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

public class BattleController : MonoBehaviour, IBattleEffectApplier, IBattleEffectResolver, MonsterViewpoint
{
    public HeroId[] heroIds;
    public MonsterId[] monsterIds;
    public CardId[] cardIds;
    
    public HeroInfoUI heroUIPrefab;
    public GameObject uiCanvas;
    public BattlePlayerControls battlePlayerControls;

    private HeroDeck heroDeck;
    private PlayArea playArea;

    public BattleHero[] heroes;
    private GameObject[] heroSprites;
    private HeroInfoUI[] heroUIs;

    public BattleMonster[] monsters;
    private GameObject[] monsterSprites;
    private HeroInfoUI[] monsterUIs;

    private bool heroTurn;
    private int maxEnergy;
    private int energy;

    void Awake() {
        heroes = new BattleHero[3];
        heroSprites = new GameObject[3];
        heroUIs = new HeroInfoUI[3];
        for (int i = 0; i < 3; i++) {
            HeroId id = heroIds[i];

            heroes[i] = new BattleHero(id);
            heroes[i].Init();

            heroSprites[i] = HeroDatabase.createHeroSprite(id);
            heroSprites[i].name = "Hero" + i + "_Sprite";
            heroSprites[i].transform.position = new Vector3(-1 + -3 + 3 * i, 0, 0);
            BattleParticipantSprite bps = heroSprites[i].AddComponent<BattleParticipantSprite>();
            bps.Init(battlePlayerControls, heroes[i]);
            bps.OnSpriteClicked += battlePlayerControls.NotifyParticipantSpriteClicked;

            heroUIs[i] = (HeroInfoUI) Instantiate(heroUIPrefab.gameObject, uiCanvas.transform).GetComponent(typeof(HeroInfoUI));
            heroUIs[i].Init(heroSprites[i], heroes[i]);
        }

        monsters = new BattleMonster[3];
        monsterSprites = new GameObject[3];
        monsterUIs = new HeroInfoUI[3];
        for (int i = 0; i < 3; i++) {
            MonsterId id = monsterIds[i];

            monsters[i] = MonsterDatabase.createMonsterScript(id);
            monsters[i].Init();

            monsterSprites[i] = MonsterDatabase.createMonsterSprite(id);
            monsterSprites[i].name = "Monster" + i + "_Sprite";
            monsterSprites[i].transform.position = new Vector3(+1 + -3 + 3 * i, 3, 0);
            BattleParticipantSprite bps = monsterSprites[i].AddComponent<BattleParticipantSprite>();
            bps.Init(battlePlayerControls, monsters[i]);
            bps.OnSpriteClicked += battlePlayerControls.NotifyParticipantSpriteClicked;

            monsterUIs[i] = (HeroInfoUI) Instantiate(heroUIPrefab.gameObject, uiCanvas.transform).GetComponent(typeof(HeroInfoUI));
            monsterUIs[i].Init(monsterSprites[i], monsters[i]);
        }

        BattleParticipant[] cardOwners = new BattleParticipant[this.cardIds.Length];
        for (int i = 0; i < this.cardIds.Length; i++) {
            cardOwners[i] = FindHeroByClass(CardDatabase.GetHeroIdOfCard(this.cardIds[i]));
        }
        this.heroDeck = new HeroDeck(this.cardIds, cardOwners);

        this.playArea = new PlayArea();

        this.battlePlayerControls.Init(this.heroDeck, this.playArea);
        this.battlePlayerControls.OnCardUsed += this.NotifyHeroCardUsed;
        this.battlePlayerControls.OnTurnPassed += this.NotifyHeroTurnPassed;
        this.heroDeck.OnHandPileChanged += this.battlePlayerControls.NotifyHandPileChanged;
    }

    private BattleParticipant FindHeroByClass(HeroId heroId) {
        foreach (BattleHero battleHero in this.heroes) {
            if (battleHero.GetId() == heroId) return battleHero;
        }
        return null;
    }

    // Start is called before the first frame update
    void Start()
    {
        StartHeroTurn();
    }

    // Update is called once per frame
    void Update()
    {
    }

    private void StartHeroTurn() {
        this.heroTurn = true;
        
        this.damageTriggers.RemoveAll(t => t.Expiration == TriggerExpiration.StartOfNextHeroTurn);

        this.energy = this.maxEnergy;
        foreach (BattleHero hero in this.heroes) {
            hero.ResetBlock();
        }
        this.heroDeck.DrawHand();
        this.battlePlayerControls.NotifyHandPileChanged();
        
        if (this.maxEnergy < 9) {
            this.maxEnergy++;
            this.energy++;
        }
    }

    private void StartEnemyTurn() {
        this.heroTurn = false;

        this.heroDeck.DiscardHand();

        foreach (BattleMonster monster in this.monsters) {
            monster.ResetBlock();
        }

        MonsterCard card = MonsterCardDatabase.CreateCard(MCardId.VampireFangs, this.monsters[0]);
        StartCoroutine(UseMonsterCard(card));

        StartHeroTurn();
    }

    public void NotifyHeroCardUsed(HeroCard card) {
        if (!CanUseHeroCard(card)) {
            throw new System.InvalidOperationException("Cannot use card " + card.GetDisplayName());
        }
        StartCoroutine(UseHeroCard(card));
    }

    public IEnumerator UseHeroCard(HeroCard card) {
        yield return card.Use(this, battlePlayerControls);
        PayCardCost(card);
        this.heroDeck.RemoveCardFromHand(card);
        if (card.IsPermanent()) {
            this.playArea.AddPlayedHeroPermanent(card);
        } else {
            this.heroDeck.MoveCardToDiscard(card);
        }
    }

    public IEnumerator UseMonsterCard(MonsterCard card) {
        yield return card.Use(this, this);
        // TODO: Manage monster deck.
    }

    public void NotifyHeroTurnPassed() {
        if (this.heroTurn) {
            StartEnemyTurn();
        }
    }

    public bool CanUseHeroCard(HeroCard card) {
        return this.heroTurn && this.energy >= card.GetCost();
    }

    private void PayCardCost(HeroCard card) {
        this.energy -= card.GetCost();
    }

    public int GetEnergy() {
        return this.energy;
    }

    public int GetMaxEnergy() {
        return this.maxEnergy;
    }

    public HeroDeck GetHeroDeck() {
        return this.heroDeck;
    }

    public PlayArea GetPlayArea() {
        return this.playArea;
    }

    private void EnqueueActivatedTrigger(Trigger trigger) {
        this.activatedTriggers.Add(trigger);
    }

    private void RunActivatedTriggers() {
        foreach (Trigger t in this.activatedTriggers) {
            t.Run(this);
        }
        this.activatedTriggers.Clear();

        // Cleanup expired triggers
        this.damageTriggers.RemoveAll(t => t.Expired);
    }

    // IBattleEffectApplier
    public void Apply(IBattleEffect effect) {
        effect.Apply(this);
    }

    // IBattleEffectResolver
    public void IncreaseHeroMaxEnergy(IncreaseMaxEnergyEffect effect) {
        this.maxEnergy += effect.Amount;
    }

    public void IncreaseMaxHP(IncreaseMaxHPEffect effect) {
        effect.Target.IncreaseMaxHP(effect.Amount);
    }

    public void AcquireHeroCards(AcquireCardsEffect effect) {
        BattleHero hero = (BattleHero) effect.Participant;
        foreach (CardId cardId in effect.CardIds) {
            BaseCard acquiredCard = CardDatabase.CreateCard(cardId, hero);
            switch (effect.Zone) {
                case BattleZone.DrawPile:
                    this.GetHeroDeck().PutCardOnTopOfDrawPile(acquiredCard);
                    break;
                default:
                    throw new System.NotImplementedException();
            }
        }

        if (effect.Zone == BattleZone.DrawPile) {
            this.GetHeroDeck().ShuffleDrawPile();
        }
    }

    private List<Trigger> activatedTriggers = new List<Trigger>();
    private List<DamageTrigger> damageTriggers = new List<DamageTrigger>();

    public int DealDamage(DealDamageEffect effect) {
        int damageDealt = effect.Target.DealDamage(effect.Amount);
        foreach (DamageTrigger dt in this.damageTriggers) {
            if (dt.IsTriggeredBy(effect)) {
                EnqueueActivatedTrigger(dt);
            }
        }

        // Do this after the card resolution is over to avoid reentraint effects.
        RunActivatedTriggers();

        return damageDealt;
    }

    public int Heal(HealEffect effect) {
        int healedAmount = effect.Target.Heal(effect.Amount);
        return healedAmount;
    }

    public void AddBlock(BlockEffect effect) {
        effect.Target.AddBlock(effect.Amount);
    }

    public void ArmDamageTrigger(DamageTrigger damageTrigger) {
        this.damageTriggers.Add(damageTrigger);
    }

    // MonsterViewpoint
    public BattleHero[] Heroes {get => this.heroes;}
}