#include <WiFi.h>
#include <HTTPClient.h>
#include "DHTesp.h"
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1

#define LED_PIN 2
#define DHT_PIN 15

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

DHTesp dht;

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

// ===== THINGSPEAK =====
String writeApiKey = "66P5HDZKJII66MKC";
String serverUrl = "https://api.thingspeak.com/update";

unsigned long lastSend = 0;
const unsigned long SEND_INTERVAL = 2000; // 2 detik

// ================= OLED FUNCTION =================

void tampilOLED(float suhu, float hum,
                String wifiStatus,
                String sendStatus,
                String httpInfo)
{
  display.clearDisplay();

  display.setTextSize(1);
  display.setCursor(0,0);

  display.println("Monitoring IoT");

  display.print("T:");
  display.print(suhu,1);
  display.println(" C");

  display.print("H:");
  display.print(hum,1);
  display.println(" %");

  display.println("----------------");

  display.print("WiFi : ");
  display.println(wifiStatus);

  display.print("Send : ");
  display.println(sendStatus);

  display.print("HTTP : ");
  display.println(httpInfo);

  display.display();
}

// ================= WIFI CONNECT =================

void connectWiFi()
{
  Serial.print("Menghubungkan WiFi");

  WiFi.begin(ssid, password);

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

  Serial.println("\n✅ WiFi Connected");
}

// ================= SETUP =================

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

  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  dht.setup(DHT_PIN, DHTesp::DHT22);

  Wire.begin();

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);

  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  display.setCursor(0,0);
  display.println("ESP32 Starting...");
  display.display();

  connectWiFi();

  delay(2000);
}

// ================= LOOP =================

void loop()
{
  if(millis() - lastSend < SEND_INTERVAL)
    return;

  lastSend = millis();

  TempAndHumidity data = dht.getTempAndHumidity();

  float suhu = data.temperature;
  float hum = data.humidity;

  // ==== VALIDASI SENSOR ====

  if(isnan(suhu) || isnan(hum))
  {
    Serial.println("❌ DHT22 ERROR");

    tampilOLED(0,0,
      "Connected",
      "Sensor Error",
      "-");

    digitalWrite(LED_PIN, LOW);

    return;
  }

  String wifiStatus =
    (WiFi.status()==WL_CONNECTED) ?
    "Connected" : "Disconnected";

  // ==== WIFI CHECK ====

  if(WiFi.status()!=WL_CONNECTED)
  {
    Serial.println("WiFi Putus!");

    digitalWrite(LED_PIN, LOW);

    tampilOLED(
      suhu,
      hum,
      "Disconnected",
      "Fail",
      "-"
    );

    connectWiFi();

    return;
  }

  // ==== BUILD URL ====

  String url = serverUrl +
  "?api_key=" + writeApiKey +
  "&field1=" + String(suhu,2) +
  "&field2=" + String(hum,2);

  HTTPClient http;

  http.begin(url);

  int httpCode = http.GET();

  String payload = http.getString();

  http.end();

  // ==== SERIAL MONITOR ====

  Serial.println("====== SEND DATA ======");

  Serial.println(url);

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

  Serial.print("Response : ");
  Serial.println(payload);

  // ==== VALIDASI RESPONSE ====

  String sendStatus="Fail";
  String httpInfo="-";

  if(httpCode > 0)
  {
    httpInfo = String(httpCode);

    if(payload.toInt() > 0)
    {
      Serial.println("✅ BERHASIL");

      sendStatus="Success";

      // LED BLINK
      digitalWrite(LED_PIN,HIGH);
      delay(200);
      digitalWrite(LED_PIN,LOW);
    }
    else
    {
      Serial.println("⚠ Response 0 ERROR");

      sendStatus="Resp=0";

      digitalWrite(LED_PIN,LOW);
    }
  }
  else
  {
    Serial.print("HTTP ERROR : ");
    Serial.println(httpCode);

    sendStatus="HTTP Fail";

    httpInfo = String(httpCode);

    digitalWrite(LED_PIN,LOW);
  }

  // ==== OLED DISPLAY ====

  tampilOLED(
    suhu,
    hum,
    wifiStatus,
    sendStatus,
    httpInfo
  );
}