#!/bin/bash
# Part of the xs-activity-server package
#
# based on a similarly named script in the xs-rsync package
# by Martin Langhoff <martin@laptop.org>
#
# Adapted for xs-activity-server by Douglas Bagnall
# <douglas@paradise.net.nz>
#
# Copyright: One Laptop per Child

set -e

VERBOSE=yes
MAGIC_DIR=$UM_MOUNTPOINT/xs-activity-server

FINAL_DIR=/library/xs-activity-server/activities

FILES_TO_RM=""

# combined with set -e, error() is called if something fails.
error(){
    logger -puser.err -t "xs-activity-server[$$]" "Error at line $(caller)"
    [ "$FILES_TO_RM" ] && rm -rf $FILES_TO_RM
}
trap error ERR


# Log a string via the syslog facility.
log()
{
    if test $1 != debug || expr "$VERBOSE" : "[yY]" > /dev/null; then
	logger -p user.$1 -t "xs-activity-server[$$]" -- "$2"
    fi
}


STEPS=7

[ -d $MAGIC_DIR ] || exit 0

log notice 'Found activity install directory';
log notice "[1/$STEPS] Checking whether it has a manifest";

if [ -r $MAGIC_DIR/manifest.sha1 ];then
    log notice "[2/$STEPS] Seems to have a manifest";
else
    log err "[2/$STEPS] Missing manifest"
    exit 1;
fi

## Do we have enough space?
# note: we could use awk {'print $4'} instead of the
# perl regex, but it breaks with long /dev nodes
# such as those from LVMs -which wrap. The regex captures the
# number just left of the number with the percentage sign.
NEED=`du -s -B1M $MAGIC_DIR | awk {'print $1'}`
HAVE=`df -B1M $FINAL_DIR | tail -n1 | \
    perl -pe 'm/(\d+)\s+\d+\%/; $_=($1-1);'`
if [ $NEED -gt $HAVE ];then
    log err 'Not enough free space in /library for these activities - cancelling';
    exit 1;
fi

### Copy it first - as the media is bound to be slow
# - make this atomic by cp'ing to a tmpdir, and mv'ing into place
#   to be fail-safe
# - mv aside manifest.sha1 and its sig
# - TODO? we could avoid cp'ing files we already have using
#   rsync --copy-dest instead of cp
#
log notice "[3/$STEPS] Copying activities to disk";
TMPDEST=`mktemp -d -p /library/xs-activity-server/tmp`

#make sure the tmp directory goes
FILES_TO_RM="$FILES_TO_RM '$TMPDEST'"

cp --preserve=timestamps $MAGIC_DIR/* $TMPDEST

# In a tmpdir we own, safe from race conditions
# run the checksums...
log notice "[4/$STEPS] Checking the manifest";
# mv the manifest to a different dir
TMPMANIF=`mktemp -d -p /library/xs-activity-server/tmp`

FILES_TO_RM="$FILES_TO_RM '$TMPMANIF'"


mv $TMPDEST/manifest.sha1 $TMPMANIF/
if [ -e $TMPDEST/manifest.sha1.sig ]; then
    mv $TMPDEST/manifest.sha1.sig $TMPMANIF/
fi
xs-sum -c $TMPMANIF/manifest.sha1 -d $TMPDEST

#Let syslog know what we're doing
cd $TMPDEST
log notice "found $(ls *.xo |wc -l) activities"
log debug "found these activities: $(ls *.xo)"
cd -

log notice "[5/$STEPS] Copy the directories into place";
#XXX not checking whether this clobbers existing files.
mv $TMPDEST/* $FINAL_DIR

#So, now all the activities are in place, but maybe they're not
#newer than what we have. So xs-regenerate-activities has to work that out.

log notice "[6/$STEPS] Regenerating the list of available activities";

/usr/bin/xs-regenerate-activities $FINAL_DIR 2>&1 | logger -p user.debug -t "xs-activity-server[$$]" 

log notice "[$STEPS/$STEPS] Finished - XOs can now update activities.";


rm -fr $FILES_TO_RM