# ============================================================================
# kernel/Makefile - Kernel Build
# Produces: $(RESULT_DIR)/(CONFIG_KERNEL_FILE_NAME)).elf
#
# ATM: uses config_generated.mk for compilation of drivers/filesystems/entyties.
# I hard-code it in this Makefile, but in future (TODO) i should remove it
# ============================================================================

include ../config.mk
-include ../config_generated.mk

INCLUDES := \
    -Iinclude \
    -I../include \
    -Iarch/$(ARCH)

# ── Always-compiled sources ─────────────────────────────────────────────────

ARCH_CPP_SRC := $(wildcard arch/$(ARCH)/*.cpp)
ARCH_ASM_SRC := $(wildcard arch/$(ARCH)/*.S)

#TODO: move it to special Makefiles
CORE_SRC := $(wildcard core/*.cpp)
MM_SRC   := $(wildcard mm/*.cpp)
LDR_SRC  := $(wildcard loader/*.cpp)
LIB_SRC  := $(wildcard lib/*.cpp)

# ── Firmware subsystems (both compile on all arches; unused one stays dormant) ──
FIRMWARE_SRC := $(wildcard firmware/acpi/*.cpp) $(wildcard firmware/dt/*.cpp)

# ── Conditionally-compiled sources (from .config) ───────────────────────────
# TODO: change it to Driver Makefiles
DRV_SRC :=
FS_SRC  :=

# Drivers — add src based on CONFIG_ variables
ifeq ($(CONFIG_DRIVER_FBCON),y)
    DRV_SRC += $(wildcard drivers/console/*.cpp)
endif
ifeq ($(CONFIG_DRIVER_UART_16550),y)
    DRV_SRC += $(wildcard drivers/char/uart_16550*.cpp)
endif
ifeq ($(CONFIG_DRIVER_PL011_UART),y)
    DRV_SRC += $(wildcard drivers/char/pl011*.cpp)
endif
ifeq ($(CONFIG_DRIVER_PS2KBD),y)
    DRV_SRC += $(wildcard drivers/input/ps2kbd*.cpp)
endif
ifeq ($(CONFIG_DRIVER_VIRTIO_BLK),y)
    DRV_SRC += $(wildcard drivers/block/virtio_blk*.cpp)
endif
ifeq ($(CONFIG_DRIVER_AHCI),y)
    DRV_SRC += $(wildcard drivers/block/ahci*.cpp)
endif
ifeq ($(CONFIG_DRIVER_VIRTIO_NET),y)
    DRV_SRC += $(wildcard drivers/net/virtio_net*.cpp)
endif

# Filesystems(just for example)
ifeq ($(CONFIG_FS_INITRAMFS),y)
    FS_SRC += $(wildcard fs/initramfs*.cpp)
endif
ifeq ($(CONFIG_FS_TMPFS),y)
    FS_SRC += $(wildcard fs/tmpfs*.cpp)
endif
ifeq ($(CONFIG_FS_EXT2),y)
    FS_SRC += $(wildcard fs/ext2*.cpp)
endif
ifeq ($(CONFIG_FS_FAT32),y)
    FS_SRC += $(wildcard fs/fat32*.cpp)
endif

# ── Collect all sources ─────────────────────────────────────────────────────

ALL_CPP_SRC := $(ARCH_CPP_SRC) $(CORE_SRC) $(MM_SRC) $(FIRMWARE_SRC) $(DRV_SRC) $(FS_SRC) $(LDR_SRC) $(LIB_SRC)
ALL_ASM_SRC := $(ARCH_ASM_SRC)

ALL_CPP_OBJ := $(patsubst %.cpp,%.o,$(ALL_CPP_SRC))
ALL_ASM_OBJ := $(patsubst %.S,%.o,$(ALL_ASM_SRC))
ALL_OBJ     := $(ALL_ASM_OBJ) $(ALL_CPP_OBJ)

# ── Flags ───────────────────────────────────────────────────────────────────

KERNEL_CXXFLAGS := \
    $(COMMON_CXXFLAGS) \
    $(ARCH_CFLAGS) \
    $(INCLUDES) \
    -DARCH_$(shell echo $(ARCH) | tr a-z A-Z)

KERNEL_ASFLAGS := \
    $(COMMON_ASFLAGS) \
    $(ARCH_CFLAGS)

KERNEL_LDFLAGS := \
    $(COMMON_LDFLAGS) \
    -T arch/$(ARCH)/linker.ld

# ── Targets ─────────────────────────────────────────────────────────────────

.PHONY: all clean

all: $(RESULT_DIR)/$(CONFIG_KERNEL_FILE_NAME)

$(RESULT_DIR)/$(CONFIG_KERNEL_FILE_NAME): $(ALL_OBJ) arch/$(ARCH)/linker.ld
	@mkdir -p $(dir $@)
	@echo "  LD    $@"
	@$(LD) $(KERNEL_LDFLAGS) -o $@ $(ALL_OBJ)

%.o: %.cpp
	@echo "  CXX   $<"
	@$(CXX) $(KERNEL_CXXFLAGS) -c $< -o $@

%.o: %.S
	@echo "  AS    $<"
	@$(CXX) $(KERNEL_ASFLAGS) -c $< -o $@

clean:
	rm -rf $(RESULT_DIR)
	find . -name '*.o' -delete