# Note: this whole makefile is a huge hack, is highly unportable, and probably
# won’t even do what it’s supposed to do.  So, use with care, have fun :)

PRESENTATIONS=$(patsubst %.tex, %.pdf, $(wildcard presentations/*.tex))
BUILD_DIR=build
BUILD_DECKS=$(subst presentations/,$(BUILD_DIR)/,$(wildcard presentations/content/*))
LATEX=pdflatex -output-directory $(BUILD_DIR)

all: $(PRESENTATIONS)

clean:
	rm -fr presentations/$(BUILD_DIR)

distclean: clean
	rm -f presentations/*.pdf

# Extract dependencies for presentations by looking at the source code and
# extracting all calls to \includedeck from them; it returns a list of elements
# like ’presentations/content/ccc/ccc_lokal.tex’

# Yes, we are using perl: a system that has make probably also has perl; if not,
# blame me.

define presentation_dependencies
  $(shell perl -ne '/includedeck\{(.*)\}/ && print "presentations/content/", $$1, ".tex "' $(1))
endef

# This template is called with arguments like ‘presentations/xxx.pdf’; it
# generates a rule that dependes on the corresponding tex file as well as on all
# decks used in that tex file; dependencies are of the form
# ‘presentations/content/ccc/ccc_lokal.tex’

define PRESENTATION_template
.ONESHELL: $(1)
$(1): $(subst .pdf,.tex,$(1)) $(call presentation_dependencies,$(subst .pdf,.tex,$(1)))
	echo $$^
	cd presentations
	mkdir -p $(BUILD_DECKS)
	$(LATEX) $$(notdir $$<)
	$(LATEX) $$(notdir $$<)
	mv $(subst presentations/,$(BUILD_DIR)/,$(1)) .
endef

$(foreach presentation, $(PRESENTATIONS), \
  $(eval $(call PRESENTATION_template, $(presentation))))

# This template is called with a single argument like
# ‘presentations/content/ccc/ccc_bundesweit.tex’; it generates a rule that
# dependes on all images used by the tex file.  The actual recipe just checks
# whether the tex file is existent and updates the timestamp.

define DECK_template
$(1): $(shell perl -ne '/includegraphics[^\{]*\{([^\}]*)\}/ && print "presentations/", $$1, " "' $(1))
	test -f $(1) && touch $(1)
endef

# Files contained in decks are only considered at top-level.

$(foreach deck, $(wildcard presentations/content/*/*.tex), \
  $(eval $(call DECK_template, $(deck))))