SHELL := /bin/bash

# CSS to be included as stylesheets and alternate stylesheets
CSS      := assets/ghost-dark.css
ALTCSS   := assets/ghost.css

MDFILES  := $(wildcard *.md)
TARGETS  := $(patsubst %.md,%.html,$(MDFILES))
CSSINC   := css.inc

# our main html5 template, mostly taken from :
# https://github.com/jgm/pandoc-templates/blob/master/default.html5
TEMPLATE := assets/pandoc-template.html5

define ADD_LINE
printf '<link rel="%s" href="%s" title="%s">\n' "$(2)" "$(1)" "$(notdir $(basename $(1)))" >> $(3);
endef

# provide a title to pandoc. We take the first line starting with '#',
# and remove initial '#' and spaces
TITLE = $(shell sed -n '0,/^\#/ s/^[\# ]*//p' $1)

OPTS     = --standalone --include-in-header=$(CSSINC) --template=$(TEMPLATE) \
           --from=gfm --to=html5

.PHONY: titles all html clean

#all: $(CSSINC) titles html
all: $(CSSINC) html

html: $(TARGETS)

clean:
	@echo cleaning $(TARGETS) $(CSSINC)
	@rm -f $(TARGETS) $(CSSINC)

$(CSSINC): $(CSS) $(ALTCSS)
	@echo generating $@
	@#echo deps=$^
	@rm -f $@
	@$(foreach css,$(CSS),$(call ADD_LINE,$(css),stylesheet,$@))
	@$(foreach css,$(ALTCSS),$(call ADD_LINE,$(css),alternate stylesheet,$@))

%.html: %.md $(CSSINC)
	@echo -n "generating $@... "
	@if ! grep -q "^#" $< ; then                                      \
	    echo "ERROR (no title), skipping." ;                          \
	else                                                              \
	    pandoc $(OPTS) --metadata=title:"$(call TITLE,$<)" -o $@ $< ; \
	    echo done. ;                                                  \
	fi