shell.common

#!/bin/sh

:<<DOCUMENTATION

	Description:	Defines functions frequently used in shell scripts.
	Author:			Chris Wells (https://chriswells.io)

DOCUMENTATION


# Returns:
#	full path to the current script
getScriptPath() {
	dirname "$(readlink -f "$0")"
}

# Parameters:
#	$1 = relative or full path to the script to import
importScript() {
	SCRIPT_PATH=$(getScriptPath)
	if [ -f "$SCRIPT_PATH/lib/$1" ]; then
		# shellcheck source=/dev/null
		. "$SCRIPT_PATH/lib/$1"
	elif [ -f "$SCRIPT_PATH/../lib/$1" ]; then
		# shellcheck source=/dev/null
		. "$SCRIPT_PATH/../lib/$1"
	elif [ -f "$SCRIPT_PATH/$1" ]; then
		# shellcheck source=/dev/null
		. "$SCRIPT_PATH/$1"
	elif [ -f "$1" ]; then
		# shellcheck source=/dev/null
		. "$1"
	else
		echo "Error: '$1' was not found."
		exit 1
	fi
}

# Parameters:
#	$1 (optional) = action that occurs after pressing Enter
#		Default is 'continue' when not provided.
pressEnterTo() {
	if [ -n "$1" ]; then
		ACTION="$1"
	else
		ACTION='continue'
	fi
	# shellcheck disable=SC2039
	read -r -p "
Press \"Enter\" to $ACTION..." _
}

# Parameters:
#	$1 (optional) = custom error message to display if the user is not root
requireRootOrExit() {
	if [ "$(id -u)" != "0" ]; then
		if [ -n "$1" ]; then
			MESSAGE="$1"
		else
			MESSAGE='This script must be executed as root or using sudo.'
		fi
		echo "$MESSAGE" 1>&2
		exit 1
	fi
}


################################################################################
# Hashes (Associative Arrays / Dictionaries)
################################################################################

# Parameters:
#	$1 = name of the hash variable
#	$2 = key to search for
# Returns:
#	result code indicating whether the specified key exists in the hash
hashContainsKey() {
	alias "HASH_$1_$2" > /dev/null 2>&1
}

# Parameters:
#	$1 = name of the hash variable
#	$2 = value to search for
# Returns:
#	result code indicating whether the specified value exists in the hash
hashContainsValue() {
	alias | grep -Eq "^HASH_$1_.+='?$2'?\$"
}

# Parameters:
#	$1 = name of the hash variable
#	$2 = key for the value that should be retrieved
# Returns:
#	value found for the specified key
hashGet() {
	alias "HASH_$1_$2" 2> /dev/null | awk -F"=" '{ gsub(/^'\''|'\''$/, "", $2); print $2; }'
}

# Parameters:
#	$1 = name of the hash variable
#	$2 = key to use
#	$3 (optional) = the value to store
#		Default is an empty string when not provided.
hashPut() {
	# shellcheck disable=SC2139
	alias "HASH_$1_$2=$3"
}


################################################################################
# Script Options
################################################################################

# Parameters:
#	$1 = name of the option whose value should be returned
# Returns:
#	value provided for the specified option
getOption() {
	hashGet 'SCRIPT_OPTS' "$1"
}

# Parameters:
#	$1 = name of the option to check
# Returns:
#	result code indicating whether the specified option was passed to the script
optionIsEnabled() {
	hashContainsKey 'SCRIPT_OPTS' "$1"
}

# Parameters:
#	$@ = full list of options passed to the script
parseScriptOptions() {
	for SCRIPT_ARG in "$@"; do
		case $SCRIPT_ARG in
			-* )
				setOption "$SCRIPT_ARG"
				LAST_SWITCH=$SCRIPT_ARG ;;
			* )
				if [ -n "$LAST_SWITCH" ]; then
					setOption "$LAST_SWITCH" "$SCRIPT_ARG"
				else
					setOption "$SCRIPT_ARG"
				fi
				LAST_SWITCH='' ;;
		esac
	done
}

# Parameters:
#	$1 = name of the option to set
#	$2 = value to set for the specified option
setOption() {
	hashPut 'SCRIPT_OPTS' "$1" "$2"
}


################################################################################
# Note Management
################################################################################

# Parameters:
#	$1 = message to append to the notes for the currently running script
addNote() {
	# Not using appendToFile here to ensure this file has no dependencies. -- cwells
	#appendToFile "$0.notes" "$1"
	echo "$1" >> "$(getScriptPath)/$(basename $0).notes"
}

# Parameters:
#	$1 (optional) = message to display above the notes for this script
showNotes() {
	if [ -n "$1" ]; then
		MESSAGE="$1"
	else
		MESSAGE='The following notes were saved in'
	fi
	echo "$MESSAGE $0.notes:

$(cat "$(getScriptPath)/$(basename $0).notes")"
}