wire

defmodule Wire.Encoder do
  def encode(type: :port, listen_port: listen_port) do
    << 0, 0, 0, 3, listen_port :: 16-integer-big-unsigned, 0 >>
  end

  def encode(type: request_or_cancel, index: index, begin: begin, length: length) when request_or_cancel in [:cancel, :request] do
    a = if request_or_cancel == :cancel do 8 else 6 end

    << 0, 0, 0, 0xd, a,
       index :: 32-integer-big-unsigned,
       begin :: 32-integer-big-unsigned,
       length  :: 32-integer-big-unsigned >>
  end

  def encode(type: :piece, index: index, begin: begin, block: block) do
    << (9 + byte_size(block)) :: 32-integer-big-unsigned, 8, index :: 32-integer-big-unsigned, begin :: 32-integer-big-unsigned,
       block :: binary >>
  end

  def encode(type: :bitfield, field: field) do
    << (1 + byte_size(field)) :: 32-integer-big-unsigned, 5, field :: binary>>
  end

  def encode(type: :have, piece_index: piece_index) do
    << 0, 0, 0, 5, 4, piece_index :: 32-integer-big-unsigned >>
  end

  def encode(type: :not_interested) do
    << 0, 0, 0, 1, 3 >>
  end

  def encode(type: :interested) do
    << 0, 0, 0, 1, 2 >>
  end

  def encode(type: :unchoke) do
    << 0, 0, 0, 1, 1 >>
  end

  def encode(type: :choke) do
    << 0, 0, 0, 1, 0 >>
  end

  def encode(type: :keep_alive) do
    << 0, 0, 0, 0 >>
  end
end