using UnityEngine;
using UnityEngine.UI;

public class ManaSystem : MonoBehaviour
{
    public static ManaSystem Instance { get; private set; }

    [Header("能量配置")]
    [Min(1)]
    public int maxMana = 10;

    [Min(0f)]
    public float manaRegenRate = 1f;

    [Header("UI 引用")]
    public Image[] manaBeads;

    private float currentMana;
    private float manaRegenTimer;

    public float CurrentMana => currentMana;
    public int CurrentManaInt => Mathf.FloorToInt(currentMana);

    private void Awake()
    {
        if (Instance != null && Instance != this)
        {
            Destroy(gameObject);
            return;
        }
        Instance = this;
    }

    private void Start()
    {
        currentMana = maxMana;
        UpdateManaUI();
    }

    private void Update()
    {
        if (currentMana < maxMana)
        {
            manaRegenTimer += Time.deltaTime;
            if (manaRegenTimer >= manaRegenRate)
            {
                manaRegenTimer = 0f;
                currentMana = Mathf.Min(currentMana + 1f, maxMana);
                UpdateManaUI();
            }
        }
    }

    public bool TryConsumeMana(int cost)
    {
        if (CurrentManaInt < cost)
        {
            return false;
        }

        currentMana -= cost;
        if (currentMana < 0f)
        {
            currentMana = 0f;
        }

        UpdateManaUI();
        return true;
    }

    public void AddMana(int amount)
    {
        currentMana = Mathf.Min(currentMana + amount, maxMana);
        UpdateManaUI();
    }

    private void UpdateManaUI()
    {
        if (manaBeads == null || manaBeads.Length == 0)
        {
            return;
        }

        int fullBeads = CurrentManaInt;
        for (int i = 0; i < manaBeads.Length; i++)
        {
            if (manaBeads[i] != null)
            {
                manaBeads[i].enabled = i < fullBeads;
            }
        }
    }
}