PREFIX?=/usr/local
LOCALBASE?=/usr/local
MINIROOTFS?=$(PWD)/alpine-minirootfs.tar.gz
PACKAGES?=$(PWD)/*.apk
BOOT_SERVICES?=networking urandom bootmisc modules hostname hwclock sysctl syslog
DEFAULT_SERVICES?=acpid crond
SYSINIT_SERVICES?=devfs dmesg hwdrivers mdev
ETC_SRCS?=$(PWD)/etc/wpa_supplicant

ROOT=$(PREFIX)/share/wifibox
SHAREDIR=$(DESTDIR)$(ROOT)
ETCDIR=$(DESTDIR)$(PREFIX)/etc/wifibox
MANDIR=$(DESTDIR)$(PREFIX)/share/man
RUNDIR=$(DESTDIR)/var/run/wifibox

WORKDIR?=$(PWD)/work
BOOTSTRAPDIR=$(WORKDIR)/bootstrap
GUESTDIR=$(WORKDIR)/image-contents

BOOTDIR=$(GUESTDIR)/boot

SHAREMODE?=0644

ECHO=/bin/echo
ENV=/usr/bin/env
MKDIR=/bin/mkdir
CP=/bin/cp
SH=/bin/sh
SED=/usr/bin/sed
TAR=$(LOCALBASE)/bin/gtar
FIND=/usr/bin/find
GREP=/usr/bin/grep
RM=/bin/rm
LN=/bin/ln
LS=/bin/ls
GZIP=/usr/bin/gzip
INSTALL_DATA=/usr/bin/install -m $(SHAREMODE)
ID=/usr/bin/id
UMOUNT=/sbin/umount
STAT=/usr/bin/stat
TOUCH=/usr/bin/touch
TRUE=/usr/bin/true
GIT=$(LOCALBASE)/bin/git
PATCHELF=$(LOCALBASE)/bin/patchelf
BRANDELF=/usr/bin/brandelf
TAR2SQFS=$(LOCALBASE)/bin/tar2sqfs

UID!=			$(ID) -u

ELF_INTERPRETER=	/lib/ld-musl-x86_64.so.1
APK=			sbin/apk
BUSYBOX=		bin/busybox

_APK=			$(BOOTSTRAPDIR)/$(APK)
_BUSYBOX=		$(BOOTSTRAPDIR)/$(BUSYBOX)

.if !empty(INITRD_FILES)
INITRD_IMG=		$(BOOTDIR)/initramfs
.endif

SQUASHFS_COMP?=		lzo
SQUASHFS_IMG=		$(PWD)/alpine-$(VERSION).squashfs.img
SQUASHFS_VMLINUZ=	$(BOOTDIR)/vmlinuz*

.if !defined(VERSION)
VERSION!=	$(GIT) describe --tags --always
.endif

SUB_LIST=	PREFIX=$(PREFIX) \
		LOCALBASE=$(LOCALBASE) \
		ROOT=$(ROOT)

_SUB_LIST_EXP=  ${SUB_LIST:S/$/!g/:S/^/ -e s!%%/:S/=/%%!/}

APPLIANCEDIR=	$(RUNDIR)/appliance

$(GUESTDIR)/.done:
	$(RM) -rf \
		$(GUESTDIR) \
		$(BOOTSTRAPDIR)
	$(MKDIR) -p \
		$(GUESTDIR) \
		$(BOOTSTRAPDIR)
	$(TAR) -xf $(MINIROOTFS) -C $(BOOTSTRAPDIR)
.for bin in $(_APK) $(_BUSYBOX)
	$(PATCHELF) \
		--set-interpreter $(BOOTSTRAPDIR)$(ELF_INTERPRETER) \
		${bin}
	$(BRANDELF) -t Linux ${bin}
.endfor
	# add packages without chroot(8)
	$(ENV) LD_LIBRARY_PATH=$(BOOTSTRAPDIR)/lib \
		$(_APK) add \
			--initdb \
			--no-network \
			--no-cache \
			--force-non-repository \
			--allow-untrusted \
			--no-progress \
			--clean-protected \
			--root $(GUESTDIR) \
			--no-scripts \
			--no-chown \
			$(PACKAGES)
	# remove APK metadata
	$(RM) -rf $(GUESTDIR)/lib/apk
	# rebuild module dependency data
	$(ENV) LD_LIBRARY_PATH=$(BOOTSTRAPDIR)/lib \
		$(_BUSYBOX) \
		depmod -A -b $(GUESTDIR) $$($(LS) $(GUESTDIR)/lib/modules)
	# try unmounting `linprocfs` if that was mounted (on FreeBSD 13
	# or later)
	$(UMOUNT) $(GUESTDIR)/proc || $(TRUE)
	# install extra files manually
.if exists($(PWD)/guest)
	$(CP) -R $(PWD)/guest/ $(GUESTDIR)
.endif
	# rc-update add
.for runlevel in boot default sysinit
.for service in $(${runlevel:tu}_SERVICES)
	$(LN) -s /etc/init.d/${service} $(GUESTDIR)/etc/runlevels/${runlevel}
.endfor
.endfor
	# add extra file system pass-through mounts
.if defined(EXTRA_VIRTFS_MOUNTS)
.for mnt in $(EXTRA_VIRTFS_MOUNTS)
	$(ECHO) "${mnt:C@:@ @} 9p trans=virtio,rw 0 0" \
		>> $(GUESTDIR)/etc/fstab
.endfor
.endif
	# fix symbolic links
	$(FIND) . -type l -exec stat -f "%N___%Y" {} \; \
		| $(GREP) /compat/linux \
		| $(SED) -E 's!(.*)___/compat/linux(.*)!rm \1 \&\& ln -s \2 \1!' \
		| $(SH)
	# mark the process done
	$(TOUCH) $(GUESTDIR)/.done

image-contents: $(GUESTDIR)/.done

EXCLUSIONS=	$(WORKDIR)/exclusions

.if defined(FIRMWARE_FILES)
.for fw_file in $(FIRMWARE_FILES)
__FW_FILES+=		-name ${fw_file} -or
.endfor
_FW_FILES=		-not \( ${__FW_FILES:S/ -or$//W} \)
.endif

$(SQUASHFS_IMG): image-contents
	(cd $(GUESTDIR) \
		&& $(FIND) . \
		| $(GREP) -E "[.]/((dev|proc|run|sys|tmp|var)/.*|boot|[.]done)" \
		> $(EXCLUSIONS))
.if defined(_FW_FILES)
	(cd $(GUESTDIR) \
		&& $(FIND) ./lib/firmware -not -type d -and $(_FW_FILES) \
		>> $(EXCLUSIONS))
.endif
	$(TAR) \
		--create \
		--file - \
		--directory $(GUESTDIR) \
		--owner 0 \
		--group 0 \
		--no-wildcards \
		--exclude-from $(EXCLUSIONS) \
		. \
		| $(TAR2SQFS) \
			--compressor $(SQUASHFS_COMP) \
			$(SQUASHFS_IMG)

_TARGETS=	$(SQUASHFS_IMG)

all:	$(_TARGETS)

install:
	$(MKDIR) -p $(SHAREDIR)
	$(INSTALL_DATA) $(SQUASHFS_VMLINUZ) $(SHAREDIR)/vmlinuz
	$(INSTALL_DATA) $(SQUASHFS_IMG) $(SHAREDIR)/disk.img
	$(SED) ${_SUB_LIST_EXP} share/grub.cfg > $(SHAREDIR)/grub.cfg

	$(MKDIR) -p $(ETCDIR)
.for srcs in $(ETC_SRCS)
	$(CP) -R ${srcs}/* $(ETCDIR)/
.endfor

	$(MKDIR) -p $(MANDIR)/man5
	$(SED) ${_SUB_LIST_EXP} man/wifibox-alpine.5 \
	  | $(GZIP) -c > $(MANDIR)/man5/wifibox-alpine.5.gz

	$(MKDIR) -p $(APPLIANCEDIR)
	$(CP) -R $(GUESTDIR)/var/* $(APPLIANCEDIR)/
	$(RM) -rf $(APPLIANCEDIR)/lock
	$(LN) -s /run/lock $(APPLIANCEDIR)/lock

clean:
	$(RM) -rf $(GUESTDIR)
	$(RM) -f $(SQUASHFS_IMG)

.MAIN:	all