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

namespace BeiBao
{
    /// <summary>
    /// 背包类
    /// 背包是由多个格子组成的，每个格子都可以存放不同的物品。
    /// </summary>
    public class Inventory
    {
        private int _slotCount;

        public int SlotCount => _slotCount; // 背包格子的数量

        private List<InventorySlot> slots;

        public IReadOnlyList<InventorySlot> Slots => slots;

        public Action<IReadOnlyList<InventorySlot>> RefreshInventorySlot;

        public Inventory(int slotCount)
        {
            _slotCount = slotCount;
            slots = new List<InventorySlot>();
            for (int i = 0; i < _slotCount; i++)
            {
                slots.Add(new InventorySlot());
            }
        }

        // 向背包中添加物品
        public bool AddItem(Item item, int quantity, out int restCount)
        {
            int remainingQuantity = quantity;
            int tmpQuantity = quantity;

            foreach (var slot in slots)
            {
                if (remainingQuantity == 0) break;


                if (slot.IsEmpty)
                {
                    var tmpItem = new Item(item.ItemName, item.ItemID, item.MaxStack);
                    // 如果格子为空，直接放入物品
                    remainingQuantity = tmpItem.CheckAddQuantity(remainingQuantity);
                    slot.AddItem(tmpItem, tmpQuantity - remainingQuantity);
                }
                else if (slot.Item.ItemID == item.ItemID && slot.Item.Quantity < slot.Item.MaxStack)
                {
                    // 如果格子内物品与新物品相同，并且未满堆叠，堆叠物品
                    remainingQuantity = slot.Item.CheckAddQuantity(remainingQuantity);
                    slot.Item.AddQuantity(tmpQuantity - remainingQuantity);
                }

                tmpQuantity = remainingQuantity;
            }

            Debug.Log($"向背包中添加{item.ItemName} 数量为：{quantity}");
            RefreshInventorySlot?.Invoke(Slots);
            restCount = remainingQuantity;
            return remainingQuantity == 0;
        }

        // 从背包中取出物品
        public bool RemoveItem(int itemID, int quantity, out int restCount)
        {
            int remainingQuantity = quantity;
            int tmpQuantity = quantity;

            for (var i = slots.Count - 1; i >= 0; i--)
            {
                if (remainingQuantity == 0) break;

                var slot = slots[i];
                if (!slot.IsEmpty && slot.Item.ItemID == itemID)
                {
                    remainingQuantity = slot.Item.CheckRemoveQuantity(remainingQuantity);
                    slot.RemoveItem(tmpQuantity - remainingQuantity);
                    tmpQuantity = remainingQuantity;
                }
            }

            Debug.Log($"向背包中取出物品id{itemID} 数量为：{quantity}");
            RefreshInventorySlot?.Invoke(Slots);
            restCount = remainingQuantity;
            return remainingQuantity == 0;
        }

        // 查看背包内容
        public void ShowInventory()
        {
            StringBuilder sb = new StringBuilder();
            foreach (var slot in slots)
            {
                if (!slot.IsEmpty)
                {
                    sb.AppendLine($"{slot.Item.ItemName} - {slot.Item.Quantity}/{slot.Item.MaxStack}");
                }
            }

            Debug.Log(sb.ToString());
        }
    }
}