# Copyright 1999-2023 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=8

# TODO:
# - add USE flag for remote modules? Those modules can be downloaded
#	properly before building.
# - replace usex by usev where applicable

PYTHON_COMPAT=( python3_{9..11} )
WEBAPP_OPTIONAL=yes
WEBAPP_MANUAL_SLOT=yes

inherit check-reqs cmake cuda java-pkg-opt-2 multiprocessing python-single-r1 toolchain-funcs virtualx webapp

# Short package version
MY_PV="$(ver_cut 1-2)"

DESCRIPTION="The Visualization Toolkit"
HOMEPAGE="https://www.vtk.org/"
SRC_URI="
	https://www.vtk.org/files/release/${MY_PV}/VTK-${PV}.tar.gz
	https://www.vtk.org/files/release/${MY_PV}/VTKData-${PV}.tar.gz
	https://www.vtk.org/files/release/${MY_PV}/VTKDataFiles-${PV}.tar.gz
	doc? ( https://www.vtk.org/files/release/${MY_PV}/vtkDocHtml-${PV}.tar.gz )
	examples? (
		https://www.vtk.org/files/release/${MY_PV}/VTKLargeData-${PV}.tar.gz
		https://www.vtk.org/files/release/${MY_PV}/VTKLargeDataFiles-${PV}.tar.gz
	)
	test? (
		https://www.vtk.org/files/release/${MY_PV}/VTKLargeData-${PV}.tar.gz
		https://www.vtk.org/files/release/${MY_PV}/VTKLargeDataFiles-${PV}.tar.gz
	)
"
S="${WORKDIR}/VTK-${PV}"

LICENSE="BSD LGPL-2"
SLOT="0/${MY_PV}"
KEYWORDS="~amd64 ~arm ~arm64 ~x86 ~amd64-linux ~x86-linux"
# TODO: Like to simplifiy these. Mostly the flags related to Groups.
IUSE="all-modules boost cuda debug doc examples ffmpeg freetype gdal imaging
	java las +logging mpi mysql odbc openmp openvdb pdal postgres python qt5
	qt6 +rendering sdl tbb test +threads tk video_cards_nvidia views vtkm web"

RESTRICT="!test? ( test )"

REQUIRED_USE="
	all-modules? (
		boost ffmpeg freetype gdal imaging las mysql odbc openvdb pdal
		postgres rendering views
	)
	cuda? ( video_cards_nvidia vtkm )
	java? ( rendering )
	python? ( ${PYTHON_REQUIRED_USE} )
	qt5? ( rendering )
	qt6? ( rendering )
	sdl? ( rendering )
	tk? ( python rendering )
	web? ( python )
"

# for <pegtl-3 dependency see
# https://discourse.vtk.org/t/compilation-errors-related-to-pegtl-proj/5929
# eigen, nlohmann_json, pegtl and utfcpp are referenced in the cmake files
# and need to be available when VTK consumers configure the dependencies.
RDEPEND="
	app-arch/lz4:=
	app-arch/xz-utils
	dev-cpp/eigen
	dev-cpp/nlohmann_json
	dev-db/sqlite:3
	dev-libs/double-conversion:=
	dev-libs/expat
	dev-libs/icu:=
	dev-libs/jsoncpp:=
	>=dev-libs/libfmt-8.1.1:=
	dev-libs/libxml2:2
	dev-libs/libzip:=
	<dev-libs/pegtl-3
	dev-libs/pugixml
	dev-libs/utfcpp
	media-libs/freetype
	media-libs/libjpeg-turbo
	>=media-libs/libharu-2.4.2:=
	media-libs/libogg
	media-libs/libpng:=
	media-libs/libtheora
	media-libs/tiff:=
	>=sci-libs/cgnslib-4.1.1:=[hdf5,mpi=]
	sci-libs/hdf5:=[mpi=]
	sci-libs/proj:=
	sci-libs/netcdf:=[mpi=]
	sys-libs/zlib
	boost? ( dev-libs/boost:=[mpi?] )
	cuda? ( dev-util/nvidia-cuda-toolkit:= )
	ffmpeg? ( media-video/ffmpeg:= )
	freetype? ( media-libs/fontconfig )
	gdal? ( sci-libs/gdal:= )
	java? ( >=virtual/jdk-1.8:* )
	las? ( sci-geosciences/liblas )
	mpi? ( virtual/mpi[cxx,romio] )
	mysql? ( dev-db/mariadb-connector-c )
	odbc? ( dev-db/unixODBC )
	openvdb? ( media-gfx/openvdb:= )
	pdal? ( sci-libs/pdal:= )
	postgres? ( dev-db/postgresql:= )
	python? (
		${PYTHON_DEPS}
		$(python_gen_cond_dep 'mpi? ( dev-python/mpi4py[${PYTHON_USEDEP}] )')
	)
	qt5? (
		dev-qt/qtcore:5
		dev-qt/qtopengl:5
		dev-qt/qtquickcontrols2:5
		dev-qt/qtsql:5
		dev-qt/qtwidgets:5
	)
	qt6? (
		dev-qt/qtbase:6[gui,opengl,sql,widgets]
		dev-qt/qtdeclarative:6[opengl]
		dev-qt/qtshadertools:6
		x11-libs/libxkbcommon
	)
	sdl? ( media-libs/libsdl2 )
	rendering? (
		media-libs/glew:=
		virtual/opengl
		x11-libs/gl2ps
		x11-libs/libICE
		x11-libs/libXcursor
		x11-libs/libXext
	)
	tbb? ( dev-cpp/tbb:= )
	tk? ( dev-lang/tk:= )
	video_cards_nvidia? ( x11-drivers/nvidia-drivers[tools,static-libs] )
	views? (
		x11-libs/libICE
		x11-libs/libXext
	)
	web? ( ${WEBAPP_DEPEND} )
"

# for <pegtl-3 dependency see
# https://discourse.vtk.org/t/compilation-errors-related-to-pegtl-proj/5929
DEPEND="
	${RDEPEND}
	dev-cpp/eigen
	dev-cpp/nlohmann_json
	<dev-libs/pegtl-3
	dev-libs/utfcpp
	test? (
		media-libs/glew
		x11-libs/libXcursor
		rendering? ( media-libs/freeglut )
	)
"
BDEPEND="virtual/pkgconfig"

PATCHES=(
	"${FILESDIR}"/${PN}-9.2.2-vtkGeometryFilter-add-missing-mutex-header-file.patch
	"${FILESDIR}"/${PN}-9.2.2-VTKm-respect-user-CXXFLAGS.patch
	"${FILESDIR}"/${PN}-9.2.2-link-with-glut-library-for-freeglut.patch
	"${FILESDIR}"/${PN}-9.2.5-Add-include-cstdint-to-compile-with-gcc-13.patch
	"${FILESDIR}"/${PN}-9.2.5-Fix-compilation-error-with-CUDA-12.patch
	"${FILESDIR}"/${PN}-9.2.5-More-include-cstdint-to-compile-with-gcc13.patch
)

DOCS=( CONTRIBUTING.md README.md )

vtk_check_reqs() {
	local dsk=4096
	local mem=$(( $(usex cuda 7168 0) ))

	dsk=$(( $(usex doc 3072 0) + ${dsk} ))
	dsk=$(( $(usex examples 3072 0) + ${dsk} ))
	dsk=$(( $(usex cuda 8192 0) + ${dsk} ))

	# In case users are not aware of the extra NINJAOPTS, check
	# for the more common MAKEOPTS, in case NINJAOPTS is empty
	local jobs=1
	if [[ -n "${NINJAOPTS}" ]]; then
		jobs=$(makeopts_jobs "${NINJAOPTS}" "$(get_nproc)")
	else
		if [[ -n "${MAKEOPTS}" ]]; then
			jobs=$(makeopts_jobs "${MAKEOPTS}" "$(get_nproc)")
		fi
	fi
	mem=$(( ${mem} * $(( ${jobs} > 4 ? 4 : ${jobs} )) ))

	use cuda && export CHECKREQS_MEMORY=${mem}M
	export CHECKREQS_DISK_BUILD=${dsk}M

	check-reqs_pkg_${EBUILD_PHASE}
}

pkg_pretend() {
	[[ ${MERGE_TYPE} != binary ]] && has openmp && tc-check-openmp

	if [[ $(tc-is-gcc) && $(gcc-majorversion) = 11 ]] && use cuda ; then
		# FIXME: better use eerror?
		ewarn "GCC 11 is know to fail building with CUDA support in some cases."
		ewarn "See bug #820593"
	fi

	if use qt6 && use qt5; then
		ewarn "Both qt5 and qt6 USE flags have been selected. Using qt5!"
	fi

	# bug #835659
	if use cuda; then
		if [[ ${VTK_CUDA_ARCH} = native ]]; then
			eerror "Using native CUDA arches is currently broken."
			eerror "Please set it to one of the common arch names:"
			eerror "kepler, maxwell, pascal, turing or ampere."
			die "Please set VTK_CUDA_ARCH environment variable!"
		fi
	fi

	vtk_check_reqs
}

pkg_setup() {
	[[ ${MERGE_TYPE} != binary ]] && has openmp && tc-check-openmp

	if [[ $(tc-is-gcc) && $(gcc-majorversion) = 11 ]] && use cuda ; then
		# FIXME: better use eerror?
		ewarn "GCC 11 is know to fail building with CUDA support in some cases."
		ewarn "See bug #820593"
	fi

	if use qt6 && use qt5; then
		ewarn "Both qt5 and qt6 USE flags have been selected. Using qt5!"
	fi

	# bug #835659
	if use cuda; then
		if [[ ${VTK_CUDA_ARCH} = native ]]; then
			eerror "Using native CUDA arches is currently broken."
			eerror "Please set it to one of the common arch names:"
			eerror "kepler, maxwell, pascal, turing or ampere."
			die "Please set VTK_CUDA_ARCH environment variable!"
		fi
	fi

	vtk_check_reqs

	use java && java-pkg-opt-2_pkg_setup
	use python && python-single-r1_pkg_setup
	use web && webapp_pkg_setup
}

# Note: The following libraries are marked as internal by kitware
#	and can currently not unbundled:
#	diy2, exodusII, fides, h5part, kissfft, loguru, verdict, vpic,
#	vtkm, xdmf{2,3}, zfp
# TODO: cli11 (::guru), exprtk, ioss
# Note: As of v9.2.2 we no longer drop bundled libraries, when using system
# libraries. This just saves a little space. CMake logic of VTK on ThirdParty
# libraries avoids automagic builds, so deletion is not needed to catch these.
src_prepare() {
	if use doc; then
		einfo "Removing .md5 files from documents."
		rm -f "${WORKDIR}"/html/*.md5 || die "Failed to remove superfluous hashes"
		sed -e "s|\${VTK_BINARY_DIR}/Utilities/Doxygen/doc|${WORKDIR}|" \
			-i Utilities/Doxygen/CMakeLists.txt || die
	fi

	cmake_src_prepare

	if use cuda; then
		cuda_add_sandbox -w
		cuda_src_prepare
	fi

	if use test; then
		ebegin "Copying data files to ${BUILD_DIR}"
		mkdir -p "${BUILD_DIR}/ExternalData" || die
		pushd "${BUILD_DIR}/ExternalData" >/dev/null || die
		ln -sf ../../VTK-${PV}/.ExternalData/README.rst . || die
		ln -sf ../../VTK-${PV}/.ExternalData/SHA512 . || die
		popd >/dev/null || die
		eend "$?"
	fi
}

# TODO: check these and consider to use them
#	VTK_BUILD_SCALED_SOA_ARRAYS
#	VTK_DISPATCH_{AOS,SOA,TYPED}_ARRAYS
src_configure() {
	local mycmakeargs=(
		-DCMAKE_INSTALL_LICENSEDIR="share/${PN}/licenses"

		-DVTK_ANDROID_BUILD=OFF
		-DVTK_IOS_BUILD=OFF

		-DVTK_BUILD_ALL_MODULES=$(usex all-modules ON OFF)
		# we use the pre-built documentation and install these with USE=doc
		-DVTK_BUILD_DOCUMENTATION=OFF
		-DVTK_BUILD_EXAMPLES=$(usex examples ON OFF)

		# no package in the tree: https://github.com/LLNL/conduit
		-DVTK_ENABLE_CATALYST=OFF
		-DVTK_ENABLE_KITS=OFF
		-DVTK_ENABLE_LOGGING=$(usex logging ON OFF)
		# defaults to ON: USE flag for this?
		-DVTK_ENABLE_REMOTE_MODULES=OFF

		# disable fetching files during build
		-DVTK_FORBID_DOWNLOADS=ON

		-DVTK_GROUP_ENABLE_Imaging=$(usex imaging "YES" "DEFAULT")
		-DVTK_GROUP_ENABLE_Rendering=$(usex rendering "YES" "DEFAULT")
		-DVTK_GROUP_ENABLE_StandAlone="YES"
		-DVTK_GROUP_ENABLE_Views=$(usex views "YES" "DEFAULT")
		-DVTK_GROUP_ENABLE_Web=$(usex web "YES" "DEFAULT")

		-DVTK_INSTALL_SDK=ON

		-DVTK_MODULE_ENABLE_VTK_IOCGNSReader="WANT"
		-DVTK_MODULE_ENABLE_VTK_IOExportPDF="WANT"
		-DVTK_MODULE_ENABLE_VTK_IOLAS=$(usex las "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_IONetCDF="WANT"
		-DVTK_MODULE_ENABLE_VTK_IOOggTheora="WANT"
		-DVTK_MODULE_ENABLE_VTK_IOOpenVDB=$(usex openvdb "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_IOSQL="WANT" # sqlite
		-DVTK_MODULE_ENABLE_VTK_IOPDAL=$(usex pdal "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_IOXML="WANT"
		-DVTK_MODULE_ENABLE_VTK_IOXMLParser="WANT"
		-DVTK_MODULE_ENABLE_VTK_RenderingFreeType=$(usex freetype "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_RenderingFreeTypeFontConfig=$(usex freetype "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_cgns="WANT"
		-DVTK_MODULE_ENABLE_VTK_doubleconversion="WANT"
		-DVTK_MODULE_ENABLE_VTK_eigen="WANT"
		-DVTK_MODULE_ENABLE_VTK_expat="WANT"
		-DVTK_MODULE_ENABLE_VTK_fmt="WANT"
		-DVTK_MODULE_ENABLE_VTK_freetype="WANT"
		-DVTK_MODULE_ENABLE_VTK_hdf5="WANT"
		-DVTK_MODULE_ENABLE_VTK_jpeg="WANT"
		-DVTK_MODULE_ENABLE_VTK_jsoncpp="WANT"
		-DVTK_MODULE_ENABLE_VTK_libharu="WANT"
		-DVTK_MODULE_ENABLE_VTK_libproj="WANT"
		-DVTK_MODULE_ENABLE_VTK_libxml2="WANT"
		-DVTK_MODULE_ENABLE_VTK_lz4="WANT"
		-DVTK_MODULE_ENABLE_VTK_lzma="WANT"
		-DVTK_MODULE_ENABLE_VTK_netcdf="WANT"
		-DVTK_MODULE_ENABLE_VTK_nlohmannjson="WANT"
		-DVTK_MODULE_ENABLE_VTK_ogg="WANT"
		-DVTK_MODULE_ENABLE_VTK_pegtl="WANT"
		-DVTK_MODULE_ENABLE_VTK_png="WANT"
		-DVTK_MODULE_ENABLE_VTK_pugixml="WANT"
		-DVTK_MODULE_ENABLE_VTK_sqlite="WANT"
		-DVTK_MODULE_ENABLE_VTK_theora="WANT"
		-DVTK_MODULE_ENABLE_VTK_tiff="WANT"
		-DVTK_MODULE_ENABLE_VTK_utf8="WANT"
		-DVTK_MODULE_ENABLE_VTK_vtkm=$(usex vtkm "WANT" "DEFAULT")
		-DVTK_MODULE_ENABLE_VTK_zlib="WANT"

		# not packaged in Gentoo
		-DVTK_MODULE_USE_EXTERNAL_VTK_exprtk=OFF
		-DVTK_MODULE_USE_EXTERNAL_VTK_ioss=OFF
		-DVTK_MODULE_USE_EXTERNAL_VTK_verdict=OFF

		-DVTK_RELOCATABLE_INSTALL=ON

		-DVTK_SMP_ENABLE_OPENMP=$(usex openmp ON OFF)
		-DVTK_SMP_ENABLE_STDTHREAD=$(usex threads ON OFF)
		-DVTK_SMP_ENABLE_TBB=$(usex tbb ON OFF)

		-DVTK_UNIFIED_INSTALL_TREE=ON

		-DVTK_USE_CUDA=$(usex cuda ON OFF)
		# use system libraries where possible
		-DVTK_USE_EXTERNAL=ON
		# avoid finding package from either ::guru or ::sci
		-DVTK_USE_MEMKIND=OFF
		-DVTK_USE_MPI=$(usex mpi ON OFF)
		-DVTK_USE_TK=$(usex tk ON OFF)
		-DVTK_USE_X=ON

		-DVTK_WHEEL_BUILD=OFF

		-DVTK_WRAP_JAVA=$(usex java ON OFF)
		-DVTK_WRAP_PYTHON=$(usex python ON OFF)
	)

	if use all-modules; then
		mycmakeargs+=(
			# no package in ::gentoo
			-DVTK_ENABLE_OSPRAY=OFF
			# TODO: some of these are tied to the VTK_ENABLE_REMOTE_MODULES
			# option. Check whether we can download them clean and enable
			# them.
			-DVTK_MODULE_ENABLE_VTK_DomainsMicroscopy="NO"
			-DVTK_MODULE_ENABLE_VTK_fides="NO"
			-DVTK_MODULE_ENABLE_VTK_FiltersOpenTURNS="NO"
			-DVTK_MODULE_ENABLE_VTK_IOADIOS2="NO"
			-DVTK_MODULE_ENABLE_VTK_IOFides="NO"

			-DVTK_MODULE_ENABLE_VTK_RenderingOpenVR="NO"
			-DVTK_MODULE_ENABLE_VTK_RenderingOpenXR="NO"

			# available in ::guru, so avoid  detection if installed
			-DVTK_MODULE_USE_EXTERNAL_VTK_cli11=OFF
		)
	fi

	if use boost; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_InfovisBoost="WANT"
			-DVTK_MODULE_ENABLE_VTK_InfovisBoostGraphAlgorithms="WANT"
		)
	fi

	# TODO: checks this on updates of nvidia-cuda-toolkit and update
	# the list of available arches if necessary, i.e. add new arches
	# once they are released at the end of the list before all.
	# See https://en.wikipedia.org/wiki/CUDA#GPUs_supported
	# CUDA 11.8 supports Ada Lovelace and Hopper arches, but cmake,
	# as of 3.25.1 doesn't recognize these keywords.
	# FIXME: better use numbers than names?
	if use cuda; then
		local cuda_arch=
		case ${VTK_CUDA_ARCH:-native} in
			# we ignore fermi arch, because current nvidia-cuda-toolkit-11*
			# no longer supports it
			kepler|maxwell|pascal|volta|turing|ampere|all)
				cuda_arch=${VTK_CUDA_ARCH}
				;;
#			native)
#				ewarn "If auto detection fails for you, please try and export the"
#				ewarn "VTK_CUDA_ARCH environment variable to one of the common arch"
#				ewarn "names: kepler, maxwell, pascal, volta, turing, ampere or all."
#				cuda_arch=native
#				;;
			*)
				eerror "Please properly set the VTK_CUDA_ARCH environment variable to"
				eerror "one of: kepler, maxwell, pascal, volta, turing, ampere, all"
				die "Invalid CUDA architecture given: '${VTK_CUDA_ARCH}'!"
				;;
		esac
		ewarn "Using CUDA architecture '${cuda_arch}'"

		mycmakeargs+=( -DVTKm_CUDA_Architecture=${cuda_arch} )
	fi

	if use debug; then
		mycmakeargs+=(
			-DVTK_DEBUG_LEAKS=ON
			-DVTK_DEBUG_MODULE=ON
			-DVTK_DEBUG_MODULE_ALL=ON
			-DVTK_ENABLE_SANITIZER=ON
			-DVTK_EXTRA_COMPILER_WARNINGS=ON
			-DVTK_WARN_ON_DISPATCH_FAILURE=ON
		)
		if use rendering; then
			mycmakeargs+=( -DVTK_OPENGL_ENABLE_STREAM_ANNOTATIONS=ON )
		fi
	fi

	if use examples || use test; then
		mycmakeargs+=( -DVTK_USE_LARGE_DATA=ON )
	fi

	if use ffmpeg; then
		mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_IOFFMPEG="WANT" )
		if use rendering; then
			mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_RenderingFFMPEGOpenGL2="WANT" )
		fi
	fi

	if use gdal; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_GeovisGDAL="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOGDAL="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOGeoJSON="WANT"
		)
	fi

	if use imaging; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_ImagingColor="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingCore="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingFourier="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingGeneral="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingHybrid="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingMath="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingMorphological="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingSources="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingStatistics="WANT"
			-DVTK_MODULE_ENABLE_VTK_ImagingStencil="WANT"
		)
		use rendering && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_RenderingImage="WANT" )
	fi

	if ! use java && ! use python; then
		# defaults to ON
		mycmakeargs+=( -DVTK_ENABLE_WRAPPING=OFF )
	fi

	if use java; then
		mycmakeargs+=(
			-DCMAKE_INSTALL_JARDIR="share/${PN}"
			-DVTK_ENABLE_WRAPPING=ON
			-DVTK_MODULE_ENABLE_VTK_Java="WANT"
		)
	fi

	if use mpi; then
		mycmakeargs+=(
			-DVTK_GROUP_ENABLE_MPI="YES"
			-DVTK_MODULE_ENABLE_VTK_IOH5part="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOMPIParallel="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOParallel="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOParallelNetCDF="WANT"
			-DVTK_MODULE_ENABLE_VTK_IOParallelXML="WANT"
			-DVTK_MODULE_ENABLE_VTK_ParallelMPI="WANT"
			-DVTK_MODULE_ENABLE_VTK_h5part="WANT"
			-DVTK_MODULE_USE_EXTERNAL_VTK_verdict=OFF
		)
		use imaging && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_IOMPIImage="WANT" )
		use python && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_ParallelMPI4Py="WANT" )
		if use rendering; then
			mycmakeargs+=(
				-DVTK_MODULE_ENABLE_VTK_RenderingParallel="WANT"
				-DVTK_MODULE_ENABLE_VTK_RenderingParallelLIC="WANT"
			)
		fi
		use vtkm && mycmakeargs+=( -DVTKm_ENABLE_MPI=ON )
	else
		mycmakeargs+=( -DVTK_GROUP_ENABLE_MPI="NO" )
	fi

	use mysql && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_IOMySQL="WANT" )
	use odbc && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_IOODBC="WANT" )
	use openvdb && mycmakeargs+=( -DOpenVDB_CMAKE_PATH="${ESYSROOT}/usr/$(get_libdir)/cmake/OpenVDB" )
	use postgres && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_IOPostgreSQL="WANT" )

	if use python; then
		mycmakeargs+=(
			-DPython3_EXECUTABLE="${PYTHON}"
			-DVTK_ENABLE_WRAPPING=ON
			-DVTK_MODULE_ENABLE_VTK_Python="WANT"
			-DVTK_MODULE_ENABLE_VTK_PythonInterpreter="WANT"
			-DVTK_MODULE_ENABLE_VTK_WrappingPythonCore="WANT"
			-DVTK_PYTHON_SITE_PACKAGES_SUFFIX="lib/${EPYTHON}/site-packages"
		)
		use rendering && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_PythonContext2D="WANT" )
	fi

	if use qt5 && use qt6; then
		# prefer Qt5: https://wiki.gentoo.org/wiki/Project:qt/Policies
		mycmakeargs+=(
			-DCMAKE_INSTALL_QMLDIR="${EPREFIX}/usr/$(get_libdir)/qt5/qml"
			-DVTK_QT_VERSION="5"
		)
	else
		if use qt5; then
			mycmakeargs+=(
				-DCMAKE_INSTALL_QMLDIR="${EPREFIX}/usr/$(get_libdir)/qt5/qml"
				-DVTK_QT_VERSION="5"
			)
		elif use qt6; then
			mycmakeargs+=(
				-DCMAKE_INSTALL_QMLDIR="${EPFREIX}/usr/$(get_libdir)/qt6/qml"
				-DVTK_QT_VERSION="6"
			)
		else
			mycmakeargs+=( -DVTK_GROUP_ENABLE_Qt="NO" )
		fi
	fi

	if use qt5 || use qt6; then
		mycmakeargs+=(
			-DVTK_GROUP_ENABLE_Qt:STRING="YES"
			-DVTK_MODULE_ENABLE_VTK_GUISupportQt="WANT"
			-DVTK_MODULE_ENABLE_VTK_GUISupportQtQuick="WANT"
		)
		if use mysql || use postgres; then
			mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_GUISupportQtSQL="WANT" )
		fi
		if use rendering; then
			mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_RenderingQt="WANT" )
		fi
		if use views; then
			mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_ViewsQt="WANT" )
		fi
	fi

	if use rendering; then
		mycmakeargs+=(
			-DVTK_ENABLE_OSPRAY=OFF

			-DVTK_MODULE_ENABLE_VTK_IOExportGL2PS="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingAnnotation="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingContext2D="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingContextOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingCore="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingExternal="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingGL2PSOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingHyperTreeGrid="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingLICOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingLOD="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingLabel="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingMatplotlib="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingRayTracing="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingSceneGraph="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingUI="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingVolume="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingVolumeAMR="WANT"
			-DVTK_MODULE_ENABLE_VTK_RenderingVolumeOpenGL2="WANT"
			-DVTK_MODULE_ENABLE_VTK_gl2ps="WANT"
			-DVTK_MODULE_ENABLE_VTK_glew="WANT"
			-DVTK_MODULE_ENABLE_VTK_opengl="WANT"

			-DVTK_USE_SDL2=$(usex sdl "YES" "NO")
		)
		use tk && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_RenderingTk="WANT" )
		use views && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_ViewsContext2D="WANT" )
		use web && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_RenderingVtkJS="WANT" )
	fi

	# Testing has been changed in 9.2.5: it is now allowed without
	# requiring to download, if the data files are available locally!
	if use test; then
		mycmakeargs+=(
			-DVTK_BUILD_TESTING=ON
			# disable fetching data files for the default 'all' target
			-DVTK_DATA_EXCLUDE_FROM_ALL=ON

			# requested even if all use flags are off
			-DVTK_MODULE_ENABLE_VTK_octree="WANT"
			-DVTK_MODULE_ENABLE_VTK_ViewsCore="WANT"

			# available in ::guru, so avoid  detection if installed
			-DVTK_MODULE_USE_EXTERNAL_VTK_cli11=OFF
		)
	else
		mycmakeargs+=( -DVTK_BUILD_TESTING=OFF )
	fi

	# FIXME: upstream provides 4 threading models, as of 9.1.0. These are
	# sequential, stdthread, openmp and tbb. AFAICS all of them can be
	# enabled at the same time. Sequential and Stdthread are enabled by
	# default. The default selected type for the build is sequential.
	# Assuming sequential < stdpthread < openmp < tbb wrt speed, although
	# this is dependent on the actual scenario where threading is used.
	if use tbb; then
		mycmakeargs+=( -DVTK_SMP_IMPLEMENTATION_TYPE="TBB" )
	elif use openmp; then
		mycmakeargs+=( -DVTK_SMP_IMPLEMENTATION_TYPE="OpenMP" )
	elif use threads; then
		mycmakeargs+=( -DVTK_SMP_IMPLEMENTATION_TYPE="STDThread" )
	else
		mycmakeargs+=( -DVTK_SMP_IMPLEMENTATION_TYPE="Sequential" )
	fi

	use tk && mycmakeargs+=( -DVTK_GROUP_ENABLE_Tk="YES" )

	if use views; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_ViewsCore="WANT"
			-DVTK_MODULE_ENABLE_VTK_ViewsInfovis="WANT"
		)
	fi

	if use vtkm; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_AcceleratorsVTKmCore="WANT"
			-DVTK_MODULE_ENABLE_VTK_AcceleratorsVTKmDataModel="WANT"
			-DVTK_MODULE_ENABLE_VTK_AcceleratorsVTKmFilters="WANT"

			-DVTKm_NO_INSTALL_README_LICENSE=ON # bug #793221
			-DVTKm_Vectorization=native
		)
	fi

	if use web; then
		mycmakeargs+=(
			-DVTK_MODULE_ENABLE_VTK_WebCore="WANT"
			-DVTK_MODULE_ENABLE_VTK_WebGLExporter="WANT"
		)
		use python && mycmakeargs+=( -DVTK_MODULE_ENABLE_VTK_WebPython="WANT" )
	fi

	use java && export JAVA_HOME="${EPREFIX}/etc/java-config-2/current-system-vm"

	cmake_src_configure
}

src_compile() {
	use test && cmake_build VTKData
	cmake_src_compile
}

# FIXME: avoid nonfatal?
# see https://github.com/gentoo/gentoo/pull/22878#discussion_r747204043
src_test() {
#	nonfatal virtx cmake_src_test
	virtx cmake_src_test
}

src_install() {
	use web && webapp_src_preinst

	# Stop web page images from being compressed
	if use doc; then
		HTML_DOCS=( "${WORKDIR}/html/." )
	fi

	cmake_src_install

	use java && java-pkg_regjar "${ED}"/usr/share/${PN}/${PN}.jar

	# install examples
	if use examples; then
		einfo "Installing examples"
		mv -v {E,e}xamples || die
		dodoc -r examples
		docompress -x /usr/share/doc/${PF}/examples

		einfo "Installing datafiles"
		insinto /usr/share/${PN}/data
		doins -r "${S}/.ExternalData"
	fi

	use python && python_optimize

	use web && webapp_src_install
}

# webapp.eclass exports these but we want it optional #534036
pkg_postinst() {
	use web && webapp_pkg_postinst

	if use examples; then
		einfo "You can get more and updated examples at"
		einfo "https://kitware.github.io/vtk-examples/site/"
	fi
}

pkg_prerm() {
	use web && webapp_pkg_prerm
}