From b67a992278eab31fb25174fa27da607efdbabe3e Mon Sep 17 00:00:00 2001
From: Riley Kilgore <riley-kilgore@github.com>
Date: Sat, 5 Mar 2022 05:31:11 -0800
Subject: [PATCH] Added a multi-sig validator at Agora.MultiSig

---
 agora.cabal           |  1 +
 bench/Main.hs         | 11 +++++++++
 src/Agora/MultiSig.hs | 52 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 src/Agora/MultiSig.hs

diff --git a/agora.cabal b/agora.cabal
index 1a68b80..4e3240f 100644
--- a/agora.cabal
+++ b/agora.cabal
@@ -116,6 +116,7 @@ library
   import:          lang, deps
   exposed-modules:
     Agora.AuthorityToken
+    Agora.MultiSig
     Agora.SafeMoney
     Agora.SafeMoney.QQ
     Agora.Stake
diff --git a/bench/Main.hs b/bench/Main.hs
index 150f528..c2fb603 100644
--- a/bench/Main.hs
+++ b/bench/Main.hs
@@ -16,6 +16,10 @@ import Agora.AuthorityToken (
   AuthorityToken (AuthorityToken),
   authorityTokenPolicy,
  )
+import Agora.MultiSig (
+  MultiSig (..),
+  multiSigValidator,
+ )
 import Agora.SafeMoney (LQ)
 import Agora.Stake (
   Stake (Stake),
@@ -34,9 +38,16 @@ benchmarks =
   benchGroup
     "full_scripts"
     [ bench "authorityTokenPolicy" $ authorityTokenPolicy authorityToken
+    , bench "multiSigValidator" $ multiSigValidator multiSig
     , bench "stakePolicy" $ stakePolicy (Stake @LQ)
     , bench "stakeValidator" $ stakeValidator (Stake @LQ)
     ]
 
 authorityToken :: AuthorityToken
 authorityToken = AuthorityToken (Value.assetClass "" "")
+
+multiSig :: MultiSig (s :: S)
+multiSig = MultiSig
+  { keys = PSNil
+  , minSigs = 0
+  }
\ No newline at end of file
diff --git a/src/Agora/MultiSig.hs b/src/Agora/MultiSig.hs
new file mode 100644
index 0000000..bb570bd
--- /dev/null
+++ b/src/Agora/MultiSig.hs
@@ -0,0 +1,52 @@
+{- |
+Module     : Agora.MultiSig
+Maintainer : riley_kilgore@outlook.com
+Description: A basic N of M multisignature validator.
+-}
+module Agora.MultiSig (
+  multiSigValidator,
+  MultiSig (..),
+) where
+
+import Plutarch.Api.V1 (
+  PPubKeyHash,
+  PScriptContext (..),
+ )
+import Plutarch.Monadic qualified as P
+
+--------------------------------------------------------------------------------
+
+import Agora.Utils (passert)
+
+--------------------------------------------------------------------------------
+
+import GHC.Generics qualified as GHC
+import Generics.SOP (Generic)
+import Prelude
+
+--------------------------------------------------------------------------------
+
+{- | A MultiSig represents a proof that a particular set of signatures
+     are present on a transaction.
+-}
+data MultiSig (s :: S) = MultiSig
+  { keys    :: PList PPubKeyHash s
+  -- ^ List of PubKeyHashes that must be present in the list of signatories.
+  , minSigs :: Integer
+  } deriving stock (GHC.Generic)
+    deriving anyclass (Generic)
+
+--------------------------------------------------------------------------------
+
+-- | Validator given 'MultiSig' params.
+multiSigValidator :: MultiSig s -> Term s (PData :--> PData :--> PScriptContext :--> PUnit)
+multiSigValidator params =
+  plam $ \_datum _redeemer ctx' -> P.do
+    ctx <- pletFields @'["txInfo", "purpose"] ctx'
+    let signatories = pfield @"signatories" # ctx.txInfo
+    passert "The amount of required signatures is not met."
+      ((fromInteger params.minSigs) #<= (plength #$ pfilter
+          # (plam $ \a ->
+              (pelem # pdata a # pfromData signatories))
+          # pcon params.keys))
+      (pconstant ())
\ No newline at end of file