/*
 Basic ESP8266 / ESP32 MQTT example
 This sketch demonstrates the capabilities of the pubsub library in combination
 with the ESP8266 board/library.
 It connects to an MQTT server then:
  - publishes "hello world" to the topic "outTopic" every two seconds
  - subscribes to the topic "inTopic", printing out any messages
    it receives. NB - it assumes the received payloads are strings not binary
  - If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
    else switch it off
 It will reconnect to the server if the connection is lost using a blocking
 reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
 achieve the same result without blocking the main loop.
 To install the ESP8266 board, (using Arduino 1.6.4+):
  - Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
       http://arduino.esp8266.com/stable/package_esp8266com_index.json
  - Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
  - Select your ESP8266 in "Tools -> Board"
*/

#ifdef ESP8266
#include <ESP8266WiFi.h>
#elif defined(ESP32)
#include <WiFi.h>
#include <esp_random.h>
#define BUILTIN_LED A0
#define RANDOM_REG32 esp_random()
#else
#error Platform not supported.
#endif
#include <PubSubClient.h>

// Update these with values suitable for your network.

const char* ssid = "........";
const char* password = "........";
const char* mqtt_server = "broker.mqtt-dashboard.com";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE	(50)
char msg[MSG_BUFFER_SIZE];
int value = 0;

void setup_wifi() {
    delay(10);
    // We start by connecting to a WiFi network
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);

    WiFi.mode(WIFI_STA);
    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }

    randomSeed(RANDOM_REG32);

    Serial.println("");
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
}

void callback(char* topic, uint8_t* payload, size_t length) {
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("] ");
    for (size_t i = 0; i < length; i++) {
        Serial.print((char)payload[i]);
    }
    Serial.println();

    // Switch on the LED if an 1 was received as first character
    if ((char)payload[0] == '1') {
        digitalWrite(BUILTIN_LED, LOW);  // Turn the LED on (Note that LOW is the voltage level
                                         // but actually the LED is on; this is because
                                         // it is active low on the ESP-01)
    } else {
        digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
    }
}

void reconnect() {
    // Loop until we're reconnected
    while (!client.connected()) {
        Serial.print("Attempting MQTT connection...");
        // Create a random client ID
        String clientId = "ESP8266Client-";
        clientId += String(random(0xffff), HEX);
        // Attempt to connect
        if (client.connect(clientId.c_str())) {
            Serial.println("connected");
            // Once connected, publish an announcement...
            client.publish("outTopic", "hello world");
            // ... and resubscribe
            client.subscribe("inTopic");
        } else {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");
            // Wait 5 seconds before retrying
            delay(5000);
        }
    }
}

void setup() {
    pinMode(BUILTIN_LED, OUTPUT);  // Initialize the BUILTIN_LED pin as an output
    Serial.begin(115200);
    setup_wifi();
    client.setServer(mqtt_server, 1883);
    client.setCallback(callback);
}

void loop() {
    if (!client.connected()) {
        reconnect();
    }
    client.loop();

    unsigned long now = millis();
    if (now - lastMsg > 2000) {
        lastMsg = now;
        ++value;
        snprintf(msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
        Serial.print("Publish message: ");
        Serial.println(msg);
        client.publish("outTopic", msg);
    }
}
