int SER_Pin = 0;   // blue
int RCLK_Pin = 1;  // green
int SRCLK_Pin = 2; // yellow
int PWM_Pin = 11;  // black
int BTN_Pin = 4; // orange

#define number_of_74hc595s 1
#define number_of_leds 8
#define numOfRegisterPins number_of_74hc595s * 8

boolean registers[numOfRegisterPins];
int buttonState = 0;
boolean cocked = false;

void setup() {
  // put your setup code here, to run once:
  pinMode(SER_Pin, OUTPUT);
  pinMode(RCLK_Pin, OUTPUT);
  pinMode(SRCLK_Pin, OUTPUT);
  pinMode(PWM_Pin, OUTPUT);
  pinMode(BTN_Pin, INPUT);
  effect_testLights();

  clearRegisters();
  writeRegisters();

}


void loop() {


  // read the state of the pushbutton value:
  buttonState = digitalRead(BTN_Pin);

  // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
  if (buttonState == HIGH) {
    if (!cocked){
      effect_brightness();
      cocked = true;
    } else {
      effect_fastflash();
    }
  } else {
    if (cocked) {
      effect_launch();
    }
  }

}

void effect_fastflash(){
  clearRegisters();
  writeRegisters();
  delay(100);
  setRegisterPin(7, HIGH);
  writeRegisters();
  delay(100);
}

void effect_launch() {

  for (int i = 6; i >= 0; i--) {
    clearRegisters();
    setRegisterPin(i+1, HIGH);
    setRegisterPin(i, HIGH);
    writeRegisters();
    delay(100);
  }
  clearRegisters();
  writeRegisters();
  cocked = false;
}

void effect_brightness() {
  int len, amt;

  for (len = 0; len < number_of_leds; ++len) {
    setRegisterPin(len, LOW);
  }
  writeRegisters();
  setRegisterPin(7, HIGH);
  writeRegisters();
  for (amt = 255; amt > 1; amt-=1) {
    analogWrite(PWM_Pin, amt);
    delay(10);
  }
}



void effect_testLights() {
  int len, i;

  for (len = 0; len < number_of_leds; ++len) {
    clearRegisters();
    setRegisterPin(len, HIGH);
    writeRegisters();
    delay(125);
  }

  for (i = 0; i < 2; i++) {
    clearRegisters();
    for (len = 0; len < number_of_leds; ++len) {
      setRegisterPin(len, HIGH);
    }
    writeRegisters();
    delay(500);
    clearRegisters();
    writeRegisters();
    delay(500);
  }


}







////////////////////////////////
// SHIFT REGISTER
////////////////////////////////

// Set and display registers
// Only call AFTER all values are set how you would like (slow otherwise)
void writeRegisters(){
  digitalWrite(RCLK_Pin, LOW);
  for(int i = numOfRegisterPins - 1; i >=  0; i--){
    digitalWrite(SRCLK_Pin, LOW);
    int val = registers[i];
    digitalWrite(SER_Pin, val);
    digitalWrite(SRCLK_Pin, HIGH);
  }
  digitalWrite(RCLK_Pin, HIGH);
}
// set an individual pin HIGH or LOW
void setRegisterPin(int index, int value){
  registers[index] = value;
}
// set all register pins to LOW
void clearRegisters(){
  for(int i = numOfRegisterPins - 1; i >=  0; i--){
     registers[i] = LOW;
  }
}