#include <Time.h>

#define TIME_MSG_LEN  11   // time sync to PC is HEADER followed by unix time_t as ten ascii digits
#define TIME_HEADER  'T'   // Header tag for serial time sync message
#define TIME_REQUEST  7    // ASCII bell character requests a time sync message 
int dataPin  = 11;
int latchPin = 12;
int clockPin = 13;

int ledPins[] = {10,9,8,7,6,5,4,3,2};
boolean ledStatus[9];
byte data = 0;

void setup()
{
  for(int i=2;i<=13;i++)
    pinMode(i, OUTPUT);
  pinMode(0, INPUT);
  pinMode(1, INPUT);
  
  Serial.begin(57600);
  set(0, false);
  setSyncProvider(requestSync);
}

void loop()
{
  if(Serial.available())
    processSyncMessage();
  if(timeStatus()!= timeNotSet)
    showTime();
  dimmer();
}

void showTime()
{
  time_t t = now();
  for(int i=0;i<=4;i++)
    set(10-i, hour(t) & (1 << i));
  for(int i=0;i<=5;i++)
    set(16-i, minute(t) & (1 << i));
  for(int i=0;i<=5;i++)
    set(5-i, second(t) & (1 << i));
}

void dimmer()
{
  for(int i=0;i<50;i++)
  {
    turnAll();
    turnProper();
    delay(20);
  }
}

void turnAll()
{
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 255);
  digitalWrite(latchPin, HIGH);
  for(int i=0;i<9;i++)
    digitalWrite(ledPins[i], HIGH);
}

void turnProper()
{
  for(int i=0;i<9;i++)
    digitalWrite(ledPins[i], ledStatus[i]);
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, data);
  digitalWrite(latchPin, HIGH);
}

void set(int i, boolean s)
{
  if(i >= 8)
  {
    digitalWrite(ledPins[i-8], s ? HIGH : LOW);
    ledStatus[i-8] = s;
  }
  else
  {
    digitalWrite(latchPin, LOW);
    if(s)
      data = data | (1 << i);
    else
      data = data & (255 - 1 << i);
    shiftOut(dataPin, clockPin, MSBFIRST, data);
    digitalWrite(latchPin, HIGH);
  }
}

// taken from the Time library example
void processSyncMessage() {
  // if time sync available from serial port, update time and return true
  while(Serial.available() >=  TIME_MSG_LEN ){  // time message consists of a header and ten ascii digits
    char c = Serial.read() ; 
    Serial.print(c);  
    if( c == TIME_HEADER ) {       
      time_t pctime = 0;
      for(int i=0; i < TIME_MSG_LEN -1; i++){   
        c = Serial.read();          
        if( c >= '0' && c <= '9'){   
          pctime = (10 * pctime) + (c - '0') ; // convert digits to a number    
        }
      }   
      setTime(pctime);   // Sync Arduino clock to the time received on the serial port
    }  
  }
}

time_t requestSync()
{
  Serial.print(TIME_REQUEST,BYTE);
  return 0; // the time will be sent later in response to serial mesg
}