# WASI toolchain for NumKong (standalone WASM runtimes such as Wasmer and Wasmtime).
# Usage: cmake -B build-wasi -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-wasi.cmake -DNK_BUILD_TEST=ON

set(CMAKE_SYSTEM_NAME WASI)
set(CMAKE_SYSTEM_VERSION 1)
set(CMAKE_SYSTEM_PROCESSOR wasm32)

# Locate the WASI SDK.
if (NOT DEFINED WASI_SDK_PATH)
    if (DEFINED ENV{WASI_SDK_PATH})
        set(WASI_SDK_PATH "$ENV{WASI_SDK_PATH}")
    elseif (EXISTS "$ENV{HOME}/wasi-sdk")
        set(WASI_SDK_PATH "$ENV{HOME}/wasi-sdk")
    else ()
        message(
            FATAL_ERROR
                "WASI_SDK_PATH not set and ~/wasi-sdk not found.\n"
                "Download from: https://github.com/WebAssembly/wasi-sdk/releases\n"
                "Then set: export WASI_SDK_PATH=~/wasi-sdk"
        )
    endif ()
endif ()

file(TO_CMAKE_PATH "${WASI_SDK_PATH}" WASI_SDK_PATH)

# Windows SDK archives ship executable suffixes that Unix hosts do not use.
if (CMAKE_HOST_WIN32)
    set(WASI_TOOL_SUFFIX ".exe")
else ()
    set(WASI_TOOL_SUFFIX "")
endif ()

# Set compilers.
set(CMAKE_C_COMPILER "${WASI_SDK_PATH}/bin/clang${WASI_TOOL_SUFFIX}")
set(CMAKE_CXX_COMPILER "${WASI_SDK_PATH}/bin/clang++${WASI_TOOL_SUFFIX}")
set(CMAKE_AR "${WASI_SDK_PATH}/bin/llvm-ar${WASI_TOOL_SUFFIX}")
set(CMAKE_RANLIB "${WASI_SDK_PATH}/bin/llvm-ranlib${WASI_TOOL_SUFFIX}")
set(CMAKE_SYSROOT "${WASI_SDK_PATH}/share/wasi-sysroot")
set(CMAKE_FIND_ROOT_PATH "${WASI_SDK_PATH}")

# WASM SIMD flags (same as Emscripten for consistency).
set(WASM_SIMD_FLAGS "-msimd128 -mrelaxed-simd")
set(CMAKE_C_FLAGS_INIT "${WASM_SIMD_FLAGS} --target=wasm32-wasip1-threads -pthread")
set(CMAKE_CXX_FLAGS_INIT "${WASM_SIMD_FLAGS} --target=wasm32-wasip1-threads -pthread -fno-exceptions")

# Optimization flags.
set(CMAKE_C_FLAGS_RELEASE "-O3 -DNDEBUG")
set(CMAKE_CXX_FLAGS_RELEASE "-O3 -DNDEBUG")
set(CMAKE_C_FLAGS_DEBUG "-O0 -g")
set(CMAKE_CXX_FLAGS_DEBUG "-O0 -g")

# Linker flags for WASI.
set(CMAKE_EXE_LINKER_FLAGS_INIT
    "-Wl,--allow-undefined \
     -Wl,--import-memory -Wl,--export-memory \
     -Wl,--shared-memory -Wl,--max-memory=2147483648 \
     -Wl,--export=main \
     -Wl,--export=_start"
)

# Do not look for programs in build-host directories.
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)

# Verify the WASI SDK version.
if (EXISTS "${WASI_SDK_PATH}/VERSION")
    file(READ "${WASI_SDK_PATH}/VERSION" WASI_SDK_VERSION)
    string(STRIP "${WASI_SDK_VERSION}" WASI_SDK_VERSION)
    message(STATUS "NumKong WASI: WASI-SDK ${WASI_SDK_VERSION}")
else ()
    message(STATUS "NumKong WASI: WASI-SDK version unknown")
endif ()

message(STATUS "NumKong WASI: SIMD128 and Relaxed SIMD enabled")
message(STATUS "NumKong WASI: Toolchain at ${WASI_SDK_PATH}")