oecs-sharp/Game.CardWars/CardEffects.cs

using OECS;

namespace Game.CardWars;

// ────────────────────────────────────────────────────────────
// Simple effects that resolve immediately.
// ────────────────────────────────────────────────────────────

public class WarriorEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Warrior;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        if (HasOtherOnField(world, owner, card, CardEffect.Warrior))
            CardEffectHelpers.AddHorn(world, card);
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;

    private static bool HasOtherOnField(World world, Entity player, Entity self, CardEffect effect)
    {
        return GameUtil.GetFieldCards(world, player)
            .Any(c => c != self && world.HasComponent<CardDef>(c)
                && world.ReadComponent<CardDef>(c).Effect == effect);
    }
}

public class ArcherEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Archer;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        if (HasOtherOnField(world, owner, card, CardEffect.Archer))
        {
            var banner = CardEffectHelpers.GetBanner(world, owner);
            if (banner != Entity.Null) CardEffectHelpers.AddHorn(world, banner);
        }
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;

    private static bool HasOtherOnField(World world, Entity player, Entity self, CardEffect effect)
    {
        return GameUtil.GetFieldCards(world, player)
            .Any(c => c != self && world.HasComponent<CardDef>(c)
                && world.ReadComponent<CardDef>(c).Effect == effect);
    }
}

public class MercenaryEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Mercenary;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        if (!HasOtherOnField(world, owner, card, CardEffect.Mercenary))
            return true;

        world.SetSingleton(new PendingMercenary { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingMercenary>();
        if (target != Entity.Null)
            CardEffectHelpers.AddSkull(world, target);
        world.RemoveSingleton<PendingMercenary>();
        return true;
    }

    private static bool HasOtherOnField(World world, Entity player, Entity self, CardEffect effect)
    {
        return GameUtil.GetFieldCards(world, player)
            .Any(c => c != self && world.HasComponent<CardDef>(c)
                && world.ReadComponent<CardDef>(c).Effect == effect);
    }
}

public class MerchantEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Merchant;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.Commands.Enqueue(new DrawCardCommand { Player = player, Kind = null });
        world.Commands.Enqueue(new ExtraActionCommand());
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

public class DancerEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Dancer;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        var powered = GameUtil.GetFieldCards(world, owner)
            .Where(c => world.HasComponent<Card>(c) && world.ReadComponent<Card>(c).Rank > 0)
            .ToList();

        if (powered.Count == 0) return true;
        if (powered.Count <= 2)
        {
            foreach (var c in powered)
                CardEffectHelpers.AddHorn(world, c);
            return true;
        }

        world.SetSingleton(new PendingDancer { CardEntity = card, Player = player, Step = 0 });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingDancer>();

        if (target != Entity.Null)
            CardEffectHelpers.AddHorn(world, target);

        if (pending.Step == 0)
        {
            world.SetSingleton(new PendingDancer { CardEntity = pending.CardEntity, Player = pending.Player, Step = 1 });
            return false;
        }

        world.RemoveSingleton<PendingDancer>();
        return true;
    }
}

public class PaladinEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Paladin;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.SetSingleton(new PendingPaladin { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        if (target != Entity.Null)
            CardEffectHelpers.AddHorn(world, target);
        world.RemoveSingleton<PendingPaladin>();
        return true;
    }
}

public class PrincessEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Princess;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.Commands.Enqueue(new ReplaceCastleCommand());
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

public class DuelistEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Duelist;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.Commands.Enqueue(new EndPlayPhaseCommand());
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

public class NunEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Nun;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        var fieldCards = GameUtil.GetFieldCards(world, owner);
        if (fieldCards.Count == 0)
        {
            world.Commands.Enqueue(new DrawCardCommand { Player = player, Kind = null });
            return true;
        }

        world.SetSingleton(new PendingNun { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingNun>();
        if (target != Entity.Null)
        {
            var discardDeck = CardEffectHelpers.GetDiscardDeck(world, pending.Player);
            world.RemoveComponent<OnField>(target);
            if (world.HasComponent<Card>(target))
                world.RemoveComponent<Card>(target);
            world.AddComponent(target, new InDeck { Source = target, Target = discardDeck });
        }
        world.Commands.Enqueue(new DrawCardCommand { Player = pending.Player, Kind = null });
        world.RemoveSingleton<PendingNun>();
        return true;
    }
}

public class ScoutEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Scout;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.SetSingleton(new PendingScout { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingScout>();
        if (target != Entity.Null && world.HasComponent<Player>(target))
        {
            foreach (var c in GameUtil.GetFieldCards(world, target))
            {
                if (world.TryGetComponent<Card>(c, out var cd) && cd.FaceDown)
                {
                    ref var cardRef = ref world.GetComponent<Card>(c);
                    cardRef.FaceDown = false;
                    world.MarkModified<Card>(c);
                }
            }
        }
        world.RemoveSingleton<PendingScout>();
        return true;
    }
}

public class WitchEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Witch;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        var banner = CardEffectHelpers.GetBanner(world, owner);
        if (banner != Entity.Null)
            CardEffectHelpers.AddSkull(world, banner);
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

public class ThiefEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Thief;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

// ────────────────────────────────────────────────────────────
// Face-down flip effects
// ────────────────────────────────────────────────────────────

public class PegasusEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Pegasus;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.SetSingleton(new PendingPegasus { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingPegasus>();
        if (target != Entity.Null && target != pending.CardEntity)
        {
            world.RemoveComponent<OnField>(target);
            if (world.HasComponent<Card>(target))
                world.RemoveComponent<Card>(target);
            world.AddComponent(target, new HeldBy { Source = target, Target = pending.Player });
        }
        world.RemoveSingleton<PendingPegasus>();
        return true;
    }
}

public class CurseMasterEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.CurseMaster;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        world.SetSingleton(new PendingCurseMaster { CardEntity = card, Player = player });
        return false;
    }

    public bool ResolveChoice(World world, Entity target)
    {
        var pending = world.ReadSingleton<PendingCurseMaster>();
        if (target != Entity.Null && world.HasComponent<Horn>(target))
        {
            var placedTargets = world.GetSources<PlacedOn>(target).ToList();
            world.DestroyEntity(target);
            foreach (var pt in placedTargets)
            {
                var skull = world.CreateEntity();
                world.AddComponent(skull, new Skull());
                world.AddComponent(skull, new PlacedOn { Source = skull, Target = pt });
            }
        }
        world.RemoveSingleton<PendingCurseMaster>();
        return true;
    }
}

public class MageEffect : ICardEffect
{
    public CardEffect Effect => CardEffect.Mage;

    public bool Resolve(World world, Entity card, Entity player, Entity owner)
    {
        Entity best = Entity.Null;
        int bestRank = int.MinValue;
        foreach (var p in GameUtil.FindAllEntities<Player>(world))
        {
            foreach (var c in GameUtil.GetFieldCards(world, p))
            {
                if (world.TryGetComponent<Card>(c, out var cd) && !cd.FaceDown && cd.Rank > bestRank)
                {
                    bestRank = cd.Rank;
                    best = c;
                }
            }
        }
        if (best != Entity.Null)
            CardEffectHelpers.AddSkull(world, best);
        return true;
    }

    public bool ResolveChoice(World world, Entity target) => true;
}

// ────────────────────────────────────────────────────────────
// Shared helpers
// ────────────────────────────────────────────────────────────

public static class CardEffectHelpers
{
    public static void AddHorn(World world, Entity target)
    {
        var horn = world.CreateEntity();
        world.AddComponent(horn, new Horn());
        world.AddComponent(horn, new PlacedOn { Source = horn, Target = target });
    }

    public static void AddSkull(World world, Entity target)
    {
        var skull = world.CreateEntity();
        world.AddComponent(skull, new Skull());
        world.AddComponent(skull, new PlacedOn { Source = skull, Target = target });
    }

    public static Entity GetBanner(World world, Entity player)
    {
        using var iter = world.Select<Banner>();
        while (iter.MoveNext())
        {
            if (iter.CurrentEntity == World.SingletonEntity) continue;
            var onField = world.GetSources<OnField>(player);
            if (onField.Contains(iter.CurrentEntity))
                return iter.CurrentEntity;
        }
        return Entity.Null;
    }

    public static Entity GetDiscardDeck(World world, Entity player)
    {
        using var iter = world.Select<FactionDeck>();
        while (iter.MoveNext())
        {
            if (iter.CurrentEntity != World.SingletonEntity)
                return iter.CurrentEntity;
        }
        return Entity.Null;
    }
}