/* 
a1: delete code and constants for displays
a3: refactor code
a4: add in timer for replies
*/
// ***************************************************************set up compiler constants etc.
#include "pitches.h"                                         // library of tones and tone functions

/* Constants - define pin numbers for LEDs,
   buttons and speaker, and also the game tones: */
const uint8_t ledPins[] = {9, 10, 11, 12};                   // name the various pins
const uint8_t buttonPins[] = {2, 3, 4, 5};
#define SPEAKER_PIN 8

#define MAX_GAME_LENGTH 100

const int gameTones[] = { NOTE_G3, NOTE_C4, NOTE_E4, NOTE_G5}; // create array of tones for each LED
//                                                              Global varaibles below:
uint8_t gameSequence[MAX_GAME_LENGTH] = {0};                // Set up array to hold sequence
uint8_t gameIndex = 0;                 // create index to count where we have got to in building sequence
unsigned long previousMillis = 0;  // Store the last time we did something
unsigned long currentMillis =0;
const long interval = 3000;        // Interval at which to do something (in milliseconds)

// ********************************************   SET UP ARDUINO BOARD initialize Serial communication

void setup() {
  Serial.begin(9600);
  for (byte i = 0; i < 4; i++) {                              // set up pins
    pinMode(ledPins[i], OUTPUT);
    pinMode(buttonPins[i], INPUT_PULLUP);
  }
  pinMode(SPEAKER_PIN, OUTPUT);

  // The following line primes the random number generator.
  // It assumes pin A3 is floating (disconnected):
  randomSeed(analogRead(A3));
}
//    ******************************************************************           DEFINE FUNCTIONS
//                                            =========== Lights the given LED and plays a suitable tone
void lightLedAndPlayTone(byte ledIndex) {
  digitalWrite(ledPins[ledIndex], HIGH);
  tone(SPEAKER_PIN, gameTones[ledIndex]);
  delay(300);
  digitalWrite(ledPins[ledIndex], LOW);
  noTone(SPEAKER_PIN);
}
//                                   ==== Plays the current sequence  that the user has to repeat
void playSequence() {
  for (int i = 0; i < gameIndex; i++) {     // cycle through sequence
    byte currentLed = gameSequence[i];      // identify next LED to light
    lightLedAndPlayTone(currentLed);        // light LED and play tone
    delay(50);
  }
}
//                                        =========   Keeps checking for button press, return index
byte readButtons() {
// set previous = current
currentMillis = millis();  // Get the current time
previousMillis = currentMillis; //reset starting time
// true test for next statement:    (currentMillis-previousMillis) < interval
  while ((currentMillis-previousMillis) < interval) { // Current - previous less than pause allowance
    for (byte i = 0; i < 4; i++) {                // poll pushbottons to check if one pushed 
      byte buttonPin = buttonPins[i];
      if (digitalRead(buttonPin) == LOW) {        // if pressed, exit function returning the button id 
        return i;
      }
    }
    delay(1);
    currentMillis = millis(); //update current time before repeatng loop
  }
  // return with "i" set to 4 i.e. illegal to indicate timeout and force a fail when compared to correct answer
  return 5; //to cause fail
}
//                                             ==== Play the "game over" sequence, and report the game score
void gameOver() {
  Serial.print("Game over! your score: ");
  Serial.println(gameIndex - 1);
  Serial.print("currentMillis:  ");
  Serial.println(currentMillis);
  Serial.print("previousMillis:  ");
  Serial.println(previousMillis);
  
  gameIndex = 0;
  delay(200);

  // Play a Wah-Wah-Wah-Wah sound
  tone(SPEAKER_PIN, NOTE_DS5);
  delay(300);
  tone(SPEAKER_PIN, NOTE_D5);
  delay(300);
  tone(SPEAKER_PIN, NOTE_CS5);
  delay(300);
  for (byte i = 0; i < 10; i++) {
    for (int pitch = -10; pitch <= 10; pitch++) {
      tone(SPEAKER_PIN, NOTE_C5 + pitch);
      delay(5);
    }
  }
  noTone(SPEAKER_PIN);
}

//                            ========  Get the user's input and compare it with the expected sequence.
bool checkUserSequence() {                         
  for (int i = 0; i < gameIndex; i++) {                        
    byte expectedButton = gameSequence[i];         // get next in sequence
    byte actualButton = readButtons();             // poll for pushbutton entry
    Serial.println(actualButton);
    if (actualButton == 5) {
      return false;
    }
    lightLedAndPlayTone(actualButton);             // light approprite LED
    if (expectedButton != actualButton) {          // test user entry 
      return false;
    }
  }
  return true;
}

//                                     =====    Plays a hooray sound whenever the user finishes a level
void playLevelUpSound() {
  tone(SPEAKER_PIN, NOTE_E4);
  delay(150);
  tone(SPEAKER_PIN, NOTE_G4);
  delay(150);
  tone(SPEAKER_PIN, NOTE_E5);
  delay(150);
  tone(SPEAKER_PIN, NOTE_C5);
  delay(150);
  tone(SPEAKER_PIN, NOTE_D5);
  delay(150);
  tone(SPEAKER_PIN, NOTE_G5);
  delay(150);
  noTone(SPEAKER_PIN);
}

/* ****************************************************************************   MAIN GAME LOOP     */
void loop() {                                               // loops for each round

                               // Add a random color to the end of the challenge sequence and play updated sequence
  gameSequence[gameIndex] = random(0, 4);
  gameIndex++;
  if (gameIndex >= MAX_GAME_LENGTH) {
    gameIndex = MAX_GAME_LENGTH - 1;
  }
  playSequence();                                                    // start new round with challenge

                                                                     // check  user attempt                                         
  if (!checkUserSequence()) {
    gameOver();
  }

  delay(300);

  if (gameIndex > 0) {
    playLevelUpSound();
    delay(300);
  }
}