Decision

decision.daml

module Main where

import Daml.Script
import DA.List (sortOn, head)
import DA.Time 
import DA.Assert ((===))

template Proposal 
  with 
    proposer : Party
    acceptor : Party 
    proposal : Text 
    created : Time
  where 
    signatory proposer, acceptor
    observer acceptor 
    key (acceptor, proposer) : (Party, Party)
    maintainer key._1

template Decision 
  with 
    acceptor : Party 
    decision : Text 
    observers : [Party]
  where 
    signatory acceptor 
    observer observers 

template Ballot 
  with 
    acceptor : Party 
    proposers : [Party]
  where 
    signatory acceptor 
    observer proposers 
    nonconsuming choice MakeProposal : ContractId Proposal 
      with 
        proposal : Text 
        proposer : Party 
      controller proposer 
      do 
        now <- getTime 
        create Proposal with created = now, .. 
    choice MakeDecision : ContractId Decision 
      controller acceptor 
      do 
        res <- sequence [fetchByKey @Proposal (acceptor,p) | p <- proposers ]
        assertMsg "At least one proposer has to make a proposal" $ not . null $ res
        let sorted = sortOn (\(k,v) -> v.created) res
        let (_, firstProposal) = head sorted
        create Decision with decision = firstProposal.proposal, observers = proposers, ..
      

setup : Script ()
setup = script do
-- user_setup_begin
  acceptor <- allocatePartyWithHint "Acceptor" (PartyIdHint "Acceptor")
  proposer1 <- allocatePartyWithHint "Proposer1" (PartyIdHint "Proposer1")
  proposer2 <- allocatePartyWithHint "Proposer2" (PartyIdHint "Proposer2")
  acceptorId <- validateUserId "acceptor"
  proposer1Id <- validateUserId "proposer1"
  proposer2Id <- validateUserId "proposer2"
  createUser (User acceptorId (Some acceptor)) [CanActAs acceptor]
  createUser (User proposer1Id (Some proposer1)) [CanActAs proposer1]
  createUser (User proposer2Id (Some proposer2)) [CanActAs proposer2]
-- user_setup_end

  ballotCid <- submit acceptor $ createCmd Ballot with proposers = [proposer1,proposer2], .. 
  peopoal1Cid <- submit proposer1 $ exerciseCmd ballotCid MakeProposal with proposer = proposer1, proposal = "Falafel"

  now <- getTime 
  let now' = now `addRelTime` minutes 5 
  setTime now' 

  proposal2Cid <- submit proposer2 $ exerciseCmd ballotCid MakeProposal with proposer = proposer2, proposal = "Tacos" 

  decisionCid <- submit acceptor $ exerciseCmd ballotCid MakeDecision 

  Some decision <- queryContractId acceptor decisionCid 

  decision.decision === "Falafel"