#!/bin/sh
set -eu

root=$(CDPATH= cd -- "$(dirname "$0")/.." && pwd)
. "$root/scripts/secret-file-utils.sh"

usage() {
  echo "usage: $0 --host HOST --database DB --user USER --password-file FILE --output FILE [--port PORT]" >&2
  exit 2
}

host= database= user= password_file= output= port=5432
while [ "$#" -gt 0 ]; do
  case "$1" in
    --host) host=${2-}; shift 2 ;;
    --port) port=${2-}; shift 2 ;;
    --database) database=${2-}; shift 2 ;;
    --user) user=${2-}; shift 2 ;;
    --password-file) password_file=${2-}; shift 2 ;;
    --output) output=${2-}; shift 2 ;;
    *) usage ;;
  esac
done
[ -n "$host" ] && [ -n "$database" ] && [ -n "$user" ] || usage
[ -n "$password_file" ] && [ -n "$output" ] || usage
validate_secret_file "$password_file" "backup password file"
[ ! -e "$output" ] || { echo "refusing to overwrite existing backup: $output" >&2; exit 2; }
output_dir=$(dirname "$output")
output_name=$(basename "$output")
[ -d "$output_dir" ] || { echo "backup destination directory does not exist" >&2; exit 2; }

password=$(read_secret_file "$password_file" "backup password file")

umask 077
passfile=$(mktemp "${TMPDIR:-/tmp}/thoth-vector-pgpass.XXXXXX")
temporary_output=$(mktemp "$output_dir/.${output_name}.tmp.XXXXXX")
cleanup() { rm -f "$passfile" "$temporary_output"; }
trap cleanup EXIT HUP INT TERM
escaped=$(printf '%s' "$password" | sed 's/\\/\\\\/g; s/:/\\:/g')
printf '%s:%s:%s:%s:%s\n' "$host" "$port" "$database" "$user" "$escaped" >"$passfile"
chmod 0600 "$passfile"

PGPASSFILE=$passfile pg_dump \
  --host="$host" --port="$port" --username="$user" --dbname="$database" \
  --format=custom --compress=9 \
  --table=vectors.schema_records --table=vectors.evidence --table=vectors.memory \
  --table=public.tht_vector_migrations --file="$temporary_output"
if ! ln "$temporary_output" "$output"; then
  echo "refusing to replace backup destination created concurrently: $output" >&2
  exit 2
fi
rm -f "$temporary_output"
echo "Vector backup written: $output"