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

namespace AibisDream.Framework
{
    public class MultipleSelector<T> : IMultipleSelector<T>
    {
        private readonly List<T> _items;
        private int _batchSize;
        
        public MultipleSelector(IEnumerable<T> items, int batchSize)
        {
            _items = new List<T>(items);
            _batchSize = batchSize;
        }

        public T[] Select()
        {
            int[] indexArray = IMultipleSelector<T>.MultiRange(0, Count - 1, _batchSize);
            return indexArray.Select(index => _items[index]).ToArray();
        }

        public void RemoveItem(T item)
        {
            _items.Remove(item);
        }

        public void AddItem(T item)
        {
            _items.Add(item);
        }

        public void SetBatchSize(int batchSize)
        {
            _batchSize = batchSize;
        }

        public int Count => _items.Count;
    }
    
    public interface IMultipleSelector<T>
    {
        T[] Select();
        void RemoveItem(T item);
        void AddItem(T item);
        int Count { get; }

        static int[] MultiRange(int start, int end, int batchSize)
        {
            // 确保要求的数量不超过范围
            if (batchSize > end - start + 1)
            {
                Debug.LogError("要求的数量超过了范围内的数字总数");
                return default;
            }

            var uniqueNumbers = new HashSet<int>();

            while (uniqueNumbers.Count < batchSize)
            {
                var number = Random.Range(start, end + 1);
                uniqueNumbers.Add(number);
            }
            
            return uniqueNumbers.ToArray();
        }
    }
}