5dplomacy/MultiversalDiplomacy/Adjudicate/MovementPhaseAdjudicator.cs

795 lines
33 KiB
C#

using MultiversalDiplomacy.Adjudicate.Decision;
using MultiversalDiplomacy.Model;
using MultiversalDiplomacy.Orders;
namespace MultiversalDiplomacy.Adjudicate;
/// <summary>
/// Adjudicator for the movement phase.
/// </summary>
public class MovementPhaseAdjudicator : IPhaseAdjudicator
{
public static IPhaseAdjudicator Instance { get; } = new MovementPhaseAdjudicator();
public List<OrderValidation> ValidateOrders(World world, List<Order> orders)
{
// The basic workflow of this function will be to look for invalid orders, remove these
// from the working set of orders, and then perform one final check for duplicate orders
// at the end. This is to comply with DATC 4.D.3's requirement that a unit that receives
// a legal and an illegal order follows the legal order rather than holding.
List<OrderValidation> validationResults = new List<OrderValidation>();
// Invalidate any orders that aren't a legal type for this phase and remove them from the
// working set.
AdjudicatorHelpers.InvalidateWrongTypes(
new List<Type>
{
typeof(HoldOrder),
typeof(MoveOrder),
typeof(ConvoyOrder),
typeof(SupportHoldOrder),
typeof(SupportMoveOrder)
},
ref orders,
ref validationResults);
// Invalidate any orders by a power that were given to another power's units and remove
// them from the working set.
AdjudicatorHelpers.InvalidateWrongPower(orders, ref orders, ref validationResults);
// Since all the order types in this phase are UnitOrders, downcast to get the Unit.
List<UnitOrder> unitOrders = orders.Cast<UnitOrder>().ToList();
// Invalidate any order given to a unit in the past.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => !order.Unit.Season.Futures.Any(),
ValidationReason.IneligibleForOrder,
ref unitOrders,
ref validationResults);
/***************
* HOLD ORDERS *
***************/
// Hold orders are always valid.
List<HoldOrder> holdOrders = unitOrders.OfType<HoldOrder>().ToList();
/***************
* MOVE ORDERS *
***************/
// Move order validity is far more complicated, due to multiversal time travel and convoys.
List<MoveOrder> moveOrders = unitOrders.OfType<MoveOrder>().ToList();
// Trivial check: armies cannot move to water and fleets cannot move to land.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => (order.Unit.Type == UnitType.Army && order.Location.Type == LocationType.Land)
|| (order.Unit.Type == UnitType.Fleet && order.Location.Type == LocationType.Water),
ValidationReason.IllegalDestinationType,
ref moveOrders,
ref validationResults);
// Trivial check: a unit cannot move to where it already is.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => !(order.Location == order.Unit.Location && order.Season == order.Unit.Season),
ValidationReason.DestinationMatchesOrigin,
ref moveOrders,
ref validationResults);
// If the unit is moving to a valid destination that isn't where it already is, then the
// move order is valid if there is a path from the origin to the destination. In the easy
// case, the destination is directly adjacent to the origin with respect to the map, the
// turn, and the timeline. These moves are valid. Any other move must be checked for
// potential validity as a convoy move.
ILookup<bool, MoveOrder> moveOrdersByAdjacency = moveOrders
.ToLookup(order =>
// Map adjacency
order.Unit.Location.Adjacents.Contains(order.Location)
// Turn adjacency
&& Math.Abs(order.Unit.Season.Turn - order.Season.Turn) <= 1
// Timeline adjacency
&& order.Unit.Season.InAdjacentTimeline(order.Season));
List<MoveOrder> adjacentMoveOrders = moveOrdersByAdjacency[true].ToList();
List<MoveOrder> nonAdjacentMoveOrders = moveOrdersByAdjacency[false].ToList();
// Only armies can move to non-adjacent destinations, since fleets cannot be convoyed.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => order.Unit.Type == UnitType.Army,
ValidationReason.UnreachableDestination,
ref nonAdjacentMoveOrders,
ref validationResults);
// For all remaining convoyable move orders, check if there is a path between the origin
// and the destination.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => PathFinder.ConvoyPathExists(world, order),
ValidationReason.UnreachableDestination,
ref nonAdjacentMoveOrders,
ref validationResults);
/*****************
* CONVOY ORDERS *
*****************/
// A convoy order must be to a fleet and target an army.
List<ConvoyOrder> convoyOrders = unitOrders.OfType<ConvoyOrder>().ToList();
AdjudicatorHelpers.InvalidateIfNotMatching(
order => order.Unit.Type == UnitType.Fleet && order.Target.Type == UnitType.Army,
ValidationReason.InvalidOrderTypeForUnit,
ref convoyOrders,
ref validationResults);
// A convoy for an illegal move is illegal, which means all the move validity checks
// now need to be repeated for the convoy target.
// Trivial check: cannot convoy to non-coastal province.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => order.Location.Type == LocationType.Land
&& order.Location.Province.Locations.Any(loc => loc.Type == LocationType.Water),
ValidationReason.IllegalDestinationType,
ref convoyOrders,
ref validationResults);
// Trivial check: cannot convoy a unit to its own location
AdjudicatorHelpers.InvalidateIfNotMatching(
order => !(
order.Location == order.Target.Location
&& order.Season == order.Target.Season),
ValidationReason.DestinationMatchesOrigin,
ref convoyOrders,
ref validationResults);
// By definition, the move enabled by a convoy order is a convoyable move order, so it
// should be checked for a convoy path.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => PathFinder.ConvoyPathExists(world, order),
ValidationReason.UnreachableDestination,
ref convoyOrders,
ref validationResults);
/***********************
* SUPPORT-HOLD ORDERS *
***********************/
// Support-hold orders are typically valid if the supporting unit can move to the
// destination.
List<SupportHoldOrder> supportHoldOrders = unitOrders.OfType<SupportHoldOrder>().ToList();
// Support-hold orders are invalid if the unit supports itself.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => order.Unit != order.Target,
ValidationReason.NoSelfSupport,
ref supportHoldOrders,
ref validationResults);
// Support-hold orders are invalid if the supporting unit couldn't move to the destination
// without a convoy. This is the same direct adjacency calculation as above, except that
// the supporting unit only needs to be able to move to the *province*, even if the target
// is holding in a location within that province that the supporting unit couldn't move to.
// The reverse is not true: a unit cannot support another province if that province is only
// reachable from a different location in the unit's province.
AdjudicatorHelpers.InvalidateIfNotMatching(
order =>
// Map adjacency with respect to province
order.Unit.Location.Adjacents.Any(
adjLocation => adjLocation.Province == order.Target.Location.Province)
// Turn adjacency
&& Math.Abs(order.Unit.Season.Turn - order.Target.Season.Turn) <= 1
// Timeline adjacency
&& order.Unit.Season.InAdjacentTimeline(order.Target.Season),
ValidationReason.UnreachableSupport,
ref supportHoldOrders,
ref validationResults);
/***********************
* SUPPORT-MOVE ORDERS *
***********************/
// Support-move orders, like support-hold orders, are typically valid if the supporting
// unit can move to the destination.
List<SupportMoveOrder> supportMoveOrders = unitOrders.OfType<SupportMoveOrder>().ToList();
// Support-move orders are invalid if the unit supports a move to any location in its own
// province.
AdjudicatorHelpers.InvalidateIfNotMatching(
order => order.Unit.Location.Province != order.Location.Province,
ValidationReason.NoSupportMoveAgainstSelf,
ref supportMoveOrders,
ref validationResults);
// Support-move orders, like support-hold orders, are valid only if the supporting unit
// can reach the destination *province* of the move, even if the destination *location*
// is unreachable (DATC 6.B.4). The same is not true of reachability from another location
// in the supporting unit's province (DATC 6.B.5).
AdjudicatorHelpers.InvalidateIfNotMatching(
order =>
// Map adjacency with respect to province
order.Unit.Location.Adjacents.Any(
adjLocation => adjLocation.Province == order.Location.Province)
// Turn adjacency
&& Math.Abs(order.Unit.Season.Turn - order.Season.Turn) <= 1
// Timeline adjacency
&& order.Unit.Season.InAdjacentTimeline(order.Season),
ValidationReason.UnreachableSupport,
ref supportMoveOrders,
ref validationResults);
// One more edge case: support-move orders by a fleet for an army are illegal if that army
// requires a convoy and the supporting fleet is a part of the only convoy path (DATC
// 6.D.31).
// TODO: support convoy path check with "as if this fleet were missing"
// Collect the valid orders together
unitOrders =
holdOrders.Cast<UnitOrder>()
.Concat(adjacentMoveOrders)
.Concat(nonAdjacentMoveOrders)
.Concat(convoyOrders)
.Concat(supportHoldOrders)
.Concat(supportMoveOrders)
.ToList();
// DATC 4.D.3 prefers that multiple orders to the same unit in the same order set be
// replaced by a hold order. Since this function only takes one combined list of orders,
// it is assumed that the caller has combined the order sets from all powers in a way that
// is compliant with DATC 4.D.1-2. If there are still duplicate orders in the input, they
// were not addressed by 4.D.1-2 and will be handled according to 4.D.3, i.e. replaced with
// hold orders. Note that this happens last, after all other invalidations have been
// applied in order to comply with what 4.D.3 specifies about illegal orders.
List<Unit> duplicateOrderedUnits = unitOrders
.GroupBy(o => o.Unit)
.Where(orderGroup => orderGroup.Count() > 1)
.Select(orderGroup => orderGroup.Key)
.ToList();
List<UnitOrder> duplicateOrders = unitOrders
.Where(o => duplicateOrderedUnits.Contains(o.Unit))
.ToList();
List<UnitOrder> validOrders = unitOrders.Except(duplicateOrders).ToList();
validationResults = validationResults
.Concat(duplicateOrders.Select(o => o.Invalidate(ValidationReason.DuplicateOrders)))
.Concat(validOrders.Select(o => o.Validate(ValidationReason.Valid)))
.ToList();
// Finally, add implicit hold orders for units without legal orders.
List<Unit> allOrderableUnits = world.Units
.Where(unit => !unit.Season.Futures.Any())
.ToList();
HashSet<Unit> orderedUnits = validOrders.Select(order => order.Unit).ToHashSet();
List<Unit> unorderedUnits = allOrderableUnits
.Where(unit => !orderedUnits.Contains(unit))
.ToList();
List<HoldOrder> implicitHolds = unorderedUnits
.Select(unit => new HoldOrder(unit.Power, unit))
.ToList();
validationResults = validationResults
.Concat(implicitHolds.Select(o => o.Validate(ValidationReason.Valid)))
.ToList();
return validationResults;
}
public List<AdjudicationDecision> AdjudicateOrders(World world, List<Order> orders)
{
// Define all adjudication decisions to be made.
MovementDecisions decisions = new(orders);
List<AdjudicationDecision> unresolvedDecisions = decisions.Values.ToList();
// Adjudicate all decisions.
bool progress = false;
do
{
progress = false;
foreach (AdjudicationDecision decision in unresolvedDecisions.ToList())
{
progress |= ResolveDecision(decision, world, decisions);
if (decision.Resolved) unresolvedDecisions.Remove(decision);
}
} while (progress);
if (unresolvedDecisions.Any())
{
throw new ApplicationException("Some orders not resolved!");
}
return decisions.Values.ToList();
}
public World UpdateWorld(World world, List<AdjudicationDecision> decisions)
{
Dictionary<MoveOrder, DoesMove> moves = decisions
.OfType<DoesMove>()
.ToDictionary(dm => dm.Order);
// All moves to a particular season in a single phase result in the same future. Keep a
// record of when a future season has been created.
Dictionary<Season, Season> createdFutures = new();
List<Unit> createdUnits = new();
List<RetreatingUnit> retreats = new();
// Successful move orders result in the unit moving to the destination and creating a new
// future, while unsuccessful move orders are processed the same way as non-move orders.
foreach (DoesMove doesMove in moves.Values)
{
if (doesMove.Outcome == true)
{
if (!createdFutures.TryGetValue(doesMove.Order.Season, out Season? future))
{
// A timeline that doesn't have a future yet simply continues. Otherwise, it forks.
future = !doesMove.Order.Season.Futures.Any()
? doesMove.Order.Season.MakeNext()
: doesMove.Order.Season.MakeFork();
createdFutures[doesMove.Order.Season] = future;
}
createdUnits.Add(doesMove.Order.Unit.Next(doesMove.Order.Location, future));
}
}
// Process unsuccessful moves, all holds, and all supports.
foreach (IsDislodged isDislodged in decisions.OfType<IsDislodged>())
{
UnitOrder order = isDislodged.Order;
// Skip the move orders that were processed above.
if (order is MoveOrder move && moves[move].Outcome == true)
{
continue;
}
if (!createdFutures.TryGetValue(order.Unit.Season, out Season? future))
{
// Any unit given an order is, by definition, at the front of a timeline.
future = order.Unit.Season.MakeNext();
createdFutures[order.Unit.Season] = future;
}
// For each stationary unit that wasn't dislodged, continue it into the future.
if (isDislodged.Outcome == false)
{
createdUnits.Add(order.Unit.Next(order.Unit.Location, future));
}
else
{
// Create a retreat for each dislodged unit.
// TODO check valid retreats and disbands
var validRetreats = order.Unit.Location.Adjacents
.Select(loc => (future, loc))
.ToList();
RetreatingUnit retreat = new(order.Unit, validRetreats);
retreats.Add(retreat);
}
}
// TODO provide more structured information about order outcomes
World updated = world
.WithSeasons(world.Seasons.Concat(createdFutures.Values))
.WithUnits(world.Units.Concat(createdUnits))
.WithRetreats(retreats);
return updated;
}
private bool ResolveDecision(
AdjudicationDecision decision,
World world,
MovementDecisions decisions)
=> decision.Resolved ? false : decision switch
{
IsDislodged d => ResolveIsUnitDislodged(d, world, decisions),
HasPath d => ResolveDoesMoveHavePath(d, world, decisions),
GivesSupport d => ResolveIsSupportGiven(d, world, decisions),
HoldStrength d => ResolveHoldStrength(d, world, decisions),
AttackStrength d => ResolveAttackStrength(d, world, decisions),
DefendStrength d => ResolveDefendStrength(d, world, decisions),
PreventStrength d => ResolvePreventStrength(d, world, decisions),
DoesMove d => ResolveDoesUnitMove(d, world, decisions),
_ => throw new NotSupportedException($"Unknown decision type: {decision.GetType()}")
};
private bool ResolveIsUnitDislodged(
IsDislodged decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// If this unit was ordered to move and is doing so successfully, it cannot be dislodged
// even if another unit will successfully move into the province.
if (decision.Order is MoveOrder moveOrder)
{
DoesMove move = decisions.DoesMove[moveOrder];
progress |= ResolveDecision(move, world, decisions);
// If this unit received a move order and the move is successful, it cannot be
// dislodged.
if (move.Outcome == true)
{
progress |= decision.Update(false);
return progress;
}
// If the move is undecided, then the dislodge decision is undecidable until then.
if (move.Outcome == null)
{
return progress;
}
}
// If this unit isn't moving from its current province, then it is dislodged if another
// unit has a successful move into its province, and it is not dislodged if every unit that
// could move into its province fails to do so.
bool potentialDislodger = false;
foreach (MoveOrder dislodger in decision.Incoming)
{
DoesMove move = decisions.DoesMove[dislodger];
progress |= ResolveDecision(move, world, decisions);
// If at least one invader will move, this unit is dislodged.
if (move.Outcome == true)
{
progress |= decision.Update(true);
return progress;
}
// If the invader could potentially move, the dislodge decision can't be resolved to
// false.
if (move.Outcome != false)
{
potentialDislodger = true;
}
}
if (!potentialDislodger)
{
progress |= decision.Update(false);
}
return progress;
}
private bool ResolveDoesMoveHavePath(
HasPath decision,
World world,
MovementDecisions decisions)
{
bool progress= false;
// If the origin and destination are adjacent, then there is a path.
if (// Map adjacency
decision.Order.Unit.Location.Adjacents.Contains(decision.Order.Location)
// Turn adjacency
&& Math.Abs(decision.Order.Unit.Season.Turn - decision.Order.Season.Turn) <= 1
// Timeline adjacency
&& decision.Order.Unit.Season.InAdjacentTimeline(decision.Order.Season))
{
progress |= decision.Update(true);
return progress;
}
// If the origin and destination are not adjacent, then the decision resolves to whether
// there is a path of convoying fleets that (1) have matching orders and (2) are not
// dislodged.
// The adjudicator should have received a validated set of orders, so any illegal move
// with no possible convoy path should have been invalidated.
throw new NotImplementedException(); // TODO
}
private bool ResolveIsSupportGiven(
GivesSupport decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// Support is cut when a unit moves into the supporting unit's province with nonzero
// attack strength. Support is given when there is known to be no such unit.
bool potentialNonzeroAttack = false;
foreach (MoveOrder cut in decision.Cuts)
{
AttackStrength attack = decisions.AttackStrength[cut];
progress |= ResolveDecision(attack, world, decisions);
// If at least one attack has a nonzero minimum, the support decision can be resolved
// to false.
if (attack.MinValue > 0)
{
progress |= decision.Update(false);
return progress;
}
// If at least one attack has a nonzero maximum, the support decision can't be resolved
// to true.
if (attack.MaxValue > 0)
{
potentialNonzeroAttack = true;
}
}
// Support is also cut if the unit is dislodged.
IsDislodged dislodge = decisions.IsDislodged[decision.Order.Unit];
progress |= ResolveDecision(dislodge, world, decisions);
if (dislodge.Outcome == true)
{
progress |= decision.Update(false);
return progress;
}
// If no attack has potentially nonzero attack strength, and the dislodge decision is
// resolved to false, then the support is given.
if (!potentialNonzeroAttack && dislodge.Outcome == false)
{
progress |= decision.Update(true);
return progress;
}
// Otherwise, the support remains undecided.
return progress;
}
private bool ResolveHoldStrength(
HoldStrength decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// If no unit is in the province, the hold strength is zero.
if (decision.Order == null)
{
progress |= decision.Update(0, 0);
return progress;
}
// If a unit with a move order is in the province, the strength depends on the move success.
if (decision.Order is MoveOrder move)
{
DoesMove moves = decisions.DoesMove[move];
progress |= ResolveDecision(moves, world, decisions);
progress |= decision.Update(
moves.Outcome != false ? 0 : 1,
moves.Outcome == true ? 0 : 1);
return progress;
}
// If a unit without a move order is in the province, add up the supports.
else
{
int min = 1;
int max = 1;
foreach (SupportHoldOrder support in decision.Supports)
{
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
progress |= decision.Update(min, max);
return progress;
}
}
private bool ResolveAttackStrength(
AttackStrength decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// If there is no path, the attack strength is zero.
var hasPath = decisions.HasPath[decision.Order];
progress |= ResolveDecision(hasPath, world, decisions);
if (hasPath.Outcome == false)
{
progress |= decision.Update(0, 0);
return progress;
}
// If there is a head to head battle, a unit at the destination that isn't moving away, or
// a unit at the destination that will fail to move away, then the attacking unit will have
// to dislodge it.
UnitOrder? destOrder = decisions.HoldStrength[decision.Order.Point].Order;
DoesMove? destMoveAway = destOrder is MoveOrder moveAway
? decisions.DoesMove[moveAway]
: null;
if (destMoveAway != null)
{
progress |= ResolveDecision(destMoveAway, world, decisions);
}
if (// In any case here, there will have to be a unit at the destination with an order,
// which means that destOrder will have to be populated. Including this in the if
//condition lets the compiler know it won't be null in the if block.
destOrder != null
&& (// Is head to head
decision.OpposingMove != null
// Is not moving away
|| destMoveAway == null
// Is failing to move away
|| destMoveAway.Outcome == false))
{
Power destPower = destOrder.Unit.Power;
if (decision.Order.Unit.Power == destPower)
{
// Cannot dislodge own unit.
progress |= decision.Update(0, 0);
return progress;
}
else
{
// Supports won't help to dislodge units of the same power as the support.
int min = 1;
int max = 1;
foreach (SupportMoveOrder support in decision.Supports)
{
if (support.Unit.Power == destPower) continue;
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
progress |= decision.Update(min, max);
return progress;
}
}
else if (destMoveAway != null && destMoveAway.Outcome == null)
{
// If the unit at the destination has an undecided move order, then the minimum tracks
// the case where it doesn't move and the attack strength is mitigated by supports not
// helping to dislodge units of the same power as the support. The maximum tracks the
// case where it does move and the attack strength is unmitigated.
Power destPower = destMoveAway.Order.Unit.Power;
int min = 1;
int max = 1;
foreach (SupportMoveOrder support in decision.Supports)
{
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (support.Unit.Power != destPower && givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
// Force min to zero in case of an attempt to disloge a unit of the same power.
if (decision.Order.Unit.Power == destPower) min = 0;
progress |= decision.Update(min, max);
return progress;
}
else
{
// If the unit at the destination is going somewhere else, then attack strength
// includes all supports from all powers.
int min = 1;
int max = 1;
foreach (SupportMoveOrder support in decision.Supports)
{
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
progress |= decision.Update(min, max);
return progress;
}
}
private bool ResolveDefendStrength(
DefendStrength decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// The defend strength is equal to one plus, at least, the number of known successful
// supports, and at most, also the unresolved supports were they to resolve to successes.
int min = 1;
int max = 1;
foreach (SupportMoveOrder support in decision.Supports)
{
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
progress |= decision.Update(min, max);
return progress;
}
private bool ResolvePreventStrength(
PreventStrength decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// If there is no path, the prevent strength is zero.
var hasPath = decisions.HasPath[decision.Order];
progress |= ResolveDecision(hasPath, world, decisions);
if (hasPath.Outcome == false)
{
progress |= decision.Update(0, 0);
return progress;
}
// If there's a head to head battle and the opposing unit succeeds in moving, the prevent
// strength is zero.
if (decision.OpposingMove != null
&& decisions.DoesMove[decision.OpposingMove].Outcome == true)
{
progress |= decision.Update(0, 0);
return progress;
}
// In all other cases, the prevent strength is equal to one plus, at least, the number of
// known successful supports, and at most, also the unresolved supports were they to
// resolve to successes.
int min = 1;
int max = 1;
foreach (SupportMoveOrder support in decision.Supports)
{
GivesSupport givesSupport = decisions.GivesSupport[support];
progress |= ResolveDecision(givesSupport, world, decisions);
if (givesSupport.Outcome == true) min += 1;
if (givesSupport.Outcome != false) max += 1;
}
// The minimum stays at zero if the path or head to head move decisions are unresolved, as
// they may resolve to one of the conditions above that forces the prevent strength to zero.
if (!hasPath.Resolved
|| (decision.OpposingMove != null
&& !decisions.DoesMove[decision.OpposingMove].Resolved))
{
min = 0;
}
progress |= decision.Update(min, max);
return progress;
}
private bool ResolveDoesUnitMove(
DoesMove decision,
World world,
MovementDecisions decisions)
{
bool progress = false;
// Resolve the move's attack strength.
AttackStrength attack = decisions.AttackStrength[decision.Order];
progress |= ResolveDecision(attack, world, decisions);
// In a head to head battle, the threshold for the attack strength to beat is the opposing
// defend strength. Outside a head to head battle, the threshold is the destination's hold
// strength.
NumericAdjudicationDecision defense = decision.OpposingMove != null
? decisions.DefendStrength[decision.OpposingMove]
: decisions.HoldStrength[decision.Order.Point];
progress |= ResolveDecision(defense, world, decisions);
// If the attack doesn't beat the defense, resolve the move to false.
if (attack.MaxValue <= defense.MinValue)
{
progress |= decision.Update(false);
return progress;
}
// Check if a competing move will prevent this one.
bool beatsAllCompetingMoves = true;
foreach (MoveOrder order in decision.Competing)
{
PreventStrength prevent = decisions.PreventStrength[order];
progress |= ResolveDecision(prevent, world, decisions);
// If attack doesn't beat the prevent, resolve the move to false.
if (attack.MaxValue <= prevent.MinValue)
{
progress |= decision.Update(false);
return progress;
}
// If the attack doesn't beat the prevent, it can't resolve to true.
if (attack.MinValue <= prevent.MaxValue)
{
beatsAllCompetingMoves = false;
}
}
// If the attack didn't resolve to false because the defense or a prevent beat it, then
// attempt to resolve it to true based on whether it beat the defense and all prevents.
progress |= decision.Update(attack.MinValue > defense.MaxValue && beatsAllCompetingMoves);
return progress;
}
}