From 4c770abce640903a76c4f5bad6d3140a0e60bb0b Mon Sep 17 00:00:00 2001
From: fanghr <chfanghr@gmail.com>
Date: Sat, 16 Apr 2022 23:04:22 +0800
Subject: [PATCH] get next proposal id from `pnextProposalId`

---
 agora/Agora/Governor.hs | 8 +++-----
 agora/Agora/Proposal.hs | 8 ++++++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/agora/Agora/Governor.hs b/agora/Agora/Governor.hs
index 3b7cc25..17809d0 100644
--- a/agora/Agora/Governor.hs
+++ b/agora/Agora/Governor.hs
@@ -35,6 +35,7 @@ import Agora.Proposal (
   PProposalThresholds,
   ProposalId,
   ProposalThresholds,
+  pnextProposalId 
  )
 import Agora.Utils (
   allInputs,
@@ -208,12 +209,9 @@ governorValidator params =
         -- check that nothing is minted
         passert "Nothing should be minted" $ plength # mint' #== 0
 
-        -- check proposal id +1
-        -- TODO: deriving a PNum instance for PProposalId
-        let oldPid = pto $ pfromData $ oldParams.nextProposalId
-            newPid = pto $ pfromData $ newParams.nextProposalId
+        -- check that proposal is advanced
         passert "Proposal id should be advanced by 1" $
-          oldPid + 1 #== newPid
+          pnextProposalId # oldParams.nextProposalId #== newParams.nextProposalId
 
         -- TODO: waiting for impl of proposal
         ptraceError "Not implemented yet"
diff --git a/agora/Agora/Proposal.hs b/agora/Agora/Proposal.hs
index c5e0068..751b4c0 100644
--- a/agora/Agora/Proposal.hs
+++ b/agora/Agora/Proposal.hs
@@ -30,6 +30,9 @@ module Agora.Proposal (
 
   -- * Plutarch helpers
   proposalDatumValid,
+
+  -- * Utils
+  pnextProposalId
 ) where
 
 import GHC.Generics qualified as GHC
@@ -434,3 +437,8 @@ proposalDatumValid proposal =
         , ptraceIfFalse "Proposal has fewer cosigners than the limit" $ plength # (pfromData datum.cosigners) #<= pconstant proposal.maximumCosigners
         , ptraceIfFalse "Proposal votes and effects are compatible with each other" $ pkeysEqual # datum.effects # pto (pfromData datum.votes)
         ]
+
+--------------------------------------------------------------------------------
+
+pnextProposalId :: Term s (PProposalId :--> PProposalId)
+pnextProposalId = phoistAcyclic $ plam $ \(pto -> id) -> pcon $ PProposalId $ id + 1