ifneq (,$(wildcard ./.env))
  include .env
  export
else
  $(warning .env file not found, defaults will be used)
endif

# Default configuration
FLAG_LEN ?= 32
FLAG_FORMAT ?= ctf{FLAG_GOES_HERE}
FLAG_SEED ?= false

PYTHON_EXE ?= python
BUILD_DIR ?= build

# Compilation variables
RISCV_CC ?= riscv64-unknown-elf-gcc
RISCV_ARCH_FLAGS ?= -march=rv32im -mabi=ilp32
HOST_CC ?= gcc
HOST_CFLAGS ?= -Wall -Wextra -O3 -g
HOST_LDFLAGS ?= -Wl,-s

EMU_SRC_FILES := $(wildcard src/emulated/*.c)
EMU_OBJ_FILES := $(EMU_SRC_FILES:src/emulated/%.c=$(BUILD_DIR)/%.riscv.o)
EMU_OBJ := $(BUILD_DIR)/emulated.riscv.elf
EMU_OBJ_LICENSE ?= $(BUILD_DIR)/license
EMU_OBJ_LICENSE_IF_EXISTS := $(wildcard $(EMU_OBJ_LICENSE))

README_FILE ?= $(BUILD_DIR)/README.md
ZIP_FILE ?= $(BUILD_DIR)/challenge.zip
ZIP_FILE_IF_EXISTS := $(wildcard $(ZIP_FILE))


GENERATED := $(BUILD_DIR)/include/generated.h

HOST_SRC_EXTRA := src/elf.c src/hwinfo.c src/util.c tiny-AES-c/aes.c
HOST_SRC := src/main.c $(HOST_SRC_EXTRA)
HOST_SRC_ENCRYPTOR := src/encryptor.c $(HOST_SRC_EXTRA)
HOST_INCLUDE := -I src -I tinyriscv/src -I tiny-AES-c
HOST_SRC_SPOOFER := src/spoof/spoofer.c


ifeq ($(OS),Windows_NT)
    HOST_EXE ?= $(BUILD_DIR)/main.exe
else
    HOST_EXE ?= $(BUILD_DIR)/main
endif

ifeq ($(OS),Windows_NT)
    HOST_EXE_ENCRYPTOR ?= $(BUILD_DIR)/encryptor.exe
else
    HOST_EXE_ENCRYPTOR ?= $(BUILD_DIR)/encryptor
endif

HOST_EXE_SPOOFER ?= $(BUILD_DIR)/spoofer


# Disassembly
RISCV_OBJDUMP ?= $(patsubst %-gcc,%-objdump,$(RISCV_CC))
_DISAS_TARGETS := $(filter disas-%,$(MAKECMDGOALS))
_DISAS_FILES   := $(if $(_DISAS_TARGETS),$(filter %.elf %.o,$(MAKECMDGOALS)))



.PHONY: all emulated-riscv host clean disas-risc

all: $(ZIP_FILE) $(HOST_EXE_SPOOFER)

emulated-riscv: $(EMU_OBJ_LICENSE)

host: $(HOST_EXE) $(HOST_EXE_SPOOFER)

# Build the main challenge executable
$(HOST_EXE): $(HOST_SRC) | $(BUILD_DIR)
	$(HOST_CC) $(HOST_CFLAGS) $(HOST_LDFLAGS) $(HOST_INCLUDE) $(HOST_SRC) -o $@

# Build the spoofer
$(HOST_EXE_SPOOFER): $(HOST_SRC_SPOOFER) | $(BUILD_DIR)
	$(HOST_CC) $(HOST_CFLAGS) $(HOST_LDFLAGS) -shared -fPIC $^ -o $@ -ldl

# Build the encryptor
$(HOST_EXE_ENCRYPTOR): $(HOST_SRC_ENCRYPTOR) | $(BUILD_DIR)
	$(HOST_CC) $(HOST_CFLAGS) $(HOST_LDFLAGS) $(HOST_INCLUDE) $(HOST_SRC_ENCRYPTOR) -o $@

# Build emulated object files
$(EMU_OBJ_FILES): $(EMU_SRC_FILES) $(GENERATED) | $(BUILD_DIR)
	$(RISCV_CC) $(RISCV_ARCH_FLAGS) -I $(dir $(GENERATED)) -I src/emulated -c $(EMU_SRC_FILES) -o $@


# Encrypt license file
$(EMU_OBJ_LICENSE): $(EMU_OBJ) $(HOST_EXE_ENCRYPTOR) | $(BUILD_DIR)
ifneq ($(EMU_OBJ_LICENSE_IF_EXISTS),)
	rm $(EMU_OBJ_LICENSE_IF_EXISTS)
endif
	$(HOST_EXE_ENCRYPTOR) $(EMU_OBJ) $@ $(README_FILE)

# Build (unencrypted) license file
$(EMU_OBJ): $(EMU_OBJ_FILES) | $(BUILD_DIR)
	$(RISCV_CC) $(RISCV_ARCH_FLAGS) -nostdlib -Wl,-e,entry -Wl,-Ttext=0 -Wl,--emit-relocs $(EMU_OBJ_FILES) -o $@


# Bundle the challenge
$(ZIP_FILE): $(HOST_EXE) $(EMU_OBJ_LICENSE) $(README_FILE) | $(BUILD_DIR)
ifneq ($(ZIP_FILE_IF_EXISTS),)
	rm $(ZIP_FILE_IF_EXISTS)
endif
	cd $(BUILD_DIR) && 7z a -bso0 $(CURDIR)/$@ $(notdir $^)

.FORCE:

$(GENERATED): .FORCE
	mkdir -p $(dir $@)
	$(PYTHON_EXE) codegen/generate.py $(FLAG_FORMAT) $(FLAG_LEN) $(FLAG_SEED) > $@


$(BUILD_DIR):
	mkdir -p $@

clean:
	rm -rf $(BUILD_DIR)

disas-risc: $(_DISAS_FILES)
	$(RISCV_OBJDUMP) -d $^