# LEAN_BASH: Makes the Bash shell used by the Lean build configurable.
# On Windows, when CMake/Make is spawned directly (e.g., VSCode's CMake Tools),
# it lacks a proper shell environment, so we need to manually point it to Bash.
LEAN_BASH ?= /usr/bin/env bash
SHELL := $(LEAN_BASH) -eo pipefail

# any absolute path to the stdlib breaks the Makefile
export LEAN_PATH=
export LEAN_CC=${CMAKE_C_COMPILER_LAUNCHER} ${CMAKE_C_COMPILER}
export LEAN_ABORT_ON_PANIC=1

# LEAN_OPTS: don't use native code (except for primitives) since it is from the previous stage
# MORE_DEPS: rebuild the stdlib whenever the compiler has changed
LEANMAKE_OPTS=\
	LEAN="${PREV_STAGE}/bin/lean${PREV_STAGE_CMAKE_EXECUTABLE_SUFFIX}"\
	LEANC="${CMAKE_BINARY_DIR}/leanc.sh"\
	OUT="${LIB}"\
	LIB_OUT="${LIB}/lean"\
	OLEAN_OUT="${LIB}/lean"\
	BIN_OUT="${CMAKE_BINARY_DIR}/bin"\
	LEAN_OPTS+="${LEAN_EXTRA_MAKE_OPTS}"\
	LEANC_OPTS+="${LEANC_OPTS}"\
	LEAN_AR="${CMAKE_AR}"\
	MORE_DEPS+="${PREV_STAGE}/bin/lean${PREV_STAGE_CMAKE_EXECUTABLE_SUFFIX}"\
	${EXTRA_LEANMAKE_OPTS}\
	CMAKE_LIKE_OUTPUT=1

ifeq "${STAGE}" "0"
  LEANMAKE_OPTS+=C_ONLY=1 C_OUT=../stdlib/
endif

.PHONY: Init Lean leanshared Lake lean

# These can be phony since the inner Makefile will have the correct dependencies and avoid rebuilds
Init:
	@mkdir -p "${LIB}/lean/Lean" "${LIB}/lean/Lake"
# Use `+` to use the Make jobserver with `leanmake` for parallelized builds
# Build .oleans of downstream libraries as well for better parallelism
	+"${LEAN_BIN}/leanmake" objs lib PKG=Init $(LEANMAKE_OPTS) LEANC_OPTS+=-DLEAN_EXPORTING \
	  EXTRA_SRC_ROOTS="Lean Lean.lean"

Lean: Init
	+"${LEAN_BIN}/leanmake" lib PKG=Lean $(LEANMAKE_OPTS) LEANC_OPTS+=-DLEAN_EXPORTING

${LIB}/temp/empty.c:
	touch $@

# the following targets are all invoked by separate `make` calls; see src/CMakeLists.txt

# we specify the precise file names here to avoid rebuilds
${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libInit_shared${CMAKE_SHARED_LIBRARY_SUFFIX}: ${LIB}/lean/libInit.a ${CMAKE_BINARY_DIR}/runtime/libleanrt_initial-exec.a ${LIB}/temp/empty.c
ifeq "${INIT_SHARED_LINKER_FLAGS}" ""
  # create empty library on platforms without restrictive symbol limits; avoids costly indirections and troubles with cross-library exceptions
	"${CMAKE_BINARY_DIR}/leanc.sh" -shared -o $@ ${LIB}/temp/empty.c ${TOOLCHAIN_SHARED_LINKER_FLAGS} ${LEANC_OPTS}
else
	@echo "[    ] Building $@"
# on Windows, must remove file before writing a new one (since the old one may be in use)
	@rm -f $@
	"${CMAKE_BINARY_DIR}/leanc.sh" -shared -o $@ ${INIT_SHARED_LINKER_FLAGS} ${TOOLCHAIN_SHARED_LINKER_FLAGS} ${LEANC_OPTS}
endif

Init_shared: ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libInit_shared${CMAKE_SHARED_LIBRARY_SUFFIX}

${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libleanshared${CMAKE_SHARED_LIBRARY_SUFFIX}: ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libInit_shared${CMAKE_SHARED_LIBRARY_SUFFIX} ${LIB}/lean/libLean.a ${LIB}/lean/libleancpp.a
	@echo "[    ] Building $@"
# on Windows, must remove file before writing a new one (since the old one may be in use)
	@rm -f $@
	"${CMAKE_BINARY_DIR}/leanc.sh" -shared -o $@ ${LEANSHARED_LINKER_FLAGS} ${TOOLCHAIN_SHARED_LINKER_FLAGS} ${LEANC_OPTS}

leanshared: ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libleanshared${CMAKE_SHARED_LIBRARY_SUFFIX}

Lake:
# lake is in its own subdirectory, so must adjust relative paths...
	+"${LEAN_BIN}/leanmake" -C lake bin lib PKG=Lake BIN_NAME=lake${CMAKE_EXECUTABLE_SUFFIX} $(LEANMAKE_OPTS) LINK_OPTS='${CMAKE_EXE_LINKER_FLAGS_MAKE_MAKE}' OUT="../${LIB}" LIB_OUT="../${LIB}/lean" OLEAN_OUT="../${LIB}/lean"

${CMAKE_BINARY_DIR}/bin/lean${CMAKE_EXECUTABLE_SUFFIX}: ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libInit_shared${CMAKE_SHARED_LIBRARY_SUFFIX} ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/libleanshared${CMAKE_SHARED_LIBRARY_SUFFIX} $(LEAN_SHELL)
	@echo "[    ] Building $@"
# on Windows, must remove file before writing a new one (since the old one may be in use)
	@rm -f $@
	"${CMAKE_BINARY_DIR}/leanc.sh" $(LEAN_SHELL) ${CMAKE_EXE_LINKER_FLAGS_MAKE} ${LEAN_EXE_LINKER_FLAGS} ${LEANC_OPTS} -o $@

lean: ${CMAKE_BINARY_DIR}/bin/lean${CMAKE_EXECUTABLE_SUFFIX}

Leanc:
	+"${LEAN_BIN}/leanmake" bin PKG=Leanc BIN_NAME=leanc${CMAKE_EXECUTABLE_SUFFIX} $(LEANMAKE_OPTS) LINK_OPTS='${CMAKE_EXE_LINKER_FLAGS_MAKE_MAKE}' OUT="${CMAKE_BINARY_DIR}" OLEAN_OUT="${CMAKE_BINARY_DIR}"