1 files changed, 119 insertions, 0 deletions
diff --git a/shard/lib/net/manager.ex b/shard/lib/net/manager.ex
new file mode 100644
index 0000000..17d6e06
--- /dev/null
+++ b/shard/lib/net/manager.ex
@@ -0,0 +1,119 @@
+defmodule SNet.Manager do
+  @moduledoc"""
+  - :connections (not persistent)
+
+      List of
+        { peer_info, pid, nil | {my_pk, his_pk} }
+  """
+
+  use GenServer
+
+  require Logger
+
+  def start_link(_) do
+    GenServer.start_link(__MODULE__, nil, name: __MODULE__)
+  end
+
+  def init(_) do
+    Process.flag(:trap_exit, true)
+
+    :ets.new(:connections, [:bag, :protected, :named_table])
+
+    {:ok, nil} 
+  end
+
+  def handle_call({:add_peer, peer_info}, _from, state) do
+    pid = add_peer_internal(peer_info)
+    {:reply, pid, state}
+  end
+
+  def handle_call({:accept, client}, _from, state) do
+    my_port = Application.get_env(:shard, :port)
+    {:ok, pid} = SNet.TCPConn.start_link(%{socket: client, my_port: my_port})
+    {:reply, pid, state}
+  end
+
+  def handle_call({:peer_up, pid, peer_info, auth}, _from, state) do
+    case :ets.match(:connections,  {peer_info, :_, auth}) do
+      [{_, pid2, _}] when pid2 != pid ->
+        {:reply, :redundant, state}
+      _ ->
+        :ets.insert(:connections, {peer_info, pid, auth})
+
+        # Send interested message for all our shards
+        id_list = (for {id, _, _} <- Shard.Manager.list_shards(), do: id)
+        GenServer.cast(pid, {:send_msg, {:interested, id_list}})
+
+        {:reply, :ok, state}
+    end
+  end
+
+  def handle_cast({:connect_and_send, peer_info, msg}, state) do
+    pid = add_peer_internal(peer_info)
+    GenServer.cast(pid, {:send_msg, msg})
+    {:noreply, state}
+  end
+
+  def handle_info({:EXIT, pid, _reason}, state) do
+    :ets.match_delete(:connections, {:_, pid, :_})
+    {:noreply, state}
+  end
+
+  defp add_peer_internal(peer_info) do
+    case :ets.lookup(:connections, peer_info) do
+      [{_, pid, _}|_] ->
+        pid
+      [] ->
+        my_port = Application.get_env(:shard, :port)
+        {:ok, pid} = SNet.TCPConn.start_link(%{connect_to: peer_info, my_port: my_port, auth: nil})
+        :ets.insert(:connections, {peer_info, pid, nil})
+        pid
+    end
+  end
+
+  # =========
+  # INTERFACE
+  # =========
+
+  @doc"""
+  Connect to a peer specified by ip address and port
+  """
+  def add_peer(peer_info) do
+    GenServer.call(__MODULE__, {:add_peer, peer_info})
+  end
+
+  @doc"""
+  Return the list of all connected peers
+  """
+  def list_connections() do
+    for [x] <- :ets.match(:connections, :"$1"), do: x
+  end
+
+  @doc"""
+  Return the list of connections to a given peer, possibly with different auth
+  """
+  def get_connections_to(peer_info) do
+    for {^peer_info, pid, auth} <- :ets.lookup(:connections, peer_info), do: {pid, auth}
+  end
+
+  @doc"""
+  Send message to a peer specified by peer info.
+  Opens a connection if necessary.
+  """
+  def send(peer_info, msg) do
+    case :ets.lookup(:connections, peer_info) do
+      [{^peer_info, pid, _auth}|_] ->
+        GenServer.cast(pid, {:send_msg, msg})
+      [] ->
+        GenServer.cast(__MODULE__, {:connect_and_send, peer_info, msg})
+    end
+  end
+
+  @doc"""
+  Send message to a peer specified by peer id
+  """
+  def send_pid(pid, msg) do
+    GenServer.cast(pid, {:send_msg, msg})
+  end
+end
+