box-o-sand/conway/generation_score_card.go

package conway

var (
	neighbors = []neighbor{
		neighbor{-1, -1},
		neighbor{-1, 0},
		neighbor{-1, 1},
		neighbor{0, -1},
		neighbor{0, 1},
		neighbor{1, -1},
		neighbor{1, 0},
		neighbor{1, 1},
	}
)

type GenerationScoreCard struct {
	GameState
}

type neighbor struct {
	X int
	Y int
}

func NewGenerationScoreCard(height, width int) *GenerationScoreCard {
	genScore := &GenerationScoreCard{}
	for i := 0; i < height; i++ {
		row := &GameStateRow{Y: i}
		for j := 0; j < width; j++ {
			row.Cells = append(row.Cells, 0)
		}
		genScore.Rows = append(genScore.Rows, row)
	}
	return genScore
}

func (genScore *GenerationScoreCard) Calculate(state *GameState) error {
	stateWidth := state.Width()
	stateCells, err := state.Cells()
	if err != nil {
		return err
	}

	for stateCell := range stateCells {
		if stateCell.Value == 0 {
			continue
		}

		for _, neighbor := range neighbors {
			xTarget := stateCell.X + neighbor.X
			yTarget := stateCell.Y + neighbor.Y

			if xTarget < 0 || yTarget < 0 {
				continue
			}

			if xTarget+1 > stateWidth || yTarget+1 > stateWidth {
				continue
			}

			curScore, err := genScore.Get(xTarget, yTarget)
			if err != nil {
				continue
			}

			err = genScore.Set(xTarget, yTarget, curScore+1)
			if err != nil {
				return err
			}
		}
	}

	return nil
}