CARGO ?= cargo
STRIP ?= strip
CC ?= gcc

RUST_ARCH ?= x86_64

FEATURES := ""#"env_logger"

THIS_DIR := $(dir $(realpath $(lastword $(MAKEFILE_LIST))))
REPO_ROOT := $(realpath $(THIS_DIR)/..)
export SERVICEPOINT_HEADER_OUT := $(REPO_ROOT)/include

# TODO: check if override is needed
override _libc := $(if $(MUSL),musl,gnu)
override _profile := $(if $(PROFILE),$(PROFILE),release)
override _rust_cli_profile := $(if $(filter $(_profile),debug),dev,$(_profile))
override _link_type := $(if $(LINK),$(LINK),dynamic)

# TODO: make LINK=static fails with linker error "undefined reference to `_dl_find_object'" in libgcc_eh.a

_all_profiles := release debug size-optimized
ifeq (,$(filter $(_all_profiles),$(_profile)))
  _profile := $(error "PROFILE has to be set to one of: debug, release, size-optimized")
endif

STRIPFLAGS += -s --strip-unneeded -R .comment -R .gnu.version -R .note -R .note.gnu.build-id -R .note.ABI-tag
STATIC_LINK_LIBS += -lservicepoint_binding_c

RUST_TARGET := $(RUST_ARCH)-unknown-linux-$(_libc)

size-optimized_CARGOFLAGS += -Zbuild-std="core,std,alloc,proc_macro,panic_abort" \
	-Zbuild-std-features="panic_immediate_abort"
CARGOFLAGS += --manifest-path=$(REPO_ROOT)/Cargo.toml \
	--profile=$(_rust_cli_profile) \
	--no-default-features \
	--features=$(FEATURES) \
	--target=$(RUST_TARGET) \
	$($(_profile)_CARGOFLAGS)

CFLAGS += -Wall -Wextra -pedantic -fwhole-program -fPIE -pie
_no_debug_cflags := -ffunction-sections -fdata-sections -Wl,--gc-sections
size-optimized_CFLAGS += -Oz \
	-fwrapv -fomit-frame-pointer -fno-stack-protector\
	-fno-unroll-loops \
	-fno-unwind-tables -fno-asynchronous-unwind-tables \
	-fmerge-all-constants \
	-Wl,-z,norelro \
	-Wl,--hash-style=gnu \
	-fvisibility=hidden \
	-Bsymbolic \
	-Wl,--exclude-libs,ALL \
	-fno-ident \
	-fno-exceptions \
	$(_no_debug_cflags)
release_CFLAGS += -O2 \
    $(_no_debug_cflags)
debug_CFLAGS += -Og
static_CFLAGS += -static $(STATIC_LINK_LIBS)
dynamic_CFLAGS += -Wl,-Bstatic $(STATIC_LINK_LIBS) -Wl,-Bdynamic

size-optimized_RUSTFLAGS += -Zlocation-detail=none \
	-Zfmt-debug=none \
	-C link-arg=-z,norelro \
	-C panic=abort
	#-C link-arg=--hash-style=gnu
musl_RUSTFLAGS += --crate-type=staticlib -Ctarget-feature=-crt-static

RUSTFLAGS += $($(_libc)_RUSTFLAGS) $($(_profile)_RUSTFLAGS) $($(_link_type)_RUSTFLAGS)
ifneq ($(_profile), debug)
	RUSTFLAGS += -C link-arg=-s -C link-arg=-Wl,--gc-sections
endif

CFLAGS += $($(_libc)_CFLAGS) $($(_profile)_CFLAGS) $($(_link_type)_CFLAGS)
ifeq ($(LTO), 1)
	CFLAGS += -flto
endif

RUST_TARGET_DIR := $(REPO_ROOT)/target/$(RUST_TARGET)/$(_profile)

_c_src := $(wildcard ./src/*.c)
_programs := $(basename $(notdir $(_c_src)))
_bins := $(addprefix out/, $(_programs))
_unstripped_bins := $(addsuffix _unstripped, $(_bins))
_run_programs := $(addprefix run_, $(_programs))

# TODO: use cargo --target-dir to put rust binaries into same dir

all: $(_bins)

clean: clean-c clean-rust

clean-c:
	rm -r out || true

clean-rust:
	rm $(SERVICEPOINT_HEADER_OUT)/servicepoint.h || true
	cargo clean

.PHONY: all clean sizes $(_run_programs) clean-c clean-rust build-rust help FORCE

$(_unstripped_bins): out/%_unstripped: src/%.c src/helpers.h build-rust
	mkdir -p out || true
	$(CC) $< \
		-I $(SERVICEPOINT_HEADER_OUT) \
		-L $(RUST_TARGET_DIR) \
		$(CFLAGS) \
		-o $@

$(_bins): out/%: out/%_unstripped
	$(STRIP) $(STRIPFLAGS) $^ -o $@

build-rust: FORCE
	mkdir -p $(SERVICEPOINT_HEADER_OUT) || true
	# generate servicepoint header and library to link against
	$(CARGO) rustc $(CARGOFLAGS) -- $(RUSTFLAGS)

FORCE: ;

help:
	@echo "You have the choice of the following parameters:"
	@echo ""
	@echo "Variable | Description                       | Default   | Values"
	@echo "---------+-----------------------------------+-----------+---------------------------"
	@echo "CARGO    | which cargo binary to use         | 'cargo'   | 'rustup run nightly cargo'"
	@echo "CC       | which C compiler to use           | 'gcc'     | 'musl-gcc'"
	@echo "STRIP    | which strip command to use        | 'strip'   | -"
	@echo "MUSL     | if set, use musl instead of glibc | unset     | '1'"
	@echo "PROFILE  | Compilation profile               | 'release' | 'debug' or 'size-optimized'"