# Simple bourne shell based key-value store

if [ -z "${__kvs_sh_loaded}" ]
then
  __kvs_sh_loaded=yes

  t="$(printf '\t')"

  [ "${kvs}" ] || {
    cat <<EOF
KVS v0.1
Copyright - http://wiki.cyberleo.net/wiki/CyberLeo/COPYRIGHT?version=4

Set the following variables before sourcing this library:

 kvs  - Path and filename of the kvdb database file
EOF
    kill -ABRT $$
    exit 1
  }

  [ -s "${kvs}" ] || echo "${t}${t}# KVSv0 id-key-value database" > "${kvs}"

  # Add or replace a value stored for a given key and id in the kvs
  kvs_set() {
    [ "${1}" -a "${2}" ] || return 255
    local id="${1}"
    local var="${2}"
    local val="${3}"
    printf "%s\t%s\t%s\n" "${id}" "${var}" "${val}" >> "${kvs}"
  }

  # Fetch the most recent value stored for a given key and id from the kvs
  kvs_get() {
    [ "${1}" -a "${2}" ] || return 255
    local id="${1}"
    local var="${2}"
    grep "^${id}${t}${var}${t}" "${kvs}" | tail -n 1 | cut -d"${t}" -f3-
  }

  # Does the kvs have any entries for a given ID?
  kvs_has_id() {
    [ "${1}" ] || return 255
    local id="${1}"
    grep -q "^${id}${t}" "${kvs}"
  }

  # Does the kvs have a given key for a given ID?
  kvs_has_key() {
    [ "${1}" -a "${2}" ] || return 255
    local id="${1}"
    local var="${2}"
    grep -q "^${id}${t}${var}${t}" "${kvs}"
  }

  # Remove a given key with a given ID from the kvs
  kvs_unset() {
    [ "${1}" -a "${2}" ] || return 255
    local id="${1}"
    local var="${2}"
    grep -v "^${id}${t}${var}${t}" "${kvs}" > "${kvs}.tmp" && mv -f "${kvs}.tmp" "${kvs}" || rm -f "${kvs}.tmp"
  }

  # Remove all keys with a given ID from the kvs
  kvs_unset_all() {
    [ "${1}" ] || return 255
    local id="${1}"
    grep -v "^${id}${t}" "${kvs}" > "${kvs}.tmp" && mv -f "${kvs}.tmp" "${kvs}" || rm -f "${kvs}.tmp"
  }
fi