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(** Only delegates with at least one roll take part in the amendment
   procedure.  It works as follows:

   - Proposal period: delegates can submit protocol amendment
   proposals using the proposal operation. At the end of a proposal
   period, the proposal with most supporters is selected and we move
   to an exploration period. If there are no proposals, or a tie
   between proposals, a new proposal period starts.

   - Exploration period: delegates can cast votes to test or not the
   winning proposal using the ballot operation.  At the end of an
   exploration period if participation reaches the quorum and the
   proposal has a supermajority in favor, we proceed to a cooldown
   period. Otherwise we go back to a proposal period.  In any case, if
   there is enough participation the quorum is updated.

   - Cooldown period: Nothing happens, this period is only a time gap
   between exploration and promotion periods. At the end of a cooldown
   period we move to a promotion period.

   - Promotion period: delegates can cast votes to promote or not the
   proposal using the ballot operation.  At the end of a promotion
   period if participation reaches the quorum and the proposal has a
   supermajority in favor, we move to an adoption period. Otherwise we
   go back to a proposal period.  In any case, if there is enough
   participation the quorum is updated.

   - Adoption period: At the end of an adoption period, the proposal
   is activated as the new protocol.  *)

open Alpha_context

(** If at the end of a voting period, moves to the next one following
    the state machine of the amendment procedure. *)
val may_start_new_voting_period : context -> context tzresult Lwt.t

type error +=
  | Unexpected_proposal
  | Unauthorized_proposal
  | Too_many_proposals
  | Empty_proposal

(** Records a list of proposals for a delegate.
    @raise Unexpected_proposal if [ctxt] is not in a proposal period.
    @raise Unauthorized_proposal if [delegate] is not in the listing. *)
val record_proposals :
  context -> public_key_hash -> Protocol_hash.t list -> context tzresult Lwt.t

type error += Invalid_proposal | Unexpected_ballot | Unauthorized_ballot

val record_ballot :
  context ->
  public_key_hash ->
  Protocol_hash.t ->
  Vote.ballot ->
  context tzresult Lwt.t