// ====== Core libs ======
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

// ====== Display ======
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// ====== DHT ======
#include "DHT.h"

// ====== Wi-Fi / AIO Credentials ======
#define WIFI_SSID   "Wokwi-GUEST"
#define WIFI_PASS   ""

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  8883            // Secure MQTT (TLS)
#define IO_USERNAME     "Username"      // <-- your Adafruit IO username
#define IO_KEY          "Key"           // <-- your Adafruit IO key

// ====== TLS root CA for io.adafruit.com ======
static const char* AIO_ROOT_CA PROGMEM =
"-----BEGIN CERTIFICATE-----\n"
"MIIEjTCCA3WgAwIBAgIQDQd4KhM/xvmlcpbhMf/ReTANBgkqhkiG9w0BAQsFADBh\n"
"MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3\n"
"d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBH\n"
"MjAeFw0xNzExMDIxMjIzMzdaFw0yNzExMDIxMjIzMzdaMGAxCzAJBgNVBAYTAlVT\n"
"MRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5j\n"
"b20xHzAdBgNVBAMTFkdlb1RydXN0IFRMUyBSU0EgQ0EgRzEwggEiMA0GCSqGSIb3\n"
"DQEBAQUAA4IBDwAwggEKAoIBAQC+F+jsvikKy/65LWEx/TMkCDIuWegh1Ngwvm4Q\n"
"yISgP7oU5d79eoySG3vOhC3w/3jEMuipoH1fBtp7m0tTpsYbAhch4XA7rfuD6whU\n"
"gajeErLVxoiWMPkC/DnUvbgi74BJmdBiuGHQSd7LwsuXpTEGG9fYXcbTVN5SATYq\n"
"DfbexbYxTMwVJWoVb6lrBEgM3gBBqiiAiy800xu1Nq07JdCIQkBsNpFtZbIZhsDS\n"
"fzlGWP4wEmBQ3O67c+ZXkFr2DcrXBEtHam80Gp2SNhou2U5U7UesDL/xgLK6/0d7\n"
"6TnEVMSUVJkZ8VeZr+IUIlvoLrtjLbqugb0T3OYXW+CQU0kBAgMBAAGjggFAMIIB\n"
"PDAdBgNVHQ4EFgQUlE/UXYvkpOKmgP792PkA76O+AlcwHwYDVR0jBBgwFoAUTiJU\n"
"IBiV5uNu5g/6+rkS7QYXjzkwDgYDVR0PAQH/BAQDAgGGMB0GA1UdJQQWMBQGCCsG\n"
"AQUFBwMBBggrBgEFBQcDAjASBgNVHRMBAf8ECDAGAQH/AgEAMDQGCCsGAQUFBwEB\n"
"BCgwJjAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuZGlnaWNlcnQuY29tMEIGA1Ud\n"
"HwQ7MDkwN6A1oDOGMWh0dHA6Ly9jcmwzLmRpZ2ljZXJ0LmNvbS9EaWdpQ2VydEds\n"
"b2JhbFJvb3RHMi5jcmwwPQYDVR0gBDYwNDAyBgRVHSAAMCowKAYIKwYBBQUHAgEW\n"
"HGh0dHBzOi8vd3d3LmRpZ2ljZXJ0LmNvbS9DUFMwDQYJKoZIhvcNAQELBQADggEB\n"
"AIIcBDqC6cWpyGUSXAjjAcYwsK4iiGF7KweG97i1RJz1kwZhRoo6orU1JtBYnjzB\n"
"c4+/sXmnHJk3mlPyL1xuIAt9sMeC7+vreRIF5wFBC0MCN5sbHwhNN1JzKbifNeP5\n"
"ozpZdQFmkCo+neBiKR6HqIA+LMTMCMMuv2khGGuPHmtDze4GmEGZtYLyF8EQpa5Y\n"
"jPuV6k2Cr/N3XxFpT3hRpt/3usU/Zb9wfKPtWpoznZ4/44c1p9rzFcZYrWkj3A+7\n"
"TNBJE0GmP2fhXhP1D/XVfIW/h0yCJGEiV9Glm/uGOa3DXHlmbAcxSyCRraG+ZBkA\n"
"7h4SeM6Y8l/7MBRpPCz6l8Y=\n"
"-----END CERTIFICATE-----\n";

// ====== MQTT client ======
WiFiClientSecure secureClient;
Adafruit_MQTT_Client mqtt(&secureClient, AIO_SERVER, AIO_SERVERPORT, IO_USERNAME, IO_KEY);

// ====== MQTT Feeds ======
Adafruit_MQTT_Publish statusPub      = Adafruit_MQTT_Publish(&mqtt, IO_USERNAME "/feeds/status");
Adafruit_MQTT_Publish valuePub       = Adafruit_MQTT_Publish(&mqtt, IO_USERNAME "/feeds/value");
Adafruit_MQTT_Publish percentPub     = Adafruit_MQTT_Publish(&mqtt, IO_USERNAME "/feeds/percent");
Adafruit_MQTT_Publish temperaturePub = Adafruit_MQTT_Publish(&mqtt, IO_USERNAME "/feeds/temperature");
Adafruit_MQTT_Publish humidityPub    = Adafruit_MQTT_Publish(&mqtt, IO_USERNAME "/feeds/humidity");

// ====== OLED ======
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// ====== Pins ======
#define RED     18
#define GREEN   19
#define BLUE    23
#define BUZZER  14
#define POT     34

// ====== DHT ======
#define DHTPIN   13
#define DHTTYPE  DHT11
DHT dht(DHTPIN, DHTTYPE);

// ====== LED Type ======
const bool COMMON_ANODE = false; // true if LED common goes to 3.3V

// ====== Thresholds ======
#define DRY_THRESHOLD  1365  // ~33% of 4095
#define WET_THRESHOLD  2730  // ~66% of 4095

// ====== Publish cadence / change detection ======
const unsigned long PUBLISH_MIN_MS = 2000;
unsigned long lastPublishMs = 0;
String lastStatus = "";
int    lastValue  = -1;
int    lastPct    = -1;

// ====== Helpers ======
void setColor(bool r, bool g, bool b) {
  auto drive = [](int pin, bool on, bool commonAnode) {
    if (commonAnode) digitalWrite(pin, on ? LOW : HIGH);
    else             digitalWrite(pin, on ? HIGH : LOW);
  };
  drive(RED,   r, COMMON_ANODE);
  drive(GREEN, g, COMMON_ANODE);
  drive(BLUE,  b, COMMON_ANODE);
}

void showMessage(const __FlashStringHelper* message, int value, int pct) {
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 8);
  display.println(message);

  display.setTextSize(1);
  display.setCursor(0, 40);
  display.print(F("Value: "));
  display.println(value);

  display.setCursor(0, 52);
  display.print(F("Percent: "));
  display.print(pct);
  display.println('%');
  display.display();
}

void mqttConnect() {
  if (mqtt.connected()) return;
  int8_t ret;
  uint8_t retries = 5;
  while ((ret = mqtt.connect()) != 0) {
    mqtt.disconnect();
    delay(2000);
    if (!--retries) return;
  }
}

void publishIfChanged(const String& status, int value, int pct, float tC, float h) {
  unsigned long now = millis();
  bool changed = (status != lastStatus) || (value != lastValue) || (pct != lastPct);
  bool timeOk  = (now - lastPublishMs) >= PUBLISH_MIN_MS;

  if (!timeOk) return;
  if (!mqtt.connected()) mqttConnect();
  if (!mqtt.connected()) return;

  if (changed) {
    statusPub.publish(status.c_str());
    valuePub.publish((int32_t)value);   // explicit to avoid overload ambiguity
    percentPub.publish((int32_t)pct);   // explicit to avoid overload ambiguity
    lastStatus = status;
    lastValue  = value;
    lastPct    = pct;
  }
  if (!isnan(tC)) temperaturePub.publish((double)tC);
  if (!isnan(h))  humidityPub.publish((double)h);

  lastPublishMs = now;
}

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

  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  setColor(false, false, false);

#if defined(ESP32)
  analogReadResolution(12); // 0..4095
#endif

  // I2C and OLED
  Wire.begin(21, 22); // SDA=21, SCL=22 on ESP32 by default
  if (display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.println(F("WiFi connecting..."));
    display.display();
  }

  // Wi-Fi
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(250);
  }

  // Secure MQTT
  secureClient.setCACert(AIO_ROOT_CA);
  // If TLS is problematic in sim, you can temporarily use:
  // secureClient.setInsecure(); // (not recommended for production)

  // DHT
  dht.begin();

  if (display.width()) {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println(F("WiFi OK. MQTT..."));
    display.display();
  }

  mqttConnect();

  if (display.width()) {
    display.clearDisplay();
    display.setCursor(0, 0);
    display.println(mqtt.connected() ? F("MQTTS connected") : F("MQTTS failed"));
    display.display();
    delay(600);
  }
}

// ====== Loop ======
void loop() {
  // Keep MQTT alive
  if (!mqtt.connected()) mqttConnect();
  mqtt.processPackets(10);
  if (!mqtt.ping()) {
    mqtt.disconnect();
  }

  // Read sensors
  int potValue = analogRead(POT);
  int pct = map(potValue, 0, 4095, 0, 100);

  float h = dht.readHumidity();
  float t = dht.readTemperature();

  // Decide status + outputs
  String status;
  if (potValue < DRY_THRESHOLD) {
    status = "Too dry";
    setColor(true, false, false);
    tone(BUZZER, 1000);
  } else if (potValue < WET_THRESHOLD) {
    status = "Good";
    setColor(false, true, false);
    noTone(BUZZER);
  } else {
    status = "Too wet";
    setColor(false, false, true);
    tone(BUZZER, 400);
  }

  // Update OLED
  showMessage(status == "Too dry" ? F("Too dry") :
              status == "Too wet" ? F("Too wet") : F("Good"),
              potValue, pct);

  // Publish (rate-limited, only changed for pot-derived data; DHT always if valid)
  publishIfChanged(status, potValue, pct, t, h);

  delay(200);
}