#!/bin/bash
#
# Author: Georg Voell - georg.voell@standby.cloud
# Version: @(#)errormsg 3.2.0 26.08.2024 (c)2024 Standby.cloud
# Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/
#
# This script can be used free of charge. Use it as is or customize as needed. It is not guaranteed to be
# error free and you will not be reimbursed for any damage it may cause.
#
#@  Prints an error message in red color to stderr.
#@  This script can be called with 2 or 3 parameters.
#@  If "LOGFILE" is defined, it writes error message also to log.
#@  First parameter is the error number.
#@  Second parameter is the error message.
#@  Third (optional) parameter is the error reason.
#@
#@Usage: errormsg [options] errnum errmsg [errrsn]
#@  Options:
#@    -h, --help   : Displays helptext.
#@    -v, --version: Displays the version of the script.
#@    -q, --quiet  : Just write error message to LOGFILE.
#@  ErrNum: Number between 1 and 99. 0 for Warning messages
#@  ErrMsg: Error message to be displayed.
#@  ErrRsn: Optional: Error reason.
#@
#@Examples:
#@  errormsg 0 "No internet connection."
#@    Will display the warning message "WARNING: No internet connection." to stderr.
#@  errormsg 1 "No 'curl' in PATH."
#@    Will display the error message "ERROR(01): No 'curl' in PATH." to stderr.
#@  errormsg 2 "No insternet connection." "No connection to external server"
#@    Will display "ERROR(02): No insternet connection. (No connection to external server)" to stderr.
#@  export LOGFILE="/var/log/test.log"; errormsg -q 3 "Can't delete file."
#@    Will write "2020-06-01 14:37:51 ERROR(03): Can't delete file." to $LOGFILE.
#
# Exit codes:
#  01: Unknown or wrong parameter.
#  02: Could not create logfile.
#  03: Could not write to logfile.
#
# See also:
#  **install-scripts**(1)
#
# Update history:
#
# V 1.0.0 26.10.2017 New version
# V 2.0.0 05.07.2019 Minor changes
# V 3.0.0 24.04.2020 Adding plausibility checks
# V 3.0.1 01.06.2020 Display help and version
# V 3.0.2 11.06.2020 Using library
# V 3.0.3 02.07.2020 Version was not shown by option --version
# V 3.0.4 14.10.2020 Diplay a WARNING message with errnum = 0
# V 3.1.0 05.06.2023 New copyright
# V 3.2.0 26.08.2024 New minor version
#

# Find executable bash library and source it
lib=`which lib.bash 2>/dev/null | sed 's|^no 'lib.bash' in .*||'`
if [ "$lib" != "" ]; then
	source "$lib"
else
	progdir=`dirname "$0"`
	if [ -r "${progdir}/lib.bash" ]; then
		source "${progdir}/lib.bash"
	else
		echo "Unexpected error: Unable to locate bash library 'lib.bash'."
		exit 1
	fi
fi

# Print errormsg to /dev/stderr
function DisplayError() {
	local number=${1}				# Error Number
	local errmsg=${2}				# Error Message
	local errrsn=${3}				# Error Reason

	# Display error message
	if [ $number -eq 0 ]; then
		printf "${pink}WARNING: %s${normal}\n" "$errmsg" >> /dev/stderr
	else
		if [ "$errrsn" = "" ]; then
			printf "${highred}ERROR(%02d): %s${normal}\n" $number "$errmsg" >> /dev/stderr
		else
			printf "${highred}ERROR(%02d): %s (%s)${normal}\n" $number "$errmsg" "$errrsn" >> /dev/stderr
		fi
	fi
}

# Preset
curdate=`date "+%Y-%m-%d %T"`	# For use in logfiles, etc.
quiet=false						# true to suppress error messages
errnum=""
errarg=""
erropt=""

# Check parameters: Loop until all parameters are used up
while [ $# -gt 0 ]; do
	pname=${1}
	case "$pname" in
		-v | --version)
			shift
			showversion=true
			;;
		-h | --help)
			shift
			showhelp=true
			;;
		-q | --quiet)
			shift
			quiet=true
			;;
		*)
			shift
			paramck=`echo "$pname" | grep '^-'` # Types don't begin with '-'
			if [ "$paramck" != "" ]; then
				errstr="Unknown option '$pname'."
			else
				if [ "$errnum" = "" ]; then
					errnum="$pname"
				else
					if [ "$errarg" = "" ]; then
						errarg="$pname"
					else
						if [ "$erropt" = "" ]; then
							erropt="$pname"
						else
							errstr="Unknown parameter: '$pname'."
						fi
					fi
				fi
			fi
	esac
done

# Plausibility checks
if [ "$errarg" = "" ]; then
	errstr="Please call '$progstr' with 2 or 3 parameters."
else
	if [ "$errnum" != "" ]; then
		numstr=`echo "$errnum" | grep '^[0123456789]*$'`
		if [ "$numstr" != "" ]; then
			if [ $errnum -lt 0 -o $errnum -gt 99 ]; then
				errstr="First parameter has to be between 0 and 99 (was '$errnum')."
			fi
		else
			errstr="First parameter is not a number (was '$errnum')."
		fi
	fi
fi

# Display help or error message
DisplayHelp

# Write to logfile if it is defined e.g. export LOGFILE="./test.log"
stat=0	# 0 = Everything ok
if [ "$LOGFILE" != "" ]; then
	# Check if $LOGFILE exists - otherwise create it
	if [ ! -f "$LOGFILE" ]; then
		touch "$LOGFILE" > /dev/null 2>&1
		stat=$?
	fi
	
	# Check if we can access $LOGFILE
	if [ $stat -eq 0 ]; then
		if [ -f "$LOGFILE" ]; then
			if [ $errnum -eq 0 ]; then
				printf "$curdate WARNING: %s\n" "$errarg" >> "$LOGFILE" 2>&1
			else
				if [ "$erropt" = "" ]; then
					printf "$curdate ERROR(%02d): %s\n" $errnum "$errarg" >> "$LOGFILE" 2>&1
					stat=$?
				else
					printf "$curdate ERROR(%02d): %s (%s)\n" $errnum "$errarg" "$erropt" >> "$LOGFILE" 2>&1
					stat=$?
				fi
			fi
		else
			stat=1
		fi
		
		if [ $stat -ne 0 ]; then
			exitcode=3
			if [ "$erropt" = "" ]; then
				erropt="$progstr: Could not write to logfile '$LOGFILE'"
			else
				erropt="$erropt - $progstr: Could not write to logfile '$LOGFILE'"
			fi
		fi
	else
		exitcode=2
		if [ "$erropt" = "" ]; then
			erropt="$progstr: Could not create logfile '$LOGFILE'"
		else
			erropt="$erropt - $progstr: Could not create logfile '$LOGFILE'"
		fi
	fi
fi

# Call local function
if [ "$quiet" = false ]; then
	DisplayError $errnum "$errarg" "$erropt"
fi

# Exit with exitcode
exit $exitcode