#!/usr/bin/env bash

if [[ -n ${IPF_STORAGE_SH_LOADED:-} ]]; then
  return 0
fi
IPF_STORAGE_SH_LOADED=1

: "${IPF_STORAGE_DIR:=/var/lib/iptables-forward}"
: "${IPF_STORAGE_DB:=${IPF_STORAGE_DIR}/rules.db}"
: "${IPF_LOCK_FILE:=${IPF_STORAGE_DIR}/.lock}"

storage_dir() {
  printf '%s\n' "${IPF_STORAGE_DIR}"
}

storage_db_path() {
  printf '%s\n' "${IPF_STORAGE_DB}"
}

storage_lock_path() {
  printf '%s\n' "${IPF_LOCK_FILE}"
}

storage_init() {
  local dir db lock
  dir=$(storage_dir)
  db=$(storage_db_path)
  lock=$(storage_lock_path)

  mkdir -p "${dir}"
  touch "${db}" "${lock}"
  chmod 750 "${dir}"
  chmod 640 "${db}"
  chmod 600 "${lock}"
}

storage_add() {
  local line=${1-}
  local db lock
  [[ -n ${line} ]] || return 1
  storage_init
  db=$(storage_db_path)
  lock=$(storage_lock_path)

  (
    flock -x 9
    printf '%s\n' "${line}" >>"${db}"
  ) 9>>"${lock}"
}

storage_list() {
  local db
  db=$(storage_db_path)
  [[ -f ${db} ]] || return 0
  cat "${db}"
}

storage_parse() {
  local line=${1-}
  local key=${2-}
  local part
  IFS='|' read -r -a parts <<<"${line}"
  for part in "${parts[@]}"; do
    if [[ ${part} == "${key}="* ]]; then
      printf '%s\n' "${part#*=}"
      return 0
    fi
  done
  return 1
}

storage_get() {
  local uuid=${1-}
  local line current
  [[ -n ${uuid} ]] || return 1
  while IFS= read -r line || [[ -n ${line} ]]; do
    current=$(storage_parse "${line}" uuid || true)
    if [[ ${current} == "${uuid}" ]]; then
      printf '%s\n' "${line}"
      return 0
    fi
  done < <(storage_list)
  return 1
}

storage_delete() {
  local uuid=${1-}
  local db lock tmp found=0 line current
  [[ -n ${uuid} ]] || return 1
  storage_init
  db=$(storage_db_path)
  lock=$(storage_lock_path)
  tmp="${db}.tmp.$$"

  (
    flock -x 9
    : >"${tmp}"
    while IFS= read -r line || [[ -n ${line} ]]; do
      current=$(storage_parse "${line}" uuid || true)
      if [[ ${current} == "${uuid}" ]]; then
        found=1
        continue
      fi
      printf '%s\n' "${line}" >>"${tmp}"
    done <"${db}"

    if (( found == 0 )); then
      rm -f "${tmp}"
      exit 1
    fi

    mv "${tmp}" "${db}"
  ) 9>>"${lock}"
}

storage_count() {
  local count=0 line
  while IFS= read -r line || [[ -n ${line} ]]; do
    [[ -n ${line} ]] || continue
    ((count++))
  done < <(storage_list)
  printf '%s\n' "${count}"
}