#! /usr/bin/make -f
#---
#
#  fxlibc project Makefile
#
# This makefile is grandly inspired by the Gint unikernel
# projet, many thanks to Lephenixnoir !
# 
# Build architecture:
# build/
#  |-- objects/
#  |    |-- string_strlen.o
#  |    |-- string_strcmp.o
#  |      ...
#  |    `-- signal_kill.o
#  |-- debug/
#  |    |-- fxlibc.map (ELF link map informations)
#  |      ...
#  |    `--  otherinfo.txt
#  |-- Makefile
#  |-- fxlibc.cfg
#  `-- bin/
#       |-- fxlibc_stubs.a (workaround for the shared librairie, see documentation note)
#       |-- fxlibc.so      (shared librairy)
#       `-- fxlibc.a       (static librairy)
#---

#---
#  Build configuration
#---

# Require configuration file (if you want to clean up and lost the file, you
# can either reconfigure or just delete the build directory)
CONFIG := fxlibc.cfg
ifeq "$(wildcard $(CONFIG))" ""
$(error "config file $(CONFIG) does not exist (reconfigure or wipe directory)")
endif
include $(CONFIG)


# Compiler flags, assembler flags, dependency generation, archiving
header	:= -I ../include
cflags	:= $(machine) -ffreestanding -nostdlib -Wall -Wextra -std=c11 -Os \
		-fstrict-volatile-bitfields $(header) $(CONFIG.CFLAGS)

# color definition
red	:= \033[1;31m
green	:= \033[1;32m
blue	:= \033[1;34m
white	:= \033[1;37m
nocolor	:= \033[1;0m

# This is a workaround to force a newline when the "eval" keyword is involved 
define n
# Force newline character

endef

# Define all directory used to stored informations
dir_objects	:= objects
dir_bin		:= bin

# Output configurations
name		:= fxlibc
target		:= $(dir_bin)/$(name).a

# automated variable
src		:=
directory	:= $(shell find ../src/ -not -path "*/\.*" -type d)
$(foreach path,$(directory),$(eval		\
	src	+= $(wildcard $(path)/*.c)	$n\
	src	+= $(wildcard $(path)/*.S)	$n\
	src	+= $(wildcard $(path)/*.s)	$n\
))
obj	:= $(patsubst .._src_%,$(dir_objects)/%.o,$(subst /,_,$(basename $(src))))

# check if any file have been found
ifeq ($(obj),)
$(error "source file does not exist (reconfigure or wipe directory)")
endif


#---
# Toolchain
#---
gcc	= $(CONFIG.TOOLCHAIN)-gcc
as	= $(CONFIG.TOOLCHAIN)-as
ld	= $(CONFIG.TOOLCHAIN)-ld
ar	= $(CONFIG.TOOLCHAIN)-ar
objcopy	= $(CONFIG.TOOLCHAIN)-objcopy


#---
#  Version management
#---
# TODO


#---
# Build rules
#---
all: $(target)

# linker part
$(target): $(obj) | $(dir_bin)
	$(ar) crs $@ $^

# Directory management
$(dir_bin) $(dir_objects):
	@ printf "Create $(blue)$@$(nocolor) directory\n"
	@ mkdir -p $@

.PHONY: all


#---
# Automated rules
#---
define rule-src
$(patsubst .._src_%,$(dir_objects)/%.o,$(subst /,_,$(basename $1))): $1 | $(dir_objects)
	@ printf "compiling $(white)$$<$(nocolor)..."
	@ $(gcc) $(cflags) -o $$@ -c $$< -lgcc
	@ printf "$(green)[ok]$(nocolor)\n"
endef

$(foreach source,$(src),$(eval		\
	$(call rule-src,$(source)))	\
)


#---
# Debugging rules
#---
help:
	@ echo 'make [options]...'
	@ echo ''
	@ echo 'Options:'
	@ echo '  * disasm  use objdump to display the content of the archive'
	@ echo '  * debug   display source files name and objects name'
	@ echo '  * elf_sec display ELF section of the archive'
__debug:
	@ echo 'src: $(src)'
	@ echo ''
	@ echo 'obj: $(obj)'
	@ echo ''
	@ echo 'directory: $(dir_bin) $(dir_output) $(dir_objects)'

disasm:
	@ $(objdump) -D $(target) | less

elf_sec:
	@ $(objdump) -h $(target) | less

.PHONY: help __debug disasm elf_sec


#---
# clean rules
#---
clean:
	rm -rf $(dir_objects)

fclean: clean
	rm -rf $(dir_bin)

re: fclean clean

.PHONY: clean fclean re