#This program is free software: you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.

#This program is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.

#You should have received a copy of the GNU General Public License
#along with this program. If not, see <http://www.gnu.org/licenses/>.

#Copyright 2018-2020 rexy712

#Makefile to generate a single executable from all sources in SOURCE_DIRS that end in EXT

ifeq ($(OS),Windows_NT)
	WINDOWS::=1
endif

SOURCE_DIRS::=src src/audio src/audio/impl
SOURCES::=
OBJDIR::=obj
DEPDIR::=$(OBJDIR)/dep
LIBDIRS::=
INCLUDE_DIRS::=include
CFLAGS::=-std=c18 -Wall -pedantic -Wextra
CXXFLAGS::=-std=c++17 -Wall -pedantic -Wextra
EXT::=cpp
LANG::=$(EXT)
MAIN_EXECUTABLE::=tester
RELEASE?=0
MEMCHK?=0
UNDEFCHK?=0
SAVEFLAGS?=1

ifneq ($(WINDOWS),1)
	#*nix settings
	CC::=gcc
	CXX::=g++
	LDLIBS::=
	LDFLAGS::= -lglfw -lgl3w -ldl -lm -lportaudio -lasound -lsndfile -lpthread
	STRIP::=strip
	RANLIB::=ranlib
	AR::=ar
	AS::=as
else #windows
	#windows settings
	#windows is a fuckwit
	MINGW_PREFIX::=x86_64-w64-mingw32-
	CC::=$(MINGW_PREFIX)gcc
	CXX::=$(MINGW_PREFIX)g++
	LDLIBS::=-lglfw -lgl3w -ldl -lm -lportaudio
	LDFLAGS::=
	STRIP::=$(MINGW_PREFIX)strip
	RANLIB::=$(MINGW_PREFIX)ranlib
	AR::=$(MINGW_PREFIX)ar
	AS::=$(MINGW_PREFIX)as
	MAIN_EXECUTABLE::=$(MAIN_EXECUTABLE).exe
endif #windows

#main targets
.PHONY: all
#prerun targets
all::

#main target
all:: | flags-update $(MAIN_EXECUTABLE)

#postrun targets
all::

#custom clean targets
clean::

###########################################################################################################
#Everything past this point is internal BS, probably best not to touch it unless you know what you're doing

#set the default target as the default target, otherwise the topmost target will run
.DEFAULT_GOAL::=all

#system dependant bullshit
ifeq ($(OS),Windows_NT)
	#windows' cmd commands
	mkdir=mkdir $(subst /,\,$(1)) > NUL 2>&1
	rm=del /F $(1) > NUL 2>&1
	rmdir=rd /S /Q $(1) > NUL 2>&1
	move=move /Y $(subst /,\,$(1)) $(subst /,\,$(2)) > NUL 2>&1
	copy=copy /Y /B $(subst /,\,$(1)) $(subst /,\,$(2)) > NUL 2>&1
else
	#*nix terminal commands
	mkdir=mkdir -p $(1)
	rm=rm -f $(1)
	rmdir=rm -rf $(1)
	move=mv $(1) $(2)
	copy=cp $(1) $(2)
endif

#setup compiler and flags based on language
ifeq ($(LANG),cpp)
	COMPILER_FLAGS::=$(CXXFLAGS)
	COMPILER::=$(CXX)
else ifeq ($(LANG),c)
	COMPILER_FLAGS::=$(CFLAGS)
	COMPILER::=$(CC)
endif


ifeq ($(RELEASE),1)
	#a lot of false strict aliasing warnings from gcc 9
	COMPILER_FLAGS+=-O2 -Wno-strict-aliasing
else
	#default target
	COMPILER_FLAGS+=-O0 -g3 -ggdb
	ifeq ($(MEMCHK),1)
		#use asan to check memory leaks/invalid accesses
		LDFLAGS+=-fsanitize=address -fno-omit-frame-pointer -fno-optimize-sibling-calls
		COMPILER_FLAGS+=-fsanitize=address -fno-omit-frame-pointer -fno-optimize-sibling-calls
	endif
	ifeq ($(UNDEFCHK),1)
		LDFLAGS+=-fsanitize=undefined
		COMPILER_FLAGS+=-fsanitize=undefined
	endif
endif

ifeq ($(SAVEFLAGS),1)
	CFLAGS_TMPFILE::=.cflags.tmp
	LDFLAGS_TMPFILE::=.ldflags.tmp
	OLD_COMPILEFLAGS::=$(file <$(CFLAGS_TMPFILE))
	OLD_LINKFLAGS::=$(file <$(LDFLAGS_TMPFILE))
endif


#add dependency tracking and include directories
INTERNAL_COMPILERFLAGS=-c $(foreach dir,$(INCLUDE_DIRS),-I"$(dir)") -MMD -MP -MF"$(DEPDIR)/$(notdir $(patsubst %.o,%.d,$@))"
INTERNAL_LINKFLAGS=$(foreach dir,$(LIBDIRS),-L"$(dir)")
INTERNAL_SOURCES::=$(SOURCES) $(foreach source,$(SOURCE_DIRS),$(foreach ext,$(EXT),$(wildcard $(source)/*.$(ext))))
OBJECTS::=$(addprefix $(OBJDIR)/,$(subst \,.,$(subst /,.,$(addsuffix .o,$(INTERNAL_SOURCES)))))
ALL_COMPILEFLAGS=$(COMPILER_FLAGS) $(INTERNAL_COMPILERFLAGS)
ALL_LINKFLAGS=$(INTERNAL_LINKFLAGS) $(LDFLAGS)

#just a variable for a newline
define \n


endef

.PHONY: cflags-update
cflags-update:
ifeq ($(SAVEFLAGS),1)
ifneq ($(subst -MF"$(DEPDIR)/",-MF"$(DEPDIR)/cflags-update",$(ALL_COMPILEFLAGS)),$(OLD_COMPILEFLAGS))
	$(file >$(CFLAGS_TMPFILE),$(ALL_COMPILEFLAGS))
endif
$(CFLAGS_TMPFILE): cflags-update
endif
.PHONY: ldflags-update
ldflags-update:
ifeq ($(SAVEFLAGS),1)
ifneq ($(ALL_LINKFLAGS),$(OLD_LINKFLAGS))
	$(file >$(LDFLAGS_TMPFILE),$(ALL_LINKFLAGS))
endif
$(LDFLAGS_TMPFILE): ldflags-update
endif

.PHONY: flags-update
flags-update: cflags-update ldflags-update

#Link executable
$(MAIN_EXECUTABLE): $(OBJECTS) $(LDFLAGS_TMPFILE)
	$(COMPILER) $(OBJECTS) -o "$(basename $@)" $(ALL_LINKFLAGS) $(LDLIBS)
ifeq ($(RELEASE),1)
	$(STRIP) --strip-all "$(MAIN_EXECUTABLE)"
endif

#Object target recipe
define GENERATE_INDIVIDUAL_OBJECTS
$$(OBJDIR)/$(subst \,.,$(subst /,.,$(1))).o: $(1) $(CFLAGS_TMPFILE)
	$$(COMPILER) $$(ALL_COMPILEFLAGS) "$$<" -o "$$@"
endef

#Create targets for object files
$(foreach src,$(INTERNAL_SOURCES),$(eval $(call GENERATE_INDIVIDUAL_OBJECTS,$(src))))
$(OBJECTS): | $(OBJDIR) $(DEPDIR)

#Output directory creation
$(OBJDIR):
	$(call mkdir,"$@")
$(DEPDIR):
	$(call mkdir,"$@")

.PHONY: clean
clean::
	$(call rmdir,"$(DEPDIR)")
	$(call rmdir,"$(OBJDIR)")
	$(call rm,"$(MAIN_EXECUTABLE)")
	$(call rm,"$(MAIN_EXECUTABLE).exe")
ifeq ($(SAVEFLAGS),1)
	$(call rm,"$(CFLAGS_TMPFILE)")
	$(call rm,"$(LDFLAGS_TMPFILE)")
endif

#header file dep tracking
-include $(wildcard $(DEPDIR)/*.d)