#
# Makefile for tbx unit testing
#
# Copyright (C) 2021 Christos Choutouridis <christos@choutouridis.net>
#
# The MIT License (MIT)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#

#  notes:
# ==============
# This makefile provides support for unix-like local builds and
# docker based builds for gcc and clang.
# ** msvc is not currently supported.
#
# Use cases:
# 1) build localy using **local rules** in terminal.
#    example: 
#       make -j4 MK_ARG="-std=c++14 -fconcepts" build-gcc
#
# 2) build localy using **docker based rules** via terminal or script
#    in order to compile for all compilers/versions/dialects.
#    example in bash:
#       #!/bin/bash
#       for im in gcc:8 gcc:9 gcc:10; do
#          for dial in -std=c++14 -std=c++17; do
#             make IMAGE="$im" MK_ARG="$dial" dock-gcc
#          done
#       done
#
# 3) build inside a docker instance using **local rules** in order to
#    build and test using a CD/CI system.
#    example in a yml file:
#       image: gcc:8
#       build:
#          stage: build
#          - make MK_ARG="-std=c++14" build-gcc
#          - make MK_ARG="-std=c++14 -fconcepts" build-gcc
#          - make MK_ARG="-std=c++17" build-gcc
#          - make MK_ARG="-std=c++17 -fconcepts" build-gcc
#          - make MK_ARG="-std=c++2a" build-gcc
#          ... etc
#       test:
#          stage: test
#          - bin/utlTest
#          ... etc

#

#
# ============== Project settings ==============
#
# note: STM32f101RC/D/E device configuration on SMT32CubeF1 library requires:
#   1) STM2F101xE pre-define
#   2) startup_stm32f101xe.s startup file
#

# Project's name
PROJECT         := tbx
# Excecutable's name
TARGET          := tbxTest

# Source directories list(space seperated). Relative path, under current directory only
SRC_DIR_LIST    := tests gtest

# Source files list(space seperated).
SRC_FILES_LIST  := 

# Include directories list(space seperated). Relative path
INC_DIR_LIST    := ../include gtest
ifeq ($(OS), Windows_NT)
	INC_DIR_LIST += mingw-std-threads
endif
# 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

ODUMP           := objdump
OCOPY           := objcopy

# Compiler flags for debug and release
DEB_CFLAGS      := -std=gnu++17 -DDEBUG -g3 -Wall -Wextra -fmessage-length=0
REL_CFLAGS      := -std=gnu++17 -g3 -Wall -Wextra -O2 -fmessage-length=0
# Pre-defines
PRE_DEFS        :=
ifeq ($(OS), Windows_NT)
	PRE_DEFS    += WIN_TRHEADS
endif

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

# ============== Docker settings ==============
# We need:
#  1) Bind the entire project directory(the dir that icludes all the code) as volume.
#  2) In docker instance change to working directory(where the makefile is). 
# For utl we use the directories `${PWD%/*}` and `test`.
# We double-$$ for double evaluating.
DOCKER_VOL_DIR  := "$${PWD%/*}"
DOCKER_WRK_DIR  := test
DOCKER_RUN      := docker run --rm -v $(DOCKER_VOL_DIR):/usr/src/$(PROJECT) -w /usr/src/$(PROJECT)/$(DOCKER_WRK_DIR)

# ============== Default settings ==============
# compiler and compiler flags. By default docker is not used.
CFLAGS          := $(DEB_CFLAGS)
CXX             := $(GCCXX)
DOCKER          := 

#
# =========== Main body and Patterns ===========
#
ifeq ($(OS), Windows_NT)
	TARGET := $(TARGET).exe
endif
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)))
SRC     := $(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 $(@D)
	@$(DOCKER) $(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)
	$(DOCKER) $(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)
	$(DOCKER) $(CXX) $(LDFLAGS) $(MAP_FLAG) -o $(@D)/$(TARGET) $(OBJ)
	$(DOCKER) $(ODUMP) -h -S $(BUILD_DIR)/$(TARGET) > $(BUILD_DIR)/$(basename $(TARGET)).list
#	$(DOCKER) $(OCOPY) -O ihex $(BUILD_DIR)/$(TARGET) $(BUILD_DIR)/$(basename $(TARGET)).hex
	@echo
	@echo Print size information
	@$(CSIZE) $(@D)/$(TARGET)
	@echo Done

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


#
# ================ Local build rules =================
# examples:
# make MK_ARG="-std=c++14 -fconcepts" build-gcc
# make MK_ARG="-std=c++17" build-clang
#
.PHONY: build-gcc
build-gcc: CFLAGS += $(MK_ARG)
build-gcc: $(BUILD_DIR)/$(TARGET)

.PHONY: build-clang
build-clang: CXX := $(CLANGXX)
build-clang: CFLAGS += $(MK_ARG)
build-clang: $(BUILD_DIR)/$(TARGET)

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

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

.PHONY: all
all: clean release

#
# ================ Docker based rules ================ 
# examples:
# make IMAGE="gcc:8.3" MK_ARG="-std=c++14 -fconcepts" dock-gcc
# make IMAGE="a-clang-image" MK_ARG="-std=c++17" dock-clang
#
.PHONY: dock-gcc
dock-gcc: DOCKER := $(DOCKER_RUN) $(IMAGE)
dock-gcc: CFLAGS += $(MK_ARG)
dock-gcc: $(BUILD_DIR)/$(TARGET)

.PHONY: dock-clang
dock-clang: CXX := $(CLANGXX)
dock-clang: DOCKER := $(DOCKER_RUN) $(IMAGE)
dock-clang: CFLAGS += $(MK_ARG)
dock-clang: $(BUILD_DIR)/$(TARGET)