# SPDX-License-Identifier: BSD-3-Clause
# Copyright Contributors to the OpenColorIO Project.

if(OCIO_BUILD_DOCS)

    ###########################################################################
    ### Setup PYTHONPATH ###

    include(GetPythonPreCommand)

	# Sets Python_PRE_CMD, which sets PATH and PYTHONPATH for Python
    get_python_pre_command()

	###########################################################################
	### Extract docstrings from C++ headers for Python bindings ###

	set(PYOCIO_DOCSTRINGS_DIR "${PROJECT_BINARY_DIR}/docs/_doxygen")
	set(PYOCIO_DOCSTRINGS_H "${PYOCIO_DOCSTRINGS_DIR}/docstrings.h")
    set(DOXYGEN_INDEX_XML "${PYOCIO_DOCSTRINGS_DIR}/xml/index.xml")
	set(EXTRACT_DOCSTRINGS_PY "${PROJECT_SOURCE_DIR}/share/docs/extract_docstrings.py")

	# Run docstring extraction if docstrings.h is behind doxygen XML
	add_custom_command(OUTPUT ${PYOCIO_DOCSTRINGS_H}
		COMMAND
			${Python_PRE_CMD} "${Python_EXECUTABLE}" "${EXTRACT_DOCSTRINGS_PY}" xml docstrings.h
		WORKING_DIRECTORY
			${PYOCIO_DOCSTRINGS_DIR}
		DEPENDS
			doxygen_extraction
            ${DOXYGEN_INDEX_XML}
			${EXTRACT_DOCSTRINGS_PY}
		COMMENT "Extracting Python docstrings from C++ headers"
	)

	add_custom_target(docstring_extraction
		DEPENDS ${PYOCIO_DOCSTRINGS_H}
	)

else()

	# Use stand-in docstrings.h file when docs are not built
	set(PYOCIO_DOCSTRINGS_DIR "${PROJECT_SOURCE_DIR}/share/docs")

	message(WARNING 
		"Building PyOpenColorIO with OCIO_BUILD_DOCS disabled will result in "
		"incomplete Python docstrings."
	)

endif()

###############################################################################
# Python libs

set(SOURCES
	apphelpers/PyColorSpaceHelpers.cpp
	apphelpers/PyDisplayViewHelpers.cpp
	apphelpers/PyLegacyViewingPipeline.cpp
	apphelpers/PyMixingHelpers.cpp
	transforms/PyAllocationTransform.cpp
	transforms/PyBuiltinTransform.cpp
	transforms/PyCDLTransform.cpp
	transforms/PyColorSpaceTransform.cpp
	transforms/PyDisplayViewTransform.cpp
	transforms/PyExponentTransform.cpp
	transforms/PyExponentWithLinearTransform.cpp
	transforms/PyExposureContrastTransform.cpp
	transforms/PyFileTransform.cpp
	transforms/PyFixedFunctionTransform.cpp
	transforms/PyGradingPrimaryTransform.cpp
	transforms/PyGradingRGBCurveTransform.cpp
	transforms/PyGradingToneTransform.cpp
	transforms/PyGroupTransform.cpp
	transforms/PyLogAffineTransform.cpp
	transforms/PyLogCameraTransform.cpp
	transforms/PyLogTransform.cpp
	transforms/PyLookTransform.cpp
	transforms/PyLut1DTransform.cpp
	transforms/PyLut3DTransform.cpp
	transforms/PyMatrixTransform.cpp
	transforms/PyRangeTransform.cpp
	PyBaker.cpp
	PyBuiltinConfigRegistry.cpp
	PyBuiltinTransformRegistry.cpp
	PyColorSpace.cpp
	PyColorSpaceSet.cpp
	PyConfig.cpp
	PyConfigIOProxy.cpp
	PyContext.cpp
	PyCPUProcessor.cpp
	PyDynamicProperty.cpp
	PyFileRules.cpp
	PyFormatMetadata.cpp
	PyGPUProcessor.cpp
	PyGpuShaderCreator.cpp
	PyGpuShaderDesc.cpp
	PyGradingData.cpp
	PyImageDesc.cpp
	PyLook.cpp
	PyNamedTransform.cpp
	PyOpenColorIO.cpp
	PyPackedImageDesc.cpp
	PyPlanarImageDesc.cpp
	PyProcessor.cpp
	PyProcessorMetadata.cpp
	PySystemMonitors.cpp
	PyTransform.cpp
	PyTypes.cpp
	PyUtils.cpp
	PyViewingRules.cpp
	PyViewTransform.cpp
)

# Reason not to use pybind11_add_module ?
# https://pybind11.readthedocs.io/en/stable/compiling.html#pybind11-add-module
add_library(PyOpenColorIO MODULE ${SOURCES})

if(OCIO_BUILD_DOCS)
	add_dependencies(PyOpenColorIO
		docstring_extraction
	)
endif()

set_target_properties(PyOpenColorIO PROPERTIES
	PREFIX ""
)

if(WIN32)
	# Windows uses .pyd extension for python modules
	set_target_properties(PyOpenColorIO PROPERTIES
		SUFFIX ".pyd"
	)
endif()

set(CUSTOM_COMPILE_FLAGS ${PLATFORM_COMPILE_OPTIONS})
set(CUSTOM_LINK_FLAGS ${PLATFORM_LINK_OPTIONS})

# The Python binding contains deprecated methods for backward compatibility reason,
# so disable the warning.
if(USE_GCC OR USE_CLANG)
    set(CUSTOM_COMPILE_FLAGS "${CUSTOM_COMPILE_FLAGS};-Wno-deprecated-declarations")
elseif(USE_MSVC)
    set(CUSTOM_COMPILE_FLAGS "${CUSTOM_COMPILE_FLAGS};/wd4996")
endif()

# OSX demands that the linker resolve all symbols at build time
# we pass this flag to allow dynamic linking
if(APPLE)
    set(CUSTOM_LINK_FLAGS "${CUSTOM_LINK_FLAGS};-undefined;dynamic_lookup")
endif()

set_target_properties(PyOpenColorIO
	PROPERTIES
		COMPILE_OPTIONS "${CUSTOM_COMPILE_FLAGS}"
		LINK_OPTIONS "${CUSTOM_LINK_FLAGS}"
)

if(NOT BUILD_SHARED_LIBS)
	target_compile_definitions(PyOpenColorIO
		PUBLIC
			OpenColorIO_SKIP_IMPORTS
	)
endif()

if(UNIX)
	# A 'module' is a dynamic library on Linux (i.e. '-fPIC' needed),
	# but a static library on Windows.

	# If supported for the target machine, emit position-independent code
	# suitable for dynamic linking.
	set_property(TARGET PyOpenColorIO PROPERTY POSITION_INDEPENDENT_CODE ON)
endif()

if (UNIX AND NOT CMAKE_SKIP_RPATH AND CMAKE_INSTALL_RPATH)
    # Update the default RPATH so the Python binding dynamic library can find the OpenColorIO
    # dynamic library based on the default installation directory structure.
    if (APPLE)
        set_target_properties(PyOpenColorIO PROPERTIES
            INSTALL_RPATH "@loader_path/../../..;${CMAKE_INSTALL_RPATH}")
    else()
        set_target_properties(PyOpenColorIO PROPERTIES
            INSTALL_RPATH "$ORIGIN/../../..;${CMAKE_INSTALL_RPATH}")
    endif()
endif()

target_include_directories(PyOpenColorIO
	PRIVATE
		PyOpenColorIO
		${CMAKE_CURRENT_BINARY_DIR}/include
		${CMAKE_CURRENT_SOURCE_DIR}
		${pybind11_INCLUDE_DIR}
		${PYOCIO_DOCSTRINGS_DIR}
	SYSTEM
		${Python_INCLUDE_DIRS}
)

# pybind11 recommends intentionally NOT linking against libpython on Linux and 
# macOS, to prevent segfaults when potentially working with multiple Python 
# installations. See note in:
#   https://pybind11.readthedocs.io/en/stable/compiling.html#building-manually

if (WIN32)
	set(_PublicLibs ${Python_LIBRARIES})
endif()

target_link_libraries(PyOpenColorIO
	PUBLIC
		${_PublicLibs}
	PRIVATE
		OpenColorIO
		utils::strings
		pybind11::module
)

target_compile_definitions(PyOpenColorIO
	PRIVATE
		PYOCIO_NAME=PyOpenColorIO
		PY_VERSION_MAJOR=${Python_VERSION_MAJOR}
		PY_VERSION_MINOR=${Python_VERSION_MINOR}
		PY_VERSION_PATCH=${Python_VERSION_PATCH}
)

###############################################################################
# Build layout
# Mirrors the installation, using PyOpenColorIO folder and __init__.py file.
# When building the Python wheel, do not override the target directory.
set(_PyOpenColorIO_BUILD_PACKAGE_DIR  "${CMAKE_CURRENT_BINARY_DIR}/PyOpenColorIO")
if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
	set_target_properties(PyOpenColorIO PROPERTIES
		LIBRARY_OUTPUT_DIRECTORY "${_PyOpenColorIO_BUILD_PACKAGE_DIR}"
		# For Windows compatibility
		LIBRARY_OUTPUT_DIRECTORY_DEBUG "${_PyOpenColorIO_BUILD_PACKAGE_DIR}"
		LIBRARY_OUTPUT_DIRECTORY_RELEASE "${_PyOpenColorIO_BUILD_PACKAGE_DIR}"
	)
endif()

file(COPY package/__init__.py DESTINATION "${_PyOpenColorIO_BUILD_PACKAGE_DIR}")

###############################################################################
# Install layout
# Set to site-package location.
if(WIN32)
    set(_Python_VARIANT_PATH "${CMAKE_INSTALL_LIBDIR}/site-packages")
else()
    set(_Python_VARIANT_PATH "${CMAKE_INSTALL_LIBDIR}/python${Python_VERSION_MAJOR}.${Python_VERSION_MINOR}/site-packages")
endif()

# Create an internal global variable to access it in another scope but not publicly visible.
# The site-package location is needed in setup_ocio.bat.in and setup_ocio.sh.in.
set(PYTHON_VARIANT_PATH ${_Python_VARIANT_PATH} CACHE INTERNAL "")

# Set to PyOpenColorIO site-package location.
set(_PyOpenColorIO_SITE_PACKAGE_DIR "${PYTHON_VARIANT_PATH}/PyOpenColorIO")

include(StripUtils)
ocio_strip_binary(PyOpenColorIO)

install(TARGETS PyOpenColorIO
    LIBRARY DESTINATION ${_PyOpenColorIO_SITE_PACKAGE_DIR}
)

install(FILES package/__init__.py DESTINATION ${_PyOpenColorIO_SITE_PACKAGE_DIR})