#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>

// --- Hardware setup ---
#define DHTPIN 15
#define DHTTYPE DHT22
#define LDRPIN 34
#define BUTTON_PIN 0

DHT dht(DHTPIN, DHTTYPE);

// --- WiFi + MQTT ---
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

// --- FreeRTOS handles ---
QueueHandle_t sensorQueue;
SemaphoreHandle_t otaSem;

// --- Data structures ---
struct SensorData {
  float temp;
  float hum;
  int light;
};

// --- Tasks ---
void SensorTask(void *pvParameters) {
  while (1) {
    SensorData data;
    data.temp = dht.readTemperature();
    data.hum = dht.readHumidity();
    data.light = analogRead(LDRPIN);
    xQueueSend(sensorQueue, &data, portMAX_DELAY);
    vTaskDelay(2000 / portTICK_PERIOD_MS);
  }
}

void MqttTask(void *pvParameters) {
  while (1) {
    if (!client.connected()) {
      while (!client.connected()) {
        if (client.connect("esp32-wokwi-demo")) {
          client.subscribe("greenhouse/cmd/ota");
        } else {
          vTaskDelay(2000 / portTICK_PERIOD_MS);
        }
      }
    }
    client.loop();

    SensorData data;
    if (xQueueReceive(sensorQueue, &data, 0) == pdTRUE) {
      char msg[100];
      sprintf(msg, "{\"temp\":%.2f,\"hum\":%.2f,\"light\":%d}", data.temp, data.hum, data.light);
      client.publish("greenhouse/telemetry", msg);
      Serial.println(msg);
    }
    vTaskDelay(5000 / portTICK_PERIOD_MS);
  }
}

void OtaTask(void *pvParameters) {
  while (1) {
    if (xSemaphoreTake(otaSem, portMAX_DELAY)) {
      Serial.println("OTA Update triggered (simulated in Wokwi)!");
      // Real OTA would use HTTP GET here
    }
  }
}

// --- MQTT callback ---
void callback(char* topic, byte* payload, unsigned int length) {
  String msg;
  for (int i = 0; i < length; i++) msg += (char)payload[i];
  if (String(topic) == "greenhouse/cmd/ota") {
    xSemaphoreGive(otaSem);
  }
}

// --- Setup ---
void setup() {
  Serial.begin(115200);
  dht.begin();
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) { delay(500); }

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);

  sensorQueue = xQueueCreate(5, sizeof(SensorData));
  otaSem = xSemaphoreCreateBinary();

  xTaskCreate(SensorTask, "SensorTask", 4096, NULL, 1, NULL);
  xTaskCreate(MqttTask, "MqttTask", 4096, NULL, 1, NULL);
  xTaskCreate(OtaTask, "OtaTask", 4096, NULL, 1, NULL);

  // Button ISR to trigger OTA
  attachInterrupt(BUTTON_PIN, []() { xSemaphoreGiveFromISR(otaSem, NULL); }, FALLING);
}

void loop() {
  // Nothing here (tasks handle everything)
}