TOP_DIR = ../..
OUT_DIR = $(TOP_DIR)/public
EXTENSIONS = md org
V = 0

v = $(call v_$(V),$(1),$(2))
v_0 = @echo $(1) $(2);
v_1 =

dirname = $(patsubst %/,%,$(dir $(1)))
dirnames = $(sort $(call dirname,$(1)))

page_patterns = $(foreach ext,$(EXTENSIONS),'$(TOP_DIR)/**.$(ext)')
page_folders = $(call dirnames,$(shell git ls-files $(page_patterns)))
top_readme = $(shell git ls-files $(addprefix $(TOP_DIR)/README.,$(EXTENSIONS)))
html_template = template.html
lua_filters = convert-internal-links.lua

all: site

cache = .cache
# Site title, parsed from the top-level README.
title = $(cache)/title
# Maps folders to their contents (files and subfolders).
site_tree = $(cache)/site-tree.json
# Lua module to let filters know about the configuration.
lua_config = $(cache)/config.lua
# Defines $(pages) and $(indices).
dependencies = $(cache)/deps.mk

$(title): $(top_readme) | $(cache)
	pandoc --lua-filter print-title.lua $< > $@

$(site_tree): $(page_folders) | $(cache)
	./generate-tree.py -o $@ $(EXTENSIONS)

$(lua_config): | $(cache)
	./generate-lua-config.py EXTENSIONS="$(EXTENSIONS)" > $@

$(dependencies): $(site_tree) | $(cache)
	./generate-deps.py $< $@ $(OUT_DIR)

include $(dependencies)

site: $(pages) $(indices)

# List of output folders.  Compute this from the full list of HTML
# pages, since $(page_folders) may be missing some intermediate
# directories (e.g. folders that only contain subfolders).
html_folders = $(call dirnames,$(pages) $(indices))

$(html_folders) $(cache):
	mkdir -p $@

$(pages) $(subindices): $(title)

$(pages) $(indices): $(html_template) $(lua_filters) $(lua_config)

$(pages): $(OUT_DIR)/%.html:
	$(call v,PAGE,$*)                                               \
	./generate-page.py --site-title="$$(cat $(title))" --title="$*" \
		$(foreach f,$(lua_filters),--lua-filter $(f))           \
		--template=$(html_template) $< $@

top_index = $(OUT_DIR)/index.html
subindices = $(filter-out $(top_index),$(indices))

$(top_index): index_options =
$(subindices): index_options = --site-title="$$(cat $(title))"

# ⚠ When tweaking this rule, check whether it still works for the
#   top-level index.html.
$(indices): $(OUT_DIR)/%index.html:
	$(call v,INDEX,$*)                                                      \
	./generate-index.py $(index_options) --template=$(html_template)        \
		$(foreach f,$(lua_filters),--lua-filter $(f))                   \
		$(site_tree) "$(patsubst %/,%,$*)" $@

clean:
	-rm -r $(cache)
	-rm -r $(OUT_DIR)