#include <Arduino_FreeRTOS.h>
#include <semphr.h>  // add the FreeRTOS functions for Semaphores (or Flags).
#include <Servo.h> // Servo Library *Gutus


Servo myservo;  // create servo object to control a servo

// Declare a mutex Semaphore Handle which we will use to manage the Serial Port.
// It will be used to ensure only one Task is accessing this resource at any time.
SemaphoreHandle_t xSerialSemaphore;
int sensorPin = A0;
int sensorValue = 0;
int servoValue = 0;
bool SelenoidNC = false;

// define two Tasks for DigitalRead & AnalogRead Sub routine
void TaskDigitalRead( void *pvParameters );
void TaskAnalogRead( void *pvParameters );
void displayMonitor( void *pvParameters);
void servoTask( void *pvParameters);

// the setup function runs once when you press reset or power the board
void setup() {

  // Servo initialization
  myservo.attach(9);  // no 9 for servo

  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
  
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB, on LEONARDO, MICRO, YUN, and other 32u4 based boards.
  }

  // Semaphores are useful to stop a Task proceeding, where it should be paused to wait,
  // because it is sharing a resource, such as the Serial port.
  // Semaphores should only be used whilst the scheduler is running, but we can set it up here.
  if ( xSerialSemaphore == NULL )  // Check to confirm that the Serial Semaphore has not already been created.
  {
    xSerialSemaphore = xSemaphoreCreateMutex();  // Create a mutex semaphore we will use to manage the Serial Port
    if ( ( xSerialSemaphore ) != NULL )
      xSemaphoreGive( ( xSerialSemaphore ) );  // Make the Serial Port available for use, by "Giving" the Semaphore.
  }

  // Now set up two Tasks to run independently.
  xTaskCreate(
    TaskDigitalRead
    ,  "DigitalRead - Emergency Button"  // A name just for humans
    ,  128  // This stack size can be checked & adjusted by reading the Stack Highwater
    ,  NULL //Parameters for the task
    ,  1  // Priority, with 3 (configMAX_PRIORITIES - 1) being the highest, and 0 being the lowest.
    ,  NULL ); //Task Handle

  xTaskCreate(
    TaskAnalogRead
    ,  "AnalogRead - Flow Meter" // A name just for humans
    ,  128  // Stack size
    ,  NULL //Parameters for the task
    ,  2  // Priority
    ,  NULL ); //Task Handle

  xTaskCreate(displayMonitor, "Display -  Monitoring", 128, NULL, 4, NULL);
  xTaskCreate(servoTask, "Display -  Monitoring", 128, NULL, 3, NULL);
  // Now the Task scheduler, which takes over control of scheduling individual Tasks, is automatically started.
}

void loop()
{
  // Empty. Things are done in Tasks.
}

/*--------------------------------------------------*/
/*---------------------- Tasks ---------------------*/
/*--------------------------------------------------*/

void TaskDigitalRead( void *pvParameters __attribute__((unused)) )  // This is a Task.
{
  /*
    DigitalReadSerial
    Reads a digital input on pin 2, prints the result to the serial monitor

    This example code is in the public domain.
  */

  // digital pin 2 has a pushbutton attached to it. Give it a name:
  uint8_t pushButton = 0;

  // make the pushbutton's pin an input:
  pinMode(pushButton, INPUT);

  for (;;) // A Task shall never return or exit.
  {
    // read the input pin:
    int buttonState = digitalRead(pushButton);

    // See if we can obtain or "Take" the Serial Semaphore.
    // If the semaphore is not available, wait 5 ticks of the Scheduler to see if it becomes free.
    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
    {
      if (buttonState == LOW){
        SelenoidNC = !SelenoidNC;
        vTaskDelay(100);
      }
      // We were able to obtain or "Take" the semaphore and can now access the shared resource.
      // We want to have the Serial Port for us alone, as it takes some time to print,
      // so we don't want it getting stolen during the middle of a conversion.
      // print out the state of the button:
      

      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.
    }

    vTaskDelay(10);  // one tick delay (15ms) in between reads for stability
  }
}

void TaskAnalogRead( void *pvParameters __attribute__((unused)) )  // This is a Task.
{
  for (;;)
  {
    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
    {
      sensorValue = analogRead(sensorPin);
      //sensorValue = map(sensorValue, 0, 1024, 0, 101);// map sensorValue to 0-1024 as 1-100 percentage
      if(SelenoidNC == true){
        sensorValue = 0;
      }
      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.
    }

    vTaskDelay(10);  // one tick delay (15ms) in between reads for stability
  }
}

void servoTask( void *pvParameters __attribute__((unused)) )  // This is a Task.
{

  for (;;)
  {
    int K = 1; //initial K=1 for Direct Acting, and K= -1 for Reverse Acting
    servoValue = sensorValue * K; //Equation to dertermina servoValue
    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
    {
      servoValue = map(servoValue, 0, 1024, 0, 181);// map servoValue to 0-100% as 1-180 degree
      
      myservo.write(servoValue); //output sensorValue as servoValue

      if(SelenoidNC == true){
        myservo.write(0);
      }
      
      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.
    }

    vTaskDelay(10);  // one tick delay (15ms) in between reads for stability
  }
}

void displayMonitor( void *pvParameters __attribute__((unused)) )  // This is a Task.
{
  for(;;)
  {
    if ( xSemaphoreTake( xSerialSemaphore, ( TickType_t ) 5 ) == pdTRUE )
    {
      if (!SelenoidNC){
        Serial.print("Emergency Status : "); 
        Serial.println(" SAFE");
        Serial.print("Flow Meter Value (%):\t"); 
        Serial.print(sensorValue);// print Flow Meter Value
        Serial.print(" Servo  Value (deg):\t"); 
        Serial.println(servoValue); //print Servo Degree Value
      }else{
        Serial.print("Emergency Status :\t"); 
        Serial.println("ALERT!!!");
      }
            
      xSemaphoreGive( xSerialSemaphore ); // Now free or "Give" the Serial Port for others.
    }
    vTaskDelay(pdMS_TO_TICKS(1000));  // one tick delay (15ms) in between reads for stability
  }
}