UNAME_S := $(shell uname -s)

ifeq ($(UNAME_S),Darwin)
# --- macOS / Apple Silicon ---
# Apple clang non include il runtime OpenMP: se c'e' libomp di Homebrew lo usa
# (brew install libomp), altrimenti compila single-thread (i pragma omp sono ignorati).
# Niente -march: su arm64 NEON e' baseline (i kernel __ARM_NEON si attivano da soli).
CC      = clang
OMPDIR := $(shell brew --prefix libomp 2>/dev/null)
ifneq ($(OMPDIR),)
OMPC    = -Xclang -fopenmp -I$(OMPDIR)/include
OMPL    = -L$(OMPDIR)/lib -lomp
else
$(warning libomp non trovato: build SINGLE-THREAD. Per il multithread: brew install libomp)
OMPC    =
OMPL    =
endif
CFLAGS  = -O3 $(OMPC) -Wall -Wextra -Wno-unused-parameter -Wno-misleading-indentation -Wno-unused-function
LDFLAGS = -lm $(OMPL)
else
# --- Linux x86-64 (percorso originale, invariato) ---
CC      = gcc
# ARCH=native -> ottimizzato per QUESTA macchina (default, piu' veloce).
# ARCH=x86-64-v3 -> binario PORTABILE su qualsiasi x86-64 moderno con AVX2 (per distribuire).
# ARCH=x86-64 -> massima compatibilita' (niente AVX2: usa il path scalare di fallback).
ARCH   ?= native
CFLAGS  = -O3 -march=$(ARCH) -fopenmp -Wall -Wextra -Wno-unused-parameter -Wno-misleading-indentation -Wno-unused-function
LDFLAGS = -lm -fopenmp
endif

# CUDA=1 adds an opt-in backend for resident tensors. The default build remains
# pure C and keeps the original zero-dependency runtime.
CUDA      ?= 0
CUDA_HOME ?= /usr/local/cuda
NVCC      ?= $(CUDA_HOME)/bin/nvcc
CUDA_ARCH ?= native
NVCCFLAGS ?= -O3 -std=c++17 -arch=$(CUDA_ARCH) -Xcompiler=-Wall,-Wextra
CUDA_OBJ  =
ifeq ($(CUDA),1)
ifeq ($(UNAME_S),Darwin)
$(error CUDA=1 is supported only on Linux)
endif
CFLAGS   += -DCOLI_CUDA
LDFLAGS  += -L$(CUDA_HOME)/lib64 -Wl,-rpath,$(CUDA_HOME)/lib64 -lcudart -lstdc++
CUDA_OBJ  = backend_cuda.o
endif

all: glm

glm: glm.c st.h json.h tok.h tok_unicode.h compat.h $(CUDA_OBJ)
	$(CC) $(CFLAGS) glm.c $(CUDA_OBJ) -o glm $(LDFLAGS)

backend_cuda.o: backend_cuda.cu backend_cuda.h
	@command -v $(NVCC) >/dev/null 2>&1 || { echo "nvcc not found: set CUDA_HOME or NVCC" >&2; exit 1; }
	$(NVCC) $(NVCCFLAGS) -c backend_cuda.cu -o $@

cuda-test: backend_cuda.cu backend_cuda.h backend_cuda_test.cu
	@command -v $(NVCC) >/dev/null 2>&1 || { echo "nvcc not found: set CUDA_HOME or NVCC" >&2; exit 1; }
	$(NVCC) $(NVCCFLAGS) backend_cuda.cu backend_cuda_test.cu -o backend_cuda_test
	./backend_cuda_test

olmoe: olmoe.c st.h json.h
	$(CC) $(CFLAGS) olmoe.c -o olmoe $(LDFLAGS)

# binario portabile da distribuire su altre macchine x86-64
portable:
	$(MAKE) glm ARCH=x86-64-v3

clean:
	rm -f olmoe glm backend_cuda.o backend_cuda_test