top := $(shell pwd)

CAT    = cat
CP     = cp
ECHO   = echo
EXISTS = test -e
FAIL   = exit 1
FIND   = find
GIT    = git
LNDIR  = lndir -silent
MKDIRS = mkdir -p
PATCH  = patch
RM     = rm -f
SED    = sed
SVN    = svn
TAR    = bsdtar
TOUCH  = touch
WGET   = wget

all: package

# configuration ################################################################

packages := $(filter-out _%,$(shell $(SED) "s/[\# ].*//" conf/sources.mk))
include conf/sources.mk
include conf/dependencies.mk
export MAVEN_LOCAL_REPO := $(shell $(CAT) conf/maven.local.repo.txt)
export JAR_DIR := $(shell $(CAT) conf/jardir.txt)

# download #####################################################################

download: PHONY $(foreach package,$(packages),build/download/$(shell utils/spec2file '$($(package))'))

build/download/git/%: .tokens/network
	if [ -d '$@' ]; then \
		cd '$@' && $(GIT) fetch --all -p; \
	else \
		$(MKDIRS) '$(@D)' && $(GIT) clone --mirror '$(shell utils/file2url 'git/$*')' '$@'; \
	fi
	$(TOUCH) '$@'
build/download/svn/%: .tokens/network
	if ! [ -d '$(shell utils/file2base 'svn/$*')' ]; then \
		$(RM) -r '$@' && \
		$(MKDIRS) build/download/svn && \
		$(SVN) checkout --depth=empty \
			               '$(shell utils/file2url  'svn/$*')' \
			build/download/'$(shell utils/file2base 'svn/$*')' && \
		cd build/download/'$(shell utils/file2base 'svn/$*')'; \
	else \
		cd build/download/'$(shell utils/file2base 'svn/$*')' && \
		$(SVN) update; \
	fi && \
	$(SVN) update --parents '$(shell utils/file2extra 'svn/$*')'
	$(EXISTS) '$@'
	$(TOUCH) '$@'
build/download/tar/%: .tokens/network
	$(MKDIRS) '$(@D)'
	$(WGET) -c -O '$@' '$(shell utils/file2url 'tar/$*')'
	$(TOUCH) '$@'

# extract ######################################################################

extract: PHONY $(foreach package,$(packages),build/extract/$(shell utils/spec2file '$($(package))'))

# This is a little gross because to get the dependencies right for
# `git` and `tar`, we need to do a bit more complex processing of
# `%`/`$*`.  We could do that with `.SECONDEXPANSION:`, but that is a
# whole can of worms.  Instead, we use a foreach loop to loop over all
# possibilities.  `svn` doesn't have this issue, because, unlike `git`
# and `tar`, it's `extra` component is present in `build/download`.

build/extract/git/%: # magic foreach loop
	gitref='$(shell utils/file2extra 'git/$*'|cut -d/ -f1)' && \
	gitdir=build/extract/'$(shell utils/file2base 'git/$*')'/$${gitref} && \
	$(RM) -r "$$gitdir" && \
	{ \
		$(MKDIRS) "$$(dirname "$$gitdir")" && \
		$(GIT) clone build/download/'$(shell utils/file2base 'git/$*')' "$$gitdir" && \
		( cd "$$gitdir" && $(GIT) checkout "$$gitref" ) && \
		$(EXISTS) '$@'; \
	} || { $(RM) -r "$$gitdir"; $(FAIL); }
	$(TOUCH) '$@'

build/extract/svn/%: build/download/svn/%
	$(RM) -r '$@'
	$(MKDIRS) '$(@D)'
	$(CP) -a '$<' '$@'
	$(TOUCH) '$@'

build/extract/tar/%: # magic foreach loop
	basedir='build/extract/$(shell utils/file2base 'tar/$*')' && \
	$(RM) -r "$$basedir" && \
	{ \
		$(MKDIRS) "$$basedir" && \
		( cd "$$basedir" && $(TAR) -m --strip-components 1 -xf '$(top)/$<' ); \
	} || { $(RM) -r "$$basedir"; $(FAIL); }

$(foreach package,$(packages),$(if $(filter-out svn|%,$($(package))),$(eval \
    build/extract/$(shell utils/spec2file '$($(package))'): \
        build/download/$(shell utils/file2base "$$(utils/spec2file '$($(package))')") \
)))

# place (patch) ################################################################

place: PHONY $(addprefix build/workdir/,$(packages))

$(addprefix build/workdir/,$(packages)): \
build/workdir/%:
	$(RM) -r '$@'
	$(MKDIRS) '$(@D)'
	$(CP) -a '$<' '$@'
	cd '$@' && \
	for patch in $(sort $(wildcard $(top)/rules/$*/*.patch)); do \
		$(PATCH) -p1 < $$patch || { $(RM) -r '$@'; $(FAIL); }; \
	done && \
	if [ -f '$(top)/rules/$*/delete.list' ]; then \
		$(RM) -r -- $$(< '$(top)/rules/$*/delete.list'); \
	fi
	$(TOUCH) '$@'

# Loop over our source configuration and set up the dependencies
# beteen `build/compile` and `build/extract`.
$(foreach package,$(packages),$(eval \
    build/workdir/$(package): \
        build/extract/$(shell utils/spec2file '$($(package))') \
        $(shell $(FIND) rules/$(package) 2>/dev/null) \
))

# package ######################################################################

package: PHONY $(addprefix build/packages/,$(packages))

package_specific=$(filter     $(patsubst rules/%/Makefile,%,$(wildcard rules/*/Makefile)),$(packages))
package_generic =$(filter-out $(patsubst rules/%/Makefile,%,$(wildcard rules/*/Makefile)),$(packages))

dirs2jars = $(if $1,$(shell $(FIND) $1 -name '*.jar'))
deps2jars = $(filter %.jar,$1) $(call dirs2jars,$(filter build/packages/%,$1))
deps2classpath = $(shell $(ECHO) $(abspath $(call deps2jars,$1)) | $(SED) 'y/ /:/')

recurse = CLASSPATH='$(call deps2classpath,$^)' extra_makefiles='$(abspath $(wildcard rules/$*/*.mk))' $(MAKE) -C build/workdir/$* -f '$1' install DESTDIR='$(top)/$@'

$(addprefix build/packages/,$(package_specific)): \
build/packages/%: RECURSIVE build/workdir/% rules/%/Makefile
	$(call recurse,$(top)/rules/$*/Makefile)
	$(MKDIRS) build/packages/all && $(LNDIR) '$(top)/$@' build/packages/all

$(addprefix build/packages/,$(package_generic)): \
build/packages/%: RECURSIVE build/workdir/% rules/generic/Makefile
	$(call recurse,$(top)/rules/generic/Makefile)
	$(MKDIRS) build/packages/all && $(LNDIR) '$(top)/$@' build/packages/all

# boilerplate ##################################################################

clean: PHONY
	$(RM) -r build/compile build/packages
distclean: PHONY
	$(RM) -r .tokens build
.tokens/%:
	$(MKDIRS) '$(@D)'
	$(TOUCH) '$@'

.PHONY: RECURSIVE PHONY
.DELETE_ON_ERROR: