stack_path != which stack

binout = ./bin/countdown

all: $(if $(stack_path),,install-stack)
	stack build
	ln -sfT $$(stack path --local-install-root)/bin ./bin

.PHONY: all run install install-dev-tools deploy

install:
	stack install

$(binout): install

run: all
	$(binout)

install-dev-tools:
	stack install apply-refact hlint stylish-haskell hasktags hoogle

become_root != [ "$$(id -u)" = 0 ] || echo sudo
install-stack:
ifneq (,$(shell which curl))
	curl -sSL https://get.haskellstack.org/ | sh
else
ifneq (,$(shell which wget))
	wget -qO- https://get.haskellstack.org/ | sh
else
ifneq (,$(shell which apt))
	$(become_root) apt install haskell-stack
else
	$(error No stack binary found; and no known means of installing (no curl, wget, or apt).\
	Follow instructions at <https://haskellstack.org>)
endif
endif
endif

define prompt_user
@bash -c \
      'read -p $(1) && printf "%s\n" "$${REPLY}" > "$$1"' \
      bash \
      "$@"
endef

deploy-target.url:
	$(call prompt_user, "Enter deploy target rsync URL: ")

deploy: $(binout) deploy-target.url
	@read target < deploy-target.url && set -x && \
	rsync -i4zaP $(binout) "$$target"

%.html: %.md
	pandoc -f markdown -t html -o $@ $^