#include <helianthus.h></helianthus.h>

#define SIZE 32

#define WIDTH 16

#define HEIGHT 16

#define MAXLEN (WIDTH*HEIGHT+1)

#define MAXFOOD 5

#define FRAMERATE 24

enum TileType {

  NONE,

  WALL,

  FOOD,

  SNAKE

};

enum GameMode {

  MENU,

  START,

  PLAY,

  GAMEOVER

};

int grid[WIDTH][HEIGHT];

Sprite sprites[WIDTH][HEIGHT];

Group gridGroup;

Sound nom, cut;

int snake[MAXLEN][2];

int len;

int foodCount;

int dx, dy;

int framesRemain;

int optStop;

int optCut;

double optWalls;

int optStepFrames;

int difficulty;

int mode;

Animation tileWall;

Animation tileFood;

Animation tileHead;

Animation tileBody;

Animation tileBend;

Animation tileTail;

Font font;

void putFood() {

  for(int i = 0; i < 100 && foodCount < MAXFOOD; ++i) {

    int x = randomNumber(0, WIDTH-1);

    int y = randomNumber(0, HEIGHT-1);

    if (grid[x][y] == NONE) {

      grid[x][y] = FOOD;

      spriteSetAnimation(sprites[x][y], tileFood);

      ++foodCount;

    }

  }

}

void setSnakeTile(int i) {

  int x = snake[i][0];

  int y = snake[i][1];

  Sprite s = sprites[x][y];

  Animation tile = tileBody;

  double rotation = 0;

  int left   = FALSE;

  int right  = FALSE;

  int top    = FALSE;

  int bottom = FALSE;

  if (i > 0) {

    left   = left   || snake[i-1][0] < x;

    right  = right  || snake[i-1][0] > x;

    top    = top    || snake[i-1][1] < y;

    bottom = bottom || snake[i-1][1] > y;

  }

  if (i < len-1) {

    left   = left   || snake[i+1][0] < x;

    right  = right  || snake[i+1][0] > x;

    top    = top    || snake[i+1][1] < y;

    bottom = bottom || snake[i+1][1] > y;

  }

  if (i == 0) {

    tile = tileHead;

    if (top)    rotation =  90;

    if (bottom) rotation = -90;

    if (right)  rotation = 180;

  } else

  if (i == len-1) {

    tile = tileTail;

    if (top)    rotation = -90;

    if (bottom) rotation =  90;

    if (left)   rotation = 180;

  } else

  if (left && top) {

    tile = tileBend;

    rotation = 180;

  } else

  if (left && bottom) {

    tile = tileBend;

    rotation = 90;

  } else

  if (right && top) {

    tile = tileBend;

    rotation = -90;

  } else

  if (right && bottom) {

    tile = tileBend;

    rotation = 0;

  } else

  if (top) {

    rotation = 90;

  }

  spriteSetAnimation(s, tile);

  spriteSetRotation(s, rotation);

}

void resetTile(int x, int y) {

  grid[x][y] = NONE;

  Sprite s = sprites[x][y];

  spriteSetNoAnimation(s);

  spriteSetRotation(s, 0);

}

void moveSnake() {

  int x = snake[0][0] + dx;

  int y = snake[0][1] + dy;

  int cell = grid[x][y];

  if (cell == WALL) {

    if (!optStop) mode = GAMEOVER;

    dx = snake[0][0] - snake[1][0];

    dy = snake[0][1] - snake[1][1];

    return;

  }

  if (cell == SNAKE) {

    if (!optCut) { mode = GAMEOVER; return; }

    int prevLen = len;

    for(int i = 0; i < len; ++i)

      if (snake[i][0] == x && snake[i][1] == y)

        { len=i; setSnakeTile(len-1); break; }

    for(int i = len; i < prevLen; ++i)

      resetTile(snake[i][0], snake[i][1]);

    soundPlay(cut, FALSE);

  }

  if (cell != NONE && cell != FOOD && cell != SNAKE)

    { mode = GAMEOVER; return; }

  for(int i = len; i > 0; --i) {

    snake[i][0] = snake[i-1][0];

    snake[i][1] = snake[i-1][1];

  }

  snake[0][0] = x;

  snake[0][1] = y;

  if (cell == FOOD || cell == SNAKE) {

    grid[x][y] = SNAKE;

    ++len;

    setSnakeTile(0);

    setSnakeTile(1);

  } else {

    grid[x][y] = SNAKE;

    setSnakeTile(0);

    setSnakeTile(1);

    setSnakeTile(len-1);

    resetTile(snake[len][0], snake[len][1]);

  }

  if (cell == FOOD) {

    --foodCount;

    soundPlay(nom, FALSE);

    putFood();

  }

}

void restart() {

  optStepFrames = 12;

  optWalls = 0;

  optCut = TRUE;

  optStop = TRUE;

  switch(difficulty) {

  case 2:

    optStepFrames = 12;

    optWalls = 0.01;

    break;

  case 3:

    optStepFrames = 10;

    optWalls = 0.02;

    optCut = FALSE;

    break;

  case 4:

    optStepFrames = 8;

    optWalls = 0.04;

    optCut = FALSE;

    optStop = FALSE;

    break;

  case 5:

    optStepFrames = 6;

    optWalls = 0.06;

    optCut = FALSE;

    optStop = FALSE;

    break;

  };

  for(int x = 0; x < WIDTH; ++x) {

    for(int y = 0; y < HEIGHT; ++y) {

      grid[x][y] = NONE;

      Sprite s = sprites[x][y];

      spriteSetRotation(s, 0);

      spriteSetNoAnimation(s);

      if ( x == 0 || y == 0

        || x == WIDTH-1 || y == HEIGHT-1

        || randomFloat() < optWalls )

      {

        grid[x][y] = WALL;

        spriteSetAnimation(s, tileWall);

      }

    }

  }

  len = 2;

  snake[0][0] = WIDTH/2;

  snake[0][1] = HEIGHT/2;

  snake[1][0] = snake[0][0] - 1;

  snake[1][1] = snake[0][1];

  for(int i = 0; i < len; ++i)

    grid[ snake[i][0] ][ snake[i][1] ] = SNAKE;

  for(int i = 0; i < len; ++i)

    setSnakeTile(i);

  dx = 1;

  dy = 0;

  foodCount = 0;

  putFood();

  framesRemain = optStepFrames;

  mode = START;

}

void init() {

  tileWall = createAnimation("data/sprite/bricks.png");

  tileFood = createAnimation("data/sprite/apple.png");

  tileHead = createAnimation("data/sprite/snake/head.png");

  tileBody = createAnimation("data/sprite/snake/body.png");

  tileBend = createAnimation("data/sprite/snake/bend.png");

  tileTail = createAnimation("data/sprite/snake/tail.png");

  font = createFont("data/fonts/blackcry.ttf");

  textFont(font);

  gridGroup = createGroup();

  for(int x = 0; x < WIDTH; ++x) {

    for(int y = 0; y < HEIGHT; ++y) {

      Sprite s = createSprite((x + 0.5)*SIZE, (y + 0.5)*SIZE, SIZE, SIZE);

      spriteSetShapeColor(s, colorByName("transparent"));

      groupAdd(gridGroup, s);

      sprites[x][y] = s;

    }

  }

  nom = createSound("data/sound/beep.ogg");

  cut = createSound("data/sound/nom.ogg");

  mode = MENU;

}

void draw() {

  double cx = windowGetWidth()/2.0;

  double cy = windowGetHeight()/2.0;

  if (mode == PLAY) {

    int prevdx = snake[0][0] - snake[1][0];

    int prevdy = snake[0][1] - snake[1][1];

    if      (keyWentDown("left")  && (prevdx !=  1 || prevdy !=  0)) { dx = -1; dy =  0; framesRemain = 0; }

    else if (keyWentDown("right") && (prevdx != -1 || prevdy !=  0)) { dx =  1; dy =  0; framesRemain = 0; }

    else if (keyWentDown("up")    && (prevdx !=  0 || prevdy !=  1)) { dx =  0; dy = -1; framesRemain = 0; }

    else if (keyWentDown("down")  && (prevdx !=  0 || prevdy != -1)) { dx =  0; dy =  1; framesRemain = 0; }

    if (--framesRemain <= 0) {

      moveSnake();

      framesRemain = optStepFrames;

    }

    drawSprites();

    if (keyWentDown("escape")) mode = MENU;

  } else

  if (mode == GAMEOVER) {

    drawSprites();

    fill(colorByRGBA(1, 1, 1, 0.25));

    rect(0, 0, windowGetWidth(), windowGetHeight());

    noFill();

    textAlign(HALIGN_CENTER, HALIGN_CENTER);

    textSize(24);

    text(cx, cy, "Game Over");

    textSize(12);

    text(cx, cy + 24, "Game Over");

    if (keyWentDown("return")) mode = MENU;

    if (keyWentDown("escape")) mode = MENU;

  } else

  if (mode == START) {

    drawSprites();

    fill(colorByRGBA(1, 1, 1, 0.25));

    rect(0, 0, windowGetWidth(), windowGetHeight());

    noFill();

    textAlign(HALIGN_CENTER, VALIGN_CENTER);

    textSize(24);

    text(cx, cy, "Press enter to start");

    if (keyWentDown("return")) mode = PLAY;

    if (keyWentDown("escape")) mode = MENU;

  } else

  if (mode == MENU) {

    noFill();

    textAlign(HALIGN_LEFT, VALIGN_CENTER);

    textSize(24);

    int x = cx - 100;

    int y = cy - 24*3;

    text(x, y, "Select difficulty level:"); y += 24;

    text(x, y, "1 - very easy"           ); y += 24;

    text(x, y, "2 - easy"                ); y += 24;

    text(x, y, "3 - medium"              ); y += 24;

    text(x, y, "4 - hard"                ); y += 24;

    text(x, y, "5 - very hard"           ); y += 24;

    difficulty = 0;

    if (keyWentDown("any 1")) difficulty = 1;

    if (keyWentDown("any 2")) difficulty = 2;

    if (keyWentDown("any 3")) difficulty = 3;

    if (keyWentDown("any 4")) difficulty = 4;

    if (keyWentDown("any 5")) difficulty = 5;

    if (difficulty) restart();

    if (keyWentDown("escape")) windowStop();

  }

}

int main() {

  windowSetTitle("Snake");

  windowSetWidth(SIZE * WIDTH);

  windowSetHeight(SIZE * HEIGHT);

  windowSetFrameRate(FRAMERATE);

  windowSetInit(&init);

  windowSetDraw(&draw);

  windowRun();

  return 0;

}