# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

find_package(Doxygen REQUIRED)
find_package(Sphinx REQUIRED)

# Find all the public headers
get_target_property(FBGEMM_PUBLIC_HEADER_DIR
  fbgemm INTERFACE_INCLUDE_DIRECTORIES)
file(GLOB_RECURSE FBGEMM_PUBLIC_HEADERS
  ${FBGEMM_PUBLIC_HEADER_DIR}/fbgemm/*.h)

set(DOXYGEN_INPUT_DIR ${FBGEMM_SOURCE_DIR}/include/fbgemm)
set(DOXYGEN_OUTPUT_DIR ${CMAKE_CURRENT_BINARY_DIR}/doxygen)
set(DOXYGEN_INDEX_FILE ${DOXYGEN_OUTPUT_DIR}/xml/index.xml)
set(DOXYFILE_IN ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in)
set(DOXYFILE_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)

# Set the Doxygen input and output directories in the Doxyfile
configure_file(${DOXYFILE_IN} ${DOXYFILE_OUT} @ONLY)

# Doxygen won't create this for us
file(MAKE_DIRECTORY ${DOXYGEN_OUTPUT_DIR})

# Only regenerate Doxygen when the Doxyfile or public headers change
add_custom_command(OUTPUT ${DOXYGEN_INDEX_FILE}
  DEPENDS ${FBGEMM_PUBLIC_HEADERS}
    COMMAND ${DOXYGEN_EXECUTABLE} ${DOXYFILE_OUT}
  MAIN_DEPENDENCY ${DOXYFILE_OUT} ${DOXYFILE_IN}
    COMMENT "Generating docs"
  VERBATIM)

# Nice named target so we can run the job easily
add_custom_target(Doxygen ALL DEPENDS ${DOXYGEN_INDEX_FILE})

set(SPHINX_SOURCE ${CMAKE_CURRENT_SOURCE_DIR})
set(SPHINX_BUILD ${CMAKE_CURRENT_BINARY_DIR}/sphinx)
set(SPHINX_INDEX_FILE ${SPHINX_BUILD}/index.html)

# Only regenerate Sphinx when:
#  - Doxygen has rerun
#  - Our doc files have been updated
#  - The Sphinx config has been updated
add_custom_command(OUTPUT ${SPHINX_INDEX_FILE}
  COMMAND
    ${SPHINX_EXECUTABLE} -b html
    # Tell Breathe where to find the Doxygen output
      -Dbreathe_projects.FBGEMM=${DOXYGEN_OUTPUT_DIR}/xml
    ${SPHINX_SOURCE} ${SPHINX_BUILD}
  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
  DEPENDS
    # Other docs files you want to track should go here (or in some variable)
    ${CMAKE_CURRENT_SOURCE_DIR}/index.rst
    ${DOXYGEN_INDEX_FILE}
  MAIN_DEPENDENCY ${SPHINX_SOURCE}/conf.py
  COMMENT "Generating documentation with Sphinx")

# Nice named target so we can run the job easily
add_custom_target(Sphinx ALL DEPENDS ${SPHINX_INDEX_FILE})

include(GNUInstallDirs)
install(DIRECTORY ${SPHINX_BUILD}
  DESTINATION ${CMAKE_INSTALL_DOCDIR})