#! /bin/sh
set -e

self=`basename $0`

usage () {
    echo "$self: tladir cscvsdir wcvsdir"
    echo "  tladir: tla tree tracking cvs, only totla commits there."
    echo "  cscvsdir: cvs tree used by cscvs."
    echo "  wcvsdir: commitable cvs tree, used to get CVS metadata."
}

if test $# -ne 3 ; then
    usage
    exit 1
fi

cd "$1" ; tladir="$PWD" ; cd -
cd "$2" ; cscvsdir="$PWD" ; cd -
cd "$3" ; wcvsdir="$PWD" ; cd -

yesno () {
    while true; do
	read -p "$1 [y/n]: " yn
	if test "$yn" != "y" -a "$yn" != "n" ; then
	    echo 'Please type "y" or "n".'
	    continue
	else
	    if test "$yn" = "y" ; then
		yes="true"
		no="false"
	    else
		yes="false"
		no="true"
	    fi
	    break
	fi
    done
}

gone_wrong () {
    echo "Something has gone wrong, bailing out."
    exit 1
}

shell () {
    set +e
    $SHELL
    status=$?
    set -e
    if test $status -ne 0 ; then
	yesno "$SHELL exited with status $status, is there a problem?"
	if $yes ; then
	    gone_wrong
	fi
    fi
}

cscvs_update () {
    cvs up -r1.1
    cscvs cache -h -u
}

cscvs_update_and_act () {
    echo "*** Updating cscvs cache ***"
    cd "$cscvsdir"
    maybe_changes=false
    cscvs_update | while read x ; do
	maybe_changes=true
    done
    if $maybe_changes ; then
	yesno "Are there new changesets?"
	if $yes ; then
	    echo "Import changes, then exit the shell to continue."
	    cd "$cscvsdir"
	    shell
	fi
    else
	echo "No changes"
    fi
}

cscvs_update_and_merge () {
    echo "*** Updating cscvs cache ***"
    cd "$cscvsdir"
    cscvs_update
    echo "Import changes, then exit the shell to continue."
    echo "Do NOT commit the changeset for your merge."
    cd "$cscvsdir"
    shell
}

cvs_update () {
    echo "*** Updating writeable CVS tree ***"
    cd "$wcvsdir"
    cvs up -A
}

# Synch wcvsdir and cscvsdir
cscvs_update_and_act
while true; do
    cvs_update
    cscvs_update_and_act
    if $no ; then
	break
    fi
done

remove_cvs_dirs () {
    tla inventory -p -d | egrep -e '(^|/)CVS$' | xargs rm -rf
}

# Place new CVS metadata in the totla tree
cd "$cscvsdir"
remove_cvs_dirs
( cd "$wcvsdir" ; find . -name CVS | tar cTf - - ) \
    | ( cd "$tladir" ; tar xf - )


# Sanity: check for changes, there should not be any.

check_diff () {
    which $1 > /dev/null # fail if command not found
    set +e
    $@
    status=$?
    set -e
    if test $status -eq 1 ; then
	diff_found=true
    elif test $status -ne 0 ; then
	echo "$* exited with status $status"
	gone_wrong
    fi
}

diff_found=false
cd "$tladir"
echo "*** Updating revision library ***"
tla library-add `tla tree-version` > /dev/null
echo "*** Checking tla changes ***"
check_diff tla changes
echo "*** Checking cvs diff ***"
check_diff cvs diff --brief
if $diff_found ; then
    yesno "Are there any abnormal changes?"
    if $yes ; then
	gone_wrong
    fi
fi

# Merge and save logs
cat /dev/null > +logfile
echo 'Please merge change. Do not forget "cvs add" and "cvs remove".'
echo 'Write the log in +logfile then exit the shell instead of "cvs commit".'
shell
cvs commit -F +logfile
tar cf +arch.tar '{arch}'

# Clean up totla tree
tla undo -n
remove_cvs_dirs

# Import the merge changeset
cscvs_update_and_merge
cd "$tladir"
tar xf +arch.tar
tla commit --strict
rm +arch.tar +logfile