refactor(input): extract the gameplay frame

src/AcDream.App/Combat/CombatAttackTargetSource.cs

@@ -0,0 +1,116 @@
+using System.Numerics;
+using AcDream.App.Input;
+using AcDream.App.World;
+using AcDream.Core.Combat;
+using AcDream.Core.Items;
+using AcDream.Core.Physics;
+using AcDream.Core.Selection;
+using AcDream.Core.World;
+
+namespace AcDream.App.Combat;
+
+/// <summary>
+/// Focused automatic-attack target owner. It shares canonical selection and
+/// live-entity state without retaining the broader interaction controller.
+/// </summary>
+internal sealed class CombatAttackTargetSource : ICombatAttackTargetSource
+{
+    private readonly SelectionState _selection;
+    private readonly LiveEntityRuntime _liveEntities;
+    private readonly ClientObjectTable _objects;
+    private readonly ILocalPlayerIdentitySource _player;
+
+    public CombatAttackTargetSource(
+        SelectionState selection,
+        LiveEntityRuntime liveEntities,
+        ClientObjectTable objects,
+        ILocalPlayerIdentitySource player)
+    {
+        _selection = selection ?? throw new ArgumentNullException(nameof(selection));
+        _liveEntities = liveEntities
+            ?? throw new ArgumentNullException(nameof(liveEntities));
+        _objects = objects ?? throw new ArgumentNullException(nameof(objects));
+        _player = player ?? throw new ArgumentNullException(nameof(player));
+    }
+
+    public uint? SelectedObjectId => _selection.SelectedObjectId;
+
+    public uint? GetSelectedOrClosestCombatTarget(bool autoTarget)
+    {
+        if (_selection.SelectedObjectId is { } selected
+            && IsHostileMonster(selected))
+        {
+            return selected;
+        }
+
+        if (!autoTarget)
+            return null;
+
+        (uint Guid, float DistanceSquared)? closest = FindClosestHostileMonster();
+        if (closest is not { } best)
+        {
+            _selection.Clear(SelectionChangeSource.Keyboard);
+            return null;
+        }
+
+        _selection.Select(best.Guid, SelectionChangeSource.Keyboard);
+        string? name = _objects.Get(best.Guid)?.Name;
+        string label = string.IsNullOrWhiteSpace(name)
+            ? $"0x{best.Guid:X8}"
+            : name;
+        Console.WriteLine(
+            $"combat: selected target 0x{best.Guid:X8} {label} dist={MathF.Sqrt(best.DistanceSquared):F1}");
+        return best.Guid;
+    }
+
+    private (uint Guid, float DistanceSquared)? FindClosestHostileMonster()
+    {
+        if (!_liveEntities.TryGetWorldEntity(
+                _player.ServerGuid,
+                out WorldEntity playerEntity))
+        {
+            return null;
+        }
+
+        (uint Guid, float DistanceSquared)? best = null;
+        foreach ((uint guid, WorldEntity entity) in _liveEntities.WorldEntities)
+        {
+            if (!IsHostileMonster(guid))
+                continue;
+
+            float distanceSquared = Vector3.DistanceSquared(
+                entity.Position,
+                playerEntity.Position);
+            if (best is null || distanceSquared < best.Value.DistanceSquared)
+                best = (guid, distanceSquared);
+        }
+        return best;
+    }
+
+    private bool IsHostileMonster(uint serverGuid)
+    {
+        uint playerGuid = _player.ServerGuid;
+        if (serverGuid == playerGuid
+            || !_liveEntities.TryGetInteractionEligibleRecord(
+                serverGuid,
+                out LiveEntityRecord record)
+            || record.WorldEntity is not { } entity)
+        {
+            return false;
+        }
+
+        if (_liveEntities.TryGetAnimationRuntime(entity.Id, out var animation)
+            && animation.CurrentMotion == MotionCommand.Dead)
+        {
+            return false;
+        }
+
+        ClientObject? candidate = _objects.Get(serverGuid);
+        return candidate is not null
+            && (candidate.Type & ItemType.Creature) != 0
+            && CombatTargetPolicy.IsHostileMonster(
+                playerGuid,
+                _objects.Get(playerGuid),
+                candidate);
+    }
+}