#!/usr/bin/env bash
# Daily backup of the mail stack. Designed for cron.
#
# Crontab (deeily):
#   30 3 * * *  /home/deeily/mail/deploy/backup.sh >>/var/log/mail-backup.log 2>&1
#
# Vars (override via /home/deeily/mail/.env or systemd env):
#   BACKUP_DIR       — куда писать архивы (default /var/backups/mail)
#   BACKUP_RETAIN    — сколько ежедневных оставлять (default 14)
#   POSTGRES_USER, POSTGRES_DB — для pg_dump (default mail/mail)
#   DMS_DATA_DIR     — куда DMS пишет /var/mail (default /home/deeily/mail/docker/dms-data)

set -euo pipefail

# shellcheck disable=SC1091
[ -f /home/deeily/mail/.env ] && set -a && . /home/deeily/mail/.env && set +a

BACKUP_DIR="${BACKUP_DIR:-/var/backups/mail}"
RETAIN="${BACKUP_RETAIN:-14}"
PG_USER="${POSTGRES_USER:-mail}"
PG_DB="${POSTGRES_DB:-mail}"
DMS_DATA_DIR="${DMS_DATA_DIR:-/home/deeily/mail/docker/dms-data}"
PG_CONTAINER="${PG_CONTAINER:-docker-postgres-1}"
REDIS_CONTAINER="${REDIS_CONTAINER:-docker-redis-1}"

mkdir -p "$BACKUP_DIR"
TS=$(date +%Y%m%d-%H%M)
TARGET="$BACKUP_DIR/$TS"
mkdir -p "$TARGET"

echo "[$(date -Is)] backup → $TARGET"

# 1. Postgres dump
echo "  postgres…"
docker exec "$PG_CONTAINER" pg_dump -U "$PG_USER" -F c "$PG_DB" \
  | gzip -9 > "$TARGET/postgres-$PG_DB.dump.gz"

# 2. Redis snapshot
echo "  redis…"
docker exec "$REDIS_CONTAINER" sh -c 'redis-cli SAVE >/dev/null && cat /data/dump.rdb' \
  | gzip -9 > "$TARGET/redis.rdb.gz"

# 3. DMS maildir + config (rsync hardlinked snapshot)
if [ -d "$DMS_DATA_DIR" ]; then
  echo "  maildir…"
  tar -C "$(dirname "$DMS_DATA_DIR")" --warning=no-file-changed -czf "$TARGET/dms-data.tar.gz" "$(basename "$DMS_DATA_DIR")" || true
fi
if [ -d /home/deeily/mail/docker/dms-config ]; then
  echo "  dms-config…"
  tar -C /home/deeily/mail/docker -czf "$TARGET/dms-config.tar.gz" dms-config
fi

# 4. .env (только структура — пароли в шифрованных файлах не нужны)
cp /home/deeily/mail/.env "$TARGET/env.snapshot" 2>/dev/null || true
chmod 600 "$TARGET/env.snapshot" 2>/dev/null || true

# 5. Wrap up
SIZE=$(du -sh "$TARGET" | awk '{print $1}')
echo "  done, total $SIZE"

# 6. Retain only last N daily snapshots
ls -1d "$BACKUP_DIR"/[0-9]* 2>/dev/null | sort -r | tail -n +$((RETAIN+1)) | xargs -r rm -rf
echo "[$(date -Is)] backup ok"