#include <stdio.h></stdio.h>

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

#define CELLSIZE 128

Group edges;

Group group;

Animation frame;

Sprite selected;

double dx, dy;

void generate() {

  int snake[16];

  for(int i = 0; i < 16; ++i)

    snake[i] = i;

  for(int i = 0; i < 128; ++i) {

    int j = randomNumber(0, 15);

    int k = randomNumber(0, 15);

    int s = snake[j];

    snake[j] = snake[k];

    snake[k] = s;

  }

  int count = 0;

  for(int i = 0; i < 16; ++i)

    for(int j = i+1; j < 16; ++j)

      if (snake[i] && snake[j] && snake[i] < snake[j])

        ++count;

  if (count % 2) {

    for(int i = 0; i < 15; ++i) {

      if (snake[i] && snake[i+1]) {

        int s = snake[i];

        snake[i] = snake[i+1];

        snake[i+1] = s;

        break;

      }

    }

  }

  for(int i = 0; i < 16; ++i) {

    int y = i/4;

    int x = i%4;

    if (y%2) x = 3 - x;

    if (snake[i])

      spriteSetXY(groupGet(group, snake[i] - 1), x + 0.5, y + 0.5);

  }

}

void init() {

  edges = createEdgesGroupEx(0, 0, 4, 4, 1, 100);

  groupSetVisibleEach(edges, FALSE);

  frame = createAnimation("data/sprite/15/frame.png");

  group = createGroup();

  for(int i = 0; i < 15; ++i) {

    char filename[256] = {};

    sprintf(filename, "data/sprite/15/%d.png", i+1);

    Sprite sprite = createSpriteEx(0, 0, 1, 1, createAnimation(filename));

    spriteSetColliderRectangle(sprite, 0, 0, 0, 1, 1, 0.1);

    groupAdd(group, sprite);

  }

  generate();

}

void draw() {

  saveState();

  zoom(CELLSIZE);

  noStroke();

  rectTextured(frame, 0, 0, 6, 6);

  translate(1, 1);

  if (mouseDown("left")) {

    double mx = mouseTransformedX();

    double my = mouseTransformedY();

    if (!selected) {

      selected = groupSpriteByPoint(group, mx, my, TRUE);

      if (selected) {

        dx = spriteGetX(selected) - mx;

        dy = spriteGetY(selected) - my;

      }

    }

    if (selected) {

      double d = 0.1;

      double x0 = spriteGetX(selected);

      double y0 = spriteGetY(selected);

      double x1 = mx + dx;

      double y1 = my + dy;

      if (x1 < x0 - d) x1 = x0 - d;

      if (x1 > x0 + d) x1 = x0 + d;

      if (y1 < y0 - d) y1 = y0 - d;

      if (y1 > y0 + d) y1 = y0 + d;

      spriteSetXY(selected, x1, y1);

    }

  } else {

    selected = NULL;

  }

  if (mouseWentDown("right") || keyWentDown("space"))

    generate();

  groupCollideBetween(group);

  groupCollideGroup(edges, group);

  drawSprites();

  restoreState();

}

int main() {

  windowSetTitle("15");

  windowSetInit(&init);

  windowSetDraw(&draw);

  windowSetSize(6*CELLSIZE, 6*CELLSIZE);

  windowSetVariableFrameRate();

  windowRun();

  return 0;

}