From f498228bb9030d643fd2deb23da1a91f68906bf2 Mon Sep 17 00:00:00 2001
From: Mark Spanbroek <mark@spanbroek.net>
Date: Wed, 17 Mar 2021 12:53:30 +0100
Subject: [PATCH] Replace Channel by ChannelId

---
 nitro/destination.nim      |  2 ++
 nitro/wallet.nim           | 25 ++++++++++++++-----------
 tests/nitro/testWallet.nim | 29 +++++++++++------------------
 3 files changed, 27 insertions(+), 29 deletions(-)

diff --git a/nitro/destination.nim b/nitro/destination.nim
index 44ee379..0bc6de2 100644
--- a/nitro/destination.nim
+++ b/nitro/destination.nim
@@ -1,3 +1,4 @@
+import std/hashes
 import pkg/questionable
 import pkg/questionable/results
 import pkg/stew/byteutils
@@ -17,6 +18,7 @@ func parse*(_: type Destination, s: string): ?Destination =
    Destination(array[32, byte].fromHex(s)).catch.option
 
 func `==`*(a, b: Destination): bool {.borrow.}
+func hash*(destination: Destination): Hash {.borrow.}
 
 func toDestination*(address: EthAddress): Destination =
   var bytes: array[32, byte]
diff --git a/nitro/wallet.nim b/nitro/wallet.nim
index f831177..a2a91e3 100644
--- a/nitro/wallet.nim
+++ b/nitro/wallet.nim
@@ -1,3 +1,4 @@
+import std/tables
 import ./basics
 import ./keys
 import ./protocol
@@ -13,9 +14,8 @@ export channelupdate
 type
   Wallet* = object
     key: PrivateKey
-    channels*: seq[Channel]
-  Channel* = object
-    latest*: ChannelUpdate
+    channels: Table[ChannelId, ChannelUpdate]
+  ChannelId* = Destination
 
 func init*(_: type Wallet, key: PrivateKey): Wallet =
   result.key = key
@@ -23,31 +23,34 @@ func init*(_: type Wallet, key: PrivateKey): Wallet =
 func address*(wallet: Wallet): EthAddress =
   wallet.key.toPublicKey.toAddress
 
+func `[]`*(wallet: Wallet, channel: ChannelId): ?ChannelUpdate =
+  wallet.channels[channel].catch.option
+
 func sign(wallet: Wallet, update: ChannelUpdate): ChannelUpdate =
   var signed = update
   signed.signatures &= @{wallet.address: wallet.key.sign(update.state)}
   signed
 
-func createChannel(wallet: var Wallet, update: ChannelUpdate): Channel =
+func createChannel(wallet: var Wallet, update: ChannelUpdate): ChannelId =
   let signed = wallet.sign(update)
-  let channel = Channel(latest: signed)
-  wallet.channels.add(channel)
-  channel
+  let id = getChannelId(signed.state.channel)
+  wallet.channels[id] = signed
+  id
 
 func openLedgerChannel*(wallet: var Wallet,
                         hub: EthAddress,
                         chainId: UInt256,
                         nonce: UInt48,
                         asset: EthAddress,
-                        amount: UInt256): Channel =
+                        amount: UInt256): ChannelId =
   let update = startLedger(wallet.address, hub, chainId, nonce, asset, amount)
   wallet.createChannel(update)
 
-func acceptChannel*(wallet: var Wallet, update: ChannelUpdate): ?!Channel =
+func acceptChannel*(wallet: var Wallet, update: ChannelUpdate): ?!ChannelId =
   if not update.participants.contains(wallet.address):
-    return Channel.failure "wallet owner is not a participant"
+    return ChannelId.failure "wallet owner is not a participant"
 
   if not verifySignatures(update):
-    return Channel.failure "incorrect signatures"
+    return ChannelId.failure "incorrect signatures"
 
   wallet.createChannel(update).success
diff --git a/tests/nitro/testWallet.nim b/tests/nitro/testWallet.nim
index 5753711..759ed9c 100644
--- a/tests/nitro/testWallet.nim
+++ b/tests/nitro/testWallet.nim
@@ -17,34 +17,31 @@ suite "wallet: opening ledger channel":
   let nonce = UInt48.example
 
   var wallet: Wallet
-  var channel: Channel
+  var channel: ChannelId
 
   setup:
     wallet = Wallet.init(key)
     channel = wallet.openLedgerChannel(hub, chainId, nonce, asset, amount)
 
   test "sets correct channel definition":
-    let definition = channel.latest.state.channel
+    let definition = wallet[channel].get.state.channel
     check definition.chainId == chainId
     check definition.nonce == nonce
     check definition.participants == @[wallet.address, hub]
 
   test "provides correct outcome":
-    let outcome = channel.latest.state.outcome
+    let outcome = wallet[channel].get.state.outcome
     let destination = wallet.address.toDestination
     check outcome == Outcome.init(asset, {destination: amount})
 
-  test "signs the upcoming state":
-    let state = channel.latest.state
-    let signatures = channel.latest.signatures
+  test "signs the state":
+    let state = wallet[channel].get.state
+    let signatures = wallet[channel].get.signatures
     check signatures == @{wallet.address: key.sign(state)}
 
   test "sets app definition and app data to zero":
-    check channel.latest.state.appDefinition == EthAddress.zero
-    check channel.latest.state.appData.len == 0
-
-  test "updates the list of channels":
-    check wallet.channels == @[channel]
+    check wallet[channel].get.state.appDefinition == EthAddress.zero
+    check wallet[channel].get.state.appData.len == 0
 
 suite "wallet: accepting incoming channel":
 
@@ -57,18 +54,14 @@ suite "wallet: accepting incoming channel":
     update = ChannelUpdate(state: State.example)
     update.state.channel.participants &= @[wallet.address]
 
-  test "returns the new channel instance":
+  test "returns the new channel id":
     let channel = wallet.acceptChannel(update).get
-    check channel.latest.state == update.state
-
-  test "updates the list of channels":
-    let channel = wallet.acceptChannel(update).get
-    check wallet.channels == @[channel]
+    check wallet[channel].get.state == update.state
 
   test "signs the channel state":
     let channel = wallet.acceptChannel(update).get
     let expectedSignatures = @{wallet.address: key.sign(update.state)}
-    check channel.latest.signatures == expectedSignatures
+    check wallet[channel].get.signatures == expectedSignatures
 
   test "fails when wallet address is not a participant":
     let wrongParticipants = seq[EthAddress].example