using System;
using Server.Items;
using Server.PathAlgorithms;
using Server.PathAlgorithms.FastAStar;
using Server.PathAlgorithms.SlowAStar;
using Server.Spells;
using Server.Targeting;

namespace Server
{
  public sealed class MovementPath
  {
    public MovementPath(Mobile m, Point3D goal)
    {
      Point3D start = m.Location;
      Map map = m.Map;

      Map = map;
      Start = start;
      Goal = goal;

      if (map == null || map == Map.Internal)
        return;

      if (Utility.InRange(start, goal, 1))
        return;

      try
      {
        PathAlgorithm alg = OverrideAlgorithm ?? FastAStarAlgorithm.Instance;

        if (alg?.CheckCondition(m, map, start, goal) == true)
          Directions = alg.Find(m, map, start, goal);
      }
      catch (Exception e)
      {
        Console.WriteLine("Warning: {0}: Pathing error from {1} to {2}", e.GetType().Name, start, goal);
      }
    }

    public Map Map{ get; }

    public Point3D Start{ get; }

    public Point3D Goal{ get; }

    public Direction[] Directions{ get; }

    public bool Success => Directions?.Length > 0;

    public static PathAlgorithm OverrideAlgorithm{ get; set; }

    public static void Initialize()
    {
      CommandSystem.Register("Path", AccessLevel.GameMaster, Path_OnCommand);
    }

    public static void Path_OnCommand(CommandEventArgs e)
    {
      e.Mobile.BeginTarget(-1, true, TargetFlags.None, Path_OnTarget);
      e.Mobile.SendMessage("Target a location and a path will be drawn there.");
    }

    private static void Path(Mobile from, IPoint3D p, PathAlgorithm alg, string name, int zOffset)
    {
      OverrideAlgorithm = alg;

      long start = DateTime.UtcNow.Ticks;
      MovementPath path = new MovementPath(from, new Point3D(p));
      long end = DateTime.UtcNow.Ticks;
      double len = Math.Round((end - start) / 10000.0, 2);

      if (!path.Success)
      {
        from.SendMessage("{0} path failed: {1}ms", name, len);
      }
      else
      {
        from.SendMessage("{0} path success: {1}ms", name, len);

        int x = from.X;
        int y = from.Y;
        int z = from.Z;

        for (int i = 0; i < path.Directions.Length; ++i)
        {
          Movement.Movement.Offset(path.Directions[i], ref x, ref y);

          new RecallRune().MoveToWorld(new Point3D(x, y, z + zOffset), from.Map);
        }
      }
    }

    public static void Path_OnTarget(Mobile from, object targeted)
    {
      if (!(targeted is IPoint3D p))
        return;

      SpellHelper.GetSurfaceTop(ref p);

      Path(from, p, FastAStarAlgorithm.Instance, "Fast", 0);
      Path(from, p, SlowAStarAlgorithm.Instance, "Slow", 2);
      OverrideAlgorithm = null;
    }
  }
}