From 981f15fe87bf268a55e5caabbc2f4e4d81cae873 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Fri, 31 Aug 2018 17:51:30 +0200
Subject: Some refactoring, more functionality for the manager

---
 lib/app/chat.ex | 57 +++++++++++++++++++++++----------------------------------
 1 file changed, 23 insertions(+), 34 deletions(-)

(limited to 'lib/app')

diff --git a/lib/app/chat.ex b/lib/app/chat.ex
index bc9f5de..85f5265 100644
--- a/lib/app/chat.ex
+++ b/lib/app/chat.ex
@@ -36,18 +36,21 @@ defmodule SApp.Chat do
     manifest = {:chat, channel}
     id = SData.term_hash manifest
 
-    GenServer.cast(Shard.Manager, {:register, id, manifest, self()})
-    GenServer.cast(self(), :init_pull)
-
-    {:ok,
-      %{channel: channel,
-        id: id,
-        manifest: manifest,
-        store: store, 
-        peers: MapSet.new,
-        subs: MapSet.new,
-      }
-    }
+    case Shard.Manager.register(id, manifest, self()) do
+      :ok ->
+        Shard.Manager.dispatch_to(id, nil, self())
+        GenServer.cast(self(), :init_pull)
+        {:ok,
+          %{channel: channel,
+            id: id,
+            manifest: manifest,
+            store: store, 
+            subs: MapSet.new,
+          }
+        }
+      :redundant ->
+        exit(:normal)
+    end
   end
 
   @doc """
@@ -62,14 +65,6 @@ defmodule SApp.Chat do
     {:reply, ret, state}
   end
 
-  @doc """
-  Implementation of the :redundant handler: if another process is already
-  synchronizing this channel then we exit.
-  """
-  def handle_cast({:redundant, _}, _state) do
-    exit :normal
-  end
-
   @doc """
   Implementation of the :init_pull handler, which is called when the
   process starts. It contacts all currently connected peers and asks them to
@@ -99,8 +94,8 @@ defmodule SApp.Chat do
       end
     end
 
-    for peer <- state.peers do
-      push_messages(new_state, peer, nil, 5)
+    for {_, peer_id} <- :ets.lookup(:shard_peer_db, state.id) do
+      push_messages(new_state, peer_id, nil, 5)
     end
 
     {:noreply, new_state}
@@ -112,8 +107,7 @@ defmodule SApp.Chat do
   """
   def handle_cast({:interested, peer_id}, state) do
     push_messages(state, peer_id, nil, 10)
-    new_peers = MapSet.put(state.peers, peer_id)
-    {:noreply, %{ state | peers: new_peers }}
+    {:noreply, state}
   end
 
   def handle_cast({:subscribe, pid}, state) do
@@ -131,14 +125,14 @@ defmodule SApp.Chat do
   - `{:info, start, list, rest}`: put some messages and informs of the
     Merkle hash of the store of older messages.
   """
-  def handle_cast({:msg, peer_id, msg}, state) do
+  def handle_cast({:msg, peer_id, _shard_id, nil, msg}, state) do
     case msg do
       {:get_manifest} ->
-        Shard.Manager.send(peer_id, {state.id, {:manifest, state.manifest}})
+        Shard.Manager.send(peer_id, {state.id, nil, {:manifest, state.manifest}})
       {:get, start} -> push_messages(state, peer_id, start, 20)
       {:info, _start, list, rest} ->
         if rest != nil and not ML.has(state.store, rest) do
-          Shard.Manager.send(peer_id, {state.id, {:get, rest}})
+          Shard.Manager.send(peer_id, {state.id, nil, {:get, rest}})
         end
         who = self()
         spawn_link(fn ->
@@ -147,12 +141,7 @@ defmodule SApp.Chat do
         end)
       _ -> nil
     end
-
-    if MapSet.member?(state.peers, peer_id) do
-      {:noreply, state}
-    else
-      handle_cast({:interested, peer_id}, state)
-    end
+    {:noreply, state}
   end
 
   def handle_cast({:deferred_insert, list}, state) do
@@ -168,7 +157,7 @@ defmodule SApp.Chat do
   defp push_messages(state, to, start, num) do
     case ML.read(state.store, start, num) do
       {:ok, list, rest} ->
-        Shard.Manager.send(to, {state.id, {:info, start, list, rest}})
+        Shard.Manager.send(to, {state.id, nil, {:info, start, list, rest}})
       _ -> nil
     end
   end
-- 
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