# Process FEATURES variables
#
# The board/board common are responsible for defining the CPU and CPU_MODEL
# variables in their Makefile.features.
# This makes them available when setting features based on CPU_MODEL in the cpu
# Makefile.features and also during dependency resolution.

include $(RIOTBOARD)/$(BOARD)/Makefile.features

# Sanity check
ifeq (,$(CPU))
  $(error CPU must be defined by board / board_common Makefile.features)
endif

include $(RIOTCPU)/$(CPU)/Makefile.features


# Resolve FEATURES_ variables
# Their value will only be complete after resolving dependencies

# Features that are required by the application but not provided by the BSP and
# features that are used but blacklisted (prepended with "!").
# Having features missing may case the build to fail.
FEATURES_MISSING = $(sort $(filter-out $(FEATURES_PROVIDED),$(FEATURES_REQUIRED)))

# Features that are only optional and not required at the same time.
# The policy is to by default use by features if they are provided by the BSP.
FEATURES_OPTIONAL_ONLY = $(sort $(filter-out $(FEATURES_REQUIRED),$(FEATURES_OPTIONAL)))
FEATURES_OPTIONAL_USED = $(sort $(filter $(FEATURES_PROVIDED),$(FEATURES_OPTIONAL_ONLY)))
# Optional features that will not be used because they are not provided
FEATURES_OPTIONAL_MISSING = $(sort $(filter-out $(FEATURES_PROVIDED),$(FEATURES_OPTIONAL_ONLY)))

# Features that are used for an application
FEATURES_USED = $(sort $(FEATURES_REQUIRED) $(FEATURES_OPTIONAL_USED))

# Used features that conflict when used together
FEATURES_CONFLICTING = $(sort $(foreach conflict,$(FEATURES_CONFLICT),$(call _features_conflicting,$(conflict))))

# Return conflicting features from the conflict string feature1:feature2
#   $1: feature1:feature2
#   Return the list of conflicting features
_features_conflicting = $(if $(call _features_used_conflicting,$(subst :, ,$1)),$(subst :, ,$1))
# Check if all features from the list are used
#   $1: list of features that conflict together
#   Return non empty on error
_features_used_conflicting = $(filter $(words $1),$(words $(filter $(FEATURES_USED),$1)))

# Features that are used by the application but blacklisted by the BSP.
# Having blacklisted features may cause the build to fail.
FEATURES_USED_BLACKLISTED = $(sort $(filter $(FEATURES_USED), $(FEATURES_BLACKLIST)))