private bool HasDestinationToMove(IChainLink <IMainFieldSquare, Direction> item, out int destination)
{
destination = -1;
if (!item.Value.State.IsActive || item.Value.State.Direction.IsNone())
{
return(false);
}
var direction = item.Value.State.Direction;
// look for an active square;
var nextItem = item.Next(direction.Value);
while (nextItem != null && !nextItem.Value.State.IsActive)
{
nextItem = nextItem.Next(direction.Value);
}
if (nextItem != null && nextItem != item.Next(direction.Value))
{
// destination is last inactive square (before first active square!) on the way.
var prevItem = nextItem.Next(direction.Opposite).Value;
destination = direction.IsHorzOrient() ? (int)prevItem.X : (int)prevItem.Y;
}
else if (nextItem == null || CanIgnoreObstacles(item))
{
// if there aren't any obstacle or they can be ignored,
// so destination is the last square on the way
destination = (int)GetLastIndexInDirection(direction.Value);
}
return(destination != -1);
}
private void CountCombinationSize(IChainLink <IMainFieldSquare, Direction> item, SquareCombinationCounter counter = null)
{
if (item == null)
{
return;
}
var value = item.Value;
// skip if item is not active or it was already counted as part of combination
if (!value.State.IsActive || _matrixCounterRefs[value.X, value.Y] != null)
{
return;
}
if (counter == null)
{
counter = new SquareCombinationCounter(value.Color);
_counters.Add(counter);
}
if (counter.Color != value.Color)
{
return;
}
counter.Squares.Add(value);
_matrixCounterRefs[value.X, value.Y] = counter;
CountCombinationSize(item.Next(Direction.Left), counter);
CountCombinationSize(item.Next(Direction.Down), counter);
CountCombinationSize(item.Next(Direction.Right), counter);
CountCombinationSize(item.Next(Direction.Up), counter);
}
/// <summary>
/// Find out if squares on the way can be ignored.
/// There are two consecutive conditions:
/// 1) all active squares on the way move opposite direction;
/// 2) initial obstacle that the square adjacent to was destroyed and
/// all squares on the way are adjacent to the same initial obstacle;
///
/// If the first case is false so the second one should be false as well to
/// return negative result otherwise there is positive result.
/// </summary>
private bool CanIgnoreObstacles(IChainLink <IMainFieldSquare, Direction> item)
{
var direction = item.Value.State.Direction;
var obstacle = item.Value.State.Obstacle;
var nextItem = item.Next(direction.Value);
var initialObstacle = _initialObstacles[item.Value.State.Obstacle];
var obstaclesIgnored = !this[initialObstacle.X, initialObstacle.Y].Value.State.IsActive;
while (nextItem != null)
{
var square = nextItem.Value;
if (square.State.IsActive)
{
obstaclesIgnored = obstaclesIgnored && square.State.Obstacle == obstacle;
if ((square.State.Direction.Value != direction.Opposite) && !obstaclesIgnored)
{
return(false);
}
}
nextItem = nextItem.Next(direction.Value);
}
return(true);
}
