local network = require("network")
local component = require("component")

local event = {}

local addr_num = 0
local last_msg = nil

function event.listen(event, callback)
  if event ~= "modem_message" then
    error("Event '"..event"' is not supported!")
  end
  addr = "A"..addr_num
  addr_num = addr_num + 1
  function ev_callback(ev, addr1, addr2, port, dist, msg)
    last_msg = {
      ev=ev,
      addr1=addr1,
      addr2=addr2,
      port=port,
      dist=dist,
      msg=msg,
    }
    -- Inject local address so the check passes
    component.modem.address = addr1
    callback(ev, addr1, addr2, port, dist, msg)
  end
  network.register(addr, ev_callback)
end

function event.ignore(event, callback)
  if event ~= "modem_message" then
    error("Event '"..event"' is not supported!")
  end
  network.deregister(network.get_scene())
end

function event.pull(event)
  -- Just return the last message and hope it is the
  -- right one ...
  if last_msg == nil then
    return nil
  end
  local lmsg = last_msg
  last_msg = nil
  return lmsg.ev, lmsg.addr1, lmsg.addr2, lmsg.port, lmsg.dist, lmsg.msg
end

function event.pullFiltered(timeout, filter)
  if last_msg == nil then
    return nil
  end
  local lmsg = last_msg
  last_msg = nil
  if filter(lmsg.ev, lmsg.addr1, lmsg.addr2, lmsg.port, lmsg.dist, lmsg.msg) then
    return lmsg.ev, lmsg.addr1, lmsg.addr2, lmsg.port, lmsg.dist, lmsg.msg
  else
    return nil
  end
end

return event