#!/usr/bin/env bash
# Nightly logical backups for both MosswartOverlord databases.
# Install as a cron job on the live host (see docs/backups.md). Note `bash`
# in the cron line (survives a lost executable bit) and that /home/erik/backups
# must exist BEFORE the first run (cron sets up the >> redirection before this
# script's mkdir runs):
#   15 3 * * * bash /home/erik/MosswartOverlord/scripts/backup-databases.sh >> /home/erik/backups/backup.log 2>&1
#
# What is backed up:
#   - dereth (TimescaleDB):   full schema + all data EXCEPT the raw
#     telemetry_events/spawn_events hypertable chunks. Those tables hold
#     ~12 GB of data that expires via retention policies in 7-30 days
#     anyway; the irreplaceable rows (users, char_stats, rare_stats,
#     rare_events, combat_stats*, portals, character_stats, server_status)
#     are all included.
#   - inventory_db (postgres): full dump (~1 GB raw, much smaller compressed).
#
# Restore procedure: docs/backups.md (TimescaleDB needs pre/post restore calls).
set -euo pipefail
# Dumps contain the users table (bcrypt hashes) — keep them owner-only.
umask 077

BACKUP_DIR="${BACKUP_DIR:-/home/erik/backups/postgres}"
KEEP_DAYS="${KEEP_DAYS:-7}"
STAMP="$(date -u +%Y%m%d-%H%M)"
mkdir -p "$BACKUP_DIR"

# dereth: -Fc is compressed; exclude hypertable chunk DATA (schema kept so a
# restore recreates the tables empty and retention/compression jobs reattach).
docker exec dereth-db pg_dump -U postgres -Fc \
  --exclude-table-data='public.telemetry_events' \
  --exclude-table-data='public.spawn_events' \
  --exclude-table-data='_timescaledb_internal._hyper_*' \
  dereth > "$BACKUP_DIR/dereth-$STAMP.dump.tmp"
# Canary: a healthy dereth dump is ~50 MB; a tiny one means pg_dump silently
# produced garbage (fail the run so the old dumps are kept and cron logs it).
if [ "$(stat -c%s "$BACKUP_DIR/dereth-$STAMP.dump.tmp")" -lt 10000000 ]; then
  echo "$(date -u +%FT%TZ) FAIL dereth dump under 10MB — keeping old backups" >&2
  exit 1
fi
mv "$BACKUP_DIR/dereth-$STAMP.dump.tmp" "$BACKUP_DIR/dereth-$STAMP.dump"

docker exec inventory-db pg_dump -U inventory_user -Fc inventory_db \
  > "$BACKUP_DIR/inventory-$STAMP.dump.tmp"
mv "$BACKUP_DIR/inventory-$STAMP.dump.tmp" "$BACKUP_DIR/inventory-$STAMP.dump"

# Retention: keep KEEP_DAYS days of dailies.
find "$BACKUP_DIR" -name 'dereth-*.dump' -mtime +"$KEEP_DAYS" -delete
find "$BACKUP_DIR" -name 'inventory-*.dump' -mtime +"$KEEP_DAYS" -delete
# Clean up aborted runs older than a day.
find "$BACKUP_DIR" -name '*.dump.tmp' -mtime +1 -delete

echo "$(date -u +%FT%TZ) OK dereth=$(du -h "$BACKUP_DIR/dereth-$STAMP.dump" | cut -f1) inventory=$(du -h "$BACKUP_DIR/inventory-$STAMP.dump" | cut -f1)"