#!/usr/bin/env bash
set -e

# All LLVM-mingw targets you want to build for
TARGETS=(
  aarch64-w64-mingw32
  armv7-w64-mingw32
  i686-w64-mingw32
  x86_64-w64-mingw32
)

if [[ "${1}" == "--noinstall" ]]; then
	export NOINSTALL=1
	shift
fi

# Detect build system, preferring CMake
detect_build_system() {
  if [[ -f meson.build ]]; then
    echo "meson"
  elif [[ -f CMakeLists.txt ]]; then
    echo "cmake"
  elif [[ -f configure ]]; then
    echo "autotools"
  else
    echo "unknown"
  fi
}

# Configure environment for a given target
setup_env() {
  export TARGET="${1}"
  export CC="${TARGET}-clang"
  export CXX="${TARGET}-clang++"
  export RC="${TARGET}-windres"
  export AR="${TARGET}-ar"
  export RANLIB="${TARGET}-ranlib"
  export STRIP="${TARGET}-strip"
  export OBJCOPY="${TARGET}-objcopy"
  export OBJDUMP="${TARGET}-objdump"
  export PKG_CONFIG="/usr/bin/pkgconf"
  export PKG_CONFIG_LIBDIR="${TOOLCHAIN_PREFIX}/${TARGET}/lib/pkgconfig:${TOOLCHAIN_PREFIX}/${TARGET}/share/pkgconfig"
  export PKG_CONFIG_SYSROOT_DIR="${TOOLCHAIN_PREFIX}/${TARGET}"
  export RCFLAGS="--target=${TARGET} -D_WIN32=1 -I/opt/llvm-mingw/${TARGET}/include"
  export CFLAGS="--target=${TARGET}"
  case "$TARGET" in
	i686-w64-mingw32)
		export CFLAGS="${CFLAGS} -march=pentium4"
		export CXXFLAGS="${CFLAGS}"
		;;
	armv7-w64-mingw32)
		export CFLAGS="${CFLAGS} -mfpu=neon"
		export CXXFLAGS="${CFLAGS}"
		;;
	x86_64-w64-mingw32)
		export CFLAGS="${CFLAGS} -march=x86-64 -mtune=znver4"
		export CXXFLAGS="${CFLAGS}"
		;;
	aarch64-w64-mingw32)
		export CXXFLAGS="${CFLAGS}"
		;;
	*)
		unset CFLAGS
		unset CXXFLAGS
		;;
  esac
}

# Build using Autotools
build_autotools() {
  mkdir -p build-$TARGET
  pushd build-$TARGET

  ../configure \
    --host="$TARGET" \
    --build="$(../config.guess)" \
    --prefix="${TOOLCHAIN_PREFIX}/${TARGET}" \
    CC="${CC}" CXX="${CXX}" RC="$RC" \
    "${@}" || exit 1

  make -j$(nproc) || exit 1
  if [ -z ${NOINSTALL} ]; then
	make install || exit 1
  fi

  popd
}

# Build using CMake
build_cmake() {
  mkdir -p build-$TARGET
  pushd build-$TARGET

  cmake .. \
    -DCMAKE_SYSTEM_NAME=Windows \
    -DCMAKE_C_COMPILER="${CC}" \
    -DCMAKE_CXX_COMPILER="${CXX}" \
    -DCMAKE_RC_COMPILER="${RC}" \
    -DCMAKE_INSTALL_PREFIX="${TOOLCHAIN_PREFIX}/${TARGET}" \
    -DCMAKE_TOOLCHAIN_FILE="${TOOLCHAIN_PREFIX}/${TARGET}/llvm-mingw.cmake" \
    -DCMAKE_BUILD_TYPE=Release "${@}" || exit 1

  cmake --build . --config Release -- -j$(nproc) || exit 1
  if [ -z ${NOINSTALL} ]; then  
	cmake --install . || exit 1
  fi

  popd
}

# Meson
build_meson() {
  mkdir -p build-$TARGET
  pushd build-$TARGET

  meson setup .. \
    --cross-file <(cat <<EOF
[binaries]
c = '$TARGET-clang'
cpp = '$TARGET-clang++'
ar = '$TARGET-ar'
ld = '$TARGET-ld'
strip = '$TARGET-strip'
windres = '$TARGET-windres'
pkgconfig = '/usr/bin/pkgconf'

[host_machine]
system = 'windows'
cpu_family = '$(echo $TARGET | cut -d- -f1)'
cpu = '$(echo $TARGET | cut -d- -f1)'
endian = 'little'
EOF
) \
    --prefix="${TOOLCHAIN_PREFIX}/${TARGET}" \
    --buildtype=release "${@}"

  ninja -j$(nproc)
  if [ -z ${NOINSTALL} ]; then
	ninja install
  fi

  popd
}

# Main loop
if [ "${1}" == "--autotools" ]; then
	BUILD_SYSTEM=autotools
	shift
elif [ "${1}" == "--cmake" ]; then
	BUILD_SYSTEM=cmake
	shift	
else
	BUILD_SYSTEM=$(detect_build_system)
fi

if [[ "${1}" == "--target" ]] && [[ -n "${2}" ]]; then
  shift
  TARGET="${1}"
  shift
  setup_env "${TARGET}"
  "${@}"
  exit $?
else
  if [[ "$BUILD_SYSTEM" == "unknown" ]]; then
	echo "Error: No configure script or CMakeLists.txt found. Use --target to execute custom commands."
	exit 1
  fi
fi

for TARGET in "${TARGETS[@]}"; do
  echo "=============================="
  echo " Building for ${TARGET}"
  echo "=============================="

  setup_env "${TARGET}"

  case "$BUILD_SYSTEM" in
    autotools) build_autotools "${@}" ;;
    cmake)     build_cmake "${@}" ;;
    meson)     build_meson "${@}" ;;	
  esac

  rm -rf "${WRAPDIR}"
done