# By eroen <eroen-overlay@occam.eroen.eu>, 2016
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
# $Id$

# @ECLASS: steam.eclass
# @MAINTAINER:
# eroen <eroen-overlay@occam.eroen.eu>
# @AUTHOR:
# eroen <eroen-overlay@occam.eroen.eu>
# @BLURB: Eclass for fetching packages from Steam
# @DESCRIPTION:
# Conveiniently set up and authenticates with steamcmd and use it to install
# applications.

# General steamcmd documentation:
# https://developer.valvesoftware.com/wiki/SteamCMD

case "${EAPI:-0}" in
	6)
		;;
	*)
		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
		;;
esac

inherit linux-info

# Some packages use the eclass just for variables
case $CATEGORY/$PN in
	net-misc/steam-eclass-utils) ;;
	net-misc/steamcmd-bin) ;;
	*)
		EXPORT_FUNCTIONS pkg_setup src_unpack
		DEPEND="net-misc/steamcmd-bin
			net-misc/steam-eclass-utils"
		;;
esac


# @ECLASS-VARIABLE: ESTEAM_APPID
# @DEFAULT_UNSET
# @DESCRIPTION:
# Steam App ID for steam_src_unpack to fetch.  This must be set before
# steam_src_unpack is called.  The App ID for an application can be found on
# https://steamdb.info

# @ECLASS-VARIABLE: ESTEAM_ANON
# @DESCRIPTION:
# Set this to "yes" if the application can be fetched with anonymous login.
: ${ESTEAM_ANON:=no}

# @ECLASS-VARIABLE: ESTEAM_PLATFORM
# @DEFAULT_UNSET
# @DESCRIPTION:
# If this is non-empty, steam_src_unpack will override the current platform in
# order to fetch applications for other platforms.  Possible values are:
# "linux", "macos", and "windows".  This is useful if you only want to install
# non-executable data files.

# @ECLASS-VARIABLE: ESTEAM_CREDS
# @DESCRIPTION:
# Path to credentials file.  This should not be set in ebuilds, it is meant as
# user configuration.  This file not required if EVCS_OFFLINE is non-empty, nor
# for packages that set ESTEAM_ANON.  Note that this file must be readable by
# the user your package manager runs as.
#
# This file should be created by the user, and has the following format:
#
# @CODE
# STEAM_USER: mysteamusername
# STEAM_PASS: mysteampassword
# MAIL_SERVER: imap.mymailhost.com
# MAIL_USER: myemailusername
# MAIL_PASS: myemailpassword
# @CODE
#
# The STEAM_* settings are used to authenticate with Steam.
#
# The MAIL_* settings are used to obtain the 'special access code' required to
# authenticate accounts with 'Steam Guard' enabled.  This is only available if
# net-misc/steam-eclass-utils is installed with the 'steam-guard' USE flag.
#
# Authenticating with 'Steam Guard' is highly experimental and expected to be
# fragile.  It is recommended to instead disable 'Steam Guard' by visiting
# https://store.steampowered.com/twofactor/manage_action
#
# If supplied, MAIL_SERVER should refer to an imap4/TLS server on port 993 that
# supports PLAIN authentication.  For gmail, PLAIN authentication must be
# explicitly enabled.  Only the IMAP folder named "INBOX" will be checked.
: ${ESTEAM_CREDS:=${EPREFIX%/}/etc/portage/creds_steam}

# @ECLASS-VARIABLE: ESTEAM_STORE_DIR
# @DESCRIPTION:
# Location for caching downloaded files between runs of the ebuild.  To disable
# caching, set this to zero-length string.
#
# This should not be set by ebuilds, it is meant for user configuration.
# ESTEAM_STORE_DIR ?= ${DISTDIR}/steam-cache

# @ECLASS-VARIABLE: EVCS_OFFLINE
# @DEFAULT_UNSET
# @DESCRIPTION:
# If non-empty, this variable prevents any online operations.
#
# If this is enabled, ESTEAM_STORE_DIR must not be empty and a cache must exist
# for the current ESTEAM_APPID.
#
# This should not be set by ebuilds, it is meant for user configuration.

# @ECLASS-VARIABLE: ESTEAM_SCRIPTDIR
# @INTERNAL
# @DESCRIPTION:
# Where the eclass expects to find its scripts.
ESTEAM_SCRIPTDIR="/usr/lib/steam-scripts"

# @ECLASS-VARIABLE: ESTEAM_STEAMCMD_SYSTEM
# @INTERNAL
# @DESCRIPTION:
# Absolute path to system copy of steamcmd
ESTEAM_STEAMCMD_SYSTEM="/opt/steamcmd"

# @ECLASS-VARIABLE: ESTEAM_STEAMCMD
# @INTERNAL
# @DESCRIPTION:
# Absolute path to our copy of steamcmd
ESTEAM_STEAMCMD="$T/steamcmd"

# @ECLASS-VARIABLE: ESTEAM_STEAMCMD_EXE
# @INTERNAL
# @DESCRIPTION:
# Absolute path to steamcmd.sh executable
ESTEAM_STEAMCMD_EXE="$ESTEAM_STEAMCMD/steamcmd.sh"

# @FUNCTION: steam_pkg_setup
# @DESCRIPTION:
# This function is exported.  It performs sanity checks and fails early for
# some issues.
steam_pkg_setup() {
	if [[ $MERGE_TYPE != binary ]]; then
		if [[ -n $EVCS_OFFLINE ]]; then
			if [[ -v ESTEAM_STORE_DIR && -z $ESTEAM_STORE_DIR ]]; then
				die "EVCS_OFFLINE is set, but ESTEAM_STORE_DIR is set to an empty value."
			fi
		else
			# CONFIG_PAX_ELFRELOCS must not be disabled (if present, only with grsecurity).
			# Textrels are all over the place :(
			if linux_config_exists; then
				if [[ -n $(linux_chkconfig_string PAX_ELFRELOCS) ]] && \
					! linux_chkconfig_present PAX_ELFRELOCS; then
					die "steamcmd needs support for x86 TEXTRELs to run"
				fi
			else
				ewarn "Could not find kernel config.  The install will fail later if"
				ewarn "x86 TEXTRELs are not supported on the system."
			fi

			if [[ yes != ${ESTEAM_ANON,,} && ! -r $ESTEAM_CREDS ]]; then
				die "ESTEAM_CREDS=$ESTEAM_CREDS is not readable"
			fi
		fi
	fi
}

# @FUNCTION: steam_get_cred
# @INTERNAL
# @DESCRIPTION:
# Takes 1 argument, prints the corresponding value from ESTEAM_CREDS.
steam_get_cred() {
	[[ 1 == $# ]] || die "$FUNCNAME - wrong number of arguments, expected 1"
	[[ -n $1 ]] || die "$FUNCNAME - passed empty argument"
	if [[ yes = $ESTEAM_ANON ]]; then
		case "$1" in
			STEAM_USER)
				printf "anonymous\n"
				;;
			*)
				printf "\n"
				;;
		esac
	else
		awk "/^${1^^}: /{print \$2}" "$ESTEAM_CREDS" || die
	fi
}

# @FUNCTION: steam_get_mail
# @INTERNAL
# @DESCRIPTION:
# Prints the verification code required to authenticate 'Steam Guard' enabled
# accounts with Steam.  The 'special access code' is obtained through IMAP, see
# the documentation for ESTEAM_CREDS
steam_get_mail() {
	printf "%s\n%s\n%s\n" \
		"$(steam_get_cred MAIL_SERVER)" \
		"$(steam_get_cred MAIL_USER)" \
		"$(steam_get_cred MAIL_PASS)" \
		| "${EPREFIX%/}/$ESTEAM_SCRIPTDIR"/steam-mail.py
}

# @FUNCTION: esteamcmd
# @DESCRIPTION:
# Runs steamcmd.sh with some boilerplate and passes it any arguments.  Assumes
# credentials have already been supplied to steamcmd to enable passwordless
# login.  This is normally called by steam_src_install, but it can be used
# directly for specialty use.
esteamcmd() {
	# Credentials are not passed, already supplied by steam_firstlogin
	"$ESTEAM_STEAMCMD_EXE" \
		"+@ShutdownOnFailedCommand 1" \
		"+@NoPromptForPassword 1" \
		"+login $(steam_get_cred STEAM_USER)" \
		"$@" \
		"+quit" || die -n "Error $? in $FUNCNAME $*"
}

# @FUNCTION: steam_firstlogin
# @DESCRIPTION:
# Run steamcmd.sh several times in order to bring it up to date and
# login/authenticate with Steam.  For 'Steam Guard' enabled accounts, obtaining
# the 'special access code' by imap is attempted.  This is normally called by
# steam_src_install, and must be called before esteamcmd.
steam_firstlogin() {
	# Ensure steamcmd is up to date
	einfo "Update steamcmd"
	"$ESTEAM_STEAMCMD_EXE" "+quit" || die "steamcmd.sh failed with exit code $?"

	# Attempt to log in
	# Supply password on stdin to avoid leaking it in /proc/$pid/cmdline
	einfo "Attempt to log in"
	printf "%s\n" "$(steam_get_cred STEAM_PASS)" \
		| "$ESTEAM_STEAMCMD_EXE" "+login $(steam_get_cred STEAM_USER)" "+quit"
	local ret=$?

	if [[ $ret == 5 ]]; then
		# 'Steam Guard' is enabled, attempt to get the 'special access code'
		# that (hopefully) was generated.
		if ! has_version "net-misc/steam-eclass-utils[steam-guard]"; then
			die "Steam account is \"Steam Guard\" enabled, but net-misc/steam-eclass-utils" \
				"is not installed with support for it enabled."
		fi
		einfo "Login failed, attempt to get 'Steam Guard' 'special access code' from email"
		local i imax=5
		for (( i=1; i<=imax; i++ )); do
			# supply 'special access code'
			einfo "'Steam Guard' login attempt $i of $imax"
			printf "%s\n" "$(steam_get_cred STEAM_PASS)" \
				| "$ESTEAM_STEAMCMD_EXE" "+set_steam_guard_code $(steam_get_mail)" \
				"+login $(steam_get_cred STEAM_USER)" \
				"+quit" && break
			einfo "steamcmd.sh exited with code $ret"
			(( i < 5 )) || die "Unable to log in"
			sleep 10
		done
	elif [[ $ret != 0 ]]; then
		die "steamcmd.sh failed with exit code $ret"
	fi
}

# @FUNCTION: steam_src_unpack
# @DESCRIPTION:
# Run steam_firstlogin, then use esteamcmd to install the application referred
# to by ESTEAM_APPID into S.  ESTEAM_PLATFORM can be set to force installing an
# application for a non-native platform.
#
# This function is exported.
steam_src_unpack() {
	if [[ -z $ESTEAM_APPID ]]; then
		die "ESTEAM_APPID is not set, $FUNCNAME cannot be used"
	fi

	local cmd_platform=
	[[ -n $ESTEAM_PLATFORM ]] && cmd_platform="+@sSteamCmdForcePlatformType ${ESTEAM_PLATFORM}"

	# This attempts to immitate the EGIT3_STORE_DIR logic in git-r3.eclass
	local distdir=${PORTAGE_ACTUAL_DISTDIR:-${DISTDIR}}
	: ${ESTEAM_STORE_DIR=${distdir}/steam-cache}
	if [[ -n $ESTEAM_STORE_DIR ]]; then
		local fetchdir=$ESTEAM_STORE_DIR/$ESTEAM_APPID
		[[ -n $ESTEAM_PLATFORM ]] && fetchdir+="/$ESTEAM_PLATFORM"
	else
		local fetchdir=$S
	fi
	einfo "Download location: $fetchdir"

	if [[ -n $EVCS_OFFLINE ]]; then
		if [[ ! -d $fetchdir ]]; then
			die "EVCS_OFFLINE is set, but fetchdir=$fetchdir does not exist."
		fi
	else
		einfo "Copy steamcmd to ${ESTEAM_STEAMCMD}"
		cp -rf "${EPREFIX%/}/$ESTEAM_STEAMCMD_SYSTEM" "${ESTEAM_STEAMCMD}" || die
		steam_firstlogin

		if [[ ! -d $fetchdir ]]; then
			(
				addwrite /
				mkdir -p "$fetchdir"
			) || die "Unable to create ${fetchdir}"
		fi

		einfo "Install app_id ${ESTEAM_APPID}"
		(
			addwrite "${fetchdir}"
			esteamcmd \
				"$cmd_platform" \
				"+force_install_dir \"$fetchdir\"" \
				"+app_update ${ESTEAM_APPID} verify"
		)
	fi

	if [[ -n $ESTEAM_STORE_DIR ]]; then
		einfo "Copying from cache to \$S"
		cp -fPpR "$fetchdir" "$S" || die
	fi
}