-- Configuration to connect to the MQTT broker.
BROKER = "172.16.2.15"   -- Ip/hostname of MQTT broker
BRPORT = 1883             -- MQTT broker port
BRUSER = ""           -- If MQTT authenitcation is used then define the user
BRPWD  = ""            -- The above user password
CLIENTID = "ESP8266-" ..  node.chipid() -- The MQTT ID. Change to something you like

SWITCH_PIN = 0

SWITCH_ID = 0

-- MQTT topics to subscribe
topics = {"IoT/Watchdog", "IoT/Switch" .. SWITCH_ID} -- Add/remove topics to the array

-- Control variables.
pub_sem = 0         -- MQTT Publish semaphore. Stops the publishing whne the previous hasn't ended
current_topic  = 1  -- variable for one currently being subscribed to
topicsub_delay = 50 -- microseconds between subscription attempts, worked for me (local network) down to 5...YMMV
id1 = 0
id2 = 0

switch_state = 0


gpio.mode(SWITCH_PIN, gpio.OUTPUT)
gpio.write(SWITCH_PIN, gpio.LOW)

-- connect to the broker
print "Connecting to MQTT broker. Please wait..."
m = mqtt.Client( CLIENTID, 120, BRUSER, BRPWD)
m:connect( BROKER , BRPORT, 0, function(conn)
     print("Connected to MQTT:" .. BROKER .. ":" .. BRPORT .." as " .. CLIENTID )
     mqtt_sub() --run the subscription function
end)

function mqtt_sub()
     if table.getn(topics) < current_topic then
          -- if we have subscribed to all topics in the array, run the main prog
          run_main_prog()
     else
          --subscribe to the topic
          m:subscribe(topics[current_topic] , 0, function(conn)
               print("Subscribing topic: " .. topics[current_topic - 1] )
          end)
          current_topic = current_topic + 1  -- Goto next topic
          --set the timer to rerun the loop as long there is topics to subscribe
          tmr.alarm(5, topicsub_delay, 0, mqtt_sub )
     end
end

-- Sample publish functions:
function publish_heartbeat()
   if pub_sem == 0 then  -- Is the semaphore set=
     pub_sem = 1  -- Nop. Let's block it
     local uptime = tmr.time()
     local msg = "{\"metadata\":{\"device\":\"WiFiSwitch" .. SWITCH_ID .. "\"}, \"data\":{\"uptime\":" .. uptime .. "}}"
     m:publish("IoT/Heartbeat/WiFiSwitch" .. SWITCH_ID, msg ,0,0, function(conn) 
        -- Callback function. We've sent the data
        print("Heartbeat sent: " .. id1)
        pub_sem = 0  -- Unblock the semaphore
        id1 = id1 +1 -- Let's increase our counter
     end)
   end  
end

function publish_status()
   if pub_sem == 0 then  -- Is the semaphore set=
     pub_sem = 1  -- Nop. Let's block it
     local uptime = tmr.time()
     local msg = "{\"metadata\":{\"device\":\"WiFiSwitch" .. SWITCH_ID .. "\"}, \"data\":{\"uptime\":" .. uptime .. ", \"state\":" .. switch_state .. "}}"
     m:publish("IoT/Status/WiFiSwitch" .. SWITCH_ID, msg ,0,0, function(conn) 
        -- Callback function. We've sent the data
        print("Status sent: " .. id2)
        print("State: " .. switch_state)
        pub_sem = 0  -- Unblock the semaphore
        id2 = id2 +1 -- Let's increase our counter
     end)
   end  
end



--main program to run after the subscriptions are done
function run_main_prog()
     print("Main program")
     
     tmr.alarm(2, 1000, 1, publish_heartbeat )
     tmr.alarm(3, 1346, 1, publish_status )
     -- Callback to receive the subscribed topic messages. 
     m:on("message", function(conn, topic, data)
        print(topic .. ":" )
        if (data ~= nil ) then
          print ( data )
          if (data == "switch on") then
            switch_state = 1
            gpio.write(SWITCH_PIN, gpio.HIGH)
          elseif (data == "switch off") then
            switch_state = 0
            gpio.write(SWITCH_PIN, gpio.LOW)
          end
        end
      end )
end