lmc-darklight-installer

#!/bin/sh
#cito M:755 O:0 G:0 T:/usr/bin/lmc-darklight-installer
#------------------------------------------------------------------------------
# Project Name      - Extra/source/lmc-darklight/lmc-darklight-installer
# Started On        - Sun 31 Jan 22:35:39 GMT 2021
# Last Change       - Fri 25 Feb 17:36:55 GMT 2022
# Author E-Mail     - terminalforlife@yahoo.com
# Author GitHub     - https://github.com/terminalforlife
#------------------------------------------------------------------------------
# Simple, but pretty and mindful Bourne Shell installer for LMC-DarkLight.
#
# To use this installer, you can either:
#
#   Clone the repository, using git(1) command.
#
#     OR
#
#   Download the archive of it directly from GitHub, then extract its contents.
#
# Since this installer just fetches from GitHub, you needn't actually download
# the entire Extra repository to install it; only the installer.
#
# If you want a HOME-only installation, you'll have to either use Cito, or
# otherwise install it manually, but you may miss out on a lot of features.
#
# NOTE: Due to changes in BASH 4.4, running this therein will spit out errors.
#
# Dependencies:
#
#   coreutils (>= 8.25-2)
#   curl (>= 7.47.0-1) | wget (>= 1.17.1-1)
#------------------------------------------------------------------------------

Err(){
	printf 'Err: %s\n' "$2" 1>&2
	[ $1 -gt 0 ] && exit $1
}

if command -v curl 1> /dev/null 2>&1; then
	DLCMD='curl -so'
elif command -v wget 1> /dev/null 2>&1; then
	DLCMD='wget -qO'
else
	Err 1 "Neither 'wget' nor 'curl' are available."
fi

[ `id -u` -ne 0 ] && Err 1 'Root access is required for system-wide changes.'

while :; do
	printf 'Install latest version of LMC-DarkLight? [Y/N] '

	read Input
	case $Input in
		[Yy]|[Yy][Ee][Ss])
			printf 'Continuing with installation.\n'
			break ;;
		[Nn]|[Nn][Oo])
			printf 'Abandoning installation.\n'
			exit 0 ;;
		'')
			Err 0 'Empty response -- try again.' ;;
		*)
			Err 0 'Invalid response -- try again.' ;;
	esac
done

LogFile='/tmp/lmc-darklight-installer.log'
[ -f "$LogFile" ] || 1> "$LogFile"
chmod 644 "$LogFile"

TmpDir=`mktemp -d --suffix '_tfl'`

URL='https://raw.githubusercontent.com/terminalforlife'
URL="$URL/Extra/master/source/lmc-darklight"

SigHandler(){
	Sig=$?

	printf 'Cleaning up temporary files:\n'
	printf '* Removing '%s' ... ' "$TmpDir"
	ErrCount=0
	if rm -r "$TmpDir" 2>> "$LogFile"; then
		printf '\033[32m[OK]\033[0m\n'
	else
		printf '\033[31m[ERR]\033[0m\n'
	fi

	if [ -s "$LogFile" ]; then
		printf "Done! -- errors logged in: '${LogFile#$HOME}'\n"
	else
		printf 'Done!\n'
	fi

	printf 'Generate configuration file:\n\n'
	printf '  $ lmc-darklight --genconfig\n\n'
	printf 'Then check NOTES in the man page:\n\n'
	printf '  $ man lmc-darklight\n\n'

	exit $Sig
}

trap SigHandler EXIT INT QUIT ABRT TERM

printf 'Fetching files from GitHub:\n'
ErrCount=0
for File in 'completions' 'lmc-darklight' 'lmc-darklight.1.gz'; do
	printf "* Downloading '%s' ... " "$File"
	if $DLCMD "$TmpDir/$File" "$URL/$File" 2>> "$LogFile"; then
		printf '\033[32m[OK]\033[0m\n'

		printf '* Verifying file contents ... '
		Contents=`< "$TmpDir/$File"`
		if [ "$(head -n 1 "$TmpDir/$File")" = '404: Not Found' ]; then
			ErrCount=$((ErrCount + 1))
			printf '\033[31m[ERR]\033[0m\n'
			rm "$TmpDir/$File" > /dev/null 2>&1
		else
			printf '\033[32m[OK]\033[0m\n'
		fi
	else
		ErrCount=$((ErrCount + 1))
		printf '\033[31m[ERR]\033[0m\n'
	fi
done

[ $ErrCount -gt 0 ] && Err 1 'Failed to download one or more files.'

printf 'Setting correct file attributes:\n'

printf '* Assigning owner and group ... '
if chown 0:0 "$TmpDir"/* 2>> "$LogFile"; then
	printf '\033[32m[OK]\033[0m\n'
else
	printf '\033[31m[ERR]\033[0m\n'
fi

printf '* Assigning modes ... '
ErrCount=0
for File in 'completions:644' 'lmc-darklight:755' 'lmc-darklight.1.gz:644'; do
	chmod ${File##*:} "$TmpDir/${File%:*}" 2>> "$LogFile" ||
		ErrCount=$((ErrCount + 1))
done

if [ $ErrCount -eq 0 ]; then
	printf '\033[32m[OK]\033[0m\n'
else
	printf '\033[31m[ERR]\033[0m\n'
fi

printf 'Moving files into place:\n'
ErrCount=0
for File in\
\
	'lmc-darklight:/usr/bin/lmc-darklight'\
	'lmc-darklight.1.gz:/usr/share/man/man1/lmc-darklight.1.gz'\
	'completions:/usr/share/bash-completion/completions/lmc-darklight'
do
	if [ -f "${File#*:}" ]; then
		Replace='False'

		while :; do
			printf "File '%s' found.\n" "${File#*:}"
			printf 'Replace existing file? [Y/N] '

			read Input
			case $Input in
				[Yy]|[Yy][Ee][Ss])
					Replace='True'
					break ;;
				[Nn]|[Nn][Oo])
					Replace='False'
					break ;;
				'')
					Err 0 'Empty response -- try again.' ;;
				*)
					Err 0 'Invalid response -- try again.' ;;
			esac
		done

		[ "$Replace" = 'True' ] || continue
	fi

	printf "* Installing '%s' ... " "${File%%:*}"
	if mv "$TmpDir/${File%%:*}" "${File#*:}" 2>> "$LogFile"; then
		printf '\033[32m[OK]\033[0m\n'
	else
		printf '\033[31m[ERR]\033[0m\n'
	fi
done

printf 'Checking executables work:\n'

printf "* Verifying 'lmc-darklight' ... "
if lmc-darklight -v > /dev/null 2>&1; then
	printf '\033[32m[OK]\033[0m\n'
else
	printf '\033[31m[ERR]\033[0m\n'
fi

printf 'Checking for dependencies:\n'

for File in '/usr/bin/lmc-darklight'; do
	printf "* Looking in '%s' file...\n" "$File"

	FileErr=0
	if ! [ -f "$File" ]; then
		Err 0 "File '$File' missing."
		FileErr=$((FileErr + 1))
	elif ! [ -r "$File" ]; then
		Err 0 "File '$File' unreadable."
		FileErr=$((FileErr + 1))
	fi

	if [ $FileErr -ne 0 ]; then
		Err 0 'Unable to determine dependencies.'
		continue
	fi

	DepErr=0
	Found='False'
	while read Line; do
		if [ "$Line" = '#' ]; then
			continue
		elif [ "$Line" = '# Dependencies:' ]; then
			Found='True'
		elif [ "$Found" = 'True' ]; then
			# Line to help debug parsing on stubborn files.
			#printf '\e[2;37m%s\e[0m\n' "$Line"

			case $Line in
				'#'------*)
					break ;;
				*)
					case $Line in
						'#   '[!\ ]*)
							printf '\033[1;93m%s\e[0m\n' "${Line#\#   }" ;;
						*)
							DepErr=$((DepErr + 1)) ;;
					esac ;;
			esac
		fi
	done < "$File"

	[ $DepErr -eq 0 ] || Err 0 'One or more invalid dependencies detected.'
done