/// <summary>
/// Gets new round according to current game state and betting
/// </summary>
/// <param name="player">Parent player performing action. He performed <see cref="currentAction"/></param>
/// <param name="newAction">Newly performed action for next player. It can be the same player if new round starts. Decided after.</param>
/// <param name="round">Current round (on which <see cref="player"/> is</param>
/// <param name="currentAction">Current action (which <see cref="player"/> performs)</param>
/// <param name="prevAction">Previous action</param>
/// <param name="availableReraises">Available amount of reraise</param>
/// <returns>New round for next player</returns>
private Round GetNewRound(int player, Action newAction, Round round, Action currentAction, Action prevAction, int availableReraises)
{
if (newAction.OpType == OpType.Fold) //if we folds, go to Fold round
{
return(Round.Fold);
}
if (newAction.OpType == OpType.Call && currentAction.OpType == OpType.All || //call all-in => Showdown
round == Round.River && NextPlayerPosition(player) == 0 && newAction.OpType == OpType.Call || //Showdown after river & dealer player
round == Round.River && NextPlayerPosition(player) == 1 &&
newAction.OpType == OpType.Call && currentAction.OpType == OpType.Raise) //dealer raises, next player calls - Showdown
{
return(Round.Showdown);
}
if (round > Round.PreFlop)
{
if (player == 0 && currentAction.OpType == OpType.Call || //dealer only calls => next round
player == 1 && currentAction.OpType == OpType.Call && prevAction.OpType == OpType.Raise) //last to decision player calls after raise => next round
{
return(round + 1);
}
}
else //preflop
{
if (player == 1 && currentAction.OpType == OpType.Call || //last-to-decision player only calls => Flop
player == 0 && currentAction.OpType == OpType.Call && prevAction.OpType == OpType.Raise && availableReraises != _config.ReraiseAmount) //dealer calls => Flop
{
return(Round.Flop);
}
}
return(round);
}
/// <summary>
/// Gets possible actions for current game state. They will be iterated for child actions
/// </summary>
/// <param name="round">Current round</param>
/// <param name="availableReraises">Available reraises. If zero, only Fold/Call/All actions are possible</param>
/// <param name="currentAction">Current action</param>
/// <param name="pot">Current deal pot</param>
/// <returns>Possible actions for current state</returns>
private Action[] GetPossibleActions(Round round, int availableReraises, Action currentAction, int pot)
{
if (round == Round.Fold || round == Round.Showdown) //for terminal state, no actions are permited
{
return(new Action[0]);
}
if (currentAction.OpType == OpType.All) //player can only Fold or check all-in
{
return(new[]
{
new Action(OpType.Fold),
new Action(OpType.Call)
});
}
if (availableReraises <= 0) //no available reraises - just call or fold
{
if (currentAction.OpType == OpType.Call)
{
return(new[]
{
new Action(OpType.Call)
});
}
return(new[]
{
new Action(OpType.Fold),
new Action(OpType.Call)
});
}
var actions = new List <Action> //base actions
{
new Action(OpType.Call),
new Action(OpType.All, _config.Bankroll)
};
if (currentAction.OpType != OpType.Call) //we can also fold if Raise was done before
{
actions.Insert(0, new Action(OpType.Fold));
}
//beting
if (_config.RelativeBetting)
{
actions.AddRange(_config.PossibleRaises[(int)round]
.Select(possibleRaise => new Action(OpType.Raise, GetRelativeBet(pot, possibleRaise))));
}
else
{
actions.AddRange(_config.PossibleRaises[(int)round]
.Select(possibleRaise => new Action(OpType.Raise, possibleRaise)));
}
return(actions.ToArray());
}
/// <summary>
/// Cut bet to it's max value
/// </summary>
private Action SaturateBet(int[] invest, Action possibleAction)
{
if (possibleAction.OpType == OpType.All)
{
return(new Action(OpType.All, possibleAction.Bet - invest.Max()));
}
if (possibleAction.OpType == OpType.Raise &&
possibleAction.Bet + invest.Max() > _config.Bankroll) //when possible raise is bigger than current player bankroll
{
return(Action.Invalid); //since All action is always included, we will skip this action at all
}
return(possibleAction);
}
private int GetCurrentActionInvestValue(Action newAction, Action currentAction)
{
switch (newAction.OpType)
{
case OpType.Fold:
return(0);
case OpType.Call:
return(currentAction.Bet);
case OpType.Raise:
case OpType.All:
return(currentAction.Bet + newAction.Bet);
}
return(0);
}
/// <summary>
/// Generate poker game tree recursive
/// </summary>
/// <param name="player">Current player for which sub tree is generated. 0 is dealer, max is small blind</param>
/// <param name="currentAction">Currently performed action</param>
/// <param name="round">Current round</param>
/// <param name="availableReraises">Number of available reraises. If zero, only Fold/Call/All actions are possible</param>
/// <param name="prevAction">Previous action</param>
/// <param name="pot">Current deal pot</param>
/// <param name="invest">How much players invested</param>
/// <returns>Node with recursively generated child nodes for subtree game states</returns>
private Node GenerateRecursive(int player, Action currentAction, Round round, int availableReraises, Action prevAction, int pot, int[] invest)
{
if (IsSmallblindLimpedBigBlindOnPreflop(player, currentAction, round))
{
availableReraises = _config.ReraiseAmount;
}
//todo BUG - player=1 has only one CALL action in new section when betting was previously performed
Action[] possibleActions = GetPossibleActions(round, availableReraises, currentAction, pot);
List <Node> nodes = new List <Node>(possibleActions.Length);
foreach (var possibleAction in possibleActions)
{
Action newCurrentAction = SaturateBet(invest, possibleAction);
if (newCurrentAction.Equals(Action.Invalid))
{
continue;
}
int[] newInvest = GetNewInvest(invest);
int investValue = GetCurrentActionInvestValue(newCurrentAction, currentAction); //invest raises by current action bet
var newRound = GetNewRound(player, possibleAction, round, currentAction, prevAction, availableReraises);
bool isNewRound = newRound < Round.Showdown && newRound != round;
int nextPlayerPosition = NextPlayerPosition(player, isNewRound);
newInvest[nextPlayerPosition] += investValue; //next player invest raises by his bet
int reraiseDiff = currentAction.OpType == OpType.Raise ? 1 : 0; //if raise action is performed, number of possible reraises is decreased by one
var newReraiseAmount = isNewRound ? _config.ReraiseAmount : availableReraises - reraiseDiff;
var newPot = pot + investValue;
nodes.Add(GenerateRecursive(nextPlayerPosition, newCurrentAction, newRound, newReraiseAmount,
currentAction, //currentAction becomes prevAction
newPot, newInvest));
}
return(new Node((byte)player, currentAction, round, nodes.ToArray(),
GetPayOff(player, round, pot, invest)));
}
public Node Generate()
{
int[] invest = GetStartingInvestValues();
Node childNode = GenerateRecursive(
player: _config.NumPlayers - 1,
currentAction: Action.Initial(_config.SbValue),
round: Round.PreFlop,
availableReraises: _config.ReraiseAmount + 1, //add one for preflop - bigblind can react for smallblind raise
prevAction: Action.Initial(_config.SbValue),
pot: _config.SbValue + _config.BbValue,
invest: invest);
Node rootNode = new Node(
pos: (byte)(_config.NumPlayers - 2),
action: Action.Initial(_config.SbValue),
round: Round.PreFlop,
children: new[] { childNode },
payOff: invest.Max());
return(rootNode);
}
/// <summary>
/// Situation when Small blind player has called (limped) Bigblind. Bigblind can perform betting action
/// </summary>
private static bool IsSmallblindLimpedBigBlindOnPreflop(int player, Action currentAction, Round round)
{
return(player == 1 && currentAction.OpType == OpType.Call && round == Round.PreFlop);
}