Setup Development Environment.bash

#!/usr/bin/env bash
# shellcheck disable=SC2034

## ############ META_PROGRAM_*: Metadata about This Program ###################
### Program's description, default(optional)
declare META_PROGRAM_DESCRIPTION='Setup the environment use to develop the project'

### Years since any fraction of copyright material is activated, indicates the year when copyright protection will be outdated(optional)
declare META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE='2017, 2018'
## ######################## End of META_PROGRAM_* #############################

## META_APPLICATION_*: Metadata about the application this program belongs to
## https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#meta_application_
## You may safely remove this entire section if you don't need it
### The Software Directory Configuration this application uses, refer below section for more info
declare META_APPLICATION_INSTALL_STYLE=SHC
## ####################### End of META_APPLICATION_* ##########################

## META_RUNTIME_DEPENDENCIES: Runtime dependencies information for dependency checking
## You may safely remove this entire section if you don't need it
### Human-friendly runtime dependency name definition
declare -r META_RUNTIME_DEPENDENCIES_DESCRIPTION_GNU_COREUTILS='GNU Coreutils'

### These are the dependencies that the script foundation needs, and needs to be checked IMMEDIATELY
### BASHDOC: Bash Features - Arrays(associative array)
declare -Ar META_RUNTIME_DEPENDENCIES_CRITICAL=(
	[basename]="${META_RUNTIME_DEPENDENCIES_DESCRIPTION_GNU_COREUTILS}"
	[realpath]="${META_RUNTIME_DEPENDENCIES_DESCRIPTION_GNU_COREUTILS}"
)

### These are the dependencies that are used later and also checked later
declare -Ar META_RUNTIME_DEPENDENCIES=(
	["git"]="Git"
	["rm"]="${META_RUNTIME_DEPENDENCIES_DESCRIPTION_GNU_COREUTILS}"
	["ln"]="${META_RUNTIME_DEPENDENCIES_DESCRIPTION_GNU_COREUTILS}"
)
## #################### End of META_RUNTIME_DEPENDENCIES ######################

### Program's Commandline Options Definitions
declare -r COMMANDLINE_OPTION_DISPLAY_HELP_LONG=--help
declare -r COMMANDLINE_OPTION_DISPLAY_HELP_SHORT=-h
declare -r COMMANDLINE_OPTION_DISPLAY_HELP_DESCRIPTION='Display help message'

declare -r COMMANDLINE_OPTION_ENABLE_DEBUGGING_LONG=--debug
declare -r COMMANDLINE_OPTION_ENABLE_DEBUGGING_SHORT=-d
declare -r COMMANDLINE_OPTION_ENABLE_DEBUGGING_DESCRIPTION='Enable debug mode'

## init function: the main program's entry point
## This function is called from the end of this file,
## with the command-line parameters as it's arguments
init() {
	if ! process_commandline_arguments; then
		print_help_message
		exit 1
	fi

	export GIT_DIR="${SHC_PREFIX_DIR}/.git"
	export GIT_WORK_TREE="${SHC_PREFIX_DIR}"
	cd "${GIT_WORK_TREE}"

	printf 'Setting Project-specific Git configuration...'
	git config include.path ../.gitconfig \
		&& printf 'done\n'

	printf 'Fetching submodules...'
	git submodule init \
		'Git Clean and Smudge Filters/Clean Filter for GNU Bash Scripts'
	git submodule update --depth=30
	(
		# It is intended design to make the variable change lost outside subshell
		# shellcheck disable=SC2030
		export GIT_WORK_TREE="${GIT_WORK_TREE}/Git Clean and Smudge Filters/Clean Filter for GNU Bash Scripts"
		# It is intended design to make the variable change lost outside subshell
		# shellcheck disable=SC2030
		export GIT_DIR="${GIT_WORK_TREE}/.git"

		cd "${GIT_WORK_TREE}"
		git submodule init \
			'Code Formatters and Beautifiers/the Bash Script Beautifier'
		git submodule update --depth=30
	)

	printf 'Setting Git Hooks...'
	# It is intended design to make the variable change lost outside subshell
	# shellcheck disable=SC2031
	ln \
		--symbolic \
		--relative \
		--force \
		--verbose \
		"${RUNTIME_EXECUTABLE_DIRECTORY}/pre-commit.bash" \
		"${GIT_DIR}/hooks/pre-commit" \
		&& printf 'done\n' \
		|| printf 'failed\n'

	exit "${COMMON_RESULT_SUCCESS}"
}; declare -fr init

### Print help message whenever:
###   * User requests it
###   * An command syntax error has detected
print_help_message(){
	printf '# %s #\n' "${RUNTIME_EXECUTABLE_NAME}"

	if meta_util_is_parameter_set_and_not_null META_PROGRAM_DESCRIPTION; then
		printf '%s\n' "${META_PROGRAM_DESCRIPTION}"
		printf '\n'
	fi

	printf '## Usage ##\n'
	printf '\t%s (command-line options and parameters)\n' "${RUNTIME_COMMANDLINE_BASECOMMAND}"
	printf '\n'
	printf '## Command-line Options ##\n'
	meta_util_printSingleCommandlineOptionHelp "${COMMANDLINE_OPTION_DISPLAY_HELP_DESCRIPTION}" "${COMMANDLINE_OPTION_DISPLAY_HELP_LONG}" "${COMMANDLINE_OPTION_DISPLAY_HELP_SHORT}"
	meta_util_printSingleCommandlineOptionHelp "${COMMANDLINE_OPTION_ENABLE_DEBUGGING_DESCRIPTION}" "${COMMANDLINE_OPTION_ENABLE_DEBUGGING_LONG}" "${COMMANDLINE_OPTION_ENABLE_DEBUGGING_SHORT}"
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr print_help_message

process_commandline_arguments() {
	if [ "${#RUNTIME_COMMANDLINE_ARGUMENTS[@]}" -eq 0 ]; then
		return "${COMMON_RESULT_SUCCESS}"
	else
		# modifyable parameters for parsing by consuming
		local -a parameters=("${RUNTIME_COMMANDLINE_ARGUMENTS[@]}")

		# Normally we won't want debug traces to appear during parameter parsing, so we  add this flag and defer it activation till returning(Y: Do debug)
		local enable_debug=N

		while :; do
			# BREAK if no parameters left
			if [ ! -v parameters ]; then
				break
			else
				case "${parameters[0]}" in
					"${COMMANDLINE_OPTION_DISPLAY_HELP_LONG}"\
					|"${COMMANDLINE_OPTION_DISPLAY_HELP_SHORT}")
						print_help_message
						exit 0
						;;
					"${COMMANDLINE_OPTION_ENABLE_DEBUGGING_LONG}"\
					|"${COMMANDLINE_OPTION_ENABLE_DEBUGGING_SHORT}")
						enable_debug=Y
						;;
					*)
						printf 'ERROR: Unknown command-line parameter "%s"\n' "${parameters[0]}" >&2
						return "${COMMON_RESULT_FAILURE}"
						;;
				esac
				meta_util_array_shift parameters
			fi
		done
	fi
	if [ "${enable_debug}" = Y ]; then
		trap 'meta_trap_return "${FUNCNAME[0]}"' RETURN
		set -o xtrace
	fi
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr process_commandline_arguments

## ##################### Start of GBSST Support Code ##########################
## The following section are GNU Bash Shell Script's support code, you may
## remove the entire section if you want, just leave the last init call
declare -r GBSS_NAME='GNU Bash Shell Script Template'

### Common constant definitions
declare -ir COMMON_RESULT_SUCCESS=0
declare -ir COMMON_RESULT_FAILURE=1
declare -ir COMMON_BOOLEAN_TRUE=0
declare -ir COMMON_BOOLEAN_FALSE=1

### NOTE: realpath's commandline option, `--strip` will be replaced in favor of `--no-symlinks` after April 2019(Ubuntu 14.04's Support EOL)

### Makes debuggers' life easier - Unofficial Bash Strict Mode
### http://redsymbol.net/articles/unofficial-bash-strict-mode/
### BASHDOC: Shell Builtin Commands - Modifying Shell Behavior - The Set Builtin
#### Prematurely terminates the script on any command returning non-zero, append " || true"(BASHDOC: Basic Shell Features » Shell Commands » Lists of Commands) if the non-zero return value is rather intended to happen.  A trap on `ERR', if set, is executed before the shell exits.
set -o errexit

#### If set, any trap on `ERR' is also inherited by shell functions, command substitutions, and commands executed in a subshell environment.
set -o errtrace

#### If set, the return value of a pipeline(BASHDOC: Basic Shell Features » Shell Commands » Pipelines) is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands in the pipeline exit successfully.
set -o pipefail

#### Treat unset variables and parameters other than the special parameters `@' or `*' as an error when performing parameter expansion.  An error message will be written to the standard error, and a non-interactive shell will exit.
#### NOTE: errexit will NOT be triggered by this condition as this is not a command error
#### bash - Correct behavior of EXIT and ERR traps when using `set -eu` - Unix & Linux Stack Exchange
#### https://unix.stackexchange.com/questions/208112/correct-behavior-of-exit-and-err-traps-when-using-set-eu
set -o nounset

### Traps
### Functions that will be triggered if certain condition met
### BASHDOC: Shell Builtin Commands » Bourne Shell Builtins(trap)
meta_setup_traps(){
	# Variable is expanded when trap triggered, not now
	# shellcheck disable=SC2016
	declare -gr TRAP_ERREXIT_ARG='meta_trap_err ${LINENO} "${BASH_COMMAND}" ${?} ${FUNCNAME[0]}'
	# We separate the arguments to TRAP_ERREXIT_ARG, so it should be expand here
	# shellcheck disable=SC2064
	trap "${TRAP_ERREXIT_ARG}" ERR

	trap meta_trap_exit EXIT

	trap meta_trap_int INT

	# setup run guard
	declare -gr meta_setup_traps_called=yes
}; declare -fr meta_setup_traps

#### Collect all information useful for debugging
meta_trap_err_print_debugging_info(){
	if [ ${#} -ne 4 ]; then
		printf 'ERROR: %s: Wrong function argument quantity!\n' "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	local -ir line_error_location=${1}; shift # The line number that triggers the error
	local -r failing_command="${1}"; shift # The failing command
	local -ir failing_command_return_status=${1}; shift # The failing command's return value
	local -r failing_function="${1}"

	# Don't print trace for printf commands
	set +o xtrace

	printf \
		'ERROR: %s has encountered an error and is ending prematurely, %s for support.\n'\
		"${META_PROGRAM_NAME_OVERRIDE:-${RUNTIME_EXECUTABLE_NAME:-This program}}"\
		"${META_APPLICATION_SEEKING_HELP_OPTION:-contact developer}"\
		1>&2

	printf '\n' # Separate paragraphs

	printf 'Technical information:\n'
	printf '\n' # Separate list title and items
	printf '* The failing command is "%s"\n' "${failing_command}"
	printf "* Failing command's return status is %s\\n" "${failing_command_return_status}"
	printf '* Intepreter info: GNU Bash v%s on %s platform\n' "${BASH_VERSION}" "${MACHTYPE}"
	printf '* Stacktrace:\n'

	# Skip the trap functions in stack
	declare -i level=0; while [ "${failing_function}" != "${FUNCNAME[$level]}" ];do
		((level = level +1))
	done
	declare -i counter=0; while [ "${level}" -lt "${#FUNCNAME[@]}" ]; do
		printf '	%u. %s(%s:%u)\n'\
			"${counter}"\
			"${FUNCNAME[${level}]}"\
			"${BASH_SOURCE[${level}]}"\
			"${BASH_LINENO[((${level} - 1))]}"
		((level = level + 1))
		((counter = counter +1))
	done; unset level counter
	printf '\n' # Separate list and further content

	return "${COMMON_RESULT_SUCCESS}"
}; declare -rf meta_trap_err_print_debugging_info

meta_trap_err(){
	if [ ${#} -ne 4 ]; then
		printf 'ERROR: %s: Wrong function argument quantity!\n' "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	local -ir line_error_location=${1}; shift # The line number that triggers the error
	local -r failing_command="${1}"; shift # The failing command
	local -ir failing_command_return_status=${1}; shift # The failing command's return value
	local -r failing_function="${1}"

	meta_trap_err_print_debugging_info "${line_error_location}" "${failing_command}" "${failing_command_return_status}" "${failing_function}"

	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_trap_err

meta_trap_int(){
	printf '%s: Recieved SIGINT, script is interrupted.\n' "${FUNCNAME[0]}" 1>&2
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_trap_int

meta_trap_return(){
	if [ ${#} -ne 1 ]; then
		printf '%s: %s: ERROR: Wrong function argument quantity!\n' "${GBSS_NAME}" "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi
	local returning_function="${1}"

	printf 'DEBUG: %s: returning from %s\n' "${FUNCNAME[0]}" "${returning_function}" 1>&2
}; declare -fr meta_trap_return

# NOTE: Associative arrays are NOT supported by this function
meta_util_is_array_set_and_not_null(){
	if [ "${#}" -ne 1 ]; then
		printf '%s: Error: argument quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		exit "${COMMON_RESULT_FAILURE}"
	fi

	declare -n array_nameref="${1}"

	if [ "${#array_nameref[@]}" -eq 0 ]; then
		return "${COMMON_BOOLEAN_FALSE}"
	fi
	return "${COMMON_BOOLEAN_TRUE}"
}; declare -fr meta_util_is_array_set_and_not_null

# NOTE: Array and nameref are NOT supported by this function
meta_util_is_parameter_set_and_not_null(){
	if [ "${#}" -ne 1 ]; then
		printf '%s: Error: argument quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		exit "${COMMON_RESULT_FAILURE}"
	fi

	declare -n name_reference
	name_reference="${1}"

	if [ ! -v name_reference ]; then
		return "${COMMON_BOOLEAN_FALSE}"
	else
		if [ -z "${name_reference}" ]; then
			return "${COMMON_BOOLEAN_FALSE}"
		else
			return "${COMMON_BOOLEAN_TRUE}"
		fi
	fi
}; declare -fr meta_util_is_parameter_set_and_not_null

meta_util_make_parameter_readonly_if_not_null_otherwise_unset(){
	if [ "${#}" -eq 0 ]; then
		printf '%s: Error: argument quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	for parameter_name in "${@}"; do
		declare -n parameter_reference="${parameter_name}"
		if [ -v parameter_reference ]; then
			if [ -z "${parameter_reference}" ]; then
				unset parameter_reference
			else
				declare -r "${parameter_name}"
			fi
		fi
		unset -n parameter_reference
	done; unset parameter_name

	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_util_make_parameter_readonly_if_not_null_otherwise_unset

#### Introduce the program and software at leaving
meta_trap_exit_print_application_information(){
	# No need to debug this area, keep output simple
	set +o xtrace

	# Only print the line if:
	#
	# * There's info to be print
	# * Pausing program is desired(META_PROGRAM_PAUSE_BEFORE_EXIT=1)
	#
	# ...cause it's kinda stupid for a trailing line at end-of-program-output
	if meta_util_is_parameter_set_and_not_null META_APPLICATION_NAME\
		|| meta_util_is_parameter_set_and_not_null META_APPLICATION_DEVELOPER_NAME\
		|| meta_util_is_parameter_set_and_not_null META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE\
		|| meta_util_is_parameter_set_and_not_null META_PROGRAM_LICENSE\
		|| meta_util_is_parameter_set_and_not_null META_APPLICATION_LICENSE\
		|| meta_util_is_parameter_set_and_not_null META_APPLICATION_SITE_URL\
		|| meta_util_is_parameter_set_and_not_null META_APPLICATION_ISSUE_TRACKER_URL\
		|| (\
			meta_util_is_parameter_set_and_not_null META_PROGRAM_PAUSE_BEFORE_EXIT\
			&& [ "${META_PROGRAM_PAUSE_BEFORE_EXIT}" -eq 1 ] \
		); then
		printf -- '------------------------------------\n'
	fi
	if meta_util_is_parameter_set_and_not_null META_APPLICATION_NAME; then
		printf '%s\n' "${META_APPLICATION_NAME}"
	fi
	if meta_util_is_parameter_set_and_not_null META_APPLICATION_DEVELOPER_NAME; then
		printf '%s et. al.' "${META_APPLICATION_DEVELOPER_NAME}"
		if meta_util_is_parameter_set_and_not_null META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE; then
			printf " " # Separator with ${META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE}
		else
			printf '\n'
		fi
	fi
	if meta_util_is_parameter_set_and_not_null META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE; then
		printf '© %s\n' "${META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE}"
	fi
	if meta_util_is_parameter_set_and_not_null META_PROGRAM_LICENSE; then
		printf 'Intellectual Property License: %s\n' "${META_PROGRAM_LICENSE}"
	elif meta_util_is_parameter_set_and_not_null META_APPLICATION_LICENSE; then
		printf 'Intellectual Property License: %s\n' "${META_APPLICATION_LICENSE}"
	fi
	if meta_util_is_parameter_set_and_not_null META_APPLICATION_SITE_URL; then
		printf 'Official Website: %s\n' "${META_APPLICATION_SITE_URL}"
	fi
	if meta_util_is_parameter_set_and_not_null META_APPLICATION_ISSUE_TRACKER_URL; then
		printf 'Issue Tracker: %s\n' "${META_APPLICATION_ISSUE_TRACKER_URL}"
	fi
	if meta_util_is_parameter_set_and_not_null META_PROGRAM_PAUSE_BEFORE_EXIT\
		&& [ "${META_PROGRAM_PAUSE_BEFORE_EXIT}" -eq 1 ]; then
		local enter_holder

		printf 'Press ENTER to quit the program.\n'
		read -r enter_holder
	fi
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_trap_exit_print_application_information

meta_trap_exit(){
	meta_trap_exit_print_application_information
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_trap_exit

meta_util_declare_global_parameters(){
	if [ "${#}" -eq 0 ]; then
		printf '%s: Error: Function parameter quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	for parameter_name in "${@}"; do
		declare -g "${parameter_name}"
	done; unset parameter_name
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_util_declare_global_parameters

meta_util_unset_global_parameters_if_null(){
	if [ "${#}" -eq 0 ]; then
		printf '%s: Error: Function parameter quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	for parameter_name in "${@}"; do
		if [ -z "${parameter_name}" ]; then
			unset "${parameter_name}"
		fi
	done; unset parameter_name
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_util_unset_global_parameters_if_null

## Runtime Dependencies Checking
## shell - Check if a program exists from a Bash script - Stack Overflow
## http://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script
meta_check_runtime_dependencies() {
	local -n array_ref="${1}"

	if [ "${#array_ref[@]}" -eq 0 ]; then
		return "${COMMON_RESULT_SUCCESS}"
	else
		for a_command in "${!array_ref[@]}"; do
			if ! command -v "${a_command}" >/dev/null 2>&1; then
				printf 'ERROR: Command "%s" not found, program cannot continue like this.\n' "${a_command}" 1>&2
				printf "ERROR: Please make sure %s is installed and it's executable path is in your operating system's executable search path.\\n" "${array_ref["${a_command}"]}" >&2
				printf 'Goodbye.\n'
				exit "${COMMON_RESULT_FAILURE}"
			fi
		done; unset a_command
		return "${COMMON_RESULT_SUCCESS}"
	fi
}; declare -fr meta_check_runtime_dependencies

### RUNTIME_*: Info acquired from runtime environment
### https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#runtime-determined-settings
### The following variables defines the environment aspects that can only be detected in runtime, we use RUNTIME_ namespace for these variables.
### These variables will not be set if technically not available(e.g. the program is provided to intepreter/etc. via stdin), or just not implemented yet
meta_fsis_setup_runtime_parameters(){
	meta_util_declare_global_parameters\
		RUNTIME_EXECUTABLE_FILENAME\
		RUNTIME_EXECUTABLE_NAME\
		RUNTIME_EXECUTABLE_DIRECTORY\
		RUNTIME_EXECUTABLE_PATH_ABSOLUTE\
		RUNTIME_EXECUTABLE_PATH_RELATIVE\
		RUNTIME_COMMANDLINE_BASECOMMAND

	# Runtime environment's executable search path priority array
	declare -a RUNTIME_PATH_DIRECTORIES
	IFS=':' \
		read -r -a RUNTIME_PATH_DIRECTORIES <<< "${PATH}"\
		|| true # Without this `read` will return 1
	declare -r RUNTIME_PATH_DIRECTORIES

	if [ ! -v BASH_SOURCE ]; then
		if meta_util_is_parameter_set_and_not_null META_APPLICATION_INSTALL_STYLE\
			&& [ "${META_APPLICATION_INSTALL_STYLE}" == SHC ]; then
			printf "GNU Bash Shell Script Template: Error: META_APPLICATION_INSTALL_STYLE set to SHC, but is not possible due to unknown script location, make sure the program is not run as intepreter's standard input stream.\\n" 1>&2
			exit "${COMMON_RESULT_FAILURE}"
		fi
	else
		# BashFAQ/How do I determine the location of my script? I want to read some config files from the same place. - Greg's Wiki
		# http://mywiki.wooledge.org/BashFAQ/028
		RUNTIME_EXECUTABLE_FILENAME="$(basename "${BASH_SOURCE[0]}")"
		RUNTIME_EXECUTABLE_NAME="${META_PROGRAM_NAME_OVERRIDE:-${RUNTIME_EXECUTABLE_FILENAME%.*}}"
		RUNTIME_EXECUTABLE_DIRECTORY="$(dirname "$(realpath --strip "${0}")")"
		RUNTIME_EXECUTABLE_PATH_ABSOLUTE="${RUNTIME_EXECUTABLE_DIRECTORY}/${RUNTIME_EXECUTABLE_FILENAME}"
		RUNTIME_EXECUTABLE_PATH_RELATIVE="${0}"

		for pathdir in "${RUNTIME_PATH_DIRECTORIES[@]}"; do
			# It is possible that the pathdir is invalid (e.g. wrong configuration or misuse ":" as path content which is not allowed in PATH), simply ignore it
			if [ ! -d "${pathdir}" ]; then
				continue
			fi

			# If executable is in shell's executable search path, consider the command is the executable's filename
			# Also do so if the resolved path matches(symbolic linked)
			resolved_pathdir="$(realpath "${pathdir}")"

			if [ "${RUNTIME_EXECUTABLE_DIRECTORY}" == "${pathdir}" ]\
				|| [ "${RUNTIME_EXECUTABLE_DIRECTORY}" == "${resolved_pathdir}" ]; then
				RUNTIME_COMMANDLINE_BASECOMMAND="${RUNTIME_EXECUTABLE_FILENAME}"
				break
			fi
		done; unset pathdir resolved_pathdir
		RUNTIME_COMMANDLINE_BASECOMMAND="${RUNTIME_COMMANDLINE_BASECOMMAND:-${0}}"
	fi
	meta_util_make_parameter_readonly_if_not_null_otherwise_unset\
		RUNTIME_EXECUTABLE_FILENAME\
		RUNTIME_EXECUTABLE_NAME\
		RUNTIME_EXECUTABLE_DIRECTORY\
		RUNTIME_EXECUTABLE_PATH_ABSOLUTE\
		RUNTIME_EXECUTABLE_PATH_RELATIVE\
		RUNTIME_COMMANDLINE_BASECOMMAND

	# Collect command-line arguments
	declare -agr RUNTIME_COMMANDLINE_ARGUMENTS=("${@}")

	# Set run guard
	declare -gr meta_fsis_setup_runtime_parameters_called=yes
}; declare -fr meta_fsis_setup_runtime_parameters

### Flexible Software Installation Specification - Software Directories Configuration(S.D.C.)
### This function defines and determines the directories used by the software
### https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#software-directories-configurationsdc
meta_fsis_setup_software_directories_configuration(){
	# Run guard
	if [ ! -v meta_fsis_setup_runtime_parameters_called ]; then
		printf '%s: %s: %u: Error: This function cannot be called before meta_fsis_setup_runtime_parameters, please contact developer.\n'\
			"${GBSS_NAME}"\
			"${FUNCNAME[0]}"\
			"${LINENO}"\
			1>&2
		exit "${COMMON_RESULT_FAILURE}"
	fi

	meta_util_declare_global_parameters\
		SDC_EXECUTABLES_DIR\
		SDC_LIBRARIES_DIR\
		SDC_SHARED_RES_DIR\
		SDC_I18N_DATA_DIR\
		SDC_SETTINGS_DIR\
		SDC_TEMP_DIR

	if meta_util_is_parameter_set_and_not_null META_APPLICATION_INSTALL_STYLE; then
		case "${META_APPLICATION_INSTALL_STYLE}" in
			FHS)
				# Filesystem Hierarchy Standard(F.H.S.) configuration paths
				# http://refspecs.linuxfoundation.org/FHS_3.0/fhs
				## Software installation directory prefix, should be overridable by configure/install script
				meta_util_declare_global_parameters FHS_PREFIX_DIR
				declare -r FHS_PREFIX_DIR="/usr/local"

				declare -r SDC_EXECUTABLES_DIR="${FHS_PREFIX_DIR}/bin"
				declare -r SDC_LIBRARIES_DIR="${FHS_PREFIX_DIR}/lib"
				declare -r SDC_I18N_DATA_DIR="${FHS_PREFIX_DIR}/share/locale"
				if meta_util_is_parameter_set_and_not_null META_APPLICATION_IDENTIFIER; then
					declare -r SDC_SHARED_RES_DIR="${FHS_PREFIX_DIR}/share/${META_APPLICATION_IDENTIFIER}"
					declare -r SDC_SETTINGS_DIR="/etc/${META_APPLICATION_IDENTIFIER}"
					declare -r SDC_TEMP_DIR="/tmp/${META_APPLICATION_IDENTIFIER}"
				else
					unset\
						SDC_SHARED_RES_DIR\
						SDC_SETTINGS_DIR\
						SDC_TEMP_DIR
				fi
				;;
			SHC)
				# Setup Self-contained Hierarchy Configuration(S.H.C.)
				# https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#self-contained-hierarchy-configurationshc
				# https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#path_to_software_installation_prefix_directorysourceshc-only
				# https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#shc_prefix_dirshc-only
				meta_util_declare_global_parameters SHC_PREFIX_DIR
				if [ -f "${RUNTIME_EXECUTABLE_DIRECTORY}/APPLICATION_METADATA.source" ]; then
					SHC_PREFIX_DIR="${RUNTIME_EXECUTABLE_DIRECTORY}"
				else
					if [ ! -f "${RUNTIME_EXECUTABLE_DIRECTORY}/PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY.source" ]; then
						printf "GNU Bash Script Template: Error: PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY.source not exist, can't setup Self-contained Hierarchy Configuration.\\n" 1>&2
						exit 1
					fi
					# Scope of Flexible Software Installation Specification
					# shellcheck disable=SC1090,SC1091
					source "${RUNTIME_EXECUTABLE_DIRECTORY}/PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY.source"
					if ! meta_util_is_parameter_set_and_not_null PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY; then
						printf "GNU Bash Script Template: Error: PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY not defined, can't setup Self-contained Hierarchy Configuration.\\n" 1>&2
						exit 1
					fi
					SHC_PREFIX_DIR="$(realpath --strip "${RUNTIME_EXECUTABLE_DIRECTORY}/${PATH_TO_SOFTWARE_INSTALLATION_PREFIX_DIRECTORY}")"
				fi
				declare -gr SHC_PREFIX_DIR

				# Read external software directory configuration(S.D.C.)
				# https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#software-directories-configurationsdc
				# Scope of Flexible Software Installation Specification
				# shellcheck disable=SC1090,SC1091
				source "${SHC_PREFIX_DIR}/SOFTWARE_DIRECTORY_CONFIGURATION.source" 2>/dev/null || true
				meta_util_unset_global_parameters_if_null\
					SDC_EXECUTABLES_DIR\
					SDC_LIBRARIES_DIR\
					SDC_SHARED_RES_DIR\
					SDC_I18N_DATA_DIR\
					SDC_SETTINGS_DIR\
					SDC_TEMP_DIR
				;;
			STANDALONE)
				# Standalone Configuration
				# This program don't rely on any directories, make no attempt defining them
				unset SDC_EXECUTABLES_DIR SDC_LIBRARIES_DIR SDC_SHARED_RES_DIR SDC_I18N_DATA_DIR SDC_SETTINGS_DIR SDC_TEMP_DIR
				;;
			*)
				printf 'Error: Unknown software directories configuration, program can not continue.\n' 1>&2
				exit 1
				;;
		esac
	fi

	meta_util_make_parameter_readonly_if_not_null_otherwise_unset\
		SDC_EXECUTABLES_DIR\
		SDC_LIBRARIES_DIR\
		SDC_SHARED_RES_DIR\
		SDC_I18N_DATA_DIR\
		SDC_SETTINGS_DIR\
		SDC_TEMP_DIR

	# Set run guard
	declare -gr meta_fsis_setup_software_directories_configuration_called=yes
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_fsis_setup_software_directories_configuration

### Flexible Software Installation Specification - Setup application metadata
### This function locates and loads the metadata of the application
### https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification#application_metadatasource
meta_fsis_setup_application_metadata(){
	# Run guard
	if [ ! -v meta_fsis_setup_software_directories_configuration_called ]; then
		printf '%s: %s: %u: Error: This function cannot be called before meta_fsis_setup_software_directories_configuration_called, please contact developer.\n'\
			"${GBSS_NAME}"\
			"${FUNCNAME[0]}"\
			"${LINENO}"\
			1>&2
		exit "${COMMON_RESULT_FAILURE}"
	fi

	meta_util_declare_global_parameters\
		META_APPLICATION_NAME\
		META_APPLICATION_DEVELOPER_NAME\
		META_APPLICATION_LICENSE\
		META_APPLICATION_SITE_URL\
		META_APPLICATION_ISSUE_TRACKER_URL\
		META_APPLICATION_SEEKING_HELP_OPTION

	if meta_util_is_parameter_set_and_not_null META_APPLICATION_INSTALL_STYLE; then
		case "${META_APPLICATION_INSTALL_STYLE}" in
			FHS)
				if [ -v "${SDC_SHARED_RES_DIR}" ] && [ -n "${SDC_SHARED_RES_DIR}" ]; then
					:
				else
					# Scope of external project
					# shellcheck disable=SC1090,SC1091
					source "${SDC_SHARED_RES_DIR}/APPLICATION_METADATA.source" 2>/dev/null || true
				fi
				;;
			SHC)
				# Scope of external project
				# shellcheck disable=SC1090,SC1091
				source "${SHC_PREFIX_DIR}/APPLICATION_METADATA.source" 2>/dev/null || true
				;;
			STANDALONE)
				: # metadata can only be set from header
				;;
			*)
				printf 'Error: Unknown META_APPLICATION_INSTALL_STYLE, program can not continue.\n' 1>&2
				exit 1
				;;
		esac
	fi

	meta_util_make_parameter_readonly_if_not_null_otherwise_unset\
		META_APPLICATION_NAME\
		META_APPLICATION_DEVELOPER_NAME\
		META_APPLICATION_LICENSE\
		META_APPLICATION_SITE_URL\
		META_APPLICATION_ISSUE_TRACKER_URL\
		META_APPLICATION_SEEKING_HELP_OPTION
}; declare -fr meta_fsis_setup_application_metadata

### Drop first element from array and shift remaining elements to replace the first one
### FIXME: command error in this function doesn't not trigger ERR trap for some reason
meta_util_array_shift(){
	if [ "${#}" -ne 1 ]; then
		printf '%s: Error: argument quantity illegal\n' "${FUNCNAME[0]}" 1>&2
		exit "${COMMON_RESULT_FAILURE}"
	fi

	local -n array_ref="${1}"
	if [ "${#array_ref[@]}" -eq 0 ]; then
		printf 'ERROR: array is empty!\n' 1>&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	# Unset the 1st element
	unset 'array_ref[0]'

	# Repack array if element still available in array
	if [ "${#array_ref[@]}" -ne 0 ]; then
		array_ref=("${array_ref[@]}")
	fi

	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_util_array_shift

### Print single segment of commandline option help
meta_util_printSingleCommandlineOptionHelp(){
	if [ "${#}" -ne 3 ] && [ "${#}" -ne 4 ]; then
		printf 'ERROR: %s: Wrong parameter quantity!\n' "${FUNCNAME[0]}" >&2
		return "${COMMON_RESULT_FAILURE}"
	fi

	local description="${1}"; shift # Option description
	local long_option="${1}"; shift # The long version of option
	local short_option="${1}"; shift # The short version of option
	declare -r description long_option short_option

	if [ "${#}" -ne 0 ]; then
		local current_value="${1}"; shift # Current value of option, if option has value
		declare -r current_value
	fi

	printf '### %s / %s ###\n' "${long_option}" "${short_option}"
	printf '%s\n' "${description}"

	if [ -v current_value ]; then
		printf 'Current value: %s\n' "${current_value}"
	fi

	printf '\n' # Separate with next option(or next heading)
	return "${COMMON_RESULT_SUCCESS}"
}; declare -fr meta_util_printSingleCommandlineOptionHelp

meta_setup_traps

### Unset all null META_PROGRAM_* parameters and readonly all others
### META_APPLICATION_IDENTIFIER also as it can't be determined in runtime
meta_util_make_parameter_readonly_if_not_null_otherwise_unset\
	META_PROGRAM_NAME_OVERRIDE\
	META_PROGRAM_IDENTIFIER\
	META_PROGRAM_DESCRIPTION\
	META_PROGRAM_LICENSE\
	META_PROGRAM_PAUSE_BEFORE_EXIT\
	META_PROGRAM_COPYRIGHT_ACTIVATED_SINCE\
	META_APPLICATION_IDENTIFIER

if meta_util_is_array_set_and_not_null META_RUNTIME_DEPENDENCIES_CRITICAL; then
	meta_check_runtime_dependencies META_RUNTIME_DEPENDENCIES_CRITICAL
fi
if meta_util_is_array_set_and_not_null META_RUNTIME_DEPENDENCIES; then
	meta_check_runtime_dependencies META_RUNTIME_DEPENDENCIES
fi

meta_fsis_setup_runtime_parameters "${@}"
meta_fsis_setup_software_directories_configuration
meta_fsis_setup_application_metadata

## This script is based on the GNU Bash Shell Script Template project
## https://github.com/Lin-Buo-Ren/GNU-Bash-Shell-Script-Template
## and is based on the following version:
## GNU_BASH_SHELL_SCRIPT_TEMPLATE_VERSION="v3.0.16-1-g9d1ae36"
## You may rebase your script to incorporate new features and fixes from the template

### This script is comforming to Flexible Software Installation Specification
### https://github.com/Lin-Buo-Ren/Flexible-Software-Installation-Specification
### and is based on the following version: v1.5.0
## ###################### End of GBSST Support Code #########################

init "${@}"