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

[CreateAssetMenu(fileName = "GrantPool", menuName = "ScriptableObject/NodeGrantPool", order = 1)]
public class NodeGrantPool : ScriptableObject
{
    public List<PHomePush.NodeChoseItem> AllItems;
    public Sprite DesImage;

    public PHomePush.NodeChoseItem GetOneItemRandom()
    {
        return GetOneItemRandomFromList(AllItems);
    }

    public IEnumerable<PHomePush.NodeChoseItem> GetItemsRandom(int count = 1, bool allowRepeat = false)
    {
        if (count <= 0)
        {
            yield break;
        }

        if (allowRepeat)
        {
            for (int i = 0; i < count; i++)
            {
                yield return GetOneItemRandom();
            }
        }
        else
        {
            if (AllItems.Count < count)
            {
                throw new System.Exception($"Item pool only contains {AllItems.Count} items, but trying to get {count}");
            }

            if (count == 1)
            {
                yield return GetOneItemRandom();
                yield break;
            }
            else if (count == AllItems.Count)
            {
                foreach (var item in AllItems)
                {
                    yield return item;
                }
                yield break;
            }

            List<PHomePush.NodeChoseItem> availableItems = new List<PHomePush.NodeChoseItem>(AllItems);

            for (int i = 0; i < count; i++)
            {
                var item = GetOneItemRandomFromList(availableItems);
                availableItems.Remove(item);
                yield return item;
            }
        }
    }

    public static PHomePush.NodeChoseItem GetOneItemRandomFromList(List<PHomePush.NodeChoseItem> list)
    {
        // 计算总权重
        float totalWeight = list.Sum(x => x.Weight);

        // 根据总权重随机选择一个值
        float randomPoint = Random.Range(0, totalWeight);

        // 根据随机值选择项目
        float currentPoint = 0f;
        foreach (var item in list)
        {
            currentPoint += item.Weight;
            if (randomPoint <= currentPoint)
            {
                return item;
            }
        }

        throw new System.Exception($"Nothing to chose from");
    }
}