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

public class UIFade : Singleton<UIFade>
{
    [SerializeField] private Image fadeScreen;  // UI Image used for the fade effect
    [SerializeField] private float fadeSpeed = 1f;  // Speed at which the fade effect occurs

    private IEnumerator fadeRoutine;  // Coroutine reference for the fade effect

    // Starts a fade to black (full opacity)
    public void FadeToBlack() {
        if (fadeRoutine != null) {
            StopCoroutine(fadeRoutine);  // Stop any ongoing fade coroutine
        }

        fadeRoutine = FadeRoutine(1);  // Set target alpha to 1 (black)
        StartCoroutine(fadeRoutine);
    }

    // Starts a fade to clear (no opacity)
    public void FadeToClear() {
        if (fadeRoutine != null) {
            StopCoroutine(fadeRoutine);  // Stop any ongoing fade coroutine
        }

        fadeRoutine = FadeRoutine(0);  // Set target alpha to 0 (clear)
        StartCoroutine(fadeRoutine);
    }

    // Coroutine to smoothly transition the alpha of the fade screen
    private IEnumerator FadeRoutine(float targetAlpha) {
        while (!Mathf.Approximately(fadeScreen.color.a, targetAlpha))  // Continue until target alpha is reached
        {
            // Gradually move alpha towards the target alpha value
            float alpha = Mathf.MoveTowards(fadeScreen.color.a, targetAlpha, fadeSpeed * Time.deltaTime);
            fadeScreen.color = new Color(fadeScreen.color.r, fadeScreen.color.g, fadeScreen.color.b, alpha);
            yield return null;  // Wait until the next frame
        }
    }
}