# arguments are not strictly necessary to build

CC_EXTRA_ARGS = -Wall -Wextra -O3 -ggdb

.PHONY: default
default: build/disk.iso

# command and arguments that you should be careful about changing

NASM = nasm
CC = toolchain/usr/bin/x86_64-elf-c++
AR = toolchain/usr/bin/x86_64-elf-ar
LD = toolchain/usr/bin/x86_64-elf-ld

KERNEL_INCLUDES = \
  dependencies/limine \
  dependencies/mintsuki-headers \
  kernel/include

USER_INCLUDES = \
  dependencies/mintsuki-headers \
  euler/include \
  $(wildcard libraries/*/include)

NASM_ARGS = -f elf64

CC_ARGS_COMMON = -std=c++20 -static -mno-sse -Iinclude ${CC_EXTRA_ARGS}
CC_ARGS_KERNEL = \
  ${CC_ARGS_COMMON} -ffreestanding -fno-exceptions \
  -fno-rtti -mcmodel=kernel ${KERNEL_INCLUDES:%=-I%}
CC_ARGS_USER = ${CC_ARGS_COMMON} ${USER_INCLUDES:%=-I%}

LD_ARGS = -z noexecstack

LIBDIR = toolchain/usr/x86_64-elf/lib

SOURCES_FIND = -type f -regex '.*\.\(asm\|cpp\)'

# kernel section

build/kernel/%.asm.o: kernel/%.asm
	@mkdir -p ${@D}
	${NASM} ${NASM_ARGS} $^ -o $@

build/kernel/%.cpp.o: kernel/%.cpp
	@mkdir -p ${@D}
	${CC} -c ${CC_ARGS_KERNEL} $^ -o $@

KERNEL_SOURCES = $(shell find kernel/source ${SOURCES_FIND})
build/kernel.elf: ${KERNEL_SOURCES:%=build/%.o}
	${LD} ${LD_ARGS} -T kernel/link.ld $^ -o $@

# euler section

build/euler/%.asm.o: euler/%.asm
	@mkdir -p ${@D}
	${NASM} ${NASM_ARGS} $^ -o $@

build/euler/%.cpp.o: euler/%.cpp
	@mkdir -p ${@D}
	${CC} -c ${CC_ARGS_USER} -ffreestanding $^ -o $@

EULER_SOURCES = $(shell find euler/source ${SOURCES_FIND})
${LIBDIR}/crt0.o ${LIBDIR}/libc.a ${LIBDIR}/libg.a ${LIBDIR}/libm.a build/euler.a&: ${EULER_SOURCES:%=build/%.o}
	${AR} rcs build/euler.a $^
	cp build/euler.a ${LIBDIR}/libc.a
	${NASM} ${NASM_ARGS} /dev/null -o ${LIBDIR}/crt0.o
	${AR} rcs ${LIBDIR}/libg.a ${LIBDIR}/crt0.o
	${AR} rcs ${LIBDIR}/libm.a ${LIBDIR}/crt0.o

# libraries and applications section

ALL_LIBRARIES = daguerre pake
ALL_APPLICATIONS = clock goldman hello init

  clock_LIBRARIES = daguerre pake
goldman_LIBRARIES = daguerre
  hello_LIBRARIES = daguerre pake
   init_LIBRARIES =

build/%.cpp.o: %.cpp
	@mkdir -p ${@D}
	${CC} -c ${CC_ARGS_USER} $^ -o $@

# ${1} = library name
define LIBRARY_TEMPLATE =
${1}_SOURCES = $$(shell find libraries/${1}/source $${SOURCES_FIND})
$${LIBDIR}/lib${1}.a build/libraries/lib${1}.a&: $${${1}_SOURCES:%=build/%.o}
	$${AR} rcs build/libraries/lib${1}.a $$^
	cp build/libraries/lib${1}.a $${LIBDIR}/lib${1}.a
endef

# ${1} = application name
define APPLICATION_TEMPLATE =
${1}_SOURCES = $$(shell find applications/${1}/source $${SOURCES_FIND})
build/applications/${1}.elf: $${${1}_SOURCES:%=build/%.o} $${${1}_LIBRARIES:%=$${LIBDIR}/lib%.a} $${LIBDIR}/libc.a
	$${CC} ${CC_ARGS_USER} $${${1}_SOURCES:%=build/%.o} $$(patsubst %,-l%,$${${1}_LIBRARIES}) -o $$@
endef

$(foreach library,${ALL_LIBRARIES},$(eval $(call LIBRARY_TEMPLATE,${library})))
$(foreach application,${ALL_APPLICATIONS},$(eval $(call APPLICATION_TEMPLATE,${application})))

# initfs and disk section

build/initfs.tgz: ${ALL_APPLICATIONS:%=build/applications/%.elf}
	rm -rf build/initfs
	cp -r skeleton build/initfs
	$(foreach application,${ALL_APPLICATIONS},cp build/applications/${application}.elf build/initfs/bin/${application}; )
	cd build/initfs && tar czf ../initfs.tgz .

build/disk.iso: build/kernel.elf build/initfs.tgz
	rm -rf build/iso
	mkdir build/iso
	cp dependencies/limine/bin/limine-bios.sys dependencies/limine/bin/limine-bios-cd.bin \
	  build/kernel.elf build/initfs.tgz build/iso/
	echo 'TIMEOUT=0' > build/iso/limine.cfg
	echo ':Hilbert OS' >> build/iso/limine.cfg
	echo 'PROTOCOL=limine' >> build/iso/limine.cfg
	echo 'KERNEL_PATH=boot:///kernel.elf' >> build/iso/limine.cfg
	echo 'MODULE_PATH=$$boot:///initfs.tgz' >> build/iso/limine.cfg
	echo 'MODULE_CMDLINE=initfs' >> build/iso/limine.cfg
	xorriso -as mkisofs -b limine-bios-cd.bin -no-emul-boot -boot-load-size 4 \
	  -boot-info-table --protective-msdos-label build/iso -o $@

# phony targets

.PHONY: run
run: build/disk.iso
	gdb -x qemu.gdb

.PHONY: clean
clean:
	rm -rf build ${LIBDIR}/crt0.o ${LIBDIR}/libc.a ${LIBDIR}/libg.a ${LIBDIR}/libm.a $(foreach library,${ALL_LIBRARIES},${LIBDIR}/lib${library}.a)