.POSIX:
.SUFFIXES:

# Source code location and files to watch for changes.
SRC_DIR        := src
SRC_MAIN       := $(SRC_DIR)/main.c
SRC_APP        := $(SRC_DIR)/app.c
WATCH_SRC      := $(wildcard $(SRC_DIR)/*.c)
WATCH_SRC      += $(wildcard $(SRC_DIR)/*.h)

# Output library names and executables.
BIN_NAME       := app
LIB_NAME       := libmic.so
BUILD_DIR      := build
BIN            := $(BUILD_DIR)/$(BIN_NAME)
LIB            := $(BUILD_DIR)/$(LIB_NAME)
LIB_DIR        := $(BUILD_DIR)

# Compiler and linker configuration.
CC             := gcc
CFLAGS         := -Wall -Wextra -pedantic -std=c99
LDFLAGS        :=
LDLIBS         :=
RELEASE_CFLAGS := -DNDEBUG -O2
DEBUG_CFLAGS   := -DDEBUG -g

.PHONY: dynamic static clean run

# Setup debug/release builds.
#     make clean && make <target> DEBUG=0
#     make clean && make <target> DEBUG=1
DEBUG ?= 0
ifeq ($(DEBUG), 1)
    CFLAGS += $(DEBUG_CFLAGS)
else
    CFLAGS += $(RELEASE_CFLAGS)
endif

dynamic: CFLAGS += -fPIC
dynamic: CFLAGS += -DLIB_NAME=\"$(LIB_NAME)\"
dynamic: CFLAGS += -DLIB_DIR=\"$(LIB_DIR)\"
dynamic: LDFLAGS += -ldl
dynamic: $(BUILD_DIR) $(LIB) $(BIN)

static: SRC_MAIN += $(SRC_APP)
static: $(BUILD_DIR) $(BIN)

$(BIN): $(SRC_MAIN) $(WATCH_SRC)
	$(CC) $(CFLAGS) $(LDFLAGS) -o $(BIN) $(SRC_MAIN) $(LDLIBS)

$(LIB): $(SRC_APP) $(WATCH_SRC)
	$(CC) $(CFLAGS) -shared $(LDFLAGS) -o $@ $(SRC_APP) $(LDLIBS)

$(BUILD_DIR):
	mkdir -p $(BUILD_DIR)

run: $(BIN)
	exec $(BIN)

clean:
	rm -r $(BUILD_DIR)