MAKEFLAGS += --no-builtin-rules
.ONESHELL:

# configurables

CC ?= cc
CC := $(CC)

CFLAGS ?= -O2
LDFLAGS ?=

# the following line could remove the need of setting ERLANGDIR externally
# however it hangs the whole castle when make is invoked through bear
# ERLANGDIR = $(shell erl -eval 'io:format("~s", [code:root_dir()])' -eval 'halt()' -noshell)
ERLANGDIR ?=

ZSTDVER := 1.5.2
ZSTDDIR := priv/zstd
ZSTDTAR := vendor/zstd.tar.gz

# end configurables

COMMON_CFLAGS := \
	-fno-unwind-tables -fno-asynchronous-unwind-tables \
	-fno-plt \
	-fPIC

BASE_CFLAGS := \
	-std=c11 \
	-isystem$(ERLANGDIR)/usr/include \
	-isystem$(ZSTDDIR) \
	-DZSTD_STATIC_LINKING_ONLY=1 \
	$(COMMON_CFLAGS)

WARNING_CFLAGS := \
	-Wall -Wextra -Wvla -Wpedantic -Wconversion -Winline

BASE_LDFLAGS := \
	-shared \
	-L$(ERLANGDIR)/usr/lib \
	-lei

DEPFLAGS = -MT $@ -MMD -MF priv/c_out/$*.d

SOURCES := $(wildcard c_src/*.c)
HEADERS := $(wildcard c_src/*.h)
OBJECTS := $(SOURCES:%.c=priv/c_out/%.o)
DEPFILES := $(SOURCES:%.c=priv/c_out/%.d)

ALL_OBJECTS := $(OBJECTS) $(ZSTDDIR)/libzstd.a

all: priv/c_out/ex_zstd_nif.so

priv/c_out/ex_zstd_nif.so: $(ALL_OBJECTS)
	mkdir -p $(@D)
	$(CC) $(ALL_OBJECTS) $(BASE_LDFLAGS) $(DEPFLAGS) $(LDFLAGS) -o $@

priv/c_out/c_src/%.o: c_src/%.c $(ZSTDDIR)/zstd.h
	mkdir -p $(@D)
	$(CC) $< $(BASE_CFLAGS) $(WARNING_CFLAGS) $(DEPFLAGS) $(CFLAGS) -c -o $@

$(ZSTDDIR)/libzstd.a: $(ZSTDDIR)/zstd.h
	$(MAKE) \
		CC="$(CC)" \
		CFLAGS="$(COMMON_CFLAGS) $(CFLAGS)" \
		LDFLAGS="$(LDFLAGS)" \
		ZSTD_STATIC_LINKING_ONLY=1 \
		ZSTD_LIB_COMPRESSION=1 \
		ZSTD_LIB_DECOMPRESSION=1 \
		ZSTD_LIB_DICTBUILDER=1 \
		ZSTD_LIB_DEPRECATED=0 \
		ZSTD_LIB_MINIFY=1 \
		-C $(@D) \
		libzstd.a-mt

# this has no explicit dependency on $(ZSTDTAR)
# this is intentional! The tar is part of the package, if it's missing human judgment is required.
$(ZSTDDIR)/zstd.h:
	mkdir -p $(@D)
	tar -zx -f $(ZSTDTAR) -C $(@D) --strip-components=2 zstd-$(ZSTDVER)/lib

-include $(DEPFILES)

.PHONY: format
format:
	clang-format --style=file -i $(SOURCES) $(HEADERS)

.PHONY: lint
lint:
	clang-tidy --fix $(SOURCES)

.PHONY: check
check: compile_commands.json
	clang-format --style=file --dry-run $(SOURCES) $(HEADERS)
	clang-tidy $(SOURCES)

.PHONY: clean
clean:
	-$(MAKE) -C $(ZSTDDIR) clean
	rm -rf priv/c_out

.PHONY: clean-all
clean-all: clean
	rm -rf priv $(ZSTDDIR)

compile_commands.json: $(ZSTDDIR)/zstd.h
	bear -- $(MAKE) $(OBJECTS)

$(ZSTDTAR):
	mkdir -p $(@D)
	curl -sSL -o $(ZSTDTAR) https://github.com/facebook/zstd/releases/download/v$(ZSTDVER)/zstd-$(ZSTDVER).tar.gz

$(ZSTDTAR).sig:
	mkdir -p $(@D)
	curl -sSL -o $(ZSTDTAR).sig https://github.com/facebook/zstd/releases/download/v$(ZSTDVER)/zstd-$(ZSTDVER).tar.gz.sig

$(ZSTDTAR).asc:
	curl -sSL -o $(ZSTDTAR).asc http://zstd.net/signing-key.asc

.PHONY: zstd-pull
zstd-pull: $(ZSTDTAR) $(ZSTDTAR).sig $(ZSTDTAR).asc

.PHONY: zstd-verify
zstd-verify: $(ZSTDTAR) $(ZSTDTAR).sig $(ZSTDTAR).asc
	gpg --import $(ZSTDTAR).asc
	gpg --verify $(ZSTDTAR).sig $(ZSTDTAR)