using System;

​

public interface ISpellbook

{

    void CastSpell();

}

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public class RealSpellbook : ISpellbook

{

    private string spellName;

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    public RealSpellbook(string spellName)

    {

        this.spellName = spellName;

        LoadSpell();

    }

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    private void LoadSpell()

    {

        Console.WriteLine($"Loading spell: {spellName}");

    }

​

    public void CastSpell()

    {

        Console.WriteLine($"Casting spell: {spellName}");

    }

}

​

public class SpellbookProxy : ISpellbook

{

    private RealSpellbook realSpellbook;

    private string spellName;

    private int wizardMana;

    private int spellManaCost;

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    public SpellbookProxy(string spellName, int spellManaCost, int wizardMana)

    {

        this.spellName = spellName;

        this.spellManaCost = spellManaCost;

        this.wizardMana = wizardMana;

    }

​

    public void CastSpell()

    {

        if (wizardMana >= spellManaCost)

        {

            if (realSpellbook == null)

            {

                realSpellbook = new RealSpellbook(spellName);

            }

            realSpellbook.CastSpell();

        }

        else

        {

            Console.WriteLine($"Not enough mana to cast {spellName}. Mana required: {spellManaCost}, Mana available: {wizardMana}");

        }

    }

}

​

class Program

{

    static void Main(string[] args)

    {

        int wizardMana = 50;

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        ISpellbook fireballSpell = new SpellbookProxy("Fireball", 30, wizardMana);

        ISpellbook lightningSpell = new SpellbookProxy("Lightning Bolt", 60, wizardMana);

​

        fireballSpell.CastSpell(); // Should succeed

        lightningSpell.CastSpell(); // Should fail due to insufficient mana

    }

}

​

​