local P = {}
local m, topic, cid
local subscriptions = {}

local function p(msg)
  print("MQTT: "..msg)
end

local function mq_client_connected(con)
  p("connected")
end

local function disconnect()
  p("Lost wifi connection, disconnecting")
  m:close()
  m = nil
end

function mq_on_timer()
  -- This crashes the module:
  -- local status = wifi.sta.status()
  -- p("checking status, status="..status)

  local status = wifi.sta.getip()

  if status and status ~= "0.0.0.0" then
    if not m then
      p("connecting")

      -- client id, keepalive, username, password
      m = mqtt.Client(cid, 120)
      -- m:on("connect", mq_connected)
      m:on("offline", function() m:close(); m = nil end)

      -- host, port, secure, auto_reconnect, function(client), ssl=8883
      m:connect("trygvis.io", 1883, 0, 0, mq_client_connected)
    end
  else
    if m then
	    disconnect()
    end
  end
end

function P.init(timer_id, device_id, client_id)
  cid = client_id

  topic = "/diller/"..device_id

  tmr.alarm(timer_id, 4 * 1000, 1, mq_on_timer)
end

function P.subscribe(path, cb)
  local subscription = subscriptions[path]
  if subscription then
    print("subscription on "..path.." already registered, state="..tostring(subscription.state))
    return
  end

  print("Registering subscription on "..path)

  subscriptions[path] = true
  -- pending_subscriptions[path] = true

  -- create_subscriptions()
end

function P.publish(path, payload)
  if not m then
    print("Not connected, dropping message to "..path)
    return false, 'not connected'
  end

  path = topic.."/"..path
  print("path="..path)
  m:publish(path, payload, 0, 0)

  return true, 'ok'
end

return P