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

public class Stamina : Singleton<Stamina>
{
    public int CurrentStamina { get; private set; } // The player's current stamina level

    [SerializeField] private Sprite fullStaminaImage, emptyStaminaImage; // Sprites representing full and empty stamina units
    [SerializeField] private int timeBetweenStaminaRefresh = 3; // Time interval for automatic stamina regeneration

    private Transform staminaContainer; // UI container holding stamina images
    private int startingStamina = 3; // Initial stamina value when the game starts
    private int maxStamina; // The maximum stamina value the player can have
    const string STAMINA_CONTAINER_TEXT = "Stamina Container"; // Name of the UI container holding stamina images

    // Initialize stamina values and set the starting stamina
    protected override void Awake() {
        base.Awake();

        maxStamina = startingStamina;
        CurrentStamina = startingStamina;
    }

    // Find the stamina container in the UI on start
    private void Start() {
        staminaContainer = GameObject.Find(STAMINA_CONTAINER_TEXT).transform;
    }

    // Decrease stamina by 1 and update the stamina UI
    public void UseStamina() {
        CurrentStamina--;
        UpdateStaminaImages();
    }

    // Increase stamina by 1 if it's below the max and update the stamina UI
    public void RefreshStamina() {
        if (CurrentStamina < maxStamina) {
            CurrentStamina++;
        }
        UpdateStaminaImages();
    }

    // Continuously refresh stamina after a set interval
    private IEnumerator RefreshStaminaRoutine() {
        while (true)
        {
            yield return new WaitForSeconds(timeBetweenStaminaRefresh);
            RefreshStamina();
        }
    }

    // Update the stamina UI based on the current stamina level
    private void UpdateStaminaImages() {
        for (int i = 0; i < maxStamina; i++)
        {
            if (i <= CurrentStamina - 1) {
                staminaContainer.GetChild(i).GetComponent<Image>().sprite = fullStaminaImage; // Show full stamina image
            } else {
                staminaContainer.GetChild(i).GetComponent<Image>().sprite = emptyStaminaImage; // Show empty stamina image
            }
        }

        // Start the stamina refresh routine if stamina isn't full
        if (CurrentStamina < maxStamina) {
            StopAllCoroutines();
            StartCoroutine(RefreshStaminaRoutine());
        }
    }
}