_bc_backend = { local_addr = "address_light", power = 12, iscb = false, cbid = 0, cbn = "" }

function _bc_backend:init(cb_handler)
  local o = {}
  setmetatable(o, self)
  self.__index = self
  o.cb_handler = cb_handler
  return o
end

function _bc_backend:fetch_list(master_id)
  return {
    nouns = {
      ["power"] = "address_power",
      ["light"] = "address_light",
    },
    verbs = {
      ["inc_pwr"] = "address_power",
      ["toggle_light"] = "address_light",
    }
  }
end

function _bc_backend:request_noun(addr, n)
  if addr == "address_power" and n == "power" then
    return self.power
  end
  return nil
end

function _bc_backend:call_verb(addr, v, param)
  if addr == "address_power" and v == "inc_pwr" then
    self.power = param
    if self.iscb then
      self.cb_handler("listen", 101010)
    end
  end
end

function _bc_backend:register_callback(addr, n, query, qparam)
  self.iscb = true
  return 101010
end

function _bc_backend:cancel_callback(addr, n, id)
  self.iscb = false
end

function _bc_backend:call_listener(addr, n, id, value)
  if id == self.cbid and addr == "foobar" and n == self.cbn then
    self.cb(value)
  end
end

-- Debug handlers
function _bc_backend:debug_request_noun(n)
  -- Ask cb for noun value
  return self.cb_handler("noun", n)
end

function _bc_backend:debug_call_verb(v, arg)
  self.cb_handler("verb", v, arg)
end

function _bc_backend:debug_register_cb(n, query, qparam, cb)
  self.cbid = self.cb_handler("reg_nl", n, {query = query, qparam = qparam, addr = "foobar"})
  self.cbn = n
  self.cb = cb
end

function _bc_backend:debug_cancel_cb()
  self.cb_handler("unreg_nl", self.cbn, self.cbid)
end

return _bc_backend