/*
 * Authors: * Erwin Ried (http://erwin.ried.cl)
 *          * Felipe Astroza (http://astroza.cl)
 * 
 */
 
#define LED_PIN 13
#define SENSOR_PIN 0
#define BUTTON_PIN 12
#define THRESHOLD  100
#define LATENCY 10
#define SEND_INTERVAL  1000
#define FIRST 0x1
#define SECOND 0x2

int state = FIRST;
unsigned long last_sent;
int present_laser;
int cajas = 0;
boolean cajas_dirty = 1;
boolean first_time = true;

void calibrate()
{ 
  digitalWrite(LED_PIN, HIGH);
  while(digitalRead(BUTTON_PIN) != LOW);
  present_laser = analogRead(SENSOR_PIN);
  digitalWrite(LED_PIN, LOW);
}

void blink(int ms)
{
  digitalWrite(LED_PIN, HIGH);
  delay(ms);
  digitalWrite(LED_PIN, LOW);
}

void blink(int ms, int repeats)
{
  for(int i=0;i<repeats;i++)
  {
    blink(ms/2);
    delay(ms/2);
  }
}

void setup()
{
  /* Initialization
  //Serial.print(0x00,BYTE); 
  //Serial.print("\\<< #131 #64 BLANK PICT STO { #0 #0 } PVIEW \\>> 'CC' STO CC");
  
  // RUTINAS HP
  // CC: Limpia
  // CT: Cajas
  // ST: Calibrar
  // REA: Ready
  // SC: Main screen
 
  //Serial.print(0x00,BYTE);
  //Serial.print("\\<< PICT { #2 #2 } \"CALIBRATION ROUTINE\" 2 \\->GROB REPL 1000 0.2 BEEP 2000 0.1 BEEP ");
  //Serial.print(0x00,BYTE);
  //Serial.print("PICT { #2 #20 } \"Set the laser and press the\" 1 \\->GROB REPL ");
  //Serial.print("PICT { #2 #29 } \"calibration button to begin.\" 1 \\->GROB REPL \\>> 'ST' STO"); 
  //Serial.print(0x00,BYTE);
  //Serial.print("\\<< PICT { #2 #48 } \"...READY\" 2 \\->GROB REPL 1000 0.2 BEEP 2000 0.1 BEEP \\>> 'RE' STO");
  //Serial.print(0x00,BYTE);
  //Serial.print("\\<< CC PICT { #2 #2 } \"Laser counting test\" 2 \\->GROB REPL  PICT { #2 #13 } \"The objects are being counted.\" 1 \\->GROB REPL 1000 0.2 BEEP 2000 0.1 BEEP \\>> 'SC' STO");
  //delay(16000);
  //Serial.print(0x00,BYTE);
  //Serial.print("\\<< \"OBJECTS: \" SWAP + 2 \\->GROB PICT SWAP { #10 #40 } SWAP REPL 2000 0.1 BEEP \\>> 'CT' STO 0 CT"); // */
  
  
  Serial.begin(9600);
   
  pinMode(BUTTON_PIN,INPUT);
  pinMode(LED_PIN,OUTPUT);
  
  Serial.print(0x00,BYTE);
  Serial.print("ST");
  calibrate();
  
  Serial.print(0x00,BYTE);
  Serial.print("REA");
  delay(1000);
  
  Serial.print(0x00,BYTE);
  Serial.print("SC");

  blink(100,5);
  last_sent = millis();
}

inline int is_present()
{
  delay(LATENCY);
  int val = analogRead(SENSOR_PIN);
  
  return val >= (present_laser - THRESHOLD) && val <= (present_laser + THRESHOLD) ? true : false;
}

inline void inc_count()
{
  blink(100);
  cajas++;
  cajas_dirty = true;
}

void notify()
{
  Serial.print(0x00,BYTE);
  Serial.print(cajas,DEC);
  Serial.print(" CT");

}

void loop()
{
  if(first_time  || ((millis() - last_sent) >= SEND_INTERVAL && cajas_dirty)) {
    first_time = false;
    cajas_dirty = false;
    notify();
    last_sent = millis();
  }
  
  switch(state) {
    case FIRST:
      if(is_present() == false)
         state = SECOND;
      break;
   case SECOND:
     if(is_present() == true) {
         state = FIRST;
         inc_count();
     }
  }
}