#!/bin/bash
########### GOG ARCHIVER ###########
#   GOG  archiver  is  a  fairly   #
#   simple self-contained script   #
#   used to download and archive   #
#   games from gog.com.            #
#   Licensed under AGPL 3.0        #
#   by Marko Zajc                  #
####################################

VERSION="1.1";
DEBUG_ENABLED='false';

# Argument parsing
COLOUR='less';
POSITIONAL=()
while [[ $# -gt 0 ]]; do
	key="$1";
	case $key in
		-p|--platforms)
			PLATFORMS="$2";
			shift; shift;
		;;
		-r|--root)
			GAR_ROOT="$2";
			shift; shift;
		;;
		-c|--colour|--color)
			COLOUR="$2";
			shift; shift;
		;;
		-g|--games)
			GAMES="$2";
			shift; shift;
		;;
		-h|--help)
			SHOWHELP=true;
			shift;
		;;
		-b|--no-banner)
			NOBANNER=true;
			shift;
		;;
		-v|--version)
			SHOWVERSION=true;
			shift;
		;;
		-i|--ignore-types)
			IGNORE="$2"
			shift; shift;
		;;
		*)   
			POSITIONAL+=("$1");
			shift;
		;;
	esac;
done;

# Constants
case $COLOUR in
	none)
	;;
	some)
		R='\033[0m'
		ERRORCOLOUR='\033[01;31m'
		INFOCOLOUR='\033[00;32m'
		DEBUGCOLOUR='\033[01;36m'
		TEXT=$R
	;;
	less)
		R='\033[0m'
		ERRORCOLOUR='\033[01;31m'
		INFOCOLOUR='\033[00;32m'
		DEBUGCOLOUR='\033[01;36m'
		DETAIL='\033[01;37m'
		LOW='\033[01;30m'
		TEXT=$R
	;;
	*)
		R='\033[0m'
		ERRORCOLOUR='\033[01;31m'
		INFOCOLOUR='\033[00;32m'
		DEBUGCOLOUR='\033[01;36m'
		DETAIL='\033[01;34m'
		LOW='\033[01;30m'
		TEXT='\033[01;37m'
	;;
esac;
INFO="[${INFOCOLOUR}INFO$TEXT] "
ERROR="[${ERRORCOLOUR}ERROR$TEXT] "
DEBUG="[${DEBUGCOLOUR}DEBUG$TEXT] "
DOWNLOADS_ROOT='download'
DEPENDENCIES=( jq perl wget )

# Parameters:
# - substring
# - text
# Returns: nothing
string_contains() { [ -z "$1" ] || { [ -z "${2##*$1*}" ] && [ -n "$2" ];};}

# Parameters:
# - message
# Returns: the log line
log() {
	echo -e "$TEXT$1$R";
}

# - message
# Returns: the wrapped log line
wlog() {
	printf "$TEXT";
	echo -e "$1" | fmt;
	printf "$R";
}

# Parameters:
# - message
# Returns: the log line
banner() {
	if [ -v NOBANNER ]; then
		return 0;
	fi;
	log "GOG archiver $DETAIL$VERSION$TEXT by ${DETAIL}Marko Zajc$TEXT.";
}

# Parameters:
# - message
# Returns: the log line
elog() {
	log "$ERROR$1";
}

# Parameters:
# - message
# Returns: the log line
ilog() {
	log "$INFO$1";
}

# Parameters:
# - message
# Returns: the log line
dlog() {
	if [[ $DEBUG_ENABLED = 'true' ]]; then
		echo -e "$DEBUG$TEXT$1$R";
	fi;
}

# Parameters: none
# Returns: nothing
check_files() {
	if [ ! -s "$GAR_ROOT/authorization.txt" ]; then
		touch "$GAR_ROOT/authorization.txt"
		elog "Authorization cookie not found. Please log into your GOG account in a browser, and";
		elog "copy the ${DETAIL}gog-al$TEXT cookie into $DETAIL$GAR_ROOT/authorization$TEXT.";
		elog "Copy just the cookie value, not including the 'gog-alc' part or any quotation marks";
		elog "or apostrophes.";
		exit 1;
	fi
}

# Configuration
[ -v GAR_ROOT ] || GAR_ROOT="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )";
check_files;
AUTH=$(head -n 1 "$GAR_ROOT/authorization.txt")
DOWNLOAD_LOCATION="$GAR_ROOT/gog_download"

# Parameters:
# - log
# Returns: self user metadata json
get_selfuser_metadata() {
	execute_request 'userData.json' '-';
}

# Parameters:
# - game id
# Returns: game metadata json
get_game_metadata() {
	execute_request "account/gameDetails/$1.json" '-';
}

# Parameters:
# - game id
# - download identifier
# Returns: nothing
download() {
	execute_request "$1" "$DOWNLOAD_LOCATION-$2" '--show-progress';
}

# Parameters: none
# Returns: nothing
is_version() {
	if [ ! -v SHOWVERSION ]; then
		return 0;
	fi;
	echo $VERSION
	exit 0;
}

# Parameters: none
# Returns: nothing
is_help() {
	if [ ! -v SHOWHELP ]; then
		return 0;
	fi;
	
	wlog "$DETAIL-p$TEXT, $DETAIL--platforms";
	wlog "   A comma-separated list of platforms. Supported are ${DETAIL}linux$TEXT, ${DETAIL}mac$TEXT, and ${DETAIL}windows$TEXT.";
	wlog "$DETAIL-g$TEXT, $DETAIL--games";
	wlog "   A comma-separated list of games to download. To get the list of games, please visit ${DETAIL}https://www.gogdb.org/$TEXT, find your games, and use their ID values.";
	wlog "   For example:";
	wlog "   ${DETAIL}1207666073,1296025128,2083200433$TEXT will download the games Akalabeth: World of Doom, M.U.L.E., and Dragon's Lair Trilogy. Do note that GOG archiver is not a piracy tool, and can only download games your account owns.";
	wlog "$DETAIL-c$TEXT, $DETAIL--colour$TEXT, $DETAIL--color";
	wlog "   How much colour should be used in the output.";
	wlog "   Choose between ${DETAIL}all, less, some,$TEXT and ${DETAIL}none$TEXT.";
	wlog "   ${DETAIL}less$TEXT is used by default.";
	wlog "$DETAIL-r$TEXT, $DETAIL--root";
	wlog "   Sets the root directory for GOG archiver.";
	wlog "   The root directory holds downloaded games and the authorization cookie file. By default it is the same directory as the script file.";
	wlog "$DETAIL-h$TEXT, $DETAIL--help";
	wlog "   Displays this help page.";
	wlog "$DETAIL-b$TEXT, $DETAIL--no-banner";
	wlog "   Hides the banner.";
	wlog "$DETAIL-v$TEXT, $DETAIL--version";
	wlog "   Prints GOG archiver's version.";
	wlog "$DETAIL-i$TEXT, $DETAIL--ignore-types";
	wlog "   Comma-separated list of types of downloads to ignore, for example ${DETAIL}patch$TEXT or ${DETAIL}installer$TEXT.";
	wlog "${DETAIL}Examples:";
	wlog "   ${DETAIL}gogarchiver -p windows -g 1207665503 -i patch";
	wlog "      Downloads the Windows release of Terraria, ignoring patches."
	wlog ""
	wlog "   ${DETAIL}gogarchiver -p windows,linux,mac -g 1296025128 -c none";
	wlog "      Downloads windows, linux, and mac releases of Akalabeth: World of Doom, and disables colour in the output."
	exit 0;
}

# Parameters:
# - path
# - output file (hyphen for stdout)
# - additional wget parameters
# Returns: wget's output
execute_request() {
	wget "https://www.gog.com/$1" \
		--header 'accept: application/json' \
		--header 'user-agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36' \
		--header "cookie: gog-al=$AUTH" \
		--header 'dnt: 1' \
		"$3" \
		-q \
		-O "$2"
}

# Parameters: none
# Returns: nothing
check_commands() {
	for command in "${DEPENDENCIES[@]}"; do
		if ! command -v "$command" > /dev/null; then
			elog "$DETAIL$command$TEXT is required for this script. It is likely in the '$command' package of your distribution.";
			exit 1;
		fi
	done;
}

# Parameters: none
# Returns: nothing
check_root() {
	if ! test -d "$GAR_ROOT"; then
		elog "The GOG archiver root directory at $DETAIL$GAR_ROOT$TEXT does not exist or is not a directory.";
		exit 1;
	fi
}

# Parameters: none
# Returns: nothing
check_arguments() {
	if [ -z "$PLATFORMS" ]; then
		elog "Please specify a comma-separated list of platforms with $DETAIL--platforms$TEXT. Supported are ${DETAIL}linux$TEXT, ${DETAIL}mac$TEXT, and ${DETAIL}windows$TEXT.";
		exit 1;
	fi
	if [ -z "$GAMES" ]; then
		elog "Please specify a list of games with $DETAIL--games$TEXT. Consult $DETAIL--help$TEXT if you don't know what to do.";
		exit 1;
	fi
}

# Parameters: none
# Returns: nothing
check_authorization() {
	local user_metadata;
	local username;
	ilog "Checking authentication...";
	user_metadata="$(get_selfuser_metadata)";
	if [[ "$(echo "$user_metadata" | jq -r '.isLoggedIn')" == 'true' ]]; then
		username="$(echo "$user_metadata" | jq -r '.username')";
		echo -e "$LOW	   ┗ ${TEXT}Logged in as $DETAIL$username$TEXT.$R";
	else
		elog "Invalid authorization cookie has been provided. Please make sure that you're using the exact value of the 'gog-al' cookie from your browser.";
		exit 1;
	fi
}

# Parameters: none
# Returns: nothing
check_platform() {
	if ! grep -E '(linux|windows|mac)' <<< "$1" > /dev/null; then
		elog "$DETAIL$1$TEXT is not a supported platform. Please use ${DETAIL}linux$TEXT, ${DETAIL}mac$TEXT, or ${DETAIL}windows$TEXT.";
		return 1;
	fi
}

# Parameters:
# - json
# - jq query
# - additional jq arguments
# Returns: result
get_from_json() {
	echo "$1" | jq "$2" "$3"
}

# Parameters:
# - download metadata json
# Returns: nothing
# Sets:
# - name
# - version
# - size
# - manualUrl
# -type
set_download_metadata() {
	name="$(get_from_json "$download" '.name' '-r')";
	version="$(get_from_json "$download" '.version' '-r')";
	size="$(get_from_json "$download" '.size' '-r')";
	manualUrl="$(get_from_json "$download" '.manualUrl' '-r')";
	type="$(perl -pe 's#\/downloads\/[a-z_]*?\/.{2}\d+(.*?)\d+#\1#p' <<< "$manualUrl")"
}

# Perform a sanity check
is_version
banner
is_help
check_commands;
check_root;
check_arguments;
check_authorization;

# Iterate over all IDs in 'games'
for id in ""${GAMES//,/ }; do
	ilog "Reading metadata of $DETAIL$id$TEXT...";
	metadata="$(get_game_metadata "$id")";
	if [[ "$metadata" == '[]' ]]; then
		elog "Unable to fetch metadata for $DETAIL$id$TEXT. Does the currently authenticated account own the game?.";
		continue;
	fi;
	
	title="$(get_from_json "$metadata" '.title' '-r')";

	for plat in ${PLATFORMS//,/ }; do
		platform="$(tr '[:upper:]' '[:lower:]' <<< "$plat")";
		check_platform "$platform" || continue;
		
		if [[ "$(get_from_json "$metadata" ".downloads[0][1].$platform" '-r')" == 'null' ]]; then
			elog "$DETAIL$title$TEXT does not feature a release compatible with $DETAIL$platform$TEXT.";
			continue;
		fi
		
		ilog "Extracted metadata for $DETAIL$title$TEXT on $DETAIL$platform$TEXT:";
		
		downloads="$(get_from_json "$metadata" ".downloads[0][1].$platform|.[]" '-rc')";
		while IFS= read -r download; do
			set_download_metadata;
			echo -e "$LOW	   ┣ $DETAIL$name$R";
			echo -e "$LOW	   ┃ ┣ ${TEXT}Version: $DETAIL$version$R";
			echo -e "$LOW	   ┃ ┣ ${TEXT}Type:	$DETAIL$type$R";
			echo -e "$LOW	   ┃ ┗ ${TEXT}Size:	$DETAIL$size$R";
		done <<< "$downloads";
		
		directory="$GAR_ROOT/$DOWNLOADS_ROOT/$title/$platform";
		[ -d "$directory" ] || mkdir -p "$directory";

		while IFS= read -r download; do
			set_download_metadata;
			unset ignored;
			for ignore in ${IGNORE//,/ }; do
				if [ "$type" == "$ignore" ]; then
					ignored=true;
					break;
				fi;
			done;
			if [ -v ignored ]; then
				ilog "Not downloading $DETAIL$title/$name$TEXT for $DETAIL$platform$TEXT because it is of type $DETAIL$type$TEXT, which is ignored."
				continue;
			fi;
			
			cleanname="$(tr -d ')(.' <<< "$name" | tr ' ' '_')"
			file="$directory/$cleanname-$version";
			if compgen -G "$file*" > /dev/null; then
				ilog "Not downloading $DETAIL$title/$name$TEXT for $DETAIL$platform$TEXT because it is already downloaded";
			else
				ilog "Downloading $DETAIL$title/$name$TEXT version $DETAIL$version$TEXT...";
				download "$manualUrl" "$platform-$cleanname"
				location="$DOWNLOAD_LOCATION-$platform-$cleanname"
				extension="$(file -b --extension "$location" | perl -pe 's#^([^?]*?)\/.*$#.\1#p' | sed 's/???//')"
				[ -n "$extension" ] && dlog "Extension is $DETAIL$extension$TEXT.";
				fullfile="$file$extension"
				if [ -z "$extension" ] && grep -E '(linux|mac)' <<< "$platform" > /dev/null; then
					chmod +x "$location";
					dlog "Platform is linux or mac, and the extension could not be determined, so I'm setting the executable bit on the file.";
				fi
				mv "$location" "$fullfile"
				ilog "Downloaded to $DETAIL$fullfile$TEXT.";
			fi
		done <<< "$downloads";
	done
done
dlog "Finished execution non-erroneously."