switch relay on and send data to firestore

test_relay_with_firestore.cpp

#include <ESP8266WiFi.h>
#include <ESP8266HTTPClient.h>
#include <WiFiClientSecure.h>
#include <time.h>

const char* ssid = "<id>";
const char* password = "<pwd>";

const String FIREBASE_PROJECT_ID = "<id>";
const String API_KEY = "<api_key>";

#define RELAY_PIN D0

WiFiClientSecure client;

// =======================
// CONNECT WIFI
// =======================
void connectWiFi()
{
    WiFi.begin(ssid, password);

    Serial.print("Connecting");

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

    Serial.println("");
    Serial.println("WiFi connected");
}

// =======================
// INIT INTERNET TIME
// =======================
void initTime()
{
    configTime(8 * 3600, 0, "pool.ntp.org", "time.nist.gov");

    Serial.print("Waiting for NTP time");

    time_t now = time(nullptr);

    while (now < 100000)
    {
        delay(500);
        Serial.print(".");

        now = time(nullptr);
    }

    Serial.println("");
    Serial.println("Time synchronized");
}

// =======================
// SEND TO FIRESTORE
// =======================
void sendToFirestore(String relayState)
{
    HTTPClient https;

    client.setInsecure();

    String url =
        "https://firestore.googleapis.com/v1/projects/" +
        FIREBASE_PROJECT_ID +
        "/databases/(default)/documents/relay_logs?key=" +
        API_KEY;

    Serial.println(url);

    // Get current timestamp
    time_t now = time(nullptr);

    Serial.print("Unix Timestamp: ");
    Serial.println(now);

    if (https.begin(client, url))
    {
        https.addHeader("Content-Type", "application/json");

        String payload =
            "{"
            "\"fields\": {"
                "\"status\": {"
                    "\"stringValue\": \"" + relayState + "\""
                "},"
                "\"last_on_timestamp\": {"
                    "\"integerValue\": \"" + String((long)now) + "\""
                "}"
            "}"
            "}";

        Serial.println(payload);

        int httpCode = https.POST(payload);

        Serial.print("HTTP Response: ");
        Serial.println(httpCode);

        String response = https.getString();

        Serial.println(response);

        https.end();
    }
    else
    {
        Serial.println("HTTPS connection failed");
    }
}

// =======================
// SETUP
// =======================
void setup()
{
    Serial.begin(115200);

    pinMode(RELAY_PIN, OUTPUT);

    connectWiFi();

    initTime();
}

// =======================
// LOOP
// =======================
void loop()
{
    // Relay ON
    digitalWrite(RELAY_PIN, HIGH);

    Serial.println("Relay ON");

    sendToFirestore("ON");

    delay(5000);

    // Relay OFF
    digitalWrite(RELAY_PIN, LOW);

    Serial.println("Relay OFF");

    delay(3600000); // 1 hour
}