Add grpc protos

Sources/Hedera/Client.swift

@@ -1,34 +1,32 @@
 import Sodium
+import SwiftGRPC
 
 public typealias Node = (accountId: AccountId, address: String)
 
 let defaultMaxTransactionFee: UInt64 = 100_000_000
 
 public struct Client {
-    let operatorId: AccountId
-    let operatorSigner: (Bytes) -> Bytes
+    var operatorId: AccountId?
+    var operatorSigner: ((Bytes) -> Bytes)?
 
-    let nodes: [AccountId: Node]
+    var nodes: [AccountId: Node]
     var node: AccountId?
 
+    var channels: [AccountId: Channel] = [:]
+
     /// The default maximum fee for a transaction.
     /// This can be overridden for an individual transaction with `.setTransactionFee()`. 
-    let maxTransactionFee = defaultMaxTransactionFee
+    var maxTransactionFee = defaultMaxTransactionFee
 
     // TODO: once queries are implemented    
     // /// The maximum payment that can be automatically attached to a query.
     // /// If this is not set, payments will not be made automatically for queries.
     // /// This can be overridden for an individual query with `.setPaymentDefault()`.
     // var maxQueryPayment: UInt64?
-
-}
 
-public struct ClientBuilder {
-    var operatorId: AccountId?
-    var operatorSigner: ((Bytes) -> Bytes)?
-    var node: AccountId?
-
-    public init() {}
+    public init(node id: AccountId, address url: String) {
+        nodes = [ id: Node(accountId: id, address: url) ]
+    }
 
     public mutating func setOperator(id: AccountId, secret: Ed25519PrivateKey) -> Self {
         operatorId = id
@@ -40,12 +38,31 @@ public struct ClientBuilder {
     public mutating func setOperator(id: AccountId, signer: @escaping (Bytes) -> Bytes) -> Self {
         operatorId = id
         operatorSigner = signer
-
+        
         return self
     }
 
     public mutating func setNode(_ id: AccountId) -> Self {
         node = id
         return self
     }
-}
+
+    public mutating func addNode(id: AccountId, address url: String) -> Self {
+        nodes[id] = Node(accountId: id, address: url)
+        return self
+    }
+
+    func pickNode() -> Node {
+        nodes.randomElement()!.value
+    }
+
+    mutating func channelFor(node: Node) -> Channel {
+        // TODO: what if the node is not on the client?
+        if let channel = channels[node.accountId] {
+            return channel
+        } else {
+            channels[node.accountId] = Channel(address: node.address)
+            return channels[node.accountId]!
+        }
+    }
+}