##
## Makefile for managing periodic mail-archive symlinks
##
## $Id: Makefile,v 1.2 2000/07/27 10:16:23 dgc Exp $
##
## DIRECTIONS:
## 1. Drop this Makefile into a directory where you want to keep links to
##    your archives.
## 2. Create subdirectories there named "annual", "monthly", and/or
##    "quarterly", or whatever you'd rather call them.
## 3. For each archive:
##    a. Decide whether you want to cycle the archive on an annual,
##       quarterly, or monthly basis.
##    b. Run "make add ARCHIVE=name-of-archive PERIOD=xxx", where "xxx" is
##       the period you decide on.  This will create the initial symlink.
## 4. Set up procmail to deliver mail into the "name-of-archive" folder.
## 5. Create a cron(1) task to run "cd .../path/to/dir; make rotate" once
##    per month.  This will update all symlinks.  (Actually, you can run
##    this more or less often; it doesn't matter.  If you made a weekly
##    period, you could run it monthly *and* weekly.)
## 
## NOTES:
## The file for the "family" archive (cycled monthly) for April, 1998
## will be .../monthly/family-199804.  You can gzip these if you wish --
## no trouble.
## 
## To add support for a new period, create a subdirectory for it, and
## add a macro definition for SFXfoo as below.  SFXfoo should expand
## to the correct suffix for today's date, and be unique among all
## iterations of that period.  For example, a period of one week, labelled
## according to the ISO definition, could use
##	SFXweekly = `date %Y-%V`
##
## You can change SFX* macros as you wish if you don't like these formats,
## but be sure to change $(STRIP) accordingly.  $(STRIP) must be capable
## of removing any of your SFX* macros from the end of a filename.
##


## Uncomment to debug, or use "make DO=echo".
#DO	= echo

## Default period for rotation of new archives with "make add-archive".
## Supercede this with (for example) "make add-archive PERIOD=quarterly".
## A valid
PERIOD	= monthly


##### You probably don't need to touch anything else. #####

## Generates a suffix for PERIOD=annual
SFXannual	= `date +%Y`


## Generates a suffix for PERIOD=monthly
SFXmonthly	= `date +%Y%m`


## Generates a suffix for PERIOD=quarterly, like "1997q2".  (Hi Mikko! :)
SFXquarterly	= `date '+[%Yq] P %m 1 - 3 / 1 + p' | dc`


## A command to strip suffices from archive files.
STRIP	= sed -e 's/-[0-9][0-9][0-9][0-9q-]*$$//' -e 's/-[0-9][0-9][0-9][0-9q-]*\.gz$$//'


## How to create and remove locks.
LOCK	= lockfile
UNLOCK	= rm -f


## A default target that tells you available targets.
all:
	@echo
	@echo "make rotate                        - rotate all archives"
	@echo "make add ARCHIVE=name [PERIOD=xxx] - link new archive (default period=$(PERIOD))"
	@echo
	@echo "or, if you prefer:"
	@echo "make add-annual ARCHIVE=name       - link new archive (annual period)"
	@echo "make add-monthly ARCHIVE=name      - link new archive (monthly period)"
	@echo "make add-quarterly ARCHIVE=name    - link new archive (quarterly period)"
	@echo


## Safety valves
check-archive:
	@ if [ -z "$(ARCHIVE)" ]; then \
		echo; \
		echo '!!! You need to give ARCHIVE=name on the command line.'; \
		echo; \
		exit 255; \
	fi

check-period:
	@ if [ -z "$(PERIOD)" ]; then \
		echo; \
		echo '!!! PERIOD is not set.'; \
		echo; \
		exit 255; \
	fi

## Add an archive
add-any: check-period check-archive
	@ if [ -f $(ARCHIVE) ]; then \
		$(DO) mv $(ARCHIVE) $(PERIOD)/$(ARCHIVE)-$(SFX$(PERIOD)); \
	fi; \
	$(DO) ln -s $(PERIOD)/$(ARCHIVE)-$(SFX$(PERIOD)) $(ARCHIVE)


## Add an archive using default period.
add:
	@ $(MAKE) add-any PERIOD=$(PERIOD) ARCHIVE=$(ARCHIVE) DO=$(DO)


## Add archives with explicit period.
add-annual:
	@ $(MAKE) add-any PERIOD=annual ARCHIVE=$(ARCHIVE) DO=$(DO)

add-monthly:
	@ $(MAKE) add-any PERIOD=monthly ARCHIVE=$(ARCHIVE) DO=$(DO)

add-quarterly:
	@ $(MAKE) add-any PERIOD=quarterly ARCHIVE=$(ARCHIVE) DO=$(DO)


## A target that's always made but never up to date.
always:


rotate:
	@ $(MAKE) rotate-annual    PERIOD=annual    ARCHIVE=$(ARCHIVE) DO=$(DO)
	@ $(MAKE) rotate-monthly   PERIOD=monthly   ARCHIVE=$(ARCHIVE) DO=$(DO)
	@ $(MAKE) rotate-quarterly PERIOD=quarterly ARCHIVE=$(ARCHIVE) DO=$(DO)

rotate-$(PERIOD): rotate-any

rotate-any:	always check-period
	/bin/ls $(PERIOD)/$(ARCHIVE)* 2>/dev/null \
	| sed -e 's#.*/##' \
	| $(STRIP) \
	| uniq \
	| while read archive; do \
		$(DO) $(LOCK) $$archive.lock; \
		$(DO) rm -f $$archive; \
		$(DO) ln -s $(PERIOD)/$$archive-$(SFX$(PERIOD)) $$archive; \
		$(DO) $(UNLOCK) $$archive.lock; \
	done