# if $CXX is not set, guess default `cxx'. It has to be in system
CXX ?= cxx
# compile options
CXXFLAGS ?= -Os -Wall -Wpedantic -Wextra
# link options
LDFLAGS ?= -s

target      ?= debug
<<targets>> := debug release
# addons
with     ?= gmp
without  ?=
<<addons>> := gmp

# Echo function
<< := echo
ifneq ($(shell eval 'echo -e'),-e)
 << += -e
endif

# <<debug-dir>   = Debug
# <<release-dir>>= Release
<<target>>     = $(firstword $(filter $(<<targets>>),$(target)))
ifeq ($(<<target>>),release)
 <<tdir>> = Release
else
 <<tdir>> = Debug
endif

# optional addons
<<with>>       = $(sort $(filter-out $(without),$(filter $(<<addons>>),$(with))))
# project configs
CXXFLAGS += -I$(PWD)/headers -I$(PWD)/

# rebuild on optional deps change
ifneq ($(filter gmp,$(<<with>>)),)
 ifneq ($(shell pkg-config --exists gmp gmpxx && echo exists),)
  PKGS += gmpxx gmp
  CFLAGS += -D_USE_GMP
 endif
endif

ifneq ($(PKGS),)
 CXXFLAGS += $(shell pkg-config --cflags $(PKGS))
 LDFLAGS += $(shell pkg-config --libs $(PKGS))
endif

<<sources>> := \
 main.cpp \
 headers/allElements.cpp \
 headers/readElementState.cpp


<<objects>> := $(<<sources>>:%=obj/$(<<tdir>>)/%.o)

# Output file name
ifeq ($(filter $(shell uname -o),Msys Cygwin),)
 BINARY ?= entropy-calculator
else
 ifeq ($(MSYSTEM_CARCH),i686)
  BINARY ?= entropy-calculator.exe
 else
  BINARY ?= entropy-calculator64.exe
 endif
endif

<<bindep>> = bin/$(<<tdir>>)/.$(BINARY).dep
<<binpth>> = bin/$(<<tdir>>)/$(BINARY)
<<->> := $(shell mkdir -p $(dir $(<<binpth>>)))
# Use $(<<bindep>>) file to track backend change
<<depends>> = $(sort $(<<with>>))
ifneq ($(sort $(file < $(<<bindep>>))),$(<<depends>>))
 <<null>> := $(file  > $(<<bindep>>),$(<<depends>>))
endif
undefine <<depends>> <<null>> <<->>
# using some makefile sorcery

all: $(<<binpth>>)

obj/$(<<tdir>>)/%.o: %
 @$(<<) "  CXX\t" $(<:src/%=%)
 @mkdir -p $(shell dirname $(@))
 @$(CXX) -c $(<) -o $(@) $(CXXFLAGS)

$(<<binpth>>): $(<<objects>>)
 @if test -n "$(<<with>>)"; then $(<<) "WITH\t" $(<<with>>);fi
 @$(<<) "LINK\t" "$(BINARY)$(^:obj/%=\\n\\t + %)"
 @$(CXX) $(^) -o $(@) $(LDFLAGS)

install: $(<<binpth>>)
 install -Dm0755 $(<) $(DESTDIR)$(PREFIX)/$(BINDIR)/$(BINARY)

uninstall:
 sudo $(RM) -f $(DESTDIR)$(PREFIX)/$(BINDIR)/$(BINARY)

clean:
 @$(<<) "  RM\t" "$(BINARY)$(<<objects>>:obj/%=\\n\\t + %)"
 @$(RM) -f $(<<objects>>) $(<<binpth>>) $(<<bindep>>)

test: $(BINARY)
 ./$(BINARY)

$(<<objects>>): $(<<bindep>>)
.PHONY: all clean install uninstall test