### -*-makefile-gmake-*-
###
### Top-level build script for toy project.
###
### (c) 2019 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This program is free software; you can redistribute it and/or modify
### it under the terms of the GNU Library General Public License as
### published by the Free Software Foundation; either version 2 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 Library General Public License for more details.
###
### You should have received a copy of the GNU Library General Public
### License along with this program; if not, write to the Free
### Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
### MA 02111-1307, USA.

## Default target.
all::

###--------------------------------------------------------------------------
### Configuration things.

## (This is a toy.  More stuff is needed in a proper project.)

## Source and build directories.
srcdir			 = @srcdir@
abs_srcdir		 = @abs_srcdir@
abs_builddir		 = @abs_builddir@

## Installation directories.
prefix			 = @prefix@
exec_prefix		 = @exec_prefix@
bindir			 = @bindir@

## Build options.
CC			 = @CC@
CFLAGS			 = @CFLAGS@
DEFS			 = @DEFS@
INCLUDES		 = @INCLUDES@
LD			 = @CC@
LDFLAGS			 = @LDFLAGS@
LIBS			 = @LIBS@

INCLUDES		+= -I$(srcdir)/lib/

###--------------------------------------------------------------------------
### Machinery.

dirvars			 =
dirtargets		 =
ALL_SUBDIRS		:=
D			:=
%dirstack		:=

dirvars			+= TARGETS PROGRAMS LIBS CLEANFILES
dirtargets		+= all clean check install

define %descend-subdir
  %dirstack		:= $$D $$(%dirstack)
  D			:= $$(if $$D,$$D/)$1
  ALL_SUBDIRS		+= $$D
  include $$(srcdir)/$$D/Subdir.mk
  D			:= $$(firstword $$(dirstack))
  %dirstack		:= $$(wordlist 2,$$(words $$(%dirstack)),$$(%dirstack))
endef
descend-subdirs		 = $(foreach d,$1, \
				$(eval $(call %descend-subdir,$d)))

V			 = 0
v-tag			 = $(call %v-tag.$V,$1)
%v-tag.0		 = @printf "  %-8s %s\n" "$1" "$@";
%v-tag.1		 =

V_AT			 = $(%V_AT.$V)
%V_AT.0			 = @
%V_AT.1			 =

VPATH			 = $(srcdir)

COMPILE			 = $(call v-tag,CC)$(CC) -c -o$@ -MD \
				$(DEFS) $(INCLUDES) $(CFLAGS)
%.o: %.c
	$(COMPILE) $<

LINK			 = $(call v-tag,LD)$(LD) -o$@ \
				$(CFLAGS) $(LDFLAGS) $(LIBS)

objects			 = $(addsuffix $(if $2,$2,.o), \
				$(basename $(filter %.c %.s %.S,$1)))

ALL_DEPFILES		:=
notice-objects		 = $(eval ALL_DEPFILES += $$(patsubst %.o,%.d,$1))

###--------------------------------------------------------------------------
### Descend into subdirectories.

SUBDIRS			 =

SUBDIRS			+= lib
SUBDIRS			+= src

$(call descend-subdirs, $(SUBDIRS))

###--------------------------------------------------------------------------
### Maintaining the build system.

$(srcdir)/configure: $(srcdir)/configure.ac
	$(call v-tag,AUTOCONF)cd $(srcdir) && autoconf

config.status: $(srcdir)/configure
	$(call v-tag,CONFIG)./config.status --recheck

Makefile: config.status $(srcdir)/Makefile.in \
		$(foreach d,$(ALL_SUBDIRS), $d/Makefile)
	$(call v-tag,SUBST)./config.status Makefile
$(foreach d,$(ALL_SUBDIRS), \
	$(eval $d/Makefile: config.status $$(srcdir)/$d/Makefile.in; \
		$$(call v-tag,SUBST)./config.status $$@))

###--------------------------------------------------------------------------
### More machinery.

all_dirtargets		 = $(foreach d,$(ALL_SUBDIRS), \
				$(foreach t,$(dirtargets), $d/$t))

$(all_dirtargets)::

ifeq ($(origin SUBDIR),undefined)
$(foreach t,$(dirtargets), \
	$(eval $t:: $(foreach d,$(ALL_SUBDIRS),$d/$t)))
else
$(foreach t,$(dirtargets), \
	$(eval $t:: $(SUBDIR)/$t))
endif
$(foreach d,$(SUBDIRS), \
	$(foreach t,$(dirtargets), \
		$(eval $d/$t::)))
.PHONY: $(foreach t,$(dirtargets),$t $(foreach d,$(ALL_SUBDIRS),$d/$t))

$(foreach d,$(ALL_SUBDIRS), $d/clean):: %/clean:
	rm -f $*/*.o $*/*.d $($*_CLEANFILES)

realclean:: clean
	rm -f config.status config.log
	rm -f Makefile $(foreach d,$(ALL_SUBDIRS), $d/Makefile)

-include $(ALL_DEPFILES)

###----- That's all, folks --------------------------------------------------