#!/bin/bash

# Postgres backup/restore hook for the immich `database` service (VectorChord/pgvecto.rs image).
# Invoked by backupbot-two via the deploy labels:
#   backupbot.backup.pre-hook              = "/pg_backup.sh backup"
#   backupbot.backup.volumes.postgres.path = "backup.sql"
#   backupbot.restore.post-hook            = "/pg_backup.sh restore"
#
# Two image-specific constraints shape this hook, and BOTH are handled:
#
# 1. NEVER drop the database. immich's image bundles the legacy pgvecto.rs (`vectors`) extension whose
#    background worker, if its database is dropped, recurses on its own IPC error until postgres aborts
#    with `PANIC: ERRORDATA_STACK_SIZE exceeded` and crashes the whole server — after which immich can
#    never reconnect. So we do NOT `DROP DATABASE`. Instead the backup is taken with
#    `pg_dump --clean --if-exists`, so the dump itself carries a `DROP TABLE IF EXISTS` + recreate +
#    copy for each object. Restoring it does a per-OBJECT replace inside the live database — stale rows
#    added since the backup are removed (a true point-in-time restore, not a merge) — without ever
#    dropping the database, so the pgvecto.rs worker is never destabilised. (Per-table DROP TABLE is
#    fine; only DROP DATABASE triggers the PANIC.)
#
# 2. VectorChord search_path. A plain pg_dump emits
#      SELECT pg_catalog.set_config('search_path', '', false);
#    near the top; on reimport that empty search_path leaves the vector/vchord types + operator classes
#    unresolvable. immich's documented restore (https://docs.immich.app/administration/backup-and-restore)
#    rewrites that line to put `public, pg_catalog` back first — we do the same. ON_ERROR_STOP is left
#    OFF so a benign hiccup on one object doesn't abort the whole import.

set -e

BACKUP_FILE='/var/lib/postgresql/data/backup.sql'
export PGPASSWORD=$(cat "${POSTGRES_PASSWORD_FILE:-/run/secrets/db_password}")
DB_USER="${POSTGRES_USER:-postgres}"
DB_NAME="${POSTGRES_DB:-immich}"

function backup {
  pg_dump --clean --if-exists -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
}

function restore {
  gunzip -c "$BACKUP_FILE" \
    | sed "s/SELECT pg_catalog.set_config('search_path', '', false);/SELECT pg_catalog.set_config('search_path', 'public, pg_catalog', true);/g" \
    | psql -U "$DB_USER" -d "$DB_NAME" -f -
}

$@