#include <WiFi.h>
#include <ThingSpeak.h>
#include "time.h"

#define DO_PIN 35    // LDR DO output
#define LED_PIN 33   // LED pin

const char* ssid     = "Wokwi-GUEST";
const char* password = "";

// ThingSpeak channel info (user provided)
unsigned long myChannelNumber = 2272204UL;
const char* myWriteAPIKey = "E8I7Z8Q88LSYNJDJ";

WiFiClient client;

// NTP server and timezone (IST)
const char* ntpServer = "pool.ntp.org";
const long  gmtOffset_sec = 19800; // +5:30
const int   daylightOffset_sec = 0;

// ThingSpeak upload interval (ms)
const unsigned long uploadInterval = 20000UL; // 20 seconds
unsigned long lastUpload = 0;

void setup() {
  Serial.begin(115200);

  pinMode(DO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  // Connect to WiFi
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(300);
    Serial.print(".");
  }
  Serial.println();
  Serial.println("WiFi connected");

  // Init NTP
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);

  // Init ThingSpeak
  ThingSpeak.begin(client);
}

void loop() {
  // Get current local time
  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    Serial.println("Failed to obtain time");
    // still continue, but skip time-based checks for now
  }

  int hourNow = timeinfo.tm_hour;   // 0-23
  int minuteNow = timeinfo.tm_min;

  // Read LDR digital output
  int lightState = digitalRead(DO_PIN); // 0 = dark, 1 = bright

  // Define night window 18:00 - 05:59
  bool isNightTime = (hourNow >= 18 || hourNow < 6);

  // Determine LED state based on time + LDR
  int ledState = 0;
  if (isNightTime && lightState == 0) {
    digitalWrite(LED_PIN, HIGH);
    ledState = 1;
  } else {
    digitalWrite(LED_PIN, LOW);
    ledState = 0;
  }

  // Debug print
  Serial.printf("Time %02d:%02d | LDR DO=%d | Night=%d | LED=%d\n",
                hourNow, minuteNow, lightState, isNightTime ? 1 : 0, ledState);

  // Upload to ThingSpeak at defined interval
  unsigned long now = millis();
  if (now - lastUpload >= uploadInterval) {
    lastUpload = now;

    ThingSpeak.setField(1, lightState);   // field1 = LDR DO
    ThingSpeak.setField(2, ledState);     // field2 = LED state
    ThingSpeak.setField(3, hourNow);      // field3 = hour for reference

    int response = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
    if (response == 200) {
      Serial.println("ThingSpeak: update successful");
    } else {
      Serial.printf("ThingSpeak: update failed, code=%d\n", response);
    }
  }

  delay(500); // small delay for responsiveness
}