#!/bin/sh
#
# Daily backup of /srv to Backblaze B2 via restic.
# Initializes the repo on first run. Prunes per the retention policy
# (7 daily, 4 weekly, 6 monthly) after each successful backup.
#
# Snapshots are tagged with --host=$RESTIC_HOST for parity with the
# webdev backups. Set RESTIC_HOST in /root/.restic/b2-env (e.g. "alpine").
#
# Credentials:
#   /root/.restic/password   restic repo password (0600 root)
#   /root/.restic/b2-env     exports B2_ACCOUNT_ID, B2_ACCOUNT_KEY, RESTIC_HOST (0600 root)
#

. /root/.restic/b2-env
export RESTIC_REPOSITORY="b2:overshard-backups:alpine"
export RESTIC_PASSWORD_FILE="/root/.restic/password"

info() { printf "\n%s %s\n\n" "$(date)" "$*" >&2; }
trap 'echo $(date) Backup interrupted >&2; exit 2' INT TERM

if [ -z "${RESTIC_HOST:-}" ]; then
    info "ERROR: RESTIC_HOST is not set. Add 'export RESTIC_HOST=alpine' to /root/.restic/b2-env"
    exit 1
fi

if ! restic cat config >/dev/null 2>&1; then
    info "Repository not initialized. Running restic init..."
    restic init
fi

info "Starting backup"

restic backup \
    --verbose \
    --host="$RESTIC_HOST" \
    --exclude-caches \
    --exclude='node_modules' \
    --exclude='.next' \
    --exclude='.venv' \
    --exclude='__pycache__' \
    --exclude='dist' \
    --exclude='build' \
    --exclude='.cache' \
    --exclude='.vite' \
    --exclude='*.pyc' \
    /srv/git \
    /srv/docker \
    /srv/data

backup_exit=$?

info "Pruning repository"

restic forget --prune \
    --host="$RESTIC_HOST" \
    --keep-daily   7 \
    --keep-weekly  4 \
    --keep-monthly 6

prune_exit=$?

global_exit=$(( backup_exit > prune_exit ? backup_exit : prune_exit ))

if [ ${global_exit} -eq 0 ]; then
    info "Backup and prune finished successfully"
else
    info "Backup and/or prune finished with errors (exit ${global_exit})"
fi

exit ${global_exit}