textdir = ./gutenberg
datadir = ./data

source  = https://raw.githubusercontent.com/nltk/nltk_data/gh-pages/packages/corpora/gutenberg.zip

GNUPLOT   = gnuplot
JULIA     = julia
GIT       = git
WGET      = wget
UNZIP     = unzip

.SUFFIXES:
.SUFFIXES:  .txt .dat .res .gp

.PHONY: clean veryclean help settings count merge pdf png initialize

texts   = $(wildcard $(textdir)/*.txt)
dats    = $(patsubst %.txt,$(datadir)/%.dat,$(notdir $(texts)))
jprog   = wordcount.jl
res     = merged.res
stem    = $(basename $(res))
gplot   = $(res:.res=.gp)
figs    = $(res:.res=.pdf) $(res:.res=.png)

$(datadir)/%.dat: $(textdir)/%.txt $(jprog)
	$(JULIA) $(jprog) count $@ $<

## help        : Default action is to show what commands are available.
help: Makefile
	@sed -n 's/^##//p' $<
	@echo ' '

## count       : Count words in each text in the directory $(textdir)
count: $(dats)

## merge       : Merge all word counts stored in the directory $(datadir)
merge: $(res)

$(res): $(dats)
	$(JULIA) $(jprog) merge $(res) $^

## (png|pdf)   : Plot the word frequency distribution as png or pdf graphics
png pdf: $(gplot) $(res)
	$(GNUPLOT) -c $< $@ $(stem)

## clean       : Remove the auto-generated files
clean: 
	rm -f $(dats)

## veryclean   : Remove the auto-generated files, the tests results, and the graphs
veryclean: clean
	rm -f $(res) $(figs)

## settings    : Show settings.
settings:
	@echo ' '
	@echo 'textdir   :' $(textdir)
	@echo 'datadir   :' $(datadir)
	@echo 'jprog     :' $(jprog)
	@echo 'res       :' $(res)
	@echo 'gplot     :' $(gplot)
	@echo 'figs      :' $(figs)
	@echo 'stem      :' $(stem)
	@echo 'source    :' $(source)
	@echo ' '
	@echo 'JULIA     :' $(JULIA)
	@echo 'GNUPLOT   :' $(GNUPLOT)
	@echo 'WGET      :' $(WGET)
	@echo 'UNZIP     :' $(UNZIP)
	@echo ' '

## list        : List available text and data files
list:
	@echo ' '
	@echo 'texts     :'
	@echo $(texts) | fmt -s | sed 's/^/    /'
	@echo 'dats      :'
	@echo $(dats) | fmt -s | sed 's/^/    /'

## initialize  : Download Gutenber corpus and create the directory structure
initialize:
	test ! -d $(datadir) && mkdir $(datadir) || echo -n ''
	test ! -d $(textdir) && $(WGET) $(source) && $(UNZIP) -u $(notdir $(source)) || echo -n ''
	test ! -f $(notdir $(source)) && rm -f $(notdir $(source)) || echo ' '