MAKEFLAGS+=--no-builtin-rules
SHELL:=/usr/bin/env bash

# Default list of exclude modules
ifndef EXCLUDE
  # EXCLUDE:=go,java
endif

# Functions
packages_from_file=\
	$(patsubst %/$1,%$(if $2,/$2,),\
	$(filter $(wildcard */$1),$(addsuffix /$1,$(packages))))

# Search for packages, ensuring that OS packages are first with any filters
# http://blog.jgc.org/2007/06/escaping-comma-and-space-in-gnu-make.html
# [backup] http://archive.is/XYuEV
,:=,
space:=$(null) $(null)
$(space):=
$(space)+=
os:=$(shell source helpers && echo $$OS)
gui:=$(shell source helpers && echo $$GUI)
os_packages:=macos manjaro ubuntu
packages:=\
	$(filter $(os_packages),$(os))\
	$(filter-out $(os_packages),$(subst /,,$(wildcard */)))
ifdef EXCLUDE
	packages:=$(filter-out $(subst $(,),$( ),$(EXCLUDE)),$(packages))
endif
ifdef INCLUDE
	packages:=$(filter $(subst $(,),$( ),$(INCLUDE)),$(packages))
endif

# Search for specific files based on package
installers:=$(call packages_from_file,install)
stows:=$(call packages_from_file,.stow-local-ignore)
envs:=\
	$(foreach p,$(packages),\
	$(sort\
	$(patsubst %/,%,$(dir\
	$(wildcard $p/*.sh)))))

# Establish rules
installer_rules:=$(addsuffix /install,$(installers))

.PHONY: help clean auto install symlink update $(installer_rules)
.SUFFIXES:

#
# Tasks
# https://blog.sneawo.com/blog/2017/06/13/makefile-help-target/
# [backup] http://archive.is/XFLAz
#
help:
	@echo
	@echo '=== OS'
	@echo "$(os)"
	@echo
	@echo '=== Packages'
	@echo "Install	- $(sort $(installers))"
	@echo "Symlink	- $(sort $(stows))"
	@echo "Shell	- $(sort $(envs))"
	@echo
	@echo '=== Variables'
	@echo 'INCLUDE	- Packages to only include: $(INCLUDE)'
	@echo 'EXCLUDE	- Packages to exclude: $(EXCLUDE)'
	@echo
	@echo '=== Commands'
	@egrep '^(.+)\:\ .*##\ (.+)' ${MAKEFILE_LIST} | sed 's/:.*## /	- /'
	@echo
clean: ## Clean up
	@printf '==> '
	stow -D $(stows)
auto: update install symlink ## Run update, install, and symlink
install: $(installer_rules) ## Install required dependencies
symlink: ## Symlink configuration files
	@printf '==> '
	stow --target="$$HOME" $(stows)
update: ## Update dotfiles
	@printf '==> '
	git pull --rebase --autostash
	@printf '==> '
	git submodule update --init --remote

#
# Internal tasks
#
$(installer_rules): %/install:
	@printf '==> '
	$@