local network = {
  allow_blackhole = false,
}

local nodes = {}
local active_node = {}

function network.register(addr, callback)
  if nodes[addr] ~= nil then
    error("Address "..addr.." already registered!")
  end
  nodes[addr] = callback

  active_node = {}
  table.insert(active_node, addr)
end

function network.deregister(addr)
  nodes[addr] = nil
end

function network.send(addr, port, msg)
  local callback = nodes[addr]
  if callback == nil then
    if not network.allow_blackhole then
      error("Send message to offline node: "..tostring(addr))
    end
    return nil
  end

  local current_node = active_node[#active_node]
  -- Push target onto node-stack
  table.insert(active_node, addr)
  -- print("Sending from "..current_node.." to "..addr..": "..msg)
  -- print(require("inspect").inspect(active_node))
  callback("modem_message", addr, current_node, port, 0, msg)
  -- Remove again
  active_node[#active_node] = nil
end

function network.broadcast(port, msg)
  local current_node = active_node[#active_node]
  -- print("Broadcasting from "..current_node)
  for addr in pairs(nodes) do
    if addr ~= current_node then
      network.send(addr, port, msg)
    end
  end
end

function network.set_scene(addr)
  active_node = {}
  table.insert(active_node, addr)
end

function network.get_scene(addr)
  return active_node[#active_node]
end

return network