# Makefile for building a single configuration of Wren. It allows the
# following variables to be passed to it:
#
# MODE - The build mode, "debug" or "release".
#				 If omitted, defaults to "release".
# LANG - The language, "c" or "cpp".
# 		   If omitted, defaults to "c".
# ARCH - The processor architecture, "32", "64", or nothing, which indicates
#				 the compiler's default.
#        If omitted, defaults to the compiler's default.
#
# It builds a static library, shared library, and command-line interpreter for
# the given configuration. Libraries are built to "lib", and the interpreter
# is built to "bin".
#
# The output file is initially "wren". If in debug mode, "d" is appended to it.
# If the language is "cpp", then "-cpp" is appended to that. If the
# architecture is not the default then "-32" or "-64" is appended to that.
# Then, for the libraries, the correct extension is added.

# Files.
HEADERS   := include/wren.h $(wildcard src/*.h)
SOURCES   := $(wildcard src/*.c)
BUILD_DIR := build

CFLAGS := -Wall -Werror
# TODO: Add -Wextra.

# Mode configuration.
ifeq ($(MODE),debug)
	WREN := wrend
	CFLAGS += -O0 -DDEBUG -g
	BUILD_DIR := $(BUILD_DIR)/debug
else
	WREN += wren
	CFLAGS += -Os
	BUILD_DIR := $(BUILD_DIR)/release
endif

# Language configuration.
ifeq ($(LANG),cpp)
	WREN := $(WREN)-cpp
	CFLAGS += -std=c++98
	FILE_FLAG := -x c++
	BUILD_DIR := $(BUILD_DIR)-cpp
else
	CFLAGS += -std=c99
endif

# Architecture configuration.
ifeq ($(ARCH),32)
	CFLAGS += -m32
	WREN := $(WREN)-32
	BUILD_DIR := $(BUILD_DIR)-32
endif

ifeq ($(ARCH),64)
	CFLAGS += -m64
	WREN := $(WREN)-64
	BUILD_DIR := $(BUILD_DIR)-64
endif

# Don't add -fPIC on Windows since it generates a warning which gets promoted
# to an error by -Werror.
OS := $(lastword $(subst -, ,$(shell $(CC) -dumpmachine)))
ifeq      ($(OS),mingw32)
else ifeq ($(OS),cygwin)
	# Do nothing.
else
	CFLAGS += -fPIC
endif

# Clang on Mac OS X has different flags and a different extension to build a
# shared library.
ifneq (,$(findstring darwin,$(OS)))
	SHARED_EXT := dylib
else
	SHARED_LIB_FLAGS := -Wl,-soname,$@.so
	SHARED_EXT := so
endif

# TODO: Simplify this if we mode main.c to a different directory.
OBJECTS := $(addprefix $(BUILD_DIR)/, $(notdir $(SOURCES:.c=.o)))
# Don't include main.c in the libraries.
LIB_OBJECTS := $(subst $(BUILD_DIR)/main.o,,$(OBJECTS))

# Targets ---------------------------------------------------------------------

all: prep bin/$(WREN) lib/lib$(WREN).a lib/lib$(WREN).$(SHARED_EXT)

prep:
	@mkdir -p bin lib $(BUILD_DIR)

# Command-line interpreter.
bin/$(WREN): $(OBJECTS)
	$(CC) $(CFLAGS) -Iinclude -o $@ $^ -lm

# Static library.
lib/lib$(WREN).a: $(LIB_OBJECTS)
	$(AR) rcu $@ $^

# Shared library.
lib/lib$(WREN).$(SHARED_EXT): $(LIB_OBJECTS)
	$(CC) $(CFLAGS) -shared $(SHARED_LIB_FLAGS) -o $@ $^

# Object files.
$(BUILD_DIR)/%.o: src/%.c $(HEADERS)
	$(CC) -c $(CFLAGS) -Iinclude -o $@ $(FILE_FLAG) $<