defprotocol SNet.Chan do
  @moduledoc"""
  Abstract definition for a communication channel
  """

  @doc"""
  Function to send a message to relevant peers.
  """
  def send(chan, msg)

  @doc"""
  Function to declare a handler for a channel
  """
  def handle(chan, func)
end

defmodule SNet.PeerChan do
  @moduledoc"""
  Direct channel to a peer
  """

  defstruct [:peer_id, :shard_id, :path]

  def new(peer_id, shard_id, path) do
    %__MODULE__{peer_id: peer_id, shard_id: shard_id, path: path}
  end

  defimpl SNet.Chan do
    def send(chan, msg) do
      Shard.Manager.send(chan.peer_id, {chan.shard_id, chan.path, msg})
    end

    def handle(chan, func) do
      # DO NOT USE THIS
      raise :do_not_use_this
      # assert false
    end
  end
end

defmodule SNet.FloodChan do
  @moduledoc"""
  Channel that send a message to all know peers for shard (floods the network)
  """

  defstruct [:shard_id, :path]

  def new(shard_id, path) do
    %__MODULE__{shard_id: shard_id, path: path}
  end

  defimpl SNet.Chan do
    def send(chan, msg) do
      for x <- Shard.Manager.get_shard_peers(chan.shard_id) do
        Shard.Manager.send(x, {chan.shard_id, chan.path, msg})
      end
    end

    def handle(chan, func) do
      # TODO
    end
  end
end

defmodule SNet.CipherChan do
  # TODO
end