#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include <vector>
#include <SimpleTimer.h>

#define clk PB13
#define din PB15
#define dc  PB14
#define cs  PB12
#define rst PA15
// Software SPI (slower updates, more flexible pin options):
// pin 7 - Serial clock out (SCLK)
// pin 6 - Serial data out (DIN)
// pin 5 - Data/Command select (D/C)
// pin 4 - LCD chip select (CS)
// pin 3 - LCD reset (RST)
Adafruit_PCD8544 display = Adafruit_PCD8544(clk, din, dc, cs, rst);

//speed in ms
#define SPEED 250
SimpleTimer timer;

#define SNAKE_INIT_LENGTH 10 //Initial length of snake
#define SNAKE_START_X 42 //Initial x position
#define SNAKE_START_Y 20 //Initial y position

//Pin setup according to the board
#define left PA1
#define right PB8
#define up PA0
#define down PB9
#define center PC13
#define left_led PB6
#define right_led PB7

//Store the coordinates in a structure
struct coordinates
{
  int x;
  int y;
};

std::vector<coordinates> snake; //store the snake points
coordinates snake_last_piece; //store the last point | needed for visualisation

coordinates food; //food coordinates

bool leds = true; //for LED blink

int direction = 0;
int last_direction = 0;

int points = 0;

void setup() {
  // put your setup code here, to run once:
  //Serial port
  Serial.begin(9600);

  //Set inputs and outputs
  pinMode(left, INPUT_PULLUP);
  pinMode(right, INPUT_PULLUP);
  pinMode(up, INPUT_PULLUP);
  pinMode(down, INPUT_PULLUP);
  pinMode(center, INPUT_PULLUP);
  pinMode(left_led, OUTPUT);
  pinMode(right_led, OUTPUT);

  display.begin();
  display.setContrast(63);
  
  display.display(); //show splashscreen
  delay(2000);
  display.clearDisplay();

  init_game();

  timer.setInterval(SPEED, TimerCallbackFunc); //Timer for moving the snake
}

void init_game()
{
  /*
   * This function initializes the snake, clears the points and direction, and generate a new food.
   * Can be used to reset the game.
   */
  
  //init the snake
  direction = 0;

  points = 0;
  
  snake.clear(); //clear the vector
  for(int i = 0; i < SNAKE_INIT_LENGTH; i++)
  {
    coordinates helper;
    helper.x = SNAKE_START_X - i;
    helper.y = SNAKE_START_Y;
    snake.push_back(helper);
  }

  snake_last_piece.x = 0;
  snake_last_piece.y = 0;

  generate_food();
}

void TimerCallbackFunc()
{
  //blinks the 2 LED
  digitalWrite(left_led, leds);
  digitalWrite(right_led, !leds);
  leds = !leds;

  //Moving in the given direction
  snake_move(direction);
}

void generate_food()
{
  /*
   * Generates random x and y points until it's out of the snake's points.
   */
  bool equal = true;
  while(equal)
  {
    equal = false;
    food.x = random(0, 83);
    food.y = random(0,47);
    for(int i = 0; i < snake.size(); i++)
    {
      if(snake[0].x == food.x && snake[0].y == food.y)
      {
        equal = true;
      }
    }
  }
  display.drawPixel(food.x, food.y, BLACK);
  display.display();
}

void draw_snake()
{
  /*
   * Draw the snake points.
   */
  for(int i = 0; i < snake.size(); i++)
  {
    display.drawPixel(snake[i].x, snake[i].y, BLACK);
  }
  display.drawPixel(snake_last_piece.x, snake_last_piece.y, WHITE);
  display.display();
}

bool check_crash()
{
  /*
   * Returns true if the snake crashing into itself.
   */
  for(int i = 1; i < snake.size(); i++)
  {
    if(snake[0].x == snake[i].x && snake[0].y == snake[i].y)
    {
      return true;
    }
  }
  return false;
}

void snake_move(int direction)
{
  /*
   * Handling the moving directions and next points.
   */
  last_direction = direction;
  
  snake_last_piece.x = snake[snake.size()-1].x;
  snake_last_piece.y = snake[snake.size()-1].y;

  coordinates helper;
  
  if(direction == 0) //right
  {
    helper = snake[0];
    helper.x++;
    if(helper.x > 83)
    {
      helper.x = 0;
    }
  }
  else if(direction == 1) //left
  {
    helper = snake[0];
    helper.x--;
    if(helper.x < 0)
    {
      helper.x = 83;
    }
  }
  else if(direction == 2) //up
  {
    helper = snake[0];
    helper.y--;
    if(helper.y < 0)
    {
      helper.y = 47;
    }
  }
  else if(direction == 3) //down
  {
    helper = snake[0];
    helper.y++;
    if(helper.y > 47)
    {
      helper.y = 0;
    }
  }

  //move forward every coordinate and replace the first with the new one
  for(int i = snake.size(); i > 0; i--)
  {
    snake[i] = snake [i-1];
  }
  snake[0] = helper;
  draw_snake();

  //if the snake ate the food, then increment by one and generate a new one
  if(snake[0].x == food.x && snake[0].y == food.y)
  {
    increment_snake();
    generate_food();
  }
}

void increment_snake()
{
  snake.push_back(snake[snake.size()]);
  points++;
}

void loop() {
  // put your main code here, to run repeatedly:
  timer.run();
  if(digitalRead(left) == 0)
  {
    Serial.print("Left button pressed");
    if(last_direction != 0)
    {
      direction = 1;
    }
  }

  if(digitalRead(right) == 0)
  {
    Serial.print("Right button pressed");
    if(last_direction != 1)
    {
      direction = 0;
    }
  }

  if(digitalRead(up) == 0)
  {
    Serial.print("Up button pressed");
    if(last_direction != 3)
    {
      direction = 2;
    }
  }

  if(digitalRead(down) == 0)
  {
    Serial.print("Down button pressed");
    if(last_direction != 2)
    {
      direction = 3;
    }
  }

  if(digitalRead(center) == 0)
  {
    Serial.print("Center button pressed");
    display.drawPixel(food.x, food.y, BLACK);
    display.display();
  }
  if(check_crash())
  {
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(BLACK);
    display.setCursor(0,0);
    display.println("Game over!");
    //display.setCursor(0,10);
    display.println("Score: ");
    display.print(points, DEC);
    display.display();
    
    while(digitalRead(center) != 0)
    {
    }
    display.clearDisplay();
    init_game();
  }
}