Makefile for generating a static website

Static_Website.mk

SRC_DIR = src
DST_DIR = build

CSS_DIR = $(DST_DIR)/css
SCSS_DIR = $(SRC_DIR)/scss
SCSS_INCLUDES_DIR = $(SCSS_DIR)/includes

SCSS_FILES = $(wildcard $(SCSS_DIR)/*.scss)
CSS_FILES=$(patsubst $(SCSS_DIR)/%.scss, $(CSS_DIR)/%.css, $(SCSS_FILES))

MD_FILES = $(shell find $(SRC_DIR) -type f -name '*.md')
HTML_FILES = $(patsubst $(SRC_DIR)/%.md, $(DST_DIR)/%.html, $(MD_FILES))
TEMPLATE = $(SRC_DIR)/template.html

BASE_URL = "https://www.example.org"

.PHONY: all
all: html css $(DST_DIR)/robots.txt $(DST_DIR)/sitemap.xml ## Build the whole website

#
# HTML
#

.PHONY: html
html: $(HTML_FILES) ## Build all HTML files from SLIM files (even nested)

$(DST_DIR)/%.html: $(SRC_DIR)/%.md
	pandoc --from markdown --to html --standalone $< -o $@

$(DST_DIR)/%.html: $(SRC_DIR)/%.md $(TEMPLATE)
	pandoc \
	--from markdown_github+smart+yaml_metadata_block+auto_identifiers \
	--to html \
	--template $(TEMPLATE) \
	-o $@ $<

#
# CSS
#

.PHONY: css
css: $(CSS_FILES) ## Build all CSS files from SCSS

$(CSS_DIR):
	mkdir -p $@
	
$(CSS_DIR)/%.css: $(SCSS_DIR)/%.scss $(SCSS_INCLUDES_DIR)/_*.scss | $(CSS_DIR)
	sass --load-path=$(SCSS_INCLUDES_DIR) --style=compressed --scss $< $@

#
# Robots.txt
#

$(DST_DIR)/robots.txt:
	@echo "User-agent: *" > $@
	@echo "Allow: *" >> $@
	@echo "Sitemap: $(BASE_URL)/sitemap.xml" >> $@

#
# Sitemap.xml
#

$(DST_DIR)/sitemap.xml: $(HTML_FILES)
	@echo '<?xml version="1.0" encoding="UTF-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' > $@
	for f in $^; do \
		@echo "<url><loc>$(BASE_URL)$${f#$(DST_DIR)}<loc></url>" >> $@
	done
	@echo '</urlset>' >> $@

#
# Helpers
#

.PHONY: clean
clean:
	rm $(HTML_FILES)
	rm -rf $(CSS_DIR)
	
.PHONY: help
help: ## Show this help
	@egrep -h '\s##\s' $(MAKEFILE_LIST) | \
	awk 'BEGIN {FS = ":.*?## "}; {printf "\033[34m%-15s\033[0m %s\n", $$1, $$2}'