Pathfinder rework (#11452)

Content.Server/NPC/Pathfinding/PathRequest.cs

@@ -0,0 +1,110 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Content.Shared.NPC;
+using Robust.Shared.Map;
+using Robust.Shared.Timing;
+using Robust.Shared.Utility;
+
+namespace Content.Server.NPC.Pathfinding;
+
+/// <summary>
+/// Stores the in-progress data of a pathfinding request.
+/// </summary>
+public abstract class PathRequest
+{
+    public EntityCoordinates Start;
+
+    public Task<PathResult> Task => Tcs.Task;
+    public readonly TaskCompletionSource<PathResult> Tcs;
+
+    public Queue<PathPoly> Polys = new();
+
+    public bool Started = false;
+
+    #region Pathfinding state
+
+    public readonly Stopwatch Stopwatch = new();
+    public PriorityQueue<ValueTuple<float, PathPoly>> Frontier = default!;
+    public readonly Dictionary<PathPoly, float> CostSoFar = new();
+    public readonly Dictionary<PathPoly, PathPoly> CameFrom = new();
+
+    #endregion
+
+    #region Data
+
+    public readonly PathFlags Flags;
+    public readonly float Range;
+    public readonly int CollisionLayer;
+    public readonly int CollisionMask;
+
+    #endregion
+
+    public PathRequest(EntityCoordinates start, PathFlags flags, float range, int layer, int mask, CancellationToken cancelToken)
+    {
+        Start = start;
+        Flags = flags;
+        Range = range;
+        CollisionLayer = layer;
+        CollisionMask = mask;
+        Tcs = new TaskCompletionSource<PathResult>(cancelToken);
+    }
+}
+
+public sealed class AStarPathRequest : PathRequest
+{
+    public EntityCoordinates End;
+
+    public AStarPathRequest(
+        EntityCoordinates start,
+        EntityCoordinates end,
+        PathFlags flags,
+        float range,
+        int layer,
+        int mask,
+        CancellationToken cancelToken) : base(start, flags, range, layer, mask, cancelToken)
+    {
+        End = end;
+    }
+}
+
+public sealed class BFSPathRequest : PathRequest
+{
+    /// <summary>
+    /// How far away we're allowed to expand in distance.
+    /// </summary>
+    public float ExpansionRange;
+
+    /// <summary>
+    /// How many nodes we're allowed to expand
+    /// </summary>
+    public int ExpansionLimit;
+
+    public BFSPathRequest(
+        float expansionRange,
+        int expansionLimit,
+        EntityCoordinates start,
+        PathFlags flags,
+        float range,
+        int layer,
+        int mask,
+        CancellationToken cancelToken) : base(start, flags, range, layer, mask, cancelToken)
+        {
+            ExpansionRange = expansionRange;
+            ExpansionLimit = expansionLimit;
+        }
+}
+
+/// <summary>
+/// Stores the final result of a pathfinding request
+/// </summary>
+public sealed class PathResultEvent
+{
+    public PathResult Result;
+    public readonly Queue<PathPoly> Path;
+
+    public PathResultEvent(PathResult result, Queue<PathPoly> path)
+    {
+        Result = result;
+        Path = path;
+    }
+}