#include <PubSubClient.h>

#include <WiFiClient.h>

#include "config.h"

bool readPCStillAlive();

float readPCStillAliveValue();

void togglePC();

WiFiClient espClient;

PubSubClient client(espClient);

char* topic_power = "ultrazaziki/power";

char* topic_status = "ultrazaziki/status";

char* username = MQTT_USER;

char* password = MQTT_PASSWORD;

bool last_alive = false;

bool alive = false;

unsigned long last_millis_5s = 0;

unsigned long last_millis_5m = 0;

unsigned long last_millis_reconnect = 0;

unsigned long mills = 0;

void setup_mqtt(){

// setup function to connect to the MQTT Server defined in config.h

char * server = (char *) malloc(32);

server = MQTT_SERVER; // cast from bytes to char*

client.setServer(server, 1883);

client.setCallback(callback);

Serial.print("Setup Mqtt with server ");

Serial.println(server);

}

void loop_mqtt(){

if (!client.connected()) {

reconnect();

}

mills = millis();

// we don't have to handle overflow because the result of unsigned longs overflows as well

// around every 50 days, the update inverval goes from 5 seconds to maximum 10 seconds once

// which does not affect it at all

if (mills - last_millis_5s >= 5000) {

// reads status every 5 seconds

last_millis_5s = mills;

last_alive = alive;

alive = readPCStillAlive();

// no overflow handling as well for the same reason as above, it might take 10 minutes for one

// update approximately every 50 days

if (mills - last_millis_5m >= 300000) {

// publish status every 5 minutes

last_millis_5m = mills;

client.publish(topic_status, (alive)? "1" : "0");

} else if (last_alive != alive) {

// publish status if changed by mqtt command

client.publish(topic_status, (alive)? "1" : "0");

}

}

client.loop();

}

void callback(char* topic, byte* payload, unsigned int param_length) {

// print incoming messages

Serial.print("Message arrived [");

Serial.print(topic);

Serial.print("] ");

String str_payload = "";

for (int i = 0; i < param_length; i++) {

Serial.print((char)payload[i]);

str_payload += (char)payload[i];

}

Serial.println();

last_alive = alive;

alive = readPCStillAlive();

if (strcmp(topic, topic_power) == 0){

if (str_payload.toInt() == 1 && !alive) {

// turn on pc if 1 was sent on topic and pc is not already powered

Serial.println("PC on");

togglePC();

} else if(str_payload.toInt() == 0 && alive) {

// turn off pc if 0 was sent on topic and pc is already powered

Serial.println("PC off");

togglePC();

}

// always publish status after receiving any mqtt command

alive = readPCStillAlive();

client.publish(topic_status, (alive)? "1" : "0");

}

}

void reconnect() {

// reconnecting to MQTT server after losing connection

if (!client.connected()) {

if (millis() - last_millis_reconnect < 5000) {

// only try reconnect every 5 seconds

return;

}

last_millis_reconnect = millis();

Serial.print("Attempting MQTT connection...");

String clientId = "PCSwitch-";

clientId += String(random(0xffff), HEX);

if (client.connect(clientId.c_str(), username, password)) {

// connection successful, subscribe to power topic

Serial.println("MQTT connected!");

client.subscribe(topic_power);

} else {

// connection failed, retry after 5 seconds

Serial.println(" failed, trying again in 5 seconds");

}

}

}