ModernUO/Projects/Scripts/Spells/Base/SpellHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Server.Engines.CannedEvil;
using Server.Engines.ConPVP;
using Server.Engines.PartySystem;
using Server.Factions;
using Server.Guilds;
using Server.Items;
using Server.Misc;
using Server.Mobiles;
using Server.Multis;
using Server.Regions;
using Server.Spells.Fifth;
using Server.Spells.Necromancy;
using Server.Spells.Ninjitsu;
using Server.Spells.Seventh;
using Server.Targeting;

namespace Server
{
  public class DefensiveSpell
  {
    public static void Nullify(Mobile from)
    {
      if (!from.CanBeginAction<DefensiveSpell>())
        new InternalTimer(from).Start();
    }

    private class InternalTimer : Timer
    {
      private Mobile m_Mobile;

      public InternalTimer(Mobile m)
        : base(TimeSpan.FromMinutes(1.0))
      {
        m_Mobile = m;

        Priority = TimerPriority.OneSecond;
      }

      protected override void OnTick()
      {
        m_Mobile.EndAction<DefensiveSpell>();
      }
    }
  }
}

namespace Server.Spells
{
  public enum TravelCheckType
  {
    RecallFrom,
    RecallTo,
    GateFrom,
    GateTo,
    Mark,
    TeleportFrom,
    TeleportTo
  }

  public class SpellHelper
  {
    private static TimeSpan AosDamageDelay = TimeSpan.FromSeconds(1.0);
    private static TimeSpan OldDamageDelay = TimeSpan.FromSeconds(0.5);

    private static TimeSpan CombatHeatDelay = TimeSpan.FromSeconds(30.0);
    private static bool RestrictTravelCombat = true;

    private static int[] m_Offsets =
    {
      -1, -1,
      -1, 0,
      -1, 1,
      0, -1,
      0, 1,
      1, -1,
      1, 0,
      1, 1
    };

    private static TravelValidator[] m_Validators =
    {
      IsFeluccaT2A,
      IsKhaldun,
      IsIlshenar,
      IsTrammelWind,
      IsFeluccaWind,
      IsFeluccaDungeon,
      IsTrammelSolenHive,
      IsFeluccaSolenHive,
      IsCrystalCave,
      IsDoomGauntlet,
      IsDoomFerry,
      IsSafeZone,
      IsFactionStronghold,
      IsChampionSpawn,
      IsTokunoDungeon,
      IsLampRoom,
      IsGuardianRoom,
      IsHeartwood,
      IsMLDungeon
    };

    // TODO: Find a better way
    private static bool[,] m_Rules =
    {
      /*T2A(Fel),	Khaldun,	Ilshenar,	Wind(Tram),	Wind(Fel),	Dungeons(Fel),	Solen(Tram),	Solen(Fel),	CrystalCave(Malas),	Gauntlet(Malas),	Gauntlet(Ferry),	SafeZone,	Stronghold,	ChampionSpawn,	Dungeons(Tokuno[Malas]),	LampRoom(Doom),	GuardianRoom(Doom),	Heartwood,	MLDungeons */
      /* Recall From */
      {
        false, false, true, true, false, false, true, false, false, false, false, true, true, false, true, false,
        false, false, false
      },
      /* Recall To */
      {
        false, false, false, false, false, false, false, false, false, false, false, false, false, false, false,
        false, false, false, false
      },
      /* Gate From */
      {
        false, false, false, false, false, false, false, false, false, false, false, false, false, false, false,
        false, false, false, false
      },
      /* Gate To */
      {
        false, false, false, false, false, false, false, false, false, false, false, false, false, false, false,
        false, false, false, false
      },
      /* Mark In */
      {
        false, false, false, false, false, false, false, false, false, false, false, false, false, false, false,
        false, false, false, false
      },
      /* Tele From */
      {
        true, true, true, true, true, true, true, true, false, true, true, true, false, true, true, true, true,
        false, true
      },
      /* Tele To */
      {
        true, true, true, true, true, true, true, true, false, true, false, false, false, true, true, true, true,
        false, false
      }
    };

    private static Mobile m_TravelCaster;
    private static TravelCheckType m_TravelType;

    public static bool DisableSkillCheck{ get; set; }

    public static TimeSpan GetDamageDelayForSpell(Spell sp) =>
      !sp.DelayedDamage ? TimeSpan.Zero : Core.AOS ? AosDamageDelay : OldDamageDelay;

    public static bool CheckMulti(Point3D p, Map map, bool houses = true, int housingrange = 0)
    {
      if (map == null || map == Map.Internal)
        return false;

      Sector sector = map.GetSector(p.X, p.Y);

      for (int i = 0; i < sector.Multis.Count; ++i)
      {
        BaseMulti multi = sector.Multis[i];

        if (multi is BaseHouse bh)
        {
          if (houses && bh.IsInside(p, 16) || housingrange > 0 && bh.InRange(p, housingrange))
            return true;
        }
        else if (multi.Contains(p))
          return true;
      }

      return false;
    }

    public static void Turn(Mobile from, object to)
    {
      if (!(to is IPoint3D target))
        return;

      if (target is Item item)
      {
        if (item.RootParent != from)
          from.Direction = from.GetDirectionTo(item.GetWorldLocation());
      }
      else if (!ReferenceEquals(from, target))
        from.Direction = from.GetDirectionTo(target);
    }

    public static bool CheckCombat(Mobile m) =>
      RestrictTravelCombat &&
      (m.Aggressed.Any(info => info.Defender.Player && DateTime.UtcNow - info.LastCombatTime < CombatHeatDelay) ||
       Core.Expansion == Expansion.AOS && m.Aggressors.Any(info =>
         info.Attacker.Player && DateTime.UtcNow - info.LastCombatTime < CombatHeatDelay));

    public static bool AdjustField(ref Point3D p, Map map, int height, bool mobsBlock)
    {
      if (map == null)
        return false;

      for (int offset = 0; offset < 10; ++offset)
      {
        Point3D loc = new Point3D(p.X, p.Y, p.Z - offset);

        if (map.CanFit(loc, height, true, mobsBlock))
        {
          p = loc;
          return true;
        }
      }

      return false;
    }

    public static bool CanRevealCaster(Mobile m) => m is BaseCreature c && !c.Controlled;

    public static void GetSurfaceTop(ref IPoint3D p)
    {
      if (p is Item item)
        p = item.GetSurfaceTop();
      else if (p is StaticTarget t)
      {
        int z = t.Z;

        if ((t.Flags & TileFlag.Surface) == 0)
          z -= TileData.ItemTable[t.ItemID & TileData.MaxItemValue].CalcHeight;

        p = new Point3D(t.X, t.Y, z);
      }
    }

    public static bool AddStatOffset(Mobile m, StatType type, int offset, TimeSpan duration) =>
      offset > 0
        ? AddStatBonus(m, m, type, offset, duration)
        : offset >= 0 || AddStatCurse(m, m, type, -offset, duration);

    public static bool AddStatBonus(Mobile caster, Mobile target, StatType type) => AddStatBonus(caster, target, type, GetOffset(caster, target, type, false), GetDuration(caster, target));

    public static bool AddStatBonus(Mobile caster, Mobile target, StatType type, int bonus, TimeSpan duration)
    {
      int offset = bonus;
      string name = $"[Magic] {type} Offset";

      StatMod mod = target.GetStatMod(name);

      if (mod?.Offset < 0)
      {
        target.AddStatMod(new StatMod(type, name, mod.Offset + offset, duration));
        return true;
      }

      if (mod == null || mod.Offset < offset)
      {
        target.AddStatMod(new StatMod(type, name, offset, duration));
        return true;
      }

      return false;
    }

    public static bool AddStatCurse(Mobile caster, Mobile target, StatType type) => AddStatCurse(caster, target, type, GetOffset(caster, target, type, true), GetDuration(caster, target));

    public static bool AddStatCurse(Mobile caster, Mobile target, StatType type, int curse, TimeSpan duration)
    {
      int offset = -curse;
      string name = $"[Magic] {type} Offset";

      StatMod mod = target.GetStatMod(name);

      if (mod?.Offset > 0)
      {
        target.AddStatMod(new StatMod(type, name, mod.Offset + offset, duration));
        return true;
      }

      if (mod == null || mod.Offset > offset)
      {
        target.AddStatMod(new StatMod(type, name, offset, duration));
        return true;
      }

      return false;
    }

    public static TimeSpan GetDuration(Mobile caster, Mobile target)
    {
      if (Core.AOS)
        return TimeSpan.FromSeconds(6 * caster.Skills.EvalInt.Fixed / 50 + 1);

      return TimeSpan.FromSeconds(caster.Skills.Magery.Value * 1.2);
    }

    public static double GetOffsetScalar(Mobile caster, Mobile target, bool curse)
    {
      double percent;

      if (curse)
        percent = 8 + caster.Skills.EvalInt.Fixed / 100 - target.Skills.MagicResist.Fixed / 100;
      else
        percent = 1 + caster.Skills.EvalInt.Fixed / 100;

      percent *= 0.01;

      if (percent < 0)
        percent = 0;

      return percent;
    }

    public static int GetOffset(Mobile caster, Mobile target, StatType type, bool curse)
    {
      if (Core.AOS)
      {
        if (!DisableSkillCheck)
        {
          caster.CheckSkill(SkillName.EvalInt, 0.0, 120.0);

          if (curse)
            target.CheckSkill(SkillName.MagicResist, 0.0, 120.0);
        }

        double percent = GetOffsetScalar(caster, target, curse);

        switch (type)
        {
          case StatType.Str:
            return (int)(target.RawStr * percent);
          case StatType.Dex:
            return (int)(target.RawDex * percent);
          case StatType.Int:
            return (int)(target.RawInt * percent);
        }
      }

      return 1 + (int)(caster.Skills.Magery.Value * 0.1);
    }

    public static Guild GetGuildFor(Mobile m)
    {
      Guild g = m.Guild as Guild;

      if (g == null && m is BaseCreature c)
      {
        m = c.ControlMaster;

        if (m != null)
          g = m.Guild as Guild;

        if (g == null)
        {
          m = c.SummonMaster;

          if (m != null)
            g = m.Guild as Guild;
        }
      }

      return g;
    }

    public static bool ValidIndirectTarget(Mobile from, Mobile to)
    {
      if (from == to)
        return true;

      if (to.Hidden && to.AccessLevel > from.AccessLevel)
        return false;

      BaseCreature bcFrom = from as BaseCreature;
      BaseCreature bcTarg = to as BaseCreature;

      #region Dueling

      PlayerMobile pmFrom;
      PlayerMobile pmTarg;

      if (bcFrom?.Summoned == true)
        pmFrom = bcFrom.SummonMaster as PlayerMobile;
      else
        pmFrom = from as PlayerMobile;

      if (bcTarg?.Summoned == true)
        pmTarg = bcTarg.SummonMaster as PlayerMobile;
      else
        pmTarg = to as PlayerMobile;

      if (pmFrom?.DuelContext != null && pmFrom.DuelContext == pmTarg?.DuelContext && pmFrom.DuelContext.Started &&
          pmFrom.DuelPlayer != null && pmTarg?.DuelPlayer != null)
        return pmFrom.DuelPlayer.Participant != pmTarg.DuelPlayer.Participant;

      #endregion

      Guild fromGuild = GetGuildFor(from);
      Guild toGuild = GetGuildFor(to);

      if (fromGuild != null && toGuild != null && (fromGuild == toGuild || fromGuild.IsAlly(toGuild)))
        return false;

      Party p = Party.Get(from);

      if (p?.Contains(to) == true)
        return false;

      if (bcTarg != null && (bcTarg.Controlled || bcTarg.Summoned))
      {
        if (bcTarg.ControlMaster == from || bcTarg.SummonMaster == from)
          return false;

        if (p != null && (p.Contains(bcTarg.ControlMaster) || p.Contains(bcTarg.SummonMaster)))
          return false;
      }

      if (bcFrom != null && (bcFrom.Controlled || bcFrom.Summoned))
      {
        if (bcFrom.ControlMaster == to || bcFrom.SummonMaster == to)
          return false;

        p = Party.Get(to);

        if (p != null && (p.Contains(bcFrom.ControlMaster) || p.Contains(bcFrom.SummonMaster)))
          return false;
      }

      return bcTarg?.Controlled == false && bcTarg.InitialInnocent ||
             Notoriety.Compute(from, to) != Notoriety.Innocent || from.Kills >= 5;
    }

    public static void Summon(BaseCreature creature, Mobile caster, int sound, TimeSpan duration, bool scaleDuration,
      bool scaleStats)
    {
      Map map = caster.Map;

      if (map == null)
        return;

      double scale = 1.0 + (caster.Skills.Magery.Value - 100.0) / 200.0;

      if (scaleDuration)
        duration = TimeSpan.FromSeconds(duration.TotalSeconds * scale);

      if (scaleStats)
      {
        creature.RawStr = (int)(creature.RawStr * scale);
        creature.Hits = creature.HitsMax;

        creature.RawDex = (int)(creature.RawDex * scale);
        creature.Stam = creature.StamMax;

        creature.RawInt = (int)(creature.RawInt * scale);
        creature.Mana = creature.ManaMax;
      }

      Point3D p = new Point3D(caster);

      if (FindValidSpawnLocation(map, ref p, true))
      {
        BaseCreature.Summon(creature, caster, p, sound, duration);
        return;
      }


      /*
      int offset = Utility.Random( 8 ) * 2;

      for( int i = 0; i < m_Offsets.Length; i += 2 )
      {
        int x = caster.X + m_Offsets[(offset + i) % m_Offsets.Length];
        int y = caster.Y + m_Offsets[(offset + i + 1) % m_Offsets.Length];

        if ( map.CanSpawnMobile( x, y, caster.Z ) )
        {
          BaseCreature.Summon( creature, caster, new Point3D( x, y, caster.Z ), sound, duration );
          return;
        }
        else
        {
          int z = map.GetAverageZ( x, y );

          if ( map.CanSpawnMobile( x, y, z ) )
          {
            BaseCreature.Summon( creature, caster, new Point3D( x, y, z ), sound, duration );
            return;
          }
        }
      }
       * */

      creature.Delete();
      caster.SendLocalizedMessage(501942); // That location is blocked.
    }

    public static bool FindValidSpawnLocation(Map map, ref Point3D p, bool surroundingsOnly)
    {
      if (map == null) //sanity
        return false;

      if (!surroundingsOnly)
      {
        if (map.CanSpawnMobile(p)) //p's fine.
        {
          p = new Point3D(p);
          return true;
        }

        int z = map.GetAverageZ(p.X, p.Y);

        if (map.CanSpawnMobile(p.X, p.Y, z))
        {
          p = new Point3D(p.X, p.Y, z);
          return true;
        }
      }

      int offset = Utility.Random(8) * 2;

      for (int i = 0; i < m_Offsets.Length; i += 2)
      {
        int x = p.X + m_Offsets[(offset + i) % m_Offsets.Length];
        int y = p.Y + m_Offsets[(offset + i + 1) % m_Offsets.Length];

        if (map.CanSpawnMobile(x, y, p.Z))
        {
          p = new Point3D(x, y, p.Z);
          return true;
        }

        int z = map.GetAverageZ(x, y);

        if (map.CanSpawnMobile(x, y, z))
        {
          p = new Point3D(x, y, z);
          return true;
        }
      }

      return false;
    }

    public static void SendInvalidMessage(Mobile caster, TravelCheckType type)
    {
      if (type == TravelCheckType.RecallTo || type == TravelCheckType.GateTo)
        caster.SendLocalizedMessage(1019004); // You are not allowed to travel there.
      else if (type == TravelCheckType.TeleportTo)
        caster.SendLocalizedMessage(501035); // You cannot teleport from here to the destination.
      else
        caster.SendLocalizedMessage(501802); // Thy spell doth not appear to work...
    }

    public static bool CheckTravel(Mobile caster, TravelCheckType type) => CheckTravel(caster, caster.Map, caster.Location, type);

    public static bool CheckTravel(Map map, Point3D loc, TravelCheckType type) => CheckTravel(null, map, loc, type);

    public static bool CheckTravel(Mobile caster, Map map, Point3D loc, TravelCheckType type)
    {
      if (IsInvalid(map, loc)) // null, internal, out of bounds
      {
        if (caster != null)
          SendInvalidMessage(caster, type);

        return false;
      }

      if (caster?.AccessLevel == AccessLevel.Player && caster.Region.IsPartOf<Jail>())
      {
        caster.SendLocalizedMessage(1114345); // You'll need a better jailbreak plan than that!
        return false;
      }

      // Always allow monsters to teleport
      if (caster is BaseCreature bc && !bc.Controlled && !bc.Summoned && (type == TravelCheckType.TeleportTo || type == TravelCheckType.TeleportFrom))
        return true;

      m_TravelCaster = caster;
      m_TravelType = type;

      int v = (int)type;
      bool isValid = true;

      for (int i = 0; isValid && i < m_Validators.Length; ++i)
        isValid = m_Rules[v, i] || !m_Validators[i](map, loc);

      if (!isValid && caster != null)
        SendInvalidMessage(caster, type);

      return isValid;
    }

    public static bool IsWindLoc(Point3D loc)
    {
      int x = loc.X, y = loc.Y;

      return x >= 5120 && y >= 0 && x < 5376 && y < 256;
    }

    public static bool IsFeluccaWind(Map map, Point3D loc) => map == Map.Felucca && IsWindLoc(loc);

    public static bool IsTrammelWind(Map map, Point3D loc) => map == Map.Trammel && IsWindLoc(loc);

    public static bool IsIlshenar(Map map, Point3D loc) => map == Map.Ilshenar;

    public static bool IsSolenHiveLoc(Point3D loc)
    {
      int x = loc.X, y = loc.Y;

      return x >= 5640 && y >= 1776 && x < 5935 && y < 2039;
    }

    public static bool IsTrammelSolenHive(Map map, Point3D loc) => map == Map.Trammel && IsSolenHiveLoc(loc);

    public static bool IsFeluccaSolenHive(Map map, Point3D loc) => map == Map.Felucca && IsSolenHiveLoc(loc);

    public static bool IsFeluccaT2A(Map map, Point3D loc)
    {
      int x = loc.X, y = loc.Y;

      return map == Map.Felucca && x >= 5120 && y >= 2304 && x < 6144 && y < 4096;
    }

    public static bool IsAnyT2A(Map map, Point3D loc)
    {
      int x = loc.X, y = loc.Y;

      return (map == Map.Trammel || map == Map.Felucca) && x >= 5120 && y >= 2304 && x < 6144 && y < 4096;
    }

    public static bool IsFeluccaDungeon(Map map, Point3D loc)
    {
      Region region = Region.Find(loc, map);
      return region.IsPartOf<DungeonRegion>() && region.Map == Map.Felucca;
    }

    public static bool IsKhaldun(Map map, Point3D loc) => Region.Find(loc, map).Name == "Khaldun";

    public static bool IsCrystalCave(Map map, Point3D loc)
    {
      if (map != Map.Malas || loc.Z >= -80)
        return false;

      int x = loc.X, y = loc.Y;

      return x >= 1182 && y >= 437 && x < 1211 && y < 470
             || x >= 1156 && y >= 470 && x < 1211 && y < 503
             || x >= 1176 && y >= 503 && x < 1208 && y < 509
             || x >= 1188 && y >= 509 && x < 1201 && y < 513;
    }

    public static bool IsSafeZone(Map map, Point3D loc)
    {
      #region Duels
      if (Region.Find(loc, map).IsPartOf<SafeZone>() &&
          (m_TravelType == TravelCheckType.TeleportTo || m_TravelType == TravelCheckType.TeleportFrom)
          && (m_TravelCaster as PlayerMobile)?.DuelPlayer?.Eliminated == false)
        return true;

      #endregion

      return false;
    }

    public static bool IsFactionStronghold(Map map, Point3D loc) => Region.Find(loc, map).IsPartOf<StrongholdRegion>();

    public static bool IsChampionSpawn(Map map, Point3D loc) => Region.Find(loc, map).IsPartOf<ChampionSpawnRegion>();

    public static bool IsDoomFerry(Map map, Point3D loc)
    {
      if (map != Map.Malas)
        return false;

      int x = loc.X, y = loc.Y;

      if (x >= 426 && y >= 314 && x <= 430 && y <= 331)
        return true;

      if (x >= 406 && y >= 247 && x <= 410 && y <= 264)
        return true;

      return false;
    }

    public static bool IsTokunoDungeon(Map map, Point3D loc)
    {
      //The tokuno dungeons are really inside malas
      if (map != Map.Malas)
        return false;

      int x = loc.X, y = loc.Y, z = loc.Z;

      bool r1 = x >= 0 && y >= 0 && x <= 128 && y <= 128;
      bool r2 = x >= 45 && y >= 320 && x < 195 && y < 710;

      return r1 || r2;
    }

    public static bool IsDoomGauntlet(Map map, Point3D loc)
    {
      if (map != Map.Malas)
        return false;

      int x = loc.X - 256, y = loc.Y - 304;

      return x >= 0 && y >= 0 && x < 256 && y < 256;
    }

    public static bool IsLampRoom(Map map, Point3D loc)
    {
      if (map != Map.Malas)
        return false;

      int x = loc.X, y = loc.Y;

      return x >= 465 && y >= 92 && x < 474 && y < 102;
    }

    public static bool IsGuardianRoom(Map map, Point3D loc)
    {
      if (map != Map.Malas)
        return false;

      int x = loc.X, y = loc.Y;

      return x >= 356 && y >= 5 && x < 375 && y < 25;
    }

    public static bool IsHeartwood(Map map, Point3D loc)
    {
      int x = loc.X, y = loc.Y;

      return (map == Map.Trammel || map == Map.Felucca) && x >= 6911 && y >= 254 && x < 7167 && y < 511;
    }

    public static bool IsMLDungeon(Map map, Point3D loc) => MondainsLegacy.IsMLRegion(Region.Find(loc, map));

    public static bool IsInvalid(Map map, Point3D loc)
    {
      if (map == null || map == Map.Internal)
        return true;

      int x = loc.X, y = loc.Y;

      return x < 0 || y < 0 || x >= map.Width || y >= map.Height;
    }

    //towns
    public static bool IsTown(IPoint3D ip, Mobile caster)
    {
      if (ip is Item item)
        ip = item.GetWorldLocation();

      return IsTown(new Point3D(ip), caster);
    }

    public static bool IsTown(Point3D loc, Mobile caster)
    {
      Map map = caster.Map;

      if (map == null)
        return false;

      #region Dueling
      if (Region.Find(loc, map).GetRegion<SafeZone>() != null)
      {
        PlayerMobile pm = caster as PlayerMobile;

        if (pm.DuelContext?.Started != true || pm.DuelPlayer?.Eliminated != false)
          return true;
      }
      #endregion

      GuardedRegion reg = Region.Find(loc, map).GetRegion<GuardedRegion>();

      return reg?.IsDisabled() == false;
    }

    public static bool CheckTown(IPoint3D ip, Mobile caster)
    {
      if (ip is Item item)
        ip = item.GetWorldLocation();

      return CheckTown(new Point3D(ip), caster);
    }

    public static bool CheckTown(Point3D loc, Mobile caster)
    {
      if (IsTown(loc, caster))
      {
        caster.SendLocalizedMessage(500946); // You cannot cast this in town!
        return false;
      }

      return true;
    }

    //magic reflection
    public static void CheckReflect(int circle, Mobile caster, ref Mobile target)
    {
      CheckReflect(circle, ref caster, ref target);
    }

    public static void CheckReflect(int circle, ref Mobile caster, ref Mobile target)
    {
      if (target.MagicDamageAbsorb > 0)
      {
        ++circle;

        target.MagicDamageAbsorb -= circle;

        // This order isn't very intuitive, but you have to nullify reflect before target gets switched

        bool reflect = target.MagicDamageAbsorb >= 0;

        (target as BaseCreature)?.CheckReflect(caster, ref reflect);

        if (target.MagicDamageAbsorb <= 0)
        {
          target.MagicDamageAbsorb = 0;
          DefensiveSpell.Nullify(target);
        }

        if (reflect)
        {
          target.FixedEffect(0x37B9, 10, 5);

          Mobile temp = caster;
          caster = target;
          target = temp;
        }
      }
      else if (target is BaseCreature creature)
      {
        bool reflect = false;

        creature.CheckReflect(caster, ref reflect);

        if (reflect)
        {
          creature.FixedEffect(0x37B9, 10, 5);

          Mobile temp = caster;
          caster = creature;
          target = temp;
        }
      }
    }

    public static void Damage(Spell spell, Mobile target, double damage)
    {
      TimeSpan ts = GetDamageDelayForSpell(spell);

      Damage(spell, ts, target, spell.Caster, damage);
    }

    public static void Damage(TimeSpan delay, Mobile target, double damage)
    {
      Damage(delay, target, null, damage);
    }

    public static void Damage(TimeSpan delay, Mobile target, Mobile from, double damage)
    {
      Damage(null, delay, target, from, damage);
    }

    public static void Damage(Spell spell, TimeSpan delay, Mobile target, Mobile from, double damage)
    {
      int iDamage = (int)damage;

      if (delay == TimeSpan.Zero)
      {
        (from as BaseCreature)?.AlterSpellDamageTo(target, ref iDamage);

        (target as BaseCreature)?.AlterSpellDamageFrom(from, ref iDamage);

        target.Damage(iDamage, from);
      }
      else
      {
        new SpellDamageTimer(spell, target, from, iDamage, delay).Start();
      }

      if (target is BaseCreature c && from != null && delay == TimeSpan.Zero)
      {
        c.OnHarmfulSpell(from);
        c.OnDamagedBySpell(from);
      }
    }

    public static void Damage(Spell spell, Mobile target, double damage, int phys, int fire, int cold, int pois,
      int nrgy, int chaos = 0, DFAlgorithm dfa = DFAlgorithm.Standard)
    {
      Damage(spell, GetDamageDelayForSpell(spell), target, spell.Caster, damage, phys, fire, cold, pois, nrgy, chaos, dfa);
    }

    public static void Damage(TimeSpan delay, Mobile target, double damage, int phys, int fire, int cold, int pois,
      int nrgy, int chaos = 0, DFAlgorithm dfa = DFAlgorithm.Standard)
    {
      Damage(delay, target, null, damage, phys, fire, cold, pois, nrgy, chaos, dfa);
    }

    public static void Damage(TimeSpan delay, Mobile target, Mobile from, double damage, int phys, int fire, int cold,
      int pois, int nrgy, int chaos = 0, DFAlgorithm dfa = DFAlgorithm.Standard)
    {
      Damage(null, delay, target, from, damage, phys, fire, cold, pois, nrgy, chaos, dfa);
    }

    public static void Damage(Spell spell, TimeSpan delay, Mobile target, Mobile from, double damage, int phys, int fire,
      int cold, int pois, int nrgy, int chaos = 0, DFAlgorithm dfa = DFAlgorithm.Standard)
    {
      int dmg = (int)damage;

      if (delay == TimeSpan.Zero)
      {
        (from as BaseCreature)?.AlterSpellDamageTo(target, ref dmg);

        (target as BaseCreature)?.AlterSpellDamageFrom(from, ref dmg);

        WeightOverloading.DFA = dfa;

        int damageGiven = AOS.Damage(target, from, dmg, phys, fire, cold, pois, nrgy, chaos);

        if (from != null) // sanity check
          DoLeech(damageGiven, from, target);

        WeightOverloading.DFA = DFAlgorithm.Standard;
      }
      else
      {
        new SpellDamageTimerAOS(spell, delay, target, from, dmg, phys, fire, cold, pois, nrgy, chaos, dfa).Start();
      }

      if (target is BaseCreature c && from != null && delay == TimeSpan.Zero)
      {
        c.OnHarmfulSpell(from);
        c.OnDamagedBySpell(from);
      }
    }

    public static void DoLeech(int damageGiven, Mobile from, Mobile target)
    {
      TransformContext context = TransformationSpellHelper.GetContext(from);

      if (context == null) /* cleanup */
        return;

      if (context.Type == typeof(WraithFormSpell))
      {
        int wraithLeech =
          5 + (int)(15 * from.Skills.SpiritSpeak.Value / 100); // Wraith form gives 5-20% mana leech
        int manaLeech = AOS.Scale(damageGiven, wraithLeech);

        if (manaLeech != 0)
        {
          from.Mana += manaLeech;
          from.PlaySound(0x44D);
        }
      }
      else if (context.Type == typeof(VampiricEmbraceSpell))
      {
        from.Hits += AOS.Scale(damageGiven, 20);
        from.PlaySound(0x44D);
      }
    }

    public static void Heal(int amount, Mobile target, Mobile from, bool message = true)
    {
      //TODO: All Healing *spells* go through ArcaneEmpowerment
      target.Heal(amount, from, message);
    }

    private delegate bool TravelValidator(Map map, Point3D loc);

    private class SpellDamageTimer : Timer
    {
      private int m_Damage;
      private Spell m_Spell;
      private Mobile m_Target, m_From;

      public SpellDamageTimer(Spell s, Mobile target, Mobile from, int damage, TimeSpan delay)
        : base(delay)
      {
        m_Target = target;
        m_From = from;
        m_Damage = damage;
        m_Spell = s;

        if (m_Spell?.DelayedDamage == true && !m_Spell.DelayedDamageStacking)
          m_Spell.StartDelayedDamageContext(target, this);

        Priority = TimerPriority.TwentyFiveMS;
      }

      protected override void OnTick()
      {
        (m_From as BaseCreature)?.AlterSpellDamageTo(m_Target, ref m_Damage);

        (m_Target as BaseCreature)?.AlterSpellDamageFrom(m_From, ref m_Damage);

        m_Target.Damage(m_Damage);
        m_Spell?.RemoveDelayedDamageContext(m_Target);
      }
    }

    private class SpellDamageTimerAOS : Timer
    {
      private int m_Damage;
      private DFAlgorithm m_DFA;
      private int m_Phys, m_Fire, m_Cold, m_Pois, m_Nrgy, m_Chaos;
      private Spell m_Spell;
      private Mobile m_Target, m_From;

      public SpellDamageTimerAOS(Spell s, TimeSpan delay, Mobile target, Mobile from, int damage, int phys, int fire, int cold,
        int pois, int nrgy, int chaos, DFAlgorithm dfa)
        : base(delay)
      {
        m_Target = target;
        m_From = from;
        m_Damage = damage;
        m_Phys = phys;
        m_Fire = fire;
        m_Cold = cold;
        m_Pois = pois;
        m_Nrgy = nrgy;
        m_Chaos = chaos;
        m_DFA = dfa;
        m_Spell = s;
        if (m_Spell?.DelayedDamage == true && !m_Spell.DelayedDamageStacking)
          m_Spell.StartDelayedDamageContext(target, this);

        Priority = TimerPriority.TwentyFiveMS;
      }

      protected override void OnTick()
      {
        BaseCreature bcFrom = m_From as BaseCreature;
        BaseCreature bcTarg = m_Target as BaseCreature;

        if (bcFrom != null && m_Target != null)
          bcFrom.AlterSpellDamageTo(m_Target, ref m_Damage);

        if (bcTarg != null && m_From != null)
          bcTarg.AlterSpellDamageFrom(m_From, ref m_Damage);

        WeightOverloading.DFA = m_DFA;

        int damageGiven = AOS.Damage(m_Target, m_From, m_Damage, m_Phys, m_Fire, m_Cold, m_Pois, m_Nrgy, m_Chaos);

        if (m_From != null) // sanity check
          DoLeech(damageGiven, m_From, m_Target);

        WeightOverloading.DFA = DFAlgorithm.Standard;

        if (bcTarg != null && m_From != null)
        {
          bcTarg.OnHarmfulSpell(m_From);
          bcTarg.OnDamagedBySpell(m_From);
        }

        m_Spell?.RemoveDelayedDamageContext(m_Target);
      }
    }
  }

  public class TransformationSpellHelper
  {
    public static bool CheckCast(Mobile caster, Spell spell)
    {
      if (Sigil.ExistsOn(caster))
      {
        caster.SendLocalizedMessage(1061632); // You can't do that while carrying the sigil.
        return false;
      }

      if (!caster.CanBeginAction<PolymorphSpell>())
      {
        caster.SendLocalizedMessage(1061628); // You can't do that while polymorphed.
        return false;
      }

      if (AnimalForm.UnderTransformation(caster))
      {
        caster.SendLocalizedMessage(1061091); // You cannot cast that spell in this form.
        return false;
      }

      return true;
    }

    public static bool OnCast(Mobile caster, Spell spell)
    {
      if (!(spell is ITransformationSpell transformSpell))
        return false;

      if (Sigil.ExistsOn(caster))
      {
        caster.SendLocalizedMessage(1061632); // You can't do that while carrying the sigil.
      }
      else if (!caster.CanBeginAction<PolymorphSpell>())
      {
        caster.SendLocalizedMessage(1061628); // You can't do that while polymorphed.
      }
      else if (DisguiseTimers.IsDisguised(caster))
      {
        caster.SendLocalizedMessage(1061631); // You can't do that while disguised.
        return false;
      }
      else if (AnimalForm.UnderTransformation(caster))
      {
        caster.SendLocalizedMessage(1061091); // You cannot cast that spell in this form.
      }
      else if (!caster.CanBeginAction<IncognitoSpell>() || caster.IsBodyMod && GetContext(caster) == null)
      {
        spell.DoFizzle();
      }
      else if (spell.CheckSequence())
      {
        TransformContext context = GetContext(caster);
        Type ourType = spell.GetType();

        bool wasTransformed = context != null;
        bool ourTransform = wasTransformed && context.Type == ourType;

        if (wasTransformed)
        {
          RemoveContext(caster, context, ourTransform);

          if (ourTransform)
          {
            caster.PlaySound(0xFA);
            caster.FixedParticles(0x3728, 1, 13, 5042, EffectLayer.Waist);
          }
        }

        if (!ourTransform)
        {
          List<ResistanceMod> mods = new List<ResistanceMod>();

          if (transformSpell.PhysResistOffset != 0)
            mods.Add(new ResistanceMod(ResistanceType.Physical, transformSpell.PhysResistOffset));

          if (transformSpell.FireResistOffset != 0)
            mods.Add(new ResistanceMod(ResistanceType.Fire, transformSpell.FireResistOffset));

          if (transformSpell.ColdResistOffset != 0)
            mods.Add(new ResistanceMod(ResistanceType.Cold, transformSpell.ColdResistOffset));

          if (transformSpell.PoisResistOffset != 0)
            mods.Add(new ResistanceMod(ResistanceType.Poison, transformSpell.PoisResistOffset));

          if (transformSpell.NrgyResistOffset != 0)
            mods.Add(new ResistanceMod(ResistanceType.Energy, transformSpell.NrgyResistOffset));

          if (!((Body)transformSpell.Body).IsHuman)
          {
            IMount mt = caster.Mount;

            if (mt != null)
              mt.Rider = null;
          }

          caster.BodyMod = transformSpell.Body;
          caster.HueMod = transformSpell.Hue;

          for (int i = 0; i < mods.Count; ++i)
            caster.AddResistanceMod(mods[i]);

          transformSpell.DoEffect(caster);

          Timer timer = new TransformTimer(caster, transformSpell);
          timer.Start();

          AddContext(caster, new TransformContext(timer, mods, ourType, transformSpell));
          return true;
        }
      }

      return false;
    }

    #region Context Stuff

    private static Dictionary<Mobile, TransformContext> m_Table = new Dictionary<Mobile, TransformContext>();

    public static void AddContext(Mobile m, TransformContext context)
    {
      m_Table[m] = context;
    }

    public static void RemoveContext(Mobile m, bool resetGraphics)
    {
      TransformContext context = GetContext(m);

      if (context != null)
        RemoveContext(m, context, resetGraphics);
    }

    public static void RemoveContext(Mobile m, TransformContext context, bool resetGraphics)
    {
      if (!m_Table.ContainsKey(m))
        return;

      m_Table.Remove(m);

      List<ResistanceMod> mods = context.Mods;

      for (int i = 0; i < mods.Count; ++i)
        m.RemoveResistanceMod(mods[i]);

      if (resetGraphics)
      {
        m.HueMod = -1;
        m.BodyMod = 0;
      }

      context.Timer.Stop();
      context.Spell.RemoveEffect(m);
    }

    public static TransformContext GetContext(Mobile m)
    {
      m_Table.TryGetValue(m, out TransformContext context);

      return context;
    }

    public static bool UnderTransformation(Mobile m) => GetContext(m) != null;

    public static bool UnderTransformation(Mobile m, Type type) => GetContext(m)?.Type == type;

    #endregion
  }

  public interface ITransformationSpell
  {
    int Body{ get; }
    int Hue{ get; }

    int PhysResistOffset{ get; }
    int FireResistOffset{ get; }
    int ColdResistOffset{ get; }
    int PoisResistOffset{ get; }
    int NrgyResistOffset{ get; }

    double TickRate{ get; }
    void OnTick(Mobile m);

    void DoEffect(Mobile m);
    void RemoveEffect(Mobile m);
  }


  public class TransformContext
  {
    public TransformContext(Timer timer, List<ResistanceMod> mods, Type type, ITransformationSpell spell)
    {
      Timer = timer;
      Mods = mods;
      Type = type;
      Spell = spell;
    }

    public Timer Timer{ get; }

    public List<ResistanceMod> Mods{ get; }

    public Type Type{ get; }

    public ITransformationSpell Spell{ get; }
  }

  public class TransformTimer : Timer
  {
    private Mobile m_Mobile;
    private ITransformationSpell m_Spell;

    public TransformTimer(Mobile from, ITransformationSpell spell)
      : base(TimeSpan.FromSeconds(spell.TickRate), TimeSpan.FromSeconds(spell.TickRate))
    {
      m_Mobile = from;
      m_Spell = spell;

      Priority = TimerPriority.TwoFiftyMS;
    }

    protected override void OnTick()
    {
      if (m_Mobile.Deleted || !m_Mobile.Alive || m_Mobile.Body != m_Spell.Body || m_Mobile.Hue != m_Spell.Hue)
      {
        TransformationSpellHelper.RemoveContext(m_Mobile, true);
        Stop();
      }
      else
      {
        m_Spell.OnTick(m_Mobile);
      }
    }
  }
}