/********************************************************
/ Learning Objectives:
/ Section One (global vars):
/   Variables
/   Types
/   Initialisation
/
/ Section Two (setup):
/   setup() in arduino
/   Pin modes
/   Brief intro to functions (ie, you can call them)
/
/ Section Three (skipping to loop):
/   loop() in arduino
/   Getting data from functions
/   Conditionals
/   Blinking without delay
/   Sending info to the real world (via an LED+digitalWrite())
/
/ Section Four (success):
/   Fill this with your own code and learning material.
/   I'd recommend a brief intro to writing functions, so maybe keep
/   success() simple for now
/
/ Section Five (bang):
/   As above. Introduce sound, maybe?
/   Building on simple functions.
/
/ Section Six (attachInterrupt from setup, also check())
/   Groups of variables ("arrays")
/   More conditionals
/   Further functions (return et al.)
/
/ Section 7 (Recap):
/   The sketch as The Bigger Picture
/
/*******************************************************/

// Time-related variables
volatile int period = 1000;   // Period of timer. more mistakes = faster time decrease!
int timer = 30;               // Number of periods to wait. (initially 30)
unsigned long lasttime = 0;   // Last LED change time
unsigned long lasttime2 = 0;  // Last timer change time

boolean armed = true;  // Is bomb armed?
boolean led = false;   // Is LED on?

void setup(){
  // Set all the switch pins to input
  pinMode(14, INPUT);
  pinMode(15, INPUT);
  pinMode(16, INPUT);
  pinMode(17, INPUT);

  // Set the led and buzzer to output
  pinMode(13, OUTPUT);
  pinMode(14, OUTPUT);

  // Make check() run when button pressed
  attachInterrupt(0, check, RISING);
}

void check(){
  // Store the states the pin needs to be in to defuse
  int states[4] = {HIGH, LOW, HIGH, LOW};

  // If the code is wrong, penalise!
  if (digitalRead(14) != states[0]){
    period -= 250;
    return;
  }
  if (digitalRead(15) != states[1]){
    period -= 250;
    return;
  }
  if (digitalRead(16) != states[2]){
    period -= 250;
    return;
  }
  if (digitalRead(17) != states[3]){
    period -= 250;
    return;
  }

  // If not, disarm the bomb
  armed = false;
}

void bang(){
  // make a bang noise!
  for (;;){ delay(1000); }
}

void success(){
  // success!
  for (;;){ delay(1000); }
}

void loop(){
  // Get the time
  unsigned long time = millis();
  unsigned long time2 = millis();

  // If its time to change the LED...
  if(time - lasttime > (0.5 * period) ) {
    lasttime = time;

    // Do so!
    led = !led;
    digitalWrite(13, led);
  }

  // Count down one period, if its time to
  if(time2 - lasttime2 > period ) {
    timer--;

    // If we are now overdue, ka-boom!
    if ( timer <= 0 ){
      bang();
    }
  }

  // If the bomb has been disarmed, success.
  if (armed == false){
    success();
  }
}