#!/usr/bin/env bash
# Local locate, store DB in user directory.
# Update on run if older than configured.

set -euo pipefail

DEFAULT_LLOCATE_DB_PATH=$HOME/.cache/locate.db
DEFAULT_LLOCATE_DB_AGE=1day

LLOCATE_DB_PATH=${LLOCATE_DB_PATH:-$DEFAULT_LLOCATE_DB_PATH}
LLOCATE_DB_AGE=${LLOCATE_DB_AGE:-$DEFAULT_LLOCATE_DB_AGE}

usage() {
  cat <<EOF
Usage: ${0##*/} [-h|-u] [locate options] term

Perform locate for given term.

Options:
  -u force updatedb
  -h show this help

Envirinment variances:

  LLOCATE_DB_PATH path to databas file (default: $DEFAULT_LLOCATE_DB_PATH)
  LLOCATE_DB_AGE  period after which database need to update,
                  in date string format (default: $DEFAULT_LLOCATE_DB_AGE)
EOF
  exit 1
}

update() {
  updatedb --require-visibility 0 --output "$LLOCATE_DB_PATH"
}

is_database_old() {
  local threshold db_mtime
  threshold=$(date -d "-$LLOCATE_DB_AGE" +%s)
  db_mtime=$(date -r "$LLOCATE_DB_PATH" +%s)
  if [ "$threshold" -gt "$db_mtime" ]; then
    return 0
  fi
  return 1
}

main() {
  if [ $# -eq 0 ]; then
    usage
  fi

  while :; do
    case "$1" in
    -u)
      update
      shift
      ;;
    -h) usage ;;
    *) break ;;
    esac
  done

  if is_database_old; then
    update
  fi
  locate --database "$LLOCATE_DB_PATH" "$@" | ${PAGER:-less}
}

main "$@"