#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"
#include "esp_log.h"

void IRAM_ATTR motion_sensor_isr_handler(void* arg);

#define MOTION_SENSOR_PIN 4  //Motion sensor connected to GPIO4 (JI)
#define LED_PIN 2            //LED connected to GPIO2 (JI)

// Global flags for ISR
bool motionStateChanged = false;  //Flag to indicate the sensor state has changed. (JI)
bool isMotionDetected = false;    //Flag to track if motion is currently detected. (JI)

void app_main() {
  //Configure motion sensor pin as input with pull-up resistor
  gpio_set_direction(MOTION_SENSOR_PIN, GPIO_MODE_INPUT);
  gpio_set_pull_mode(MOTION_SENSOR_PIN, GPIO_PULLUP_ONLY);

  //Set interrupts to trigger on both rising and falling edges. (JI)
  gpio_set_intr_type(MOTION_SENSOR_PIN, GPIO_INTR_ANYEDGE);

  
  gpio_set_direction(LED_PIN, GPIO_MODE_OUTPUT); //Configure LED pin as output. (JI)
  gpio_set_pull_mode(LED_PIN, GPIO_PULLUP_ONLY); //Configure LED pin as output with pull-up resistor. (JI)

  gpio_set_level(LED_PIN, 0);  //Initially set the LED value to zero. (JI)

  //Install ISR service (interrupt handling)
  gpio_install_isr_service(0);

  //Attaching ISR handler to MOTION_SENSOR. (JI)
  gpio_isr_handler_add(MOTION_SENSOR_PIN, motion_sensor_isr_handler, NULL); //

  while (1) {
    
    if (motionStateChanged) { //Checking if the motion state has changed. (JI)
      motionStateChanged = false;  //Reset flag.

      if (isMotionDetected) { //If motion is detected, print a message and turn on the LED. (JI)
        printf("Motion Detected!\n");
        gpio_set_level(LED_PIN, 1);  
      } else { //If motion is not detected, print a message and turn off the LED. (JI)
        printf("No Motion Detected.\n"); 
        gpio_set_level(LED_PIN, 0);  
      }
    }

    printf("Main loop running...\n");
    vTaskDelay(pdMS_TO_TICKS(500)); 
  }
}

//Interrupt Service Routine (ISR)
void IRAM_ATTR motion_sensor_isr_handler(void* arg) {
 
  int sensor_state = gpio_get_level(MOTION_SENSOR_PIN);  //Read the current state of the motion sensor pin and store the value in sensor_state. (JI)

  isMotionDetected = (sensor_state == 1); //If sensor_state is HIGH, motion is detected. (JI)

  motionStateChanged = true;   //Set flag to TRUE so program can enter the "motionStateChanged" code block in the main program to print a message of motion detected or not. (JI)
}