#!/bin/sh
set -eu

. ${0%/*}/tg-datastore.inc

info() { printf "I: $@\n" >&2; }

case "$1" in
  add)
    # tg-datastore add var=val var2=val2 ...
    # only add to HEAD
    shift
    info "returns non-zero if there is already a datastore on HEAD."
    info "adding the following data to the datastore of HEAD:"
    for pair in "$@"; do
      info "  ${pair%%=*}: ${pair#*=}\n"
      printf "${pair%%=*}: ${pair#*=}\n"
    done | tg_ds_add_data || die "E: HEAD already has a datastore"
    ;;
  remove)
    # removes from HEAD
    info "always returns zero, even if there was nothing to remove."
    tg_ds_remove_data
    ;;
  list)
    # $2 is the commit
    info "returns non-zero if no datastore found at given commit."
    info "prints contents of datastore otherwise."
    tg_ds_list_data "${2:-HEAD}"
    ;;
  get)
    # get parameter $2 from $3 (default HEAD)
    info "prints the value of the parameter stored in the given commit."
    info "prints nothing if the commit has a datastore but without the parameter."
    info "returns non-zero if there is no datastore."
    tg_ds_get_value "$2" ${3:-HEAD}
    ;;
  find)
    # search for parameter $2 by backtracking from $3 (default HEAD)
    info "prints the value of the parameter, or empty if parameter is not found."
    info "returns non-zero if no datastore was found."
    tg_ds_find_value "$2" ${3:-HEAD}
    ;;
  *)
    echo "Usage: ${0##*/} [ add var=val... | remove | list | get var [commit] | find var [commit] ]"
    ;;
esac