local SSID = "xxxxxxxxxxxxx"
local SSID_PASSWORD = "xxxxxxxxxxxxx"
local SIGNAL_MODE = wifi.PHYMODE_N

MQTT_CLIENT_ID = node.chipid()
MQTT_CLIENT_USER = "openhabian"
MQTT_CLIENT_PASSWORD = "openhabian"
MQTT_CLIENT_KEEPALIVE_TIME = 120

MQTT_BROKER = "192.168.1.6"
MQTT_BROKER_PORT = 1883
MQTT_TOPIC_IN = "/esp8266_station123/in" -- commands
MQTT_TOPIC_OUT = "/esp8266_station123/out" -- send values
MQTT_BROKER_SECURE = 0
m = nil


function wait_for_wifi_conn ( callback )
   tmr.alarm (1, 1000, 1, function ( )
      if wifi.sta.getip ( ) == nil then
         print ("Waiting for Wifi connection")
      else
         tmr.stop (1)
         print("\n====================================")
         print ("ESP8266 mode is: " .. wifi.getmode ( ))
         print ("The module MAC address is: " .. wifi.ap.getmac ( ))
         print ("Config done, IP is " .. wifi.sta.getip ( ))
         print("====================================")

        callback()
      end
   end)
end


function mqtt_handler()
    m = mqtt.Client(MQTT_CLIENT_ID, MQTT_CLIENT_KEEPALIVE_TIME, MQTT_CLIENT_USER, MQTT_CLIENT_PASSWORD)
    
    -- on publish message receive event
    m:on("message", function(client, topic, data) 
      print("Received:" .. topic .. ":" ) 
      if data ~= nil then
        --print(data)
        if data == "req" then
            sendValue()
        end
      end
    end)
    m:on("offline", function(m)
        print ("\n\nDisconnected from broker")
        print("Heap: ", node.heap())
    end)

    m:connect(MQTT_BROKER, MQTT_BROKER_PORT, MQTT_BROKER_SECURE, function(client)
      print("connected")
      client:subscribe(MQTT_TOPIC_IN, 0, function(client) print("subscribe success") end)
    end,
    function(client, reason)
      print("failed reason: " .. reason)
    end)

    -- send all 30 sec
    tmr.alarm (2, 30*1000, tmr.ALARM_AUTO, function ( )
        sendValue()
    end)
    
end

function sendValue()
    -- do stuff
    local temperature = 20 + math.random()*20
    -- publish to broker on topic
    m:publish(MQTT_TOPIC_OUT, temperature, 0, 0, function(client) print("sent value="..temperature) end)
end



-- Configure the ESP as a station (client)
wifi.setmode(wifi.STATION)
wifi.setphymode(SIGNAL_MODE)
wifi.sta.config {ssid=SSID, pwd=SSID_PASSWORD}
wifi.sta.autoconnect(1)
 
-- Hang out until we get a wifi connection before the httpd server is started.
wait_for_wifi_conn( mqtt_handler )