#!/bin/sh
set -e

## true
# avoid the shell overhead of fork/exec'ing just to call /bin/true
# returns true
true() { : ; }

## false
# avoid the shell overhead of fork/exec'ing just to call /bin/false
# returns false
false() { ! : ; }

## error <message>
# displays the supplied <message> on stderr
error() { echo "error: $*" >&2; }

## die <message>
# display the supplied <message> and exit with an error
die() { error "$*"; exit 1; }

## simple_usage <cmd> <summary>
# A simplified usage interface for commands with no option arguments.
simple_usage()
{
	cmd="${1}"
	summary="${2}"
	shift 2

	if test "$#" -eq '0'; then
		error "no arguments to command"
		echo "try 'build ${cmd} --help'" >&2
		exit 1
	fi

	while test "$#" -gt '0'; do
		case "${1}" in
		(-h|-help|--help)
			echo "usage: build ${cmd} ${summary}" 2>&1
			exit 0;;
		(--)	shift; break;;
		(-*)	error "unknown option '${1}'"
			echo "try 'build ${cmd} --help'" >&2
			exit 1;;
		(*)	break;;
		esac
	done
}

## mkenv
# prepare the environment structure for the current package
mkenv()
{
	for dir in "${W}" "${L}" "${E}" "${D}" "${T}"; do
		if [ ! -d "${dir}" ]; then
			mkdir -p "${dir}"
		fi
	done
	unset dir

	if [ "$#" -gt "0" ]; then
		cat /dev/null > "${L}/${1}.log"
		set > "${E}/${1}.env"
	fi
}

## import
# import a builder library.
# During import a library can check 'BUILDER_CALL_STACK' to see if it equals
# '__main__'.  If it does, then the library is being executed directly.
# Further more, builder-libraries can do load-time tests in order to perform
# various one-time optimizations.
#
# Note: this is borrowed from 'shlib' almost verbatim w/ the only change being
# the variable names.
import()
{
	set -- "${1}" "`echo "${1}" | tr '-' '_'`"
	test -f "${BUILDER_LIBDIR}/${1}" || die "library does not exist '${1}'"
	eval "test -z \"\${BUILDER_IMPORT_${2}}\"" || return
	BUILDER_CALL_STASH="${BUILDER_CALL_STACK}"
	BUILDER_CALL_STACK="${BUILDER_CALL_STACK} ${1}" . "${BUILDER_LIBDIR}/${1}"
	eval "BUILDER_IMPORT_${2}='${BUILDER_LIBDIR}/${1}'"
	if [ -z "${BUILDER_IMPORTED}" ]; then
		BUILDER_IMPORTED="${1}"
	else
		BUILDER_IMPORTED="${BUILDER_IMPORTED} ${1}"
	fi
	BUILDER_CALL_STACK="${BUILDER_CALL_STASH}"
}

## include
# include a builder config.
# This command simply sources the named config found in TOPDIR/.builder/
include()
{
	set -- "${1}" "`echo "${1}" | tr '-' '_'`"
	test -f "${BUILDER_CFGDIR}/${1}" || die "config not found '${1}'"
	eval "test -z \"\${BUILDER_INCLUDE_${2}}\"" || return
	. "${BUILDER_CFGDIR}/${1}"
	eval "BUILDER_INCLUDE_${2}='${BUILDER_CFGDIR}/${1}'"
	if [ -z "${BUILDER_INCLUDED}" ]; then
		BUILDER_INCLUDED="${1}"
	else
		BUILDER_INCLUDED="${BUILDER_INCLUDED} ${1}"
	fi
}

# FIXME we need a build-resolv subcmd for resolving package names
parse_pkg_name()
{
	# Only allow a single '/' in the name
	if [ "1${1##*/}" != "1${1#*/}" ]; then
		return 1
	fi

	if [ "2${1#*/}" != "2${1}" ]; then
		printf '%s' "${1}"
	else
		printf '%s' "${1}/all"
	fi
}

parse_name()
{
	if ! parse_pkg_name "${1}" > /dev/null 2>&1; then
		return "$?"
	fi

	set -- "$(parse_pkg_name "${1}")"
	printf '%s' "${1#*/}"
}

parse_category()
{
	if ! parse_pkg_name "${1}" > /dev/null 2>&1; then
		return "$?"
	fi

	set -- "$(parse_pkg_name "${1}")"
	printf '%s' "${1%/*}"
}

## load_rules <package>
# load the Buildrules of a package into the current program space
load_rules()
{
	# We can aquire this data before we bother loading anything
	NAME="$(parse_name "${1}")"
	CATEGORY="$(parse_category "${1}")"
	PKG_NAME="${CATEGORY}/${NAME}"

	if [ ! -d "${BUILDER_PKGDIR}/${PKG_NAME}" ]; then
		die "no such package '${1}'"
	fi

	RULESFILE="${BUILDER_PKGDIR}/${CATEGORY}/${NAME}/Buildrules"
	if [ ! -f "${RULESFILE}" ]; then
		die "no rulesfile for package '${1}'"
	fi

	export NAME CATEGORY PKG_NAME RULESFILE

	# These variables are used by the Buildrules and fundmentally make up
	# the majority of their environ data
	F="${BUILDER_PKGDIR}/${CATEGORY}/${NAME}/files"
	W="${BUILDER_TMPDIR}/${CATEGORY}/${NAME}/work"
	L="${BUILDER_TMPDIR}/${CATEGORY}/${NAME}/log"
	E="${BUILDER_TMPDIR}/${CATEGORY}/${NAME}/env"
	T="${BUILDER_TMPDIR}/${CATEGORY}/${NAME}/tmp"
	D="${BUILDER_TMPDIR}/${CATEGORY}/${NAME}/install"

	export F W L E T D

	# Source in the category Buildrules
	if [ -f "${BUILDER_PKGDIR}/${CATEGORY}/.buildrules" ]; then
		. "${BUILDER_PKGDIR}/${CATEGORY}/.buildrules"
	fi

	# These variables are only set within a Rulesfile and thus need to be
	# cleared before sourcing it in.
	VERSION=
	RELEASE=
	DESCRIPTION=
	LICENSE=
	SOURCE_URI=
	PATCHES=
	RDEPENDS=
	BDEPENDS=
	EXTRA_SOURCES=

	# Source in the package Buildrules
	. "${RULESFILE}"

	if [ "${CATEGORY}/${NAME}" != "${1}" ]; then
		die "Buildrules can not set the package name"
	fi

	if [ -z "${VERSION}" ]; then
		die "missing version in '${NAME}'"
	fi

	if [ -z "${DESCRIPTION}" ]; then
		die "missing description in '${NAME}'"
	fi

	if test -z "${RELEASE}"; then
		RELEASE="${VERSION#*-}"
		if ! test -z "${RELEASE}" && test "${RELEASE}" != "${VERSION}"; then
			VERSION="${VERSION%-${RELEASE}}"
			if test -z "${S}"; then
				S="${W}/${NAME}-${VERSION}-${RELEASE}"
			fi
		else
			RELEASE='0'
		fi
	fi
	if test -z "${S}"; then
		S="${W}/${NAME}-${VERSION}"
	fi

	export VERSION RELEASE DESCRIPTION LICENSE SOURCE_URI PATCHES BDEPENDS RDEPENDS
}

if [ "${BUILDER_DEBUG:-0}" != '0' ]; then
	set -x
fi

##
# Check to see if we are wrapping a sub-command
BUILDER_COMMAND=
if [ -f "${1}" ]; then
	case "${1##*/}" in
	(build-*)
		BUILDER_COMMAND="${1}"
		shift
		. "${BUILDER_COMMAND}"
		# exit with the exit status of the last command from within the
		# sub-script.  This is normal shell behavior, we are just
		# making it explicit.
		exit $?
		;;
	esac
fi

##
# We are being called as 'build [options] <command>'.  Setup the environment
# for execution of a sub-command.

BUILDER_DEBUG=0
while [ "$#" -gt "0" ]; do
	case "$1" in
	(-v|-version|--version)	version; exit 0;;
	(-d|-debug|--debug)
		BUILDER_DEBUG=1
		set -x
		;;
	(-h|-help|--help)
		shift 1
		set -- help "$@"
		break
		;;
	(-*)	echo "error: unknown option '${1}'" >&2
		echo "try '${0} help'" >&2
		exit 1
		;;
	(*)	break
		;;
	esac
	shift 1
done
export BUILDER_DEBUG

##
# Done with arguments, time for setting up the enviroment for the build
TOPDIR="${PWD}"
while [ ! -z "${TOPDIR}" ]; do
	[ -d "${TOPDIR}/.builder" ] && break
	TOPDIR="${TOPDIR%/*}"
done
if [ -z "${TOPDIR}" ]; then
	echo "error: current path not in a build-tree" >&2
	exit 1
fi

# We are being executed as 'build <cmd>'
BUILDER_CALL_STACK='__main__'
export BUILDER_CALL_STACK

# set the builtin defaults based on TOPDIR.  We export TOPDIR as BUILDER_TOPDIR
# to avoid stepping on the potential usage of TOPDIR within package Makefiles
BUILDER_TOPDIR="${TOPDIR}"
BUILDER_CFGDIR="${TOPDIR}/.builder"
BUILDER_PKGDIR="${TOPDIR}/packages"
BUILDER_SRCDIR="${TOPDIR}/sources"
BUILDER_ATFDIR="${TOPDIR}/artifacts"
BUILDER_LIBDIR="${TOPDIR}/scripts/libexec"
BUILDER_TMPDIR="${TOPDIR}/tmp"

export BUILDER_CFGDIR BUILDER_PKGDIR BUILDER_SRCDIR
export BUILDER_ATFDIR BUILDER_LIBDIR BUILDER_TOPDIR
export BUILDER_TMPDIR

# The default SYSROOT .. Much of the toolchain already obeys SYSROOT .. we
# aren't setting a policy so much as obeying one.
SYSROOT="${SYSROOT:-${BUILDER_TOPDIR}/sysroot}"
export SYSROOT

# We save the pre-config PATH as BUILDER_PATH to be used by downstream tools.
# FIXME detect prefixing BUILDER_LIBDIR onto PATH multiple times?
BUILDER_PATH="${BUILDER_LIBDIR}:${PATH}"
PATH="${BUILDER_PATH}"
export BUILDER_PATH PATH

# include our default config
test -f "${BUILDER_CFGDIR}/config" && include config

# FIXME MAKE_OPTS should default to #CPUS + 1, until we can detect #CPUS, we
# just set it to 2 for uni-processor systems.
MAKE_OPTS="${MAKE_OPTS:--j2}"
export MAKE_OPTS

# Default build target
# FIXME this should default to all/all
TARGET="${TARGET:-all/all}"
export TARGET

# If unspecified go ahead and ask gcc
CBUILD="${CBUILD:-$(build-dumpmachine)}"
export CBUILD

ARCHIVE_FORMAT="${ARCHIVE_FORMAT:-tar.bz2}"
export  ARCHIVE_FORMAT

# FIXME this stuff needs to be detected in a more reliable fashion
ARCH="${ARCH:-$(uname -m)}"
export ARCH

CHOST="${CHOST:-${CBUILD}}"
export CHOST

# if we aren't given an action then we do everything
ACTION="install"
if [ "$#" -gt "0" ]; then
	ACTION="${1}"
	shift 1
fi

if command -v "build-make-${ACTION}" 2>&1 > /dev/null; then
	BUILDER_COMMAND="$(command -v 'build-make')"
	set -- "${ACTION}" "${@}"
elif command -v "build-${ACTION}" 2>&1 > /dev/null; then
	BUILDER_COMMAND="$(command -v "build-${ACTION}")"
else
	error "unknown action '${ACTION}'"
	echo "try '${0} help'" >&2
	exit 1
fi
export BUILDER_COMMAND

exec "${BUILDER_COMMAND}" "${@}"