#! /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)
#
# TODO:
# * generate all libraries for all ABI by default ?
# * handle versionning
#---

#---
#  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	:= ../include
cflags	:= $(machine) -ffreestanding -nostdlib -Wall -Wextra -std=c11 -Os \
		-fstrict-volatile-bitfields -I$(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_object	:= object
dir_output	:= output
dir_bin		:= bin

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

# automated variable
directory	:= $(shell find ../src -not -path "*/\.*" -type d)
src 		:= $(foreach path,$(directory), \
			$(wildcard $(path)/*.c)	\
			$(wildcard $(path)/*.S) \
			$(wildcard $(path)/*.s))





#---
# 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
#---
# (Make selects the first rule when you type "make" and I don't want the first
# rule to be "%/" so here's a placeholder)
first: all

# Create directory helper
# @note: Just use "$*" and "$@" to refer to the directory being created.
%/:
	@ printf "Create $(blue)$*$(nocolor) directory\n"
	@ mkdir -p $@
.PRECIOUS: %/



#---
# Automated rules
#---
# common part used to compile source file
# @params:
# *1 - source file path
# *2 - build directory path (output)
# TODO:
# * handle custom cflags (format, abi management)
# * handle verbose option
define compile-src
$(patsubst .._src_%,$2/%.o,$(subst /,_,$(basename $1))): $1 | $2/
	@ printf "compiling $(white)$$@$(nocolor)..."
	@ $(gcc) $(cflags) -o $$@ -c $$< -lgcc
	@ printf "$(green)[ok]$(nocolor)\n"
endef

# common part used by all library geneation
# @params:
# * 1 - library name
# * 2 - format (dynamic/static)
# * 3 - source file list
define generate-target
# generate the library name based on the wanted formats
lib-output-dir	:= $(dir_output)/$2/
lib-build-dir	:= $(dir_object)/$2/$1/
ifeq ($2,dynamic)
lib-name	:= $$(lib-output-dir)/lib$1.so
lib-cflags	:= -pic $(cflags)
else
lib-name	:= $$(lib-output-dir)/lib$1.a
lib-cflags	:= $(cflags)
endif

# indicate the new lib that will be ouputed
generated-libs += $$(lib-name)

# generate all file object name
$$(foreach source,$3,$$(eval \
	$$(call compile-src,$$(source),$$(lib-build-dir)) \
))

# link the library
# @note: based on the wanted format
ifeq ($2,shared)
$$(lib-name): $$(patsubst .._src_%,$$(lib-build-dir)/%.o,$$(subst /,_,$$(basename $3))) | $$(lib-output-dir)
	$(gcc) -shared -o $$@ $$^ -nostdlib -lgcc
else
$$(lib-name): $$(patsubst .._src_%,$$(lib-build-dir)/%.o,$$(subst /,_,$$(basename $3))) | $$(lib-output-dir)
	$(ar) crs $$@ $$^
endif
endef

# create all "target" variable used to determine which format
# and which libraries will be generated.
# @note: 
# * we force default variable if nothing is set
target-formats	:= $(if $(CONFIG.FORMAT),$(CONFIG.FORMAT),static)
target-libs	:= $(if $(CONFIG.TARGET),$(CONFIG.TARGET),fxlibc)

# create a variable that will be updated during the generation of
# the dynamic make code generation (generated by the "foreach")
generated-libs	:=

# Generate all targets
$(foreach format,$(target-formats), \
	$(foreach lib,$(target-libs),$(eval \
		$(call generate-target,$(lib),$(format),$(src)) \
	)) \
)



#---
# Build rule
#---
all: $(generated-libs)

DEBUG=$(call generate-target,fxlibc,static,$(dir_objects),$(src))
export DEBUG
debug:
	@ echo "$$DEBUG"
	@ echo "target-lib: $(target-libs)"
	@ echo "generated lib: $(generated-libs)"
	@ echo "target format: $(target-formats)"


#---
# clean rules
#---
clean:
	rm -rf $(dir_objects)
fclean: clean
	rm -rf $(dir_bin)
re: fclean clean
.PHONY: clean fclean re












#---
# Build rules
#---
#all: $(target)
#
## linker part
#$(target): $(obj) | $(dir_bin)
#	$(ar) crs $@ $^
#
## installation part
#install: $(target)
#	install -d $(CONFIG.PREFIX)
#	install $(target) -m 644 $(CONFIG.PREFIX)
#	cp -r $(header) $(CONFIG.PREFIX)/include/fxlibc
#uninstall:
#	rm -f $(CONFIG.PREFIX)/$(target)
#	rm -rf $(CONFIG.PREFIX)/include/fxlibc
#
## Directory management
#$(dir_bin) $(dir_objects):
#	@ printf "Create $(blue)$@$(nocolor) directory\n"
#	@ mkdir -p $@
#
#.PHONY: all install uninstall
#
#
#
##define rule-src
##$(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 '  * install    install the library and headers to the PREFIX'
#	@ echo '  * uninstall  uninstall the library and headers of the PREFIX'
#	@ 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