using System;
using System.Collections;
using System.Collections.Generic;

namespace D21._1
{
    public class SpellSequence : IEnumerable<Spell>
    {
        public Spell Spell;
        public SpellSequence NextEntry;

        public int Count() => (NextEntry?.Count() ?? 0) + 1;
        public override int GetHashCode() => HashCode.Combine(Spell, NextEntry);
        public bool Contains(Spell i)
        {
            var cur = this;
            while (cur != null)
            {
                if (i.Equals(cur.Spell)) return true;
                cur = cur.NextEntry;
            }
            return false;
        }

        public int Position(Spell i)
        {
            var cur = this;
            int pos = 0;
            while (cur != null)
            {
                if (i.Equals(cur.Spell)) return pos;
                cur = cur.NextEntry;
                pos++;
            }
            return -1;
        }

        public IEnumerator<Spell> GetEnumerator()
        {
            var cur = this;
            while (cur != null)
            {
                yield return cur.Spell;
                cur = cur.NextEntry;
            }
        }

        IEnumerator IEnumerable.GetEnumerator() => throw new NotImplementedException();
    }

    public abstract class Spell
    {
        public int Cost { get; protected set; }
        public string Name { get; protected set; }
        public int? EffectDuration { get; protected set;  }

        public override bool Equals(object obj) => obj is Spell item && Name.Equals(item.Name, StringComparison.OrdinalIgnoreCase);

        public override int GetHashCode() => HashCode.Combine(Name);

        public virtual void ActiveEffect(Heroe h, MonsterBoss b) { }
        public virtual void ApplyEffect(Heroe h, MonsterBoss b) { }
        public virtual void WornOutEffect(Heroe h, MonsterBoss b) { }
    }

    public class MagicMissile : Spell
    {
        public MagicMissile()
        {
            Name = "Magic Missile";
            Cost = 53;
        }

        public override void ActiveEffect(Heroe h, MonsterBoss b) => b.HitPoints -= 4;
    }

    public class Drain : Spell
    {
        public Drain()
        {
            Name = "Drain";
            Cost = 73;
        }

        public override void ActiveEffect(Heroe h, MonsterBoss b)
        {
            b.HitPoints -= 2;
            h.HitPoints += 2;
        }
    }

    public class Shield : Spell
    {
        public Shield()
        {
            Name = "Shield";
            EffectDuration = 6;
            Cost = 113;
        }

        public override void ActiveEffect(Heroe h, MonsterBoss b) => h.Armor += 7;
        public override void WornOutEffect(Heroe h, MonsterBoss b) => h.Armor -= 7;
    }

    public class Poison : Spell
    {
        public Poison()
        {
            Name = "Poison";
            EffectDuration = 6;
            Cost = 173;
        }

        public override void ApplyEffect(Heroe h, MonsterBoss b) => b.HitPoints -= 3;
    }

    public class Recharge : Spell
    {
        public Recharge()
        {
            Name = "Recharge";
            EffectDuration = 5;
            Cost = 229;
        }

        public override void ApplyEffect(Heroe h, MonsterBoss b) => h.Mana += 101;
    }
}