# Copyright 2018-2020 Dynatrace LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

if(BUILD_DOC)

	# find Doxygen
	find_package(Doxygen)

	if(NOT DOXYGEN_FOUND)
		 message(WARNING "Doxygen is needed to build the documentation.")
	else()

		# Copy the "Doxyfile.in" to "Doxyfile", thereby replacing the variables of the input file with their values determined by CMake
		set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/Doxyfile.in)
		set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
		configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)

		# Be sure doxygen output directory exists
		file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/docs)

		message("Doxygen build started.")

		# Add the "docs" build target (build with "make docs")
		add_custom_target(docs
						  COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYGEN_OUT}
						  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
						  COMMENT "Generating API documentation with Doxygen"
						  VERBATIM)
	endif()
endif()