#include <SD.h>
#include <SPI.h>
#include <esp_sleep.h>

// PIR sensor pin
const int pirPin = 13;
// LED pin
const int ledPin = 27;
// SD card CS pin
const int chipSelect = 5;

// Variables to store PIR state, LED brightness, and time
volatile bool motionDetected = false;
int ledBrightness = 255; // Default maximum brightness
unsigned long lastMotionTime = 0;
const unsigned long motionDelay = 5000; // Delay after motion (in milliseconds)

// Task handles
TaskHandle_t backgroundTaskHandle = NULL;

void backgroundTask(void *pvParameters) {
  for (;;) {
    // Your background tasks go here
    // Save LED brightness to SD card
    saveBrightnessToSD();

    // Check if it's time to turn off the LED
    if (millis() - lastMotionTime > motionDelay && digitalRead(ledPin) == HIGH) {
      Serial.println("Turning off LED...");
      analogWrite(ledPin, 0); // Turn off the LED
      delay(10); // Give a short delay to ensure the LED is off

      Serial.println("Entering deep sleep...");
      esp_sleep_enable_ext0_wakeup(GPIO_NUM_13, HIGH);
      esp_deep_sleep_start();
    }

    vTaskDelay(1000 / portTICK_PERIOD_MS); // Adjust the delay as needed
  }
}

void saveBrightnessToSD() {
  File file = SD.open("/brightness.txt", FILE_WRITE);
  if (file) {
    file.print(ledBrightness);
    file.close();
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(pirPin, INPUT);
  pinMode(ledPin, OUTPUT);

  // Initialize SD card
  if (!SD.begin(chipSelect)) {
    Serial.println("An Error has occurred while mounting SD card");
    return;
  }

  // Check if there's a stored brightness value on the SD card
  File file = SD.open("/brightness.txt", FILE_READ);
  if (file) {
    ledBrightness = file.parseInt();
    file.close();
  } else {
    // If the file doesn't exist, write an initial brightness value
    saveBrightnessToSD();
  }

  // Attach interrupt to PIR sensor
  attachInterrupt(digitalPinToInterrupt(pirPin), motionInterrupt, HIGH);

  // Create a background task
  xTaskCreatePinnedToCore(
    backgroundTask,      // Function to run the task
    "BackgroundTask",    // Name of the task
    10000,               // Stack size (adjust as needed)
    NULL,                // Parameter to pass to the task
    1,                   // Task priority
    &backgroundTaskHandle, // Task handle
    0                    // Core to run the task on (0 or 1)
  );
}

void loop() {
  // Enter deep sleep if no motion detected for a certain time
  if (millis() - lastMotionTime > motionDelay && digitalRead(ledPin) == LOW) {
    Serial.println("Entering deep sleep...");
    esp_sleep_enable_ext0_wakeup(GPIO_NUM_13, HIGH);
    esp_deep_sleep_start();
  }

  // No need to check for motion here as it's handled in the interrupt
}

void motionInterrupt() {
  // PIR sensor triggered the interrupt
  motionDetected = true;
  lastMotionTime = millis(); // Record the time of the last motion

  // Turn on LED
  Serial.println("Turning on LED...");
  analogWrite(ledPin, ledBrightness);
  digitalWrite(ledPin, HIGH);
}