import 'dart:html';
import 'package:trotter/trotter.dart';

void main() {
  var sprites = new ImageElement(src: "piggy_sprites.png");

  void draw(combinatoric, title) {
    BigInt n = combinatoric.length;

    CanvasElement illustrateFrom(BigInt from, {BigInt to}) {
      final int WIDTH = 275, HEIGHT = ((to - from).toInt() * 50);
      var pPic = new CanvasElement(width: WIDTH, height: HEIGHT);
      for (BigInt row = from; row < to; row += BigInt.one) {
        for (var col = 0; col < combinatoric[row].length; col++) {
          pPic.context2D.drawImageToRect(
              sprites,
              new Rectangle(
                  col * ((WIDTH - 25) ~/ 5) + 25,
                  (row - from).toInt() * (HEIGHT ~/ (to - from).toInt()),
                  WIDTH ~/ 5,
                  HEIGHT ~/ (to - from).toInt()),
              sourceRect: new Rectangle(combinatoric[row][col] * 100, 0, 100, 100));
        }

        pPic.context2D
            .fillText("[$row]", 5, (row - from).toInt() * (HEIGHT ~/ (to - from).toInt()) + 15);
      }
      return pPic;
    }

    document.body.children
        .add(new DivElement()..innerHtml = "<h1>${combinatoric.length} $title</h1>");
    if (n <= new BigInt.from(20)) {
      document.body.children.add(illustrateFrom(BigInt.zero, to: n));
    } else {
      document.body.children
        ..add(illustrateFrom(BigInt.zero, to: new BigInt.from(10)))
        ..add(new DivElement()..innerHtml = ".<br>.<br>.<br>")
        ..add(illustrateFrom(n - new BigInt.from(10), to: n));
    }
  }

  sprites.onLoad.listen((_) {
    var frames = [0, 1, 2, 3, 4];

    var perms = new Permutations(3, frames);
    draw(perms, "Permutations of 3 items from 5");

    var combos = new Combinations(3, frames);
    draw(combos, "Combinations of 3 items from 5");

    var amals = new Amalgams(3, frames);
    draw(amals, "Amalgams of 3 items from 5");

    var compos = new Compositions(3, frames);
    draw(compos, "Compositions of 3 items from 5");

    var subs = new Subsets(frames);
    draw(subs, "Subsets of 5 items");

    var comps = new Compounds(frames);
    draw(comps, "Compounds of 5 items");
  });
}