From fe673dc25553d4ffe6cdc86f55f20df838f614c1 Mon Sep 17 00:00:00 2001
From: Trolli Schmittlauch <t.schmittlauch@orlives.de>
Date: Thu, 21 May 2020 21:13:58 +0200
Subject: [PATCH] make NodeState a typeclasse, define setters and getters on
 its representations

contributes to #20
---
 FediChord.asn1            |  2 +-
 src/Hash2Pub/FediChord.hs | 92 ++++++++++++++++++++++++++++-----------
 2 files changed, 68 insertions(+), 26 deletions(-)

diff --git a/FediChord.asn1 b/FediChord.asn1
index b80b15a..254fc95 100644
--- a/FediChord.asn1
+++ b/FediChord.asn1
@@ -44,7 +44,7 @@ NodeState ::= SEQUENCE {
 	domain			Domain,
 	ipAddr			OCTET STRING (SIZE(16)),
 	dhtPort			INTEGER,
-	apPort			INTEGER,
+	servicePort		INTEGER,
 	vServerID		INTEGER (0..255)
 	}
 
diff --git a/src/Hash2Pub/FediChord.hs b/src/Hash2Pub/FediChord.hs
index fd26b6f..c5a7c43 100644
--- a/src/Hash2Pub/FediChord.hs
+++ b/src/Hash2Pub/FediChord.hs
@@ -125,26 +125,26 @@ a `localCompare` b
 
 
 -- | represents a node and all its important state
-data NodeState = NodeState
-    { nid       :: NodeID
-    , domain    :: String
+data RemoteNodeState = RemoteNodeState
+    { nid         :: NodeID
+    , domain      :: String
     -- ^ full public domain name the node is reachable under
-    , ipAddr    :: HostAddress6
+    , ipAddr      :: HostAddress6
     -- the node's public IPv6 address
-    , dhtPort   :: PortNumber
+    , dhtPort     :: PortNumber
     -- ^ port of the DHT itself
-    , apPort    :: Maybe PortNumber
-    -- ^ port of the ActivityPub relay and storage service
-    , vServerID :: Integer
+    , servicePort :: PortNumber
+    -- ^ port of the service provided on top of the DHT
+    , vServerID   :: Integer
     -- ^ ID of this vserver
-    , internals :: Maybe InternalNodeState
-    -- ^ data not present in the representation of remote nodes
     }
     deriving (Show, Eq)
 
--- | encapsulates all data and parameters that are not present for remote nodes
-data InternalNodeState = InternalNodeState
-    { nodeCache           :: IORef NodeCache
+-- | represents a node and encapsulates all data and parameters that are not present for remote nodes
+data LocalNodeState = LocalNodeState
+    { nodeState           :: RemoteNodeState
+    -- ^ represents common data present both in remote and local node representations
+    , nodeCache           :: IORef NodeCache
     -- ^ EpiChord node cache with expiry times for nodes
     , cacheWriteQueue     :: TQueue (NodeCache -> NodeCache)
     -- ^ cache updates are not written directly to the  'nodeCache' but queued and
@@ -163,6 +163,60 @@ data InternalNodeState = InternalNodeState
     }
     deriving (Show, Eq)
 
+-- | class for various NodeState representations, providing
+-- getters and setters for common values
+class NodeState a where
+    -- getters for common properties
+    getNid :: a -> NodeID
+    getDomain :: a -> String
+    getIpAddr :: a -> HostAddress6
+    getDhtPort :: a -> PortNumber
+    getServicePort :: a -> PortNumber
+    getVServerID :: a -> Integer
+    -- setters for common properties
+    setNid :: NodeID -> a -> a
+    setDomain :: String -> a -> a
+    setIpAddr :: HostAddress6 -> a -> a
+    setDhtPort :: PortNumber -> a -> a
+    setServicePort :: PortNumber -> a -> a
+    setVServerID :: Integer -> a -> a
+
+instance NodeState RemoteNodeState where
+    getNid = nid
+    getDomain = domain
+    getIpAddr = ipAddr
+    getDhtPort = dhtPort
+    getServicePort = servicePort
+    getVServerID = vServerID
+    setNid nid' ns = ns {nid = nid'}
+    setDomain domain' ns = ns {domain = domain'}
+    setIpAddr ipAddr' ns = ns {ipAddr = ipAddr'}
+    setDhtPort dhtPort' ns = ns {dhtPort = dhtPort'}
+    setServicePort servicePort' ns = ns {servicePort = servicePort'}
+    setVServerID vServerID' ns = ns {vServerID = vServerID'}
+
+-- | helper function for setting values on the 'RemoteNodeState' contained in the 'LocalNodeState'
+propagateNodeStateSet_ :: (RemoteNodeState -> RemoteNodeState) -> LocalNodeState -> LocalNodeState
+propagateNodeStateSet_ func ns = let
+        newNs = func $ nodeState ns
+    in
+        ns {nodeState = newNs}
+
+
+instance NodeState LocalNodeState where
+    getNid = getNid . nodeState
+    getDomain = getDomain . nodeState
+    getIpAddr = getIpAddr . nodeState
+    getDhtPort = getDhtPort . nodeState
+    getServicePort = getServicePort . nodeState
+    getVServerID = getVServerID . nodeState
+    setNid nid' = propagateNodeStateSet_ $ setNid nid'
+    setDomain domain' = propagateNodeStateSet_ $ setDomain domain'
+    setIpAddr ipAddr' = propagateNodeStateSet_ $ setIpAddr ipAddr'
+    setDhtPort dhtPort' = propagateNodeStateSet_ $ setDhtPort dhtPort'
+    setServicePort servicePort' = propagateNodeStateSet_ $ setServicePort servicePort'
+    setVServerID vServerID' = propagateNodeStateSet_ $ setVServerID vServerID'
+
 -- | defining Show instances to be able to print NodeState for debug purposes
 instance Typeable a => Show (IORef a) where
     show x = show (typeOf x)
@@ -170,18 +224,6 @@ instance Typeable a => Show (IORef a) where
 instance Typeable a => Show (TQueue a) where
     show x = show (typeOf x)
 
--- | extract a value from the internals of a 'NodeState'
-getInternals_ :: (InternalNodeState -> a) -> NodeState -> Maybe a
-getInternals_ func ns = func <$> internals ns
-
--- could be done better with lenses
--- | convenience function that updates an internal value of a NodeState
-putInternals_ :: (InternalNodeState -> InternalNodeState) -> NodeState -> NodeState
-putInternals_ func ns = let
-        newInternals = func <$> internals ns
-    in
-        ns {internals = newInternals }
-
 -- | convenience function for extracting the 'NodeCache' from a 'NodeState'
 getNodeCacheRef :: NodeState -> Maybe (IORef NodeCache)
 getNodeCacheRef = getInternals_ nodeCache