#include <Arduino.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <freertos/semphr.h>
#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Define the LED, LDR, PIR sensor, Buzzer, Temperature Sensor, and Stepper Motor pins
#define LED1_PIN 4
#define LDR_PIN 14
#define PIR_PIN 13
#define BUZZER_PIN 12
#define DHT_PIN 15
#define DIRECTION_PIN 26 // ESP32 pin for direction
#define STEP_PIN 25      // ESP32 pin for step
#define LED_PIN 2        // Onboard LED for ESP32

// PID constants
float Kp = 2.0;
float Ki = 0.5;
float Kd = 1.0;

// Define the DHT sensor type
#define DHT_TYPE DHT22
DHT dht(DHT_PIN, DHT_TYPE);

// Initialize the LCD with the I2C address 0x27 and dimensions 16x2
LiquidCrystal_I2C lcd(0x27, 16, 2);

// PID control variables
float setpoint = 26.0; // Desired temperature setpoint
float previousError = 0;
float integral = 0;
unsigned long lastTime = 0;

// Create mutexes for accessing shared resources
SemaphoreHandle_t dhtMutex;
SemaphoreHandle_t lcdMutex;
SemaphoreHandle_t motorMutex;

// Task 1 function - Monitors Temperature and Humidity
void Task1(void *parameter) {
  dht.begin();  // Initialize the DHT sensor
  while (1) {
    if (xSemaphoreTake(dhtMutex, portMAX_DELAY)) {
      float temperature = dht.readTemperature(); // Read temperature in Celsius
      float humidity = dht.readHumidity();       // Read humidity percentage

      if (isnan(temperature) || isnan(humidity)) {
        Serial.println("Failed to read from DHT sensor!");
      } else {
        Serial.print("Temperature: ");
        Serial.print(temperature);
        Serial.print(" °C, Humidity: ");
        Serial.print(humidity);
        Serial.println(" %");
        if (humidity < 0 || humidity > 100) {
          Serial.println("Warning: Humidity out of expected range.");
        }
      }
      xSemaphoreGive(dhtMutex);
    }
    vTaskDelay(2000 / portTICK_PERIOD_MS); // Run every 2 seconds
  }
}


// Task 2 function - Controls LED1 based on LDR input
void Task2(void *parameter) {
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LDR_PIN, INPUT);

  while (1) {
    int ldrValue = digitalRead(LDR_PIN);
    Serial.print("LDR Value: ");
    Serial.println(ldrValue);

    if (ldrValue == LOW) { // Low light (low lux value)
      digitalWrite(LED1_PIN, HIGH);  // Turn on LED1 when it's dark
    } else {                          // High light (high lux value)
      digitalWrite(LED1_PIN, LOW);   // Turn off LED1 when there's light
    }
    vTaskDelay(1000 / portTICK_PERIOD_MS); // Run every 1 second
  }
}

// Task 3 function - Controls Buzzer based on PIR sensor input
void Task3(void *parameter) {
  pinMode(PIR_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  while (1) {
    if (digitalRead(PIR_PIN) == HIGH) {
      digitalWrite(BUZZER_PIN, HIGH);  // Turn on the Buzzer if motion is detected
    } else {
      digitalWrite(BUZZER_PIN, LOW);   // Turn off the Buzzer if no motion
    }
    vTaskDelay(500 / portTICK_PERIOD_MS); // Run every 500 milliseconds
  }
}

// Task 4 function - Displays Temperature on I2C LCD
void Task4(void *parameter) {
  lcd.init();       // Initialize the LCD
  lcd.backlight();  // Turn on the LCD backlight

  while (1) {
    if (xSemaphoreTake(dhtMutex, portMAX_DELAY)) {
      float temperature = dht.readTemperature(); // Read temperature in Celsius
      xSemaphoreGive(dhtMutex);

      lcd.clear();  // Clear the LCD screen
      lcd.setCursor(0, 0);  // Set cursor to the first line
      lcd.print("Temp: ");
      lcd.print(temperature);
      lcd.print(" C");
    }
    vTaskDelay(2000 / portTICK_PERIOD_MS); // Update every 2 seconds
  }
}

// Task 5 function - Controls the Stepper Motor using PID based on Temperature
void Task5(void *parameter) {
  pinMode(DIRECTION_PIN, OUTPUT);
  pinMode(STEP_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);

  while (1) {
    float temperature;
    if (xSemaphoreTake(dhtMutex, portMAX_DELAY)) {
      temperature = dht.readTemperature(); // Read temperature in Celsius
      xSemaphoreGive(dhtMutex);
    }

    if (!isnan(temperature)) {
      // Calculate PID error
      float error = setpoint - temperature;
      integral += error;
      float derivative = error - previousError;
      float output = Kp * error + Ki * integral + Kd * derivative;
      previousError = error;

      // Determine motor direction based on temperature difference
      if (temperature > 27.0) {
        digitalWrite(DIRECTION_PIN, HIGH);  // Open window if temperature is too high
      } else if (temperature < 25.0) {
        digitalWrite(DIRECTION_PIN, LOW);   // Close window if temperature is too low
      } else {
        output = 0;  // No movement if temperature is within the range
      }

      int steps = abs(output); // Get absolute steps
      if (xSemaphoreTake(motorMutex, portMAX_DELAY)) {
        for (int n = 0; n < steps; n++) {
          digitalWrite(STEP_PIN, HIGH);
          delayMicroseconds(20);
          digitalWrite(STEP_PIN, LOW);
          delay(10);
          digitalWrite(LED_PIN, !digitalRead(LED_PIN)); // Flash LED
        }
        xSemaphoreGive(motorMutex);
      }
    }
    vTaskDelay(100 / portTICK_PERIOD_MS); // Run every 100 milliseconds
  }
}

// Task 6 function - Monitors System Health
void Task6(void *parameter) {
  while (1) {
    // Check if other tasks are running (simplified version)
    Serial.println("Monitoring system health...");
    // Here you could add checks or logs for specific task statuses if applicable
    vTaskDelay(5000 / portTICK_PERIOD_MS); // Run every 5 seconds
  }
}

void setup() {
  // Initialize Serial for debugging
  Serial.begin(115200);

  // Initialize LEDs and DHT sensor
  pinMode(LED1_PIN, OUTPUT);
  digitalWrite(LED1_PIN, LOW);
  dht.begin();

  // Create mutexes
  dhtMutex = xSemaphoreCreateMutex();
  lcdMutex = xSemaphoreCreateMutex();
  motorMutex = xSemaphoreCreateMutex();

  // Create Tasks
  xTaskCreate(Task1, "Task1", 10000, NULL, 0, NULL); // Temperature & Humidity Monitoring
  xTaskCreate(Task2, "Task2", 10000, NULL, 1, NULL); // LED Control
  xTaskCreate(Task3, "Task3", 10000, NULL, 2, NULL); // Motion Detection and Security Alert
  xTaskCreate(Task4, "Task4", 10000, NULL, 1, NULL); // User Interface (LCD Display)
  xTaskCreate(Task5, "Task5", 10000, NULL, 1, NULL); // Motor Control with PID
  xTaskCreate(Task6, "Task6", 10000, NULL, 3, NULL); // System Health Monitoring
}

void loop() {
  // Empty loop
}