#
# Makefile for utl Unit test
#
# Copyright (C) 2019-2020 Christos Choutouridis <christos@choutouridis.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 3
# 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# ========== Project settings ==========
# Excecutable's name
TARGET          := utlTest
# Source directories list(space seperated). Full or relative path
SRC_DIR_LIST    := tests gtest
# Include directories list(space seperated). Full or relative path
INC_DIR_LIST    := ../include gtest
# Exclude files list(space seperated). Filenames only.
# EXC_FILE_LIST := bad.cpp old.cpp

# Build directories
BUILD_DIR       := bin
OBJ_DIR         := $(BUILD_DIR)/obj
DEP_DIR         := $(BUILD_DIR)/.dep

# ========== Compiler settings ==========
CLANGXX         := clang++
GCCXX           := g++
CSIZE           := size
# Compiler flags for debug and release
DEB_CFLAGS      := -DDEBUG -g3 -Wall -Wextra
REL_CFLAGS      := -Wall -Wextra -O2
# Pre-defines
# PRE_DEFS := MYCAB=1729 SUPER_MODE

# ========== Linker settings ==========
# Linker flags
LDFLAGS         := -pthread
# Map output file
MAP_FILE        := output.map
MAP_FLAG        := -Xlinker -Map=$(BUILD_DIR)/$(MAP_FILE)

# ========== Default settings ==========
# compiler and compiler flagfs
CFLAGS          := $(DEB_CFLAGS)
CXX             := $(GCCXX)

#
# =========== Main body and Patterns ===========
#
INC     := $(foreach dir,$(INC_DIR_LIST),-I$(dir))
DEF     := $(foreach def,$(PRE_DEFS),-D$(def))
EXC     := $(foreach fil,$(EXC_FILE_LIST),                              \
               $(foreach dir,$(SRC_DIR_LIST),$(wildcard $(dir)/$(fil))) \
           )
# source files, object and dependencies list
# recursive search into current and source directories
SRC     := $(wildcard *.cpp)
SRC     += $(foreach dir,$(SRC_DIR_LIST),$(wildcard $(dir)/*.cpp))
SRC     += $(foreach dir,$(SRC_DIR_LIST),$(wildcard $(dir)/**/*.cpp))
SRC     := $(abspath $(filter-out $(EXC),$(SRC)))

OBJ     := $(foreach file,$(SRC:%.cpp=%.o),$(OBJ_DIR)$(file))
DEP     := $(foreach file,$(SRC:%.cpp=%.d),$(DEP_DIR)$(file))


# Make Dependencies pattern.
# This little trick enables recompilation only when dependencies change
# and it does so for changes both in source AND header files ;)
# 
# It is based on Tom Tromey's method.
# 
# Invoke cpp to create makefile rules with dependencies for each source file
$(DEP_DIR)%.d: %.cpp
	@mkdir -p $(@D)
	@$(CXX) -E $(CFLAGS) $(INC) $(DEF) -MM -MT $(OBJ_DIR)$(<:.cpp=.o) -MF $@ $<

# objects depent on .cpp AND dependency files, which have an empty recipe 
$(OBJ_DIR)%.o: %.cpp $(DEP_DIR)%.d
	@mkdir -p $(@D)
	$(CXX) -c $(CFLAGS) $(INC) $(DEF) -o $@ $<

# empty recipe for dependency files. This prevents make errors
$(DEP):

# now include all dependencies
# After all they are makefile dependency rules ;)
include $(wildcard $(DEP))

# main target rule
$(BUILD_DIR)/$(TARGET): $(OBJ)
	@mkdir -p $(@D)
	@echo Linking to target: $(TARGET)
	@echo $(CXX) $(LDFLAGS) $(MAP_FLAG) -o $(@D)/$(TARGET) '$$(OBJ)'
	@$(CXX) $(LDFLAGS) $(MAP_FLAG) -o $(@D)/$(TARGET) $(OBJ)
	@echo
	@echo Print size information
	@$(CSIZE) $(@D)/$(TARGET)
	@echo Done

.PHONY: clean
clean:
	@echo Cleaning build directories
	@rm -rf $(OBJ_DIR)
	@rm -rf $(DEP_DIR)
	@rm -rf $(BUILD_DIR)


#
# ============ User Rules =============
#

.PHONY: gcc14
gcc14:	CFLAGS += -std=c++14
gcc14:  $(BUILD_DIR)/$(TARGET)

.PHONY: gcc14_conc
gcc14_conc:	CFLAGS += -std=c++14 -fconcepts
gcc14_conc: $(BUILD_DIR)/$(TARGET)

.PHONY: gcc17
gcc17:	CFLAGS += -std=c++17
gcc17:  $(BUILD_DIR)/$(TARGET)

.PHONY: gcc17_conc
gcc17_conc:	CFLAGS += -std=c++17 -fconcepts
gcc17_conc: $(BUILD_DIR)/$(TARGET)

.PHONY: gcc2a
gcc2a:	CFLAGS += -std=c++2a
gcc2a:  $(BUILD_DIR)/$(TARGET)

.PHONY: clang14
clang14: CXX := $(CLANGXX)
clang14: CFLAGS += -std=c++14
clang14: $(BUILD_DIR)/$(TARGET)

.PHONY: clang17
clang17: CXX := $(CLANGXX)
clang17: CFLAGS += -std=c++17
clang17: $(BUILD_DIR)/$(TARGET)

.PHONY: clang2a
clang2a: CXX := $(CLANGXX)
clang2a: CFLAGS += -std=c++2a
clang2a: $(BUILD_DIR)/$(TARGET)

.PHONY: debug
debug: $(BUILD_DIR)/$(TARGET)

.PHONY: release
release: CFLAGS := $(REL_FLAGS)
release: clean $(BUILD_DIR)/$(TARGET)

.PHONY: all
all: clean release