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

public class HeroDeck
{
    public const int DEFAULT_HAND_DRAWN = 5;

    public delegate void PileChangedAction();
    public event PileChangedAction OnDrawPileChanged;
    public event PileChangedAction OnHandPileChanged;
    public event PileChangedAction OnDiscardPileChanged;

    // Piles are sorted from top to bottom.
    private List<BaseCard> drawPile;
    private List<BaseCard> handPile;
    private List<BaseCard> discardPile;

    public HeroDeck(CardId[] cardIds) {
        this.drawPile = new List<BaseCard>();
        this.handPile = new List<BaseCard>();
        this.discardPile = new List<BaseCard>();

        for (int i = 0; i < cardIds.Length; i++) {
            BaseCard newCard = CardDatabase.CreateCard(cardIds[i]);
            this.drawPile.Add(newCard);
        }
        this.drawPile.Shuffle();
    }

    public List<BaseCard> GetHand() {
        return handPile;
    }

    public void DrawHand() {
        for (int i = 0; i < DEFAULT_HAND_DRAWN; i++) {
            DrawCardInternal();
        }
        TriggerHandPileChanged();
        TriggerDrawPileChanged();
    }

    public void DrawCard() {
        DrawCardInternal();
        TriggerHandPileChanged();
        TriggerDrawPileChanged();
    }

    private void DrawCardInternal() {
        if (this.drawPile.Count == 0) {
            RemakeDrawPile();
            // If there is still no draw pile, probably because no cards were in the discard pile, just
            // skip the draw.
            if (this.drawPile.Count == 0) {
                return;
            }
        }

        BaseCard drawnCard = this.drawPile[0];
        this.drawPile.RemoveAt(0);
        this.handPile.Add(drawnCard);
    }

    public void DiscardPlayedCard(BaseCard card) {
        if (!this.handPile.Contains(card)) {
            throw new InvalidOperationException("Cannot discard card " + card.GetDisplayName()
                    + " because not in hand.");
        }

        this.discardPile.Insert(0, card);
        this.handPile.Remove(card);
        TriggerHandPileChanged();
        TriggerDiscardPileChanged();
    }

    public void DiscardHand() {
        this.discardPile.InsertRange(0, this.handPile);
        this.handPile.Clear();
        TriggerHandPileChanged();
        TriggerDiscardPileChanged();
    }

    private void RemakeDrawPile() {
        this.drawPile.AddRange(this.discardPile);
        this.discardPile.Clear();

        this.drawPile.Shuffle();
        TriggerDrawPileChanged();
        TriggerDiscardPileChanged();
    }

    private void TriggerDrawPileChanged() {
        if (OnDrawPileChanged != null) OnDrawPileChanged();
    }
    private void TriggerHandPileChanged() {
        if (OnHandPileChanged != null) OnHandPileChanged();
    }
    private void TriggerDiscardPileChanged() {
        if (OnDiscardPileChanged != null) OnDiscardPileChanged();
    }
}