ModernUO/Projects/UOContent/Items/Weapons/Abilities/DualWield.cs

using System;
using System.Collections.Generic;

namespace Server.Items
{
    /// <summary>
    ///     Attack faster as you swing with both weapons.
    /// </summary>
    public class DualWield : WeaponAbility
    {
        public static Dictionary<Mobile, DualWieldTimer> Registry { get; } = new();

        public override int BaseMana => 30;

        public override bool CheckSkills(Mobile from)
        {
            if (GetSkill(from, SkillName.Ninjitsu) < 50.0)
            {
                // You need ~1_SKILL_REQUIREMENT~ Ninjitsu skill to perform that attack!
                from.SendLocalizedMessage(1063352, "50");
                return false;
            }

            return base.CheckSkills(from);
        }

        public override void OnHit(Mobile attacker, Mobile defender, int damage)
        {
            if (!Validate(attacker) || !CheckMana(attacker, true))
            {
                return;
            }

            if (Registry.TryGetValue(attacker, out var timer))
            {
                timer.Stop();
                Registry.Remove(attacker);
            }

            ClearCurrentAbility(attacker);

            attacker.SendLocalizedMessage(1063362); // You dually wield for increased speed!
            attacker.FixedParticles(0x3779, 1, 15, 0x7F6, 0x3E8, 3, EffectLayer.LeftHand);

            timer = new DualWieldTimer(
                attacker,
                (int)(20.0 + 3.0 * (attacker.Skills.Ninjitsu.Value - 50.0) / 7.0)
            ); // 20-50 % increase

            timer.Start();
            Registry.Add(attacker, timer);
        }

        public class DualWieldTimer : Timer
        {
            private readonly Mobile m_Owner;

            public DualWieldTimer(Mobile owner, int bonusSwingSpeed)
                : base(TimeSpan.FromSeconds(6.0))
            {
                m_Owner = owner;
                BonusSwingSpeed = bonusSwingSpeed;
            }

            public int BonusSwingSpeed { get; }

            protected override void OnTick()
            {
                Registry.Remove(m_Owner);
            }
        }
    }
}