cellular-automata/lib/src/Simulation.dart

import 'dart:html' as html;
import 'dart:math' as math;

import 'package:rules_of_living/src/Cell.dart';
import 'package:rules_of_living/src/Grid.dart';

enum CellPattern { SpaceShip, Blinker }

class Simulation {
  final Grid<Cell> map;

  bool _dirty = true;
  bool _renderEdges = true;

  int _startingSeed;
  int _x;
  int _y;
  int _amount;
  int _dispersal;
  CellPattern _pattern;

  int get w => map.width;
  int get h => map.height;

  Simulation(int w, int h) : this.map = new Grid(w, h) {
    for (int i = 0; i < map.length; i++) {
      map[i] = _getGOLCell();
    }
    print("Grid creation finished");
  }

  Cell _getGOLCell([bool defaultState = false]) {
    Cell cell = Cell();
    return cell;
  }

  void reset() {
    map.setAll(0, List.filled(map.length, _getGOLCell()));
    if (_startingSeed != null)
      addPattern(
          pattern: _pattern,
          dispersal: _dispersal,
          amount: _amount,
          seed: _startingSeed,
          x: _x,
          y: _y);
    _dirty = true;
  }

  void addPattern(
      {CellPattern pattern,
      int x,
      int y,
      int amount,
      int dispersal,
      int seed}) {
    _startingSeed = seed ?? DateTime.now().millisecondsSinceEpoch;
    math.Random rng = new math.Random(_startingSeed);
    _x = x;
    _y = y;
    _amount = amount ?? rng.nextInt(20);
    _dispersal = dispersal ?? 10;
    _pattern = pattern;
    int cx = x ?? rng.nextInt(map.width ~/ 3) + (map.width ~/ 3);
    int cy = y ?? rng.nextInt(map.height ~/ 3) + (map.height ~/ 3);
    switch (pattern) {
      // Two blocks, offset
      // ##
      //   ##
      case CellPattern.Blinker:
        setCellState(cx, cy, true);
        setCellState(cx + 1, cy, true);
        setCellState(cx, cy + 1, true);
        setCellState(cx + 1, cy + 1, true);

        setCellState(cx + 2, cy + 2, true);
        setCellState(cx + 3, cy + 2, true);
        setCellState(cx + 2, cy + 3, true);
        setCellState(cx + 3, cy + 3, true);
        break;
      // A 'gliding' Spaceship
      //   #
      //    #
      //  ###
      case CellPattern.SpaceShip:
        setCellState(1 + cx, 0 + cy, true);
        setCellState(2 + cx, 1 + cy, true);
        setCellState(2 + cx, 2 + cy, true);
        setCellState(1 + cx, 2 + cy, true);
        setCellState(0 + cx, 2 + cy, true);
        break;
      default:
        int sanityCheck = 0;
        for (var i = 0; i < (_amount); i++) {
          sanityCheck++;
          getCellState(cx, cy)
              ? i--
              : setCellState(cx + rng.nextInt(_dispersal),
                  cy + rng.nextInt(_dispersal), true);
          if (sanityCheck > 100 && sanityCheck > i * 3) break;
        }
        break;
    }
    _dirty = true;
  }

  void setCellState(int x, int y, bool state) {
    if (y >= map.height || x >= map.width) return;

    state ? map.set(x, y, Cell()) : map.set(x, y, null);
  }

  bool getCellState(int x, int y) {
    if (y >= map.height || x >= map.width) return null;

    return map.get(x, y) == null ? false : true;
  }

  Map<int, Cell> update() {
    Map<int, Cell> stateChanges = Map();

    for (int i = 0; i < map.length; i++) {
      math.Point p = map.toCoordinates(i);
      Cell el = map[i];
      bool changed = false;
      int neighbors = getSurroundingNeighbors(p.x, p.y, 1);
      if (el == null && neighbors == 3) {
        stateChanges[i] = Cell();
      } else if (el != null && neighbors != 2 && neighbors != 3) {
        stateChanges[i] = null;
      }
    }
    stateChanges.forEach((i, el) => map[i] = el);
    stateChanges.length != 0 ? _dirty = true : false;
    return stateChanges;
  }

  int getSurroundingNeighbors(int x, int y, int range) {
    int count = 0;
    for (int ix = -range + x; ix <= range + x; ix++) {
      for (int iy = -range + y; iy <= range + y; iy++) {
        if (ix >= 0 &&
            iy >= 0 &&
            ix < map.width &&
            iy < map.height &&
            map.get(ix, iy) != null &&
            !(x == ix && y == iy)) count++;
      }
    }
    return count;
  }

  void render(html.CanvasElement canvas, [num interp]) {
    // only renders if any cells changed between renders
    if (!_dirty) return;

    html.CanvasRenderingContext2D ctx = canvas.getContext('2d');
    int brickW = (canvas.width ~/ map.width);
    int brickH = (canvas.height ~/ map.height);
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    for (int i = 0; i < map.length; i++) {
      math.Point p = map.toCoordinates(i);
      if (_renderEdges) {
        ctx.setStrokeColorRgb(100, 100, 100);
        ctx.strokeRect(p.x * brickW, p.y * brickH, brickW, brickH);
      }

      if (map[i] != null)
        ctx.setFillColorRgb(155, 155, 255);
      else
        ctx.setFillColorRgb(0, 0, 0);
      ctx.fillRect(p.x * brickW, p.y * brickH, brickW, brickH);
    }
    _dirty = false;
  }

  void set renderEdges(bool on) {
    _renderEdges = on;
    _dirty = true;
  }

  bool get renderEdges => _renderEdges;
}