#!/usr/bin/env bash
set -Eeuo pipefail

SRC_ROOT="/works/git/"
DEST_USER="cvtt"
DEST_HOST="hs01.cvtt.vpn"
DEST_BASE="/backup/git/snapshots"
TODAY="$(date +%F)"
DEST_TODAY="${DEST_BASE}/${TODAY}"
SSH_OPTS="ssh -o BatchMode=yes -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null"

COMMON=
COMMON+="-avHAX"
COMMON+=" --numeric-ids"
COMMON+=" --delete"
COMMON+=" --partial"
COMMON+=" --delay-updates"
COMMON+=" --no-inc-recursive"
COMMON+=" --mkpath"
COMMON+=" -e '${SSH_OPTS}'"
COMMON+=" --exclude '**/*.lock'"
COMMON+=" --exclude '**/hooks/*.sample'"

# Two-phase to avoid refs racing
PHASE1=
PHASE1+="${COMMON}"
PHASE1+=" --exclude '**/refs/**'"
PHASE1+=" --exclude '**/packed-refs'"
PHASE1+=" --exclude '**/HEAD'"

PHASE2=
PHASE2+="${COMMON}"
PHASE2+=" --include '**/refs/**'"
PHASE2+=" --include '**/packed-refs'"
PHASE2+=" --include '**/HEAD'"
PHASE2+=" --include '*/'"
PHASE2+=" --exclude '*'"

TARGET="${DEST_USER}@${DEST_HOST}:${DEST_TODAY%/}/"

echo "== Phase 1 =="
Cmd="rsync ${PHASE1} ${SRC_ROOT} ${TARGET}"
echo ${Cmd} && eval ${Cmd}

echo "== Phase 2 =="
Cmd="rsync ${PHASE2} ${SRC_ROOT} ${TARGET}"
echo ${Cmd} && eval ${Cmd}

echo "== Consistency re-check =="
echo ${Cmd} && eval ${Cmd}

echo "Snapshot completed: $DEST_TODAY"