%:: %,v
%:: RCS/%,v
%:: RCS/%
%:: s.%
%:: SCCS/s.%

BUILD_DIR := bin
OBJ_DIR := obj

# Needs to be set by the caller.
# ASSEMBLY := engine

DEFINES := -DKEXPORT

# Detect OS and architecture.
ifeq ($(OS),Windows_NT)
    # WIN32
	BUILD_PLATFORM := windows
	EXTENSION := .dll
	COMPILER_FLAGS := -Wall -Wextra -Werror -Wno-error=deprecated-declarations -Wno-error=unused-function -Wvla -Wgnu-folding-constant -Wno-missing-braces -fdeclspec -Wstrict-prototypes -Wno-unused-parameter -Wno-missing-field-initializers
	INCLUDE_FLAGS := -I$(ASSEMBLY)\src $(ADDL_INC_FLAGS)
	LINKER_FLAGS := -shared -lwinmm -L$(OBJ_DIR)\$(ASSEMBLY) -L.\$(BUILD_DIR) $(ADDL_LINK_FLAGS)
	DEFINES += -D_CRT_SECURE_NO_WARNINGS -DUNICODE

# Make does not offer a recursive wildcard function, and Windows needs one, so here it is:
	rwildcard=$(wildcard $1$2) $(foreach d,$(wildcard $1*),$(call rwildcard,$d/,$2))
	DIR := $(subst /,\,${CURDIR})
	
	# .c files
	SRC_FILES := $(call rwildcard,$(ASSEMBLY)/,*.c)
	# directories with .h files
	DIRECTORIES := \$(ASSEMBLY)\src $(subst $(DIR),,$(shell dir $(ASSEMBLY)\src /S /AD /B | findstr /i src)) 
	OBJ_FILES := $(SRC_FILES:%=$(OBJ_DIR)/%.o)
    ifeq ($(PROCESSOR_ARCHITEW6432),AMD64)
        # AMD64
    else
        ifeq ($(PROCESSOR_ARCHITECTURE),AMD64)
            # AMD64
        endif
        ifeq ($(PROCESSOR_ARCHITECTURE),x86)
            # IA32
        endif
    endif
else
    UNAME_S := $(shell uname -s)
    ifeq ($(UNAME_S),Linux)
        # LINUX
		BUILD_PLATFORM := linux
		EXTENSION := .so
		# NOTE: -fvisibility=hidden hides all symbols by default, and only those that explicitly say
		# otherwise are exported (i.e. via KAPI).
		COMPILER_FLAGS :=-fvisibility=hidden -fpic -Wall -Wno-error=deprecated-declarations -Wno-error=unused-function -Werror -Wvla -Wno-missing-braces -fdeclspec 
		INCLUDE_FLAGS := -I./$(ASSEMBLY)/src $(ADDL_INC_FLAGS)
		# NOTE: --no-undefined and --no-allow-shlib-undefined ensure that symbols linking against are resolved.
		# These are linux-specific, as the default behaviour is the opposite of this, allowing code to compile 
		# here that would not on other platforms from not being exported (i.e. Windows)
		# Discovered the solution here for this: https://github.com/ziglang/zig/issues/8180
		LINKER_FLAGS :=-Wl,--no-undefined,--no-allow-shlib-undefined,-rpath='$$ORIGIN' -shared -lxcb -lX11 -lX11-xcb -lxkbcommon -lm -L/usr/X11R6/lib -L./$(BUILD_DIR) $(ADDL_LINK_FLAGS) 		# .c files
		SRC_FILES := $(shell find $(ASSEMBLY) -name *.c)
		# directories with .h files
		DIRECTORIES := $(shell find $(ASSEMBLY) -type d)
		OBJ_FILES := $(SRC_FILES:%=$(OBJ_DIR)/%.o)
    endif
    ifeq ($(UNAME_S),Darwin)
        # OSX
		BUILD_PLATFORM := macos
		EXTENSION := .dylib
		# NOTE: -fvisibility=hidden hides all symbols by default, and only those that explicitly say
		# otherwise are exported (i.e. via KAPI).
		COMPILER_FLAGS :=-fvisibility=hidden -fpic -Wall -Werror -Wvla -Wno-error=deprecated-declarations -Wno-error=unused-function -Wgnu-folding-constant -Wno-missing-braces -fdeclspec -ObjC
		INCLUDE_FLAGS := -I./$(ASSEMBLY)/src $(ADDL_INC_FLAGS)
		# NOTE: Equivalent of the linux version above, this ensures that symbols linking against are resolved.
		# Discovered this here: https://stackoverflow.com/questions/26971333/what-is-clangs-equivalent-to-no-undefined-gcc-flag
		LINKER_FLAGS :=-Wl,-undefined,error -shared -dynamiclib -install_name @rpath/lib$(ASSEMBLY).dylib -lobjc -framework AppKit -framework QuartzCore -L./$(BUILD_DIR) $(ADDL_LINK_FLAGS)
		# .c and .m files
		SRC_FILES := $(shell find $(ASSEMBLY) -type f \( -name "*.c" -o -name "*.m" \))
		# directories with .h files
		DIRECTORIES := $(shell find $(ASSEMBLY) -type d)
		OBJ_FILES := $(SRC_FILES:%=$(OBJ_DIR)/%.o)
    endif
    UNAME_P := $(shell uname -p)
    ifeq ($(UNAME_P),x86_64)
        # AMD64
    endif
    ifneq ($(filter %86,$(UNAME_P)),)
        # IA32
    endif	
    ifneq ($(filter arm%,$(UNAME_P)),)
        # ARM
    endif
endif

# Generate version 
ifeq ($(DO_VERSION),yes)
ifeq ($(BUILD_PLATFORM),windows)
	VERFILE := $(ASSEMBLY)\src\$(ASSEMBLY)_version.h
	VERFILE_TEXT := $(ASSEMBLY)\version.txt
	KVERSION := $(shell $(DIR)\$(BUILD_DIR)\kohi.tools.versiongen.exe "$(VERFILE_TEXT)")
else
	VERFILE := $(ASSEMBLY)/src/$(ASSEMBLY)_version.h
	VERFILE_TEXT := $(ASSEMBLY)/version.txt
	KVERSION := $(shell $(BUILD_DIR)/kohi.tools.versiongen "$(VERFILE_TEXT)")
endif
VER_COMMENT := // NOTE: This file is automatically generated by the build process and should not be checked in.
endif

# Generate numeric-only version for PDBs.
ifeq ($(DO_VERSION),yes)
ifeq ($(BUILD_PLATFORM),windows)
	KNUMERIC_VERSION := $(shell $(DIR)\$(BUILD_DIR)\kohi.tools.versiongen.exe -n)
else
	KNUMERIC_VERSION := $(shell $(BUILD_DIR)/kohi.tools.versiongen -n)
endif
endif

# Defaults to debug unless release is specified.
ifeq ($(TARGET),release)
# release
DEFINES += -DKRELEASE
COMPILER_FLAGS += -MD -O2
else
# debug
DEFINES += -D_DEBUG
COMPILER_FLAGS += -g -MD -O0
LINKER_FLAGS += -g
endif

all: scaffold gen_compile_flags compile link 

.NOTPARALLEL: scaffold

.PHONY: scaffold
scaffold: # create build directory
ifeq ($(BUILD_PLATFORM),windows)
	-@setlocal enableextensions enabledelayedexpansion && mkdir $(addprefix $(OBJ_DIR), $(DIRECTORIES)) 2>NUL || cd .
	-@setlocal enableextensions enabledelayedexpansion && mkdir $(BUILD_DIR) 2>NUL || cd .
else
	@mkdir -p $(BUILD_DIR)
	@mkdir -p $(addprefix $(OBJ_DIR)/,$(DIRECTORIES))
endif

# TODO: re-enable this conditionally
# Generate version file
ifeq ($(DO_VERSION),yes)
ifeq ($(BUILD_PLATFORM),windows)
	@if exist $(VERFILE) del $(VERFILE)
# Write out the version file.
	@echo $(VER_COMMENT)\n > $(VERFILE)
	@echo #define KVERSION "$(KVERSION)" >> $(VERFILE)
else
	@rm -rf $(VERFILE)
# Write out the version file.
	@echo "$(VER_COMMENT)\n" > $(VERFILE)
	@echo "#define KVERSION \"$(KVERSION)\"" >> $(VERFILE)
endif
endif

.PHONY: link
link: scaffold $(OBJ_FILES) # link
	@echo Linking "$(ASSEMBLY)"...
ifeq ($(BUILD_PLATFORM),windows)
	@clang $(OBJ_FILES) -o $(BUILD_DIR)\$(ASSEMBLY)$(EXTENSION) $(LINKER_FLAGS) -Xlinker /INCREMENTAL  
else
	@clang $(OBJ_FILES) -o $(BUILD_DIR)/lib$(ASSEMBLY)$(EXTENSION) $(LINKER_FLAGS)
endif

.PHONY: compile
compile:
	@echo --- Performing "$(ASSEMBLY)" $(TARGET) build ---
-include $(OBJ_FILES:.o=.d)

.PHONY: clean
clean: # clean build directory
	@echo --- Cleaning "$(ASSEMBLY)" ---
ifeq ($(BUILD_PLATFORM),windows)
	@if exist $(BUILD_DIR)\$(ASSEMBLY)$(EXTENSION) del $(BUILD_DIR)\$(ASSEMBLY)$(EXTENSION)
# Windows builds include a lot of files... get them all.
	@if exist $(BUILD_DIR)\$(ASSEMBLY).* del $(BUILD_DIR)\$(ASSEMBLY).*
	@if exist $(OBJ_DIR)\$(ASSEMBLY) rmdir /s /q $(OBJ_DIR)\$(ASSEMBLY)
else
	@rm -rf $(BUILD_DIR)/lib$(ASSEMBLY)$(EXTENSION)
	@rm -rf $(OBJ_DIR)/$(ASSEMBLY)
endif

# compile .c to .o object for windows, linux and mac
$(OBJ_DIR)/%.c.o: %.c 
	@echo   $<...
	@clang $< $(COMPILER_FLAGS) -c -o $@ $(DEFINES) $(INCLUDE_FLAGS)

# compile .m to .o object only for macos
ifeq ($(BUILD_PLATFORM),macos)
$(OBJ_DIR)/%.m.o: %.m
	@echo   $<...
	@clang $< $(COMPILER_FLAGS) -c -o $@ $(DEFINES) $(INCLUDE_FLAGS)
endif

-include $(OBJ_FILES:.o=.d)

.PHONY: gen_compile_flags
gen_compile_flags:
ifeq ($(BUILD_PLATFORM),windows)
#	Updated to handle not breaking up quoted strings (i.e. paths with spaces in them) but then afterward to remove said quotes.
	$(shell powershell [regex]::matches(\"$(INCLUDE_FLAGS) $(DEFINES) -ferror-limit=0\", \"-I'[^']*'|\S+\").Value.replace('-I', '-I..\').replace('-I..\''C:', '-I''C:').replace('''', '') -join [System.Environment]::NewLine > $(ASSEMBLY)/compile_flags.txt)
else
	@echo $(INCLUDE_FLAGS) $(DEFINES) -ferror-limit=0 | tr " " "\n" | sed "s/\-I\.\//\-I\.\.\//g" > $(ASSEMBLY)/compile_flags.txt
endif