# --- CONFIGURABLE DEFAULTS ---
PLATFORM      ?= linux
BUILD_MODE    ?= debug  # 'debug' or 'release'

# --- DIRECTORIES ---
SRC_DIR       := src
BUILD_DIR     := build/$(PLATFORM)
ARCH_DIR      := $(SRC_DIR)/arch/$(PLATFORM)

# --- COMPILERS ---
ifeq ($(PLATFORM), emscripten)
    CC            := emcc
else
    CC            ?= gcc
endif

ifeq ($(PLATFORM), emscripten)
# --- SHARED FLAGS ---
BASE_CFLAGS   := -I$(SRC_DIR)

# --- CORE-SPECIFIC FLAGS (freestanding, no stdlib) ---
CORE_CFLAGS   := $(BASE_CFLAGS)

# --- PLATFORM-SPECIFIC FLAGS ---
PLATFORM_CFLAGS := $(BASE_CFLAGS)
else
# --- SHARED FLAGS ---
BASE_CFLAGS   := -I$(SRC_DIR) -Wall -Wextra -Werror -pedantic

# --- CORE-SPECIFIC FLAGS (freestanding, no stdlib) ---
CORE_CFLAGS   := $(BASE_CFLAGS) -std=c89 -ffreestanding -nostdlib -fno-builtin

# --- PLATFORM-SPECIFIC FLAGS ---
PLATFORM_CFLAGS := $(BASE_CFLAGS)
endif

# --- MODE & PLATFORM SPECIFIC FLAGS ---
ifeq ($(BUILD_MODE), release)
    CORE_CFLAGS     += -O2 -DNDEBUG
    PLATFORM_CFLAGS += -O2 -DNDEBUG
    LDFLAGS         += -s
    TARGET_SUFFIX   := -release
else
    CORE_CFLAGS     += -g -DDEBUG
    PLATFORM_CFLAGS += -g -DDEBUG
    TARGET_SUFFIX   := -debug
endif

# --- LINUX-SPECIFIC (SDL, libc) ---
ifeq ($(PLATFORM), linux)
    PLATFORM_CFLAGS += $(shell pkg-config --cflags sdl2 2>/dev/null)
    LDFLAGS         += $(shell pkg-config --libs sdl2 2>/dev/null) -lm
    TARGET          = $(BUILD_DIR)/undar-$(PLATFORM)$(TARGET_SUFFIX)
endif

# --- EMSCRIPTEN-SPECIFIC ---
ifeq ($(PLATFORM), emscripten)
    LDFLAGS += -s USE_SDL=2 -s WASM=1 \
			   -s ALLOW_MEMORY_GROWTH=1 \
               -s MAX_WEBGL_VERSION=2 \
               --preload-file test/paint-bw.rom@paint.rom \
               -s INITIAL_MEMORY=16MB

    # For release: optimize, strip debug, minimize size
    ifeq ($(BUILD_MODE), release)
		PLATFORM_CFLAGS += -O2 -flto
		LDFLAGS += -O2 -flto
    endif

    # Output: HTML + JS + WASM
    TARGET = $(BUILD_DIR)/undar.html
endif

# --- FALLBACK TARGET (if no platform matched) ---
ifndef TARGET
    TARGET = $(BUILD_DIR)/undar-$(PLATFORM)$(TARGET_SUFFIX)
endif

# --- VM CORE SOURCES ---
VM_SOURCES := \
	$(SRC_DIR)/vm/vm.c \
	$(SRC_DIR)/vm/device.c \
	$(SRC_DIR)/vm/str.c

ifeq ($(BUILD_MODE), release)
	PLATFORM_SOURCE := $(ARCH_DIR)/main.c \
		$(ARCH_DIR)/devices.c\
        $(SRC_DIR)/tools/parser.c \
		$(SRC_DIR)/tools/assembler.c
else
	PLATFORM_SOURCE := $(ARCH_DIR)/main.c \
		$(ARCH_DIR)/devices.c \
        $(SRC_DIR)/tools/parser.c \
		$(SRC_DIR)/tools/assembler.c
endif

# --- OBJECT FILES ---
VM_OBJS := $(VM_SOURCES:$(SRC_DIR)/%.c=$(BUILD_DIR)/%.o)
PLATFORM_OBJ := $(PLATFORM_SOURCE:$(SRC_DIR)/%.c=$(BUILD_DIR)/%.o)

# --- DEPENDENCIES ---
DEPS := $(VM_OBJS:.o=.d) $(PLATFORM_OBJ:.o=.d)

.PHONY: all debug release clean clean-all help

# Default target
all: $(TARGET)

# 'debug' target — just set BUILD_MODE and build
debug: BUILD_MODE=debug
debug: $(TARGET)

# 'release' target — just set BUILD_MODE and build
release: BUILD_MODE=release
release: $(TARGET)

# --- COMPILE VM CORE (freestanding) ---
$(BUILD_DIR)/vm/%.o: $(SRC_DIR)/vm/%.c
	@mkdir -p $(dir $@)
	$(CC) $(CORE_CFLAGS) -MMD -MP -c $< -o $@

# --- COMPILE TOOLS (debug only, uses PLATFORM_CFLAGS) ---
$(BUILD_DIR)/tools/%.o: $(SRC_DIR)/tools/%.c
	@mkdir -p $(dir $@)
	$(CC) $(PLATFORM_CFLAGS) -MMD -MP -c $< -o $@

# --- COMPILE PLATFORM ---
$(BUILD_DIR)/arch/$(PLATFORM)/%.o: $(ARCH_DIR)/%.c
	@mkdir -p $(dir $@)
	$(CC) $(PLATFORM_CFLAGS) -MMD -MP -c $< -o $@

# Main build rule
$(TARGET): $(VM_OBJS) $(PLATFORM_OBJ)
	@mkdir -p $(dir $@)
	$(CC) $(PLATFORM_CFLAGS) $(LDFLAGS) -o $@ $^
	@echo "Built: $@"
	@if [ "$(PLATFORM)" = "emscripten" ]; then \
		echo "Open in browser: file://$(shell pwd)/$@"; \
	fi

# --- AUTO-DEPENDENCIES ---
-include $(DEPS)

# --- CLEAN ---
clean:
	@echo "Cleaning build artifacts for $(PLATFORM)..."
	@rm -rf $(BUILD_DIR)
	@echo "Cleaned."

clean-all:
	@echo "Cleaning ALL build artifacts..."
	@rm -rf build/
	@echo "All cleaned."

# --- HELP ---
help:
	@echo "Undar VM"
	@echo ""
	@echo "Targets:"
	@echo "   make          -> debug build (default: linux)"
	@echo "   make debug    -> same as above"
	@echo "   make release   -> optimized, stripped build"
	@echo "   make clean    -> clean current platform"
	@echo "   make clean-all→ clean all platforms"
	@echo ""
	@echo "Platforms:"
	@echo "   make PLATFORM=linux      -> GCC + SDL2"
	@echo "   make PLATFORM=emscripten -> Emscripten + SDL2 for Web"
	@echo "   make PLATFORM=avr        -> (example) AVR-GCC"
	@echo ""
	@echo "Output:"
	@echo "   Linux:   build/linux/undar-linux-<debug|release>"
	@echo "   Web:     build/emscripten/undar.html (+ .js, .wasm)"