# SPDX-FileCopyrightText: 2011 Alexander Neundorf <neundorf@kde.org>
#
# SPDX-License-Identifier: BSD-3-Clause

#[=======================================================================[.rst:
ECMUseFindModules
-----------------

Selectively use some of the find modules provided by extra-cmake-modules.

This module is automatically available once extra-cmake-modules has been
found, so it is not necessary to ``include(ECMUseFindModules)`` explicitly.

::

  ecm_use_find_modules(DIR <dir>
                       MODULES module1.cmake [module2.cmake [...]]
                       [NO_OVERRIDE])

This allows selective use of the find modules provided by ECM, including
deferring to CMake's versions of those modules if it has them.  Rather than
adding ``${ECM_FIND_MODULE_DIR}`` to ``CMAKE_MODULE_PATH``, you use
``ecm_use_find_modules()`` to copy the modules you want to a local (build)
directory, and add that to ``CMAKE_MODULE_PATH``.

The find modules given to ``MODULES`` will be copied to the directory given by ``DIR``
(which should be located in ``${CMAKE_BINARY_DIR}`` and added to
``CMAKE_MODULE_PATH``).  If ``NO_OVERRIDE`` is given, only modules not also
provided by CMake will be copied.

Example:

.. code-block:: cmake

  find_package(ECM REQUIRED)
  ecm_use_find_modules(
      DIR ${CMAKE_BINARY_DIR}/cmake
      MODULES FindEGL.cmake
      NO_OVERRIDE
  )
  set(CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR}/cmake)

This example will make ``FindEGL.cmake`` available in your project, but only
as long as it is not yet part of CMake. Calls to ``find_package(EGL)`` will
then make use of this copied module (or the CMake module if it exists).

Another possible use for this macro is to take copies of find modules that can
be installed along with config files if they are required as a dependency (for
example, if targets provided by the find module are in the link interface of a
library).

Since pre-1.0.0.
#]=======================================================================]

cmake_policy(VERSION 3.16)

function(ecm_use_find_modules)
   set(_options NO_OVERRIDE )
   set(_oneValueArgs DIR )
   set(_multiValueArgs MODULES )
   cmake_parse_arguments(EUFM "${_options}" "${_oneValueArgs}" "${_multiValueArgs}" ${ARGN} )
   if(NOT EUFM_DIR)
      message(FATAL_ERROR "No DIR specified for ecm_use_find_modules() !")
   endif()

   if(NOT IS_ABSOLUTE "${EUFM_DIR}")
      set(EUFM_DIR "${CMAKE_CURRENT_BINARY_DIR}/${EUFM_DIR}")
   endif()
   file(MAKE_DIRECTORY "${EUFM_DIR}")

   foreach(file ${EUFM_MODULES})
      if(NOT EXISTS ${ECM_FIND_MODULE_DIR}/${file} )
         message(FATAL_ERROR "File ${file} not found in ${ECM_FIND_MODULE_DIR} !")
      endif()
      if(NOT EXISTS "${CMAKE_ROOT}/Modules/${file}" OR NOT EUFM_NO_OVERRIDE)
         configure_file("${ECM_FIND_MODULE_DIR}/${file}" "${EUFM_DIR}/${file}" COPYONLY)
      endif()
   endforeach()
   # This is required by some of the find modules
   file(WRITE "${EUFM_DIR}/ECMFindModuleHelpersStub.cmake"
        "include(\"${ECM_MODULE_DIR}/ECMFindModuleHelpers.cmake\")")

endfunction()
