################
# Prepare pass #
################

$(eval $(call omk_pass_template,prepare-pass))

###
# Name of the prepared rule.  This name is used as prefix of variable
# names in .omk.inc and is based on the first target
omk_inc_rule = $(firstword $(1:$(OUTPUT_DIR)/%=%))

# The name of .omk.inc file is derived from $(omk_inc_rule) and
# depends whether the target is under _build or elsewhere.
omk_inc_file = $(if $(filter $(BUILD_DIR_NAME)%,$(omk_inc_rule)),\
		    $(OMK_WORK_DIR)/$(notdir $(omk_inc_rule)).omk.inc,\
		    $(OMK_WORK_DIR)/$(subst /,_,$(omk_inc_rule)).omk.inc)

target_omk_file = $(OMK_WORK_DIR)/$(notdir $(1)).target.omk

# >\< substitution to preserve \ in echo argument
# >'< substitution is for echo to work,
# >$< substitution to preserve $ when reloading .omk.inc file
subst-cmd = $(subst $$,$$$$,$(call escsq,$(subst \,\\,$(1))))

###
# prepare_rule is used to generate .omk.inc files during prepare-pass.
# All paths in this file should be relative to $(OUTPUT_DIR)
# Usage: $(eval $(call prepare_rule,<targets>,<deps>,<msg>,<cmd>))
define prepare_rule
prepare-pass::
#TODO remove echos from the next commands
	@set -e;\
	    echo 'prepared_rules += $(omk_inc_rule)' > $(omk_inc_file).tmp; \
	    echo '$(omk_inc_rule)_targets = $$(call strip_out,$(1))' >> $(omk_inc_file).tmp; \
	    echo '$(omk_inc_rule)_deps += $$(call strip_out,$(2))' >> $(omk_inc_file).tmp; \
	    echo '$(omk_inc_rule)_msg = $(3)' >> $(omk_inc_file).tmp; \
	    echo '$(omk_inc_rule)_cmd = $(call subst-cmd,$(4))' >> $(omk_inc_file).tmp; \
	if cmp -s $(omk_inc_file).tmp $(omk_inc_file); then rm $(omk_inc_file).tmp; echo "  CHK     "$$(call strip_out,$(omk_inc_file)); else mv $(omk_inc_file).tmp $(omk_inc_file); echo "  UPD     "$$(call strip_out,$(omk_inc_file)); fi
endef

###
# prepare_rule_goal - same as prepare rules but the target is put
# as dependency to the default goal, which causes it to be built
# upon calling make
define prepare_rule_goal
$(call prepare_rule,$(1),$(2),$(3),$(4))
prepared_goals += $(call strip_out,$(1))
endef

_goals := $(OMK_WORK_DIR)/__goals.omk.inc

prepare-pass::
	@echo 'omk_goals += $(prepared_goals)' > $(_goals).tmp; \
	    if cmp -s $(_goals).tmp $(_goals); \
		then rm $(_goals).tmp; \
		else mv $(_goals).tmp $(_goals); fi