/// <summary>
/// Recursively expand the current move, or evaluate it if it is at the leaf level
/// </summary>
/// <param name="scenario"></param>
/// <param name="childMoveLevel"></param>
/// <returns>Either null if no suitable decision could be found, or the best result for the decision maker at this level</returns>
public MoveResult ExpandAndEvaluate(Scenario scenario, int childMoveLevel)
{
MoveGenerator[] moveGenerators = scenario.GetMoveGeneratorsByMoveTreeLevel();
if (childMoveLevel == moveGenerators.Length)
{
// At the leaf level, so evaluate the scenario:
return(scenario.EvaluateLeafNodeMove(this));
}
MoveGenerator moveGen = moveGenerators[childMoveLevel];
Move[] childMoves = moveGen.Generate(scenario, parentMove: this);
int bestSlackForDecisionMaker;
MoveResult bestResultForDecisionMaker = null;
bestSlackForDecisionMaker = int.MaxValue;
foreach (Move childMove in childMoves)
{
if (childMove == null)
{
continue;
}
MoveResult childMoveResult = childMove.ExpandAndEvaluate(scenario, childMoveLevel + 1);
if (childMoveResult == null)
{
continue;
}
if (childMoveResult.EvaluationOutcome != ScenarioEvaluationOutcome.Invalid)
{
if ( // Player p wants to minimize slack:
((moveGen.DecisionMaker == ScenarioDecisionMaker.p) && (childMoveResult.Slack < bestSlackForDecisionMaker))
// Player pBar wants to maximize slack:
|| (moveGen.DecisionMaker == ScenarioDecisionMaker.pBar) && (childMoveResult.Slack > bestSlackForDecisionMaker))
{
bestResultForDecisionMaker = childMoveResult;
bestSlackForDecisionMaker = childMoveResult.Slack;
}
}
else
{
// Return an invalid result rather than null if possible:
if (bestResultForDecisionMaker == null)
{
bestResultForDecisionMaker = childMoveResult;
}
}
}
return(bestResultForDecisionMaker);
}
public static MoveResult[] EvaluateScenario(Scenario scenario)
{
#if DEBUG
System.Diagnostics.Stopwatch swatch = System.Diagnostics.Stopwatch.StartNew();
#endif
MoveGenerator[] moveGenerators = scenario.GetMoveGeneratorsByMoveTreeLevel();
MoveGenerator initialMoveGenerator = moveGenerators[0];
Move[] initialMoves = initialMoveGenerator.Generate(scenario, null);
MoveResult[] moveResults = new MoveResult[initialMoves.Length];
for (int i = 0; i < moveResults.Length; i++)
{
Move initialMove = initialMoves[i];
MoveResult moveResult = initialMove.ExpandAndEvaluate(scenario, 1);
moveResults[i] = moveResult;
}
#if DEBUG
swatch.Stop();
AndrewTweddle.BattleCity.Core.Helpers.DebugHelper.LogDebugMessage(
"ScenarioEvaluator", "Duration to expand moves for scenario {0}: {1}",
scenario.GetType().Name, swatch.Elapsed);
#endif
return(moveResults);
}