From b234a360dafa0a65d797614aad5a4514570784f8 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Wed, 4 Jul 2018 13:17:26 +0200
Subject: Multiple chat rooms (no web UI yet)

---
 lib/app/chat.ex | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 76 insertions(+), 7 deletions(-)

(limited to 'lib/app')

diff --git a/lib/app/chat.ex b/lib/app/chat.ex
index 4a56085..f165514 100644
--- a/lib/app/chat.ex
+++ b/lib/app/chat.ex
@@ -1,17 +1,86 @@
 defmodule SApp.Chat do
-  def send(msg) do
+  use GenServer
+
+  def start_link(channel) do
+    GenServer.start_link(__MODULE__, channel)
+  end
+
+  def init(channel) do
+    {:ok, store} = SData.MerkleList.start_link(&msg_cmp/2)
+    manifest = {:chat, channel}
+    id = :crypto.hash(:sha256, :erlang.term_to_binary(manifest))
+
+    GenServer.cast(Shard.Manager, {:register, id, self()})
+    GenServer.cast(self(), :init_pull)
+
+    {:ok, %{channel: channel, id: id, manifest: manifest, store: store, peers: %{}}}
+  end
+
+  def handle_call(:manifest, _from, state) do
+    {:reply, state.manifest, state}
+  end
+
+  def handle_cast({:redundant, _}, _state) do
+    exit :normal
+  end
+
+  def handle_cast(:init_pull, state) do
+    GenServer.call(SNet.Manager, :get_all)
+    |> Enum.each(&(GenServer.cast(&1, {:send_msg, {:interested, [state.id]}})))
+    {:noreply, state}
+  end
+
+  def handle_cast({:chat_send, msg}, state) do
     msgitem = {(System.os_time :seconds),
                Shard.Identity.get_nickname(),
                msg}
-    GenServer.cast(SApp.Chat.Log, {:insert, msgitem})
+    GenServer.cast(state.store, {:insert, msgitem})
+
+    for {_, pid} <- state.peers do
+      push_messages(state, pid, nil, 5)
+    end
 
-    SNet.ConnSupervisor
-    |> DynamicSupervisor.which_children
-    |> Enum.each(fn {_, pid, _, _} -> GenServer.cast(pid, :init_push) end)
+    {:noreply, state}
   end
 
-  def msg_callback({ts, nick, msg}) do
-    IO.puts "#{ts |> DateTime.from_unix! |> DateTime.to_iso8601} <#{nick}> #{msg}"
+  def handle_cast({:interested, peer_id, peer_pid}, state) do
+    push_messages(state, peer_pid, nil, 10)
+    new_peers = Map.put(state.peers, peer_id, peer_pid)
+    {:noreply, %{ state | peers: new_peers }}
+  end
+
+  def handle_cast({:msg, peer_id, peer_pid, msg}, state) do
+    case msg do
+      :get_top -> push_messages(peer_id, state, nil, 10)
+      {:get, start} -> push_messages(peer_id, state, start, 20)
+      {:info, _start, list, rest} ->
+        if rest != nil and not GenServer.call(state.store, {:has, rest}) do
+          GenServer.cast(peer_pid, {:send_msg, {state.id, {:get, rest}}})
+        end
+        spawn_link(fn ->
+          Process.sleep 1000
+          GenServer.cast(state.store, {:insert_many, list, (fn msg -> msg_callback(state.channel, msg) end)})
+        end)
+    end
+
+    if Map.has_key?(state.peers, peer_id) do
+      {:noreply, state}
+    else
+      handle_cast({:interested, peer_id, peer_pid}, state)
+    end
+  end
+
+  defp push_messages(state, to, start, num) do
+    case GenServer.call(state.store, {:read, start, num}) do
+      {:ok, list, rest} ->
+        GenServer.cast(to, {:send_msg, {state.id, {:info, start, list, rest}}})
+      _ -> nil
+    end
+  end
+
+
+  def msg_callback(chan, {ts, nick, msg}) do
+    IO.puts "#{ts |> DateTime.from_unix! |> DateTime.to_iso8601}  ##{chan}  <#{nick}> #{msg}"
   end
 
   def msg_cmp({ts1, nick1, msg1}, {ts2, nick2, msg2}) do
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