Adv2015/D22.1/Program.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace D21._1
{
    public class Program
    {
        public enum EnumDifficulty
        {
            Normal = 0,
            Hard = 1
        }

        public static EnumDifficulty Difficulty { get; set; }

        static bool Attack(MonsterBoss boss, SpellSequence spellBook)
        {
            var heroe = new Heroe();
            boss.Heal();

            var activeEffects = new Queue<(Spell, int)>();
            var spellSequence = spellBook;

            while (heroe.HitPoints > 0 && boss.HitPoints > 0 && spellSequence != null)
            {
                HeroeTakesTurn(boss, heroe, activeEffects, spellSequence);

                if (heroe.Mana <= 0 || heroe.HitPoints <= 0 || boss.HitPoints <= 0)
                    break;

                BossTakesTurn(boss, heroe, activeEffects);

                spellSequence = spellSequence?.NextEntry;
            }

            return boss.HitPoints <= 0 && heroe.HitPoints > 0;
        }

        private static void BossTakesTurn(MonsterBoss boss, Heroe heroe, Queue<(Spell, int)> activeEffects)
        {
            ResolveActiveEffects(boss, heroe, activeEffects);
            if (boss.HitPoints <= 0) return;

            var batk = Math.Max(boss.Damage - heroe.Armor, 1);
            heroe.HitPoints -= batk;
        }

        public static void HeroeTakesTurn(MonsterBoss boss, Heroe heroe, Queue<(Spell, int)> activeEffects, SpellSequence spellSequence)
        {
            heroe.HitPoints -= (int) Difficulty;
            if (heroe.HitPoints <= 0) return;

            ResolveActiveEffects(boss, heroe, activeEffects);
            if (boss.HitPoints <= 0) return;

            var spell = spellSequence?.Spell;
            heroe.Mana -= spell?.Cost ?? 0;

            spell?.ActiveEffect(heroe, boss);
            if (spell?.EffectDuration.HasValue ?? false)
                activeEffects.Enqueue((spell, spell.EffectDuration.Value));
        }

        private static void ResolveActiveEffects(MonsterBoss boss, Heroe heroe, Queue<(Spell, int)> activeEffects)
        {
            int active = activeEffects.Count;
            while (active-- > 0)
            {
                (Spell s, int duration) = activeEffects.Dequeue();
                s.ApplyEffect(heroe, boss);
                if (--duration != 0) activeEffects.Enqueue((s, duration));
                else s.WornOutEffect(heroe, boss);
            }
        }

        public static void TrySpellSequence(List<Spell> spellBook, MonsterBoss boss, ref int best, int cost = 0, HashSet<SpellSequence> triedSpellSequence = null, SpellSequence spellSequence = null, int depth = 0)
        {
            if (depth > 9) return;

            if (triedSpellSequence == null) triedSpellSequence = new HashSet<SpellSequence>();
            if (triedSpellSequence.Contains(spellSequence) == false)
            {
                if (Attack(boss, spellSequence) && cost < best) best = cost;

                triedSpellSequence.Add(spellSequence);
            }

            foreach (Spell spell in spellBook)
            {
                var firstOccurence = spellSequence?.Position(spell) ?? -1;
                if (spellSequence != null && spell.EffectDuration > 0
                    && firstOccurence != -1 && firstOccurence < (spell.EffectDuration - 1) / 2)
                    continue;

                var newSpellSequence = new SpellSequence() { Spell = spell, NextEntry = spellSequence };
                TrySpellSequence(spellBook, boss, ref best, cost + spell.Cost, triedSpellSequence, newSpellSequence, depth + 1);
            }
        }

        static void Main(string[] args)
        {
            if (args.Length < 1) throw new ArgumentException();
            if (File.Exists(args[0]) == false) throw new FileNotFoundException();

            var spellBook = BuildSpellBook();

            MonsterBoss boss = ParseFile(args);

            int best = int.MaxValue;
            TrySpellSequence(spellBook, boss, ref best);

            Console.WriteLine($"Best spell sequence costs {best} MP");
        }

        public static MonsterBoss ParseFile(string[] args)
        {
            int hp = 0, atk = 0;
            using (var file = File.OpenText(args[0]))
            {
                hp = int.Parse(file.ReadLine().Split(": ")[1]);
                atk = int.Parse(file.ReadLine().Split(": ")[1]);
            }

            return new MonsterBoss(hp)
            {
                Damage = atk
            };
        }

        public static List<Spell> BuildSpellBook() => new List<Spell>
            {
                new MagicMissile(),
                new Drain(),
                new Shield(),
                new Poison(),
                new Recharge()
            };
    }
}