# Cross-compile for Windows on ARM64 (aarch64-w64-mingw32) with llvm-mingw:
# clang + libc++ + the libc++ `std` module, targeting the MSVCRT MinGW runtime.
# The same llvm-mingw release is multi-target, so only the target triple, the
# SDL3 SDK and the sysroot paths differ from the x86_64 toolchain.

# The `import std` gate must be set before the compiler is probed; a toolchain
# file is processed earlier than the project's own top-level settings.
set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD "d0edc3af-4c50-42ea-a356-e2862fe7a444")

set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR aarch64)

set(OPENRA3_LLVM_MINGW_ROOT "/opt/llvm-mingw" CACHE PATH "llvm-mingw installation root")
if(NOT EXISTS "${OPENRA3_LLVM_MINGW_ROOT}/bin/clang++")
    message(FATAL_ERROR "llvm-mingw not found at ${OPENRA3_LLVM_MINGW_ROOT} (expected bin/clang++)")
endif()

# llvm-mingw's per-target prefix/sysroot for the ARM64 target.
set(OPENRA3_MINGW_TRIPLE "aarch64-w64-mingw32")

set(CMAKE_C_COMPILER "${OPENRA3_LLVM_MINGW_ROOT}/bin/clang")
set(CMAKE_CXX_COMPILER "${OPENRA3_LLVM_MINGW_ROOT}/bin/clang++")
set(CMAKE_C_COMPILER_TARGET ${OPENRA3_MINGW_TRIPLE})
set(CMAKE_CXX_COMPILER_TARGET ${OPENRA3_MINGW_TRIPLE})
# CMake's standard-library detection does not pass COMPILER_TARGET, so without
# this it probes the host standard library. Putting the target in ARG1 makes
# the probe see libc++ (the MinGW target's library).
set(CMAKE_C_COMPILER_ARG1 "--target=${OPENRA3_MINGW_TRIPLE}")
set(CMAKE_CXX_COMPILER_ARG1 "--target=${OPENRA3_MINGW_TRIPLE}")

# libc++ standard-library module description for the MinGW target. Must be set
# before the compiler is probed so CMake can build `import std;`.
set(CMAKE_CXX_STDLIB_MODULES_JSON "${OPENRA3_LLVM_MINGW_ROOT}/${OPENRA3_MINGW_TRIPLE}/lib/libc++.modules.json")

# Select libc++ explicitly so CMake's `import std` detection recognises the
# standard library (llvm-mingw defaults to it, but CMake keys off -stdlib=).
set(CMAKE_CXX_FLAGS_INIT "-stdlib=libc++")
set(CMAKE_EXE_LINKER_FLAGS_INIT "-stdlib=libc++")
set(CMAKE_SHARED_LINKER_FLAGS_INIT "-stdlib=libc++")

# SDL3 for aarch64-w64-mingw32. The official SDL release ships no MinGW ARM64
# dev package, so the image stages one from MSYS2's clangarm64 repo under this
# root in the same `<triple>/{include,lib,bin}` layout.
set(OPENRA3_SDL3_ROOT "/opt/sdl3-aarch64" CACHE PATH "SDL3 aarch64 MinGW development package root")
set(OPENRA3_SDL3_MINGW_TRIPLE "${OPENRA3_MINGW_TRIPLE}" CACHE STRING "SDL3 MinGW triple subdirectory")

set(CMAKE_FIND_ROOT_PATH "${OPENRA3_LLVM_MINGW_ROOT}/${OPENRA3_MINGW_TRIPLE}")
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)