/// <summary>
/// Checks if predicate rectangle is clean
/// </summary>
/// <param name="cleanPredicate"></param>
/// <returns></returns>
private bool CheckClean(PClean cleanPredicate)
{
return this.board.IsEmpty(cleanPredicate.CleanRect);
}
/// <summary>
/// strips step
/// returns the executed operation.
/// if there was no Operation in the current step returns null
/// </summary>
private Operation StripsStep()
{
var item = stack.Peek();
bool satisfied = false;
bool allArePredicateKind = CheckAllArePredicate(item);
if (allArePredicateKind)
satisfied = GoalsAreSatisfied(item);
//case 1- goals is satisfied- pop and return
if (allArePredicateKind && satisfied)
{
stack.Pop();
return null;
}
//case 2- goals is unsatisfied and conjunctive- order goals by heuristic and add each one to stack
if (allArePredicateKind && item.Count > 1 && !satisfied)
{
// the list is ordered in the order of the execution
IList<StackItem> ordered = heuristics.OrderPredicates(item);
// push the items in the list in reverse order so we will get in the top of the stack
// the first item to execute
for (int i = ordered.Count - 1; i >= 0; i--)
{
var tempList = new List<StackItem>();
tempList.Add(ordered[i]);
stack.Push(tempList);
}
return null;
}
// case 3- goal is a single unsatisfied goal- choose an operation push it and all its pre condtiotions
if (allArePredicateKind && item.Count == 1 && !satisfied)
{
Operation operation = heuristics.ChooseOperation(board, (Predicate) item[0]);
stack.Push(new List<StackItem> {operation});
// push it's pre condition into stack - need to implement a function that calculates precondition per move
if (operation is Move)
{
Rectangle rectToBeClean = ((Move) operation).CalculateRectDiff();
var clean = new PClean(rectToBeClean);
clean.Forbbiden = operation.ForbbidenDirections();
stack.Push(new List<StackItem> {clean});
}
// Rotate
else
{
Rectangle rect = ((Rotate) operation).CalculateRectToBeCleanByDirection();
var clean = new PClean(rect);
clean.Forbbiden = operation.ForbbidenDirections();
stack.Push(new List<StackItem> {clean});
}
return null;
}
//case 4- item is an operation- pop it, execute it and add to operation list
if (item.Count == 1 && item.First() is Operation)
{
var operation = stack.Pop().First();
((Operation) operation).Execute();
return (Operation) operation;
}
return null;
}