#!/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"
# Backup dumps the immich DB to backup.sql (gzip) inside the postgres volume; backupbot archives that
# file. Restore reads it back and reimports.
#
# The immich DB runs the VectorChord/pgvecto.rs extensions. 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, so the first statement that references them errors. immich's official restore
# (docs.immich.app/administration/backup-and-restore) rewrites that line to put `public, pg_catalog`
# back on the search_path BEFORE the import. Without that rewrite a single-transaction import aborts
# wholesale and nothing is restored (the bug in the original ci/pg-backup attempt). We keep
# --single-transaction --set ON_ERROR_STOP=on (immich upstream) so a genuine failure is loud rather
# than silently leaving a half-restored DB.

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 -U "$DB_USER" "$DB_NAME" | gzip > "$BACKUP_FILE"
}

function restore {
  # immich-server holds TCP connections to the DB; terminate them so DROP DATABASE can proceed
  # (the matrix-synapse pg_hba "local trust" trick does not cover networked connections).
  psql -U "$DB_USER" -d postgres -c \
    "SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname='${DB_NAME}' AND pid<>pg_backend_pid();"
  psql -U "$DB_USER" -d postgres -c "DROP DATABASE ${DB_NAME} WITH (FORCE);"
  createdb -U "$DB_USER" "$DB_NAME"
  # Rewrite the empty search_path the VectorChord dump sets so vector/vchord type + operator
  # references resolve during the import (immich upstream restore procedure), then import.
  gunzip -c "$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" --single-transaction --set ON_ERROR_STOP=on
}

$@