using System;
using System.IO;
using UnityEngine;
using UnityEngine.SceneManagement;

[DefaultExecutionOrder(-1000)]
public class GameManager : MonoBehaviour
{
    public static GameManager Instance { get; private set; }
    public bool IsPaused { get; private set; }
    public event Action<bool> PauseStateChanged;

    public int world { get; private set; } = 1;
    public int stage { get; private set; } = 1;
    public int stagesByWorld { get; private set; } = 5;
    public int lives { get; private set; } = 3;
    public int coins { get; private set; } = 0;

    public GameObject playerObj;
    [SerializeField] private GameObject playerPrefab;
    [SerializeField] private string playerPrefabResourcePath = "Prefabs/Player";

    private bool _shouldSpawnPlayer;

    private void OnEnable() => SceneManager.sceneLoaded += OnSceneLoaded;
    private void OnDisable() => SceneManager.sceneLoaded -= OnSceneLoaded;

    public event Action<int> CoinsChanged;

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
    private static void Bootstrap()
    {
        if (Instance == null)
        {
            var go = new GameObject(nameof(GameManager));
            Instance = go.AddComponent<GameManager>();
            DontDestroyOnLoad(go);
        }
    }

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

        Instance = this;
        DontDestroyOnLoad(gameObject);
    }

    private void OnDestroy()
    {
        if (Instance == this) Instance = null;
    }

    //private void Start()
    //{
    //    //Application.targetFrameRate = 60;
    //    //LoadScene("MainMenu", false);
    //    //NewGame();
    //    if (SceneManager.GetActiveScene().name != "MainMenu")
    //    {
    //        TrySpawnPlayerForActiveScene();
    //    }
    //}

    private GameObject ResolvePlayerPrefab()
    {
        if (playerPrefab != null) return playerPrefab;

        var loaded = Resources.Load<GameObject>(playerPrefabResourcePath);
        if (loaded == null)
        {
            Debug.LogError(
                $"GameManager: playerPrefab is null. Resources.Load('{playerPrefabResourcePath}') вернул null. " +
                $"Ожидается файл: Assets/Resources/{playerPrefabResourcePath}.prefab (точное совпадение регистра).");
        }
        return loaded;
    }

    public void NewGame()
    {
        lives = 3;
        coins = 0;
        CoinsChanged?.Invoke(coins);
        LoadLevel(1, 1);
    }

    public void GameOver() => LoadScene("MainMenu", false);

    public void LoadLevel(int world, int stage)
    {
        this.world = world;
        this.stage = stage;

        string sceneName = $"{world}-{stage}";
        if (SceneInBuildSettingsExists(sceneName))
        {
            LoadScene(sceneName);
        }
        else
        {
            print("WIN");
            //NewGame();
            LoadScene("MainMenu", false);
        }
    }
    public void LoadScene(string sceneName, bool useUI = true)
    {
        _shouldSpawnPlayer = true;

        SceneManager.LoadScene(sceneName);

        if (useUI)
        {
            SceneManager.LoadScene("Level UI", LoadSceneMode.Additive);
        }
        else _shouldSpawnPlayer = false;
    }

    private void OnSceneLoaded(Scene scene, LoadSceneMode mode)
    {
        TrySpawnPlayerForActiveScene();
    }

    private void TrySpawnPlayerForActiveScene()
    {
        if (!_shouldSpawnPlayer) return;
        var spawn = FindFirstObjectByType<PlayerSpawn>();
        Vector3 pos = spawn ? spawn.transform.position : new Vector3(0, 1.3f, 0);
        Quaternion rot = spawn ? spawn.transform.rotation : Quaternion.identity;

        playerObj = GameObject.FindGameObjectWithTag("Player");
        if (playerObj != null) Destroy(playerObj);

        var prefab = ResolvePlayerPrefab();
        if (prefab == null) return;

        playerObj = Instantiate(prefab, pos, rot);
        SceneManager.MoveGameObjectToScene(playerObj, SceneManager.GetActiveScene());
    }

    public void NextLevel()
    {
        if (stage >= stagesByWorld) LoadLevel(world + 1, 1);
        else LoadLevel(world, stage + 1);
    }

    public void ResetLevel()
    {
        lives--;
        //print($"Lives: {lives}");
        if (lives > 0) LoadLevel(world, stage);
        else GameOver();
    }

    public void AddCoin()
    {
        coins++;
        if (coins >= 100)
        {
            coins = 0;
            AddLife();
        }
        CoinsChanged?.Invoke(coins);
    }

    public void SetPause(bool pause)
    {
        if (IsPaused == pause) return;
        IsPaused = pause;

        Time.timeScale = pause ? 0f : 1f;
        AudioListener.pause = pause;

        PauseStateChanged?.Invoke(IsPaused);
    }

    public void TogglePause() => SetPause(!IsPaused);

    public void AddLife() => lives++;

    private static bool SceneInBuildSettingsExists(string sceneName)
    {
        int count = SceneManager.sceneCountInBuildSettings;
        for (int i = 0; i < count; i++)
        {
            string path = SceneUtility.GetScenePathByBuildIndex(i);
            if (Path.GetFileNameWithoutExtension(path) == sceneName)
                return true;
        }
        return false;
    }
}