################################################################################
# Desc:   APC make script
# Author: kgr
# Date:   2016
################################################################################
# This makefile builds APC, the Asset Package Compiler for Henge, on the system.
################################################################################
# Driver sources
DRIVERS  := apc testapc

# Yacc
YACC   := bison
YFLAGS ?= -v -d -Wall
YCMD    = $(strip $(YACC) $(YFLAGS) $(if $2,$(dir $2))$1)
YCMD   += $(if $2,&& mv $(notdir $(1:%.y=%.tab.[ch])) $(dir $2))

# Ragel
RLC     ?= ragel
RLFALGS ?= -C
RLCMD    = $(strip $(RLC) $(RLFLAGS) $(if $2,-o $2 $(dir $2))$1)

# C
CC     ?= gcc
CFLAGS ?= -Wall
CCMD    = $(strip $(CC) $(CFLAGS) $(CPPFLAGS) -c $(if $2,-o $2) $1)

# Linker
LD        ?= ld
LDFLAGS   ?= 
LDLIBS    ?= -lunistring
apcLIBS   ?= 
apc-dLIBS ?= 
LDCMD      = $(strip $(LD) $(LDFLAGS) $(LDLIBS) $($1LIBS) $(if $2,-o $2) $1)

# APC is built from Ragel, Bison and C source code only.
ySRC  := $(shell find ./src -type f -name '*.y')
rlSRC := $(shell find ./src -type f -name '*.rl')
cSRC  := $(shell find ./src -type f -name '*.c')

# Generated files from Yacc/Bison and Ragel
hGEN  := $(ySRC:%.y=%.tab.h)
cGEN  := $(strip $(ySRC:%.y=%.tab.c) $(rlSRC:%.rl=%.c))

# Filter all other driver objects out of each driver's link commands.
$(foreach drv,$(DRIVERS),\
$(eval $(drv)SRC   := $(patsubst %.c,%.o,$(filter-out $(patsubst %,src/%.c,$(filter-out $(drv),$(DRIVERS))),$(cSRC) $(cGEN))))\
$(eval $(drv)-dSRC := $(patsubst %.o,%-d.o,$($(drv)SRC))))

# Unless cleaning, deps should be generated for each source file
ifeq (,$(filter clean,$(MAKECMDGOALS)))
cGENDEP = $(if $(wildcard $1),$(subst $(dir $1),,$(filter-out $1 \ %:,$(shell $(CC) -MM -MG $1))),\
$(info [<$1>: no deps - file not found]))
endif

# Construct the S2S function for generating source files during prerequisite
# expansion:
# If we are cleaning, stop.  Else print the result of calling '1'.  Then, unless
# we are in -n mode, invoke the result of calling '1' in the shell
$(if $(filter clean,$(MAKECMDGOALS)),,$(eval S2S += $$(info $$(call $$1,$$2,$$3)))\
$(if $(filter n,$(MAKEFLAGS)),,$(eval S2S += $$(shell $$(call $$1,$$2,$$3)))))

# Rules
.SECONDEXPANSION:
$(DRIVERS:%=%-d) $(DRIVERS): $$($$@SRC) | $(hGEN)
	$(strip $(call LDCMD,$^,$@))

%-d.o: CFLAGS+= -Og -ggdb
%.o %-d.o: %.c $$(call cGENDEP,$$(dir $$@)%.c)
	$(call CCMD,$<,$@)

%.tab.h: %.tab.c ;
%.tab.c: %.y $$(call S2S,YCMD,%.y,$$@) ;
%.c: %.rl $$(call S2S,RLCMD,%.rl,$$@) ;

clean: $(wildcard $(cGEN) $(hGEN) $(apcSRC) $(apc-dSRC))
	$(if $^,rm $^)