using System.Collections;
using UnityEngine;
using UnityEngine.SceneManagement;

namespace ProceduralEditor
{
    public class SceneTransitionController : MonoBehaviour
    {
        const string GameplaySceneName = "Landscape";

        [Header("Fade")]
        [Tooltip("CanvasGroup on the Fade Image object.")]
        [SerializeField] private CanvasGroup fadeGroup;

        [Min(0f)]
        [SerializeField] private float fadeDuration = 0.75f;

        private bool transitionInProgress;

        public void LoadGameplayScene()
        {
            if (transitionInProgress)
                return;

            if (fadeGroup == null)
            {
                Debug.LogError($"{nameof(SceneTransitionController)}: Fade Group is not assigned.");

                return;
            }

            transitionInProgress = true;
            StartCoroutine(FadeThenLoadGameplayScene());
        }

        private IEnumerator FadeThenLoadGameplayScene()
        {
            fadeGroup.gameObject.SetActive(true);
            fadeGroup.blocksRaycasts = true;
            fadeGroup.interactable = true;

            float startingAlpha = fadeGroup.alpha;
            float elapsed = 0f;

            while (elapsed < fadeDuration)
            {
                elapsed += Time.unscaledDeltaTime;

                float normalizedTime = Mathf.Clamp01(elapsed / fadeDuration);

                fadeGroup.alpha = Mathf.Lerp(startingAlpha, 1f, normalizedTime);

                yield return null;
            }

            fadeGroup.alpha = 1f;

            yield return null;

            Debug.Log($"Loading scene: {GameplaySceneName}");

            SceneManager.LoadScene(GameplaySceneName);
        }
    }
}