(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com>     *)
(*                                                                           *)
(* Permission is hereby granted, free of charge, to any person obtaining a   *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
(* the rights to use, copy, modify, merge, publish, distribute, sublicense,  *)
(* and/or sell copies of the Software, and to permit persons to whom the     *)
(* Software is furnished to do so, subject to the following conditions:      *)
(*                                                                           *)
(* The above copyright notice and this permission notice shall be included   *)
(* in all copies or substantial portions of the Software.                    *)
(*                                                                           *)
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(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  *)
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(* DEALINGS IN THE SOFTWARE.                                                 *)
(*                                                                           *)
(*****************************************************************************)

let exists = Storage.Commitments.mem

let committed_amount ctxt bpkh =
  Storage.Commitments.find ctxt bpkh >>=? fun balance ->
  return (Option.value ~default:Tez_repr.zero balance)

let increase_commitment_only_call_from_token ctxt bpkh amount =
  if Tez_repr.(amount = zero) then return ctxt
  else
    committed_amount ctxt bpkh >>=? fun balance ->
    Tez_repr.(amount +? balance) >>?= fun new_balance ->
    Storage.Commitments.add ctxt bpkh new_balance >|= ok

let decrease_commitment_only_call_from_token ctxt bpkh amount =
  committed_amount ctxt bpkh >>=? fun balance ->
  Tez_repr.(balance -? amount) >>?= fun new_balance ->
  if Tez_repr.(new_balance = Tez_repr.zero) then
    Storage.Commitments.remove ctxt bpkh >|= ok
  else Storage.Commitments.add ctxt bpkh new_balance >|= ok