# customizable output dir
DEST_DIR ?= dist

# find all issues and determine required output files
ISSUES != find . -path "./issues/*" -type d
DEST_PDF_FILES := $(ISSUES:./issues/%=$(DEST_DIR)/issue-%.pdf)
DEST_HTML_FILES := $(ISSUES:./issues/%=$(DEST_DIR)/issue-%.html)
DEST_EPUB_FILES := $(ISSUES:./issues/%=$(DEST_DIR)/issue-%.epub)

# deps
PANDOC != command -v pandoc 2> /dev/null
XELATEX != command -v xelatex 2> /dev/null

# default target
help:
	@echo "Targets:"
	@echo -e "\tall   - build all formats"
	@echo -e "\tpdf   - generate all issues as pdf"
	@echo -e "\thtml  - generate all issues as html"
	@echo -e "\tepub  - generate all issues as epub"
	@echo -e "\tclean - remove build artifacts"

all: pdf html epub dep-pandoc

pdf: $(DEST_PDF_FILES) dep-xelatex

html: $(DEST_HTML_FILES)

epub: $(DEST_EPUB_FILES)

$(DEST_DIR)/issue-%.pdf: issues/%
	@echo "building $@"
	@$(PANDOC) \
		--file-scope \
		--from markdown \
		--to latex \
		--pdf-engine xelatex \
		--table-of-contents \
		--lua-filter increase-header-levels.lua \
		--variable title:"tildeverse zine $@" \
		--standalone \
		--output $@ \
		$</*.md

$(DEST_DIR)/issue-%.html: issues/%
	@echo "building $@"
	@$(PANDOC) \
		--file-scope \
		--from markdown \
		--to html \
		--standalone \
		--table-of-contents \
		--lua-filter header-permalinks.lua \
		--lua-filter increase-header-levels.lua \
		--metadata title:"tildeverse zine $@" \
		--variable include-before:"<div class=\"container\">" \
		--variable include-after:"</div>" \
		--css https://tilde.team/css/hacker.css \
		--output $@ \
		$</*.md

$(DEST_DIR)/issue-%.epub: issues/%
	@echo "building $@"
	@$(PANDOC) \
		--file-scope \
		--from markdown \
		--to epub \
		--standalone \
		--table-of-contents \
		--lua-filter increase-header-levels.lua \
		--metadata title:"tildeverse zine $@" \
		--output $@ \
		$</*.md

clean:
	@echo "removing build artifacts"
	@rm $(DEST_DIR)/*.{pdf,html,epub}

dep-pandoc:
ifndef PANDOC
	$(error missing dependency 'pandoc'. please install and try again)
endif

dep-xelatex:
ifndef XELATEX
	$(error missing dependency 'xelatex'. please install and try again)
endif

.PHONY: clean help dep-pandoc dep-xelatex