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

public class LevelManager : MonoBehaviour
{
    // A serializable structure that holds a UI button and its corresponding scene
    [System.Serializable]
    public class LevelEntry
    {
        public Button levelButton;
        public string sceneName;
        public string jumpPoint;
    }

    [SerializeField]
    string jumpPointGrottoEssen;

    [SerializeField]
    string jumpPointGrottoKueche;

    [SerializeField]
    float fadeDuration = 3f;
    
    [SerializeField]
    GameObject fadeScreenObj;

    private Material _fadeMaterial;

    // A list of LevelEntry objects that can be filled in the inspector
    public List<LevelEntry> levels = new List<LevelEntry>();

    private void Awake()
    {
        // Reset entry level points
        EntryLevel.GoToGrottoKueche = false;
        EntryLevel.GoToGrottoEssen = false;

        // Loop through each level entry and hook up the button to load the correct scene
        foreach (var entry in levels)
        {
            // Check if both the button and scene name are set
            if (entry.levelButton != null && !string.IsNullOrEmpty(entry.sceneName))
            {
                // Store the scene name locally to avoid closure issues in the lambda
                string sceneToLoad = entry.sceneName;

                entry.levelButton.onClick.AddListener(() => OnClickLoadLevel(sceneToLoad));

                string goToJumpPoint = entry.jumpPoint;

                entry.levelButton.onClick.AddListener(() => SetEntryLevel(goToJumpPoint));
            }
        }

        Renderer _renderer = fadeScreenObj?.GetComponent<Renderer>();
        _fadeMaterial = _renderer?.sharedMaterial;
    }

    // This method is called when a button is clicked, and loads the given scene by name
    public void OnClickLoadLevel(string sceneName)
    {
        StartCoroutine(LoadAsyncScene(sceneName));
    }

    IEnumerator LoadAsyncScene(string sceneName)
    {
        yield return StartCoroutine(FadeOut());

        AsyncOperation asyncLoad = SceneManager.LoadSceneAsync(sceneName);

        // Wait until the asynchronous scene fully loads
        while (!asyncLoad.isDone)
        {
            yield return null;
        }
    }

    IEnumerator FadeOut()
    {
        fadeScreenObj.SetActive(true);
        float elapsedTime = 0f;
        Color color = _fadeMaterial.color;

        while (elapsedTime < fadeDuration)
        {
            elapsedTime += Time.deltaTime;
            float alpha = Mathf.Lerp(0f, 1f, elapsedTime / fadeDuration);
            color.a = alpha;
            _fadeMaterial.color = color;
            yield return null;
        }

        // Ensure the final alpha value is set
        color.a = 1f;
        _fadeMaterial.color = color;
    }

    public void SetEntryLevel(string entryPoint)
    {
        if (string.IsNullOrEmpty(entryPoint))
        {
            return;
        }

        if (entryPoint == jumpPointGrottoEssen)
        {
            EntryLevel.GoToGrottoEssen = true;
            return;
        }

        if (entryPoint == jumpPointGrottoKueche)
        {
            EntryLevel.GoToGrottoKueche = true;
            return;
        }
    }
}