if(DRACO_CMAKE_DRACO_FEATURES_CMAKE_)
  return()
endif()
set(DRACO_CMAKE_DRACO_FEATURES_CMAKE_ 1)

set(draco_features_file_name "${draco_build_dir}/draco/draco_features.h")
set(draco_features_list)

# Macro that handles tracking of Draco preprocessor symbols for the purpose of
# producing draco_features.h.
#
# draco_enable_feature(FEATURE <feature_name> [TARGETS <target_name>]) FEATURE
# is required. It should be a Draco preprocessor symbol. TARGETS is optional. It
# can be one or more draco targets.
#
# When the TARGETS argument is not present the preproc symbol is added to
# draco_features.h. When it is draco_features.h is unchanged, and
# target_compile_options() is called for each target specified.
macro(draco_enable_feature)
  set(def_flags)
  set(def_single_arg_opts FEATURE)
  set(def_multi_arg_opts TARGETS)
  cmake_parse_arguments(DEF "${def_flags}" "${def_single_arg_opts}"
                        "${def_multi_arg_opts}" ${ARGN})
  if("${DEF_FEATURE}" STREQUAL "")
    message(FATAL_ERROR "Empty FEATURE passed to draco_enable_feature().")
  endif()

  # Do nothing/return early if $DEF_FEATURE is already in the list.
  list(FIND draco_features_list ${DEF_FEATURE} df_index)
  if(NOT df_index EQUAL -1)
    return()
  endif()

  list(LENGTH DEF_TARGETS df_targets_list_length)
  if(${df_targets_list_length} EQUAL 0)
    list(APPEND draco_features_list ${DEF_FEATURE})
  else()
    foreach(target ${DEF_TARGETS})
      target_compile_definitions(${target} PRIVATE ${DEF_FEATURE})
    endforeach()
  endif()
endmacro()

# Function for generating draco_features.h.
function(draco_generate_features_h)
  file(WRITE "${draco_features_file_name}.new"
       "// GENERATED FILE -- DO NOT EDIT\n\n" "#ifndef DRACO_FEATURES_H_\n"
       "#define DRACO_FEATURES_H_\n\n")

  foreach(feature ${draco_features_list})
    file(APPEND "${draco_features_file_name}.new" "#define ${feature}\n")
  endforeach()

  file(APPEND "${draco_features_file_name}.new"
       "\n#endif  // DRACO_FEATURES_H_")

  # Will replace ${draco_features_file_name} only if the file content has
  # changed. This prevents forced Draco rebuilds after CMake runs.
  configure_file("${draco_features_file_name}.new"
                 "${draco_features_file_name}")
  file(REMOVE "${draco_features_file_name}.new")
endfunction()