_path}" -type f -not -name '.keep*') )
		if [[ -n "${unused_file[@]}" ]] ; then
			write_warning_msg "You have unused files that should be removed:"
			for f in ${unused_file[@]} ; do
				write_warning_msg $f
			done
		else
			echo "It should be safe for you to remove '${etc_path}'"
		fi
	fi
	## End Antiquity Clean Up

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

	if [[ ${slots[@]} =~ ${active_slot} ]] ; then
		# If active_slot is in the slots list, do a reset as the installation
		# may have changed.
		do_reset
	elif [[ ${#slots[@]} -ne 0 ]] ; then
		# If $slots is not empty but ${active_slot} is set, the active_slot
		# must have been unmerged and its links need to be cleaned before...
		[[ ${active_slot} != "(none)" ]] && do_unset ${active_slot}

		# Setting 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
}