using System.Collections;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.InputSystem;

/// <summary>
/// Терминал лифта: ввод 4-значного кода доступа для перехода на 2-й уровень.
/// </summary>
public class ElevatorKeypadUI : MonoBehaviour
{
    private static ElevatorKeypadUI _instance;
    public static ElevatorKeypadUI Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = Object.FindAnyObjectByType<ElevatorKeypadUI>(FindObjectsInactive.Include);
            }
            return _instance;
        }
    }

    [Header("Корневая панель")]
    [SerializeField] private GameObject keypadPanelRoot;

    [Header("Слоты для отображения цифр")]
    [SerializeField] private Text[] digitSlots = new Text[4];
    [SerializeField] private Image[] digitSlotBorders = new Image[4];

    [Header("Статусная строка")]
    [SerializeField] private Text statusText;

    [Header("Кнопки клавиатуры")]
    [SerializeField] private Button[] numberButtons; // 0..9
    [SerializeField] private Button clearButton;
    [SerializeField] private Button enterButton;
    [SerializeField] private Button exitButton;

    [Header("Цвета статуса")]
    public Color normalStatusColor = new Color(1.0f, 0.85f, 0.1f, 1.0f);
    public Color errorStatusColor = new Color(1.0f, 0.25f, 0.25f, 1.0f);
    public Color successStatusColor = new Color(0.2f, 1.0f, 0.4f, 1.0f);

    private string enteredCode = "";
    private bool isOpen = false;
    private bool isLockedSuccess = false;

    public bool IsOpen => isOpen;

    private void Awake()
    {
        _instance = this;
        if (keypadPanelRoot == null)
            keypadPanelRoot = gameObject;

        SetupButtons();
    }

    private void SetupButtons()
    {
        if (numberButtons != null)
        {
            for (int i = 0; i < numberButtons.Length; i++)
            {
                int num = i;
                if (numberButtons[i] != null)
                {
                    numberButtons[i].onClick.RemoveAllListeners();
                    numberButtons[i].onClick.AddListener(() => OnNumberPressed(num));
                }
            }
        }

        if (clearButton != null)
        {
            clearButton.onClick.RemoveAllListeners();
            clearButton.onClick.AddListener(OnClearPressed);
        }

        if (enterButton != null)
        {
            enterButton.onClick.RemoveAllListeners();
            enterButton.onClick.AddListener(OnEnterPressed);
        }

        if (exitButton != null)
        {
            exitButton.onClick.RemoveAllListeners();
            exitButton.onClick.AddListener(CloseKeypad);
        }
    }

    private int openFrame = -1;

    private void Update()
    {
        if (!isOpen) return;
        if (Time.frameCount == openFrame) return;

        HandleKeyboardInput();
    }

    private void HandleKeyboardInput()
    {
        var keyboard = Keyboard.current;
        if (keyboard != null)
        {
            if (keyboard.escapeKey.wasPressedThisFrame)
            {
                CloseKeypad();
                return;
            }

            if (!isLockedSuccess)
            {
                if (keyboard.digit0Key.wasPressedThisFrame || keyboard.numpad0Key.wasPressedThisFrame) OnNumberPressed(0);
                else if (keyboard.digit1Key.wasPressedThisFrame || keyboard.numpad1Key.wasPressedThisFrame) OnNumberPressed(1);
                else if (keyboard.digit2Key.wasPressedThisFrame || keyboard.numpad2Key.wasPressedThisFrame) OnNumberPressed(2);
                else if (keyboard.digit3Key.wasPressedThisFrame || keyboard.numpad3Key.wasPressedThisFrame) OnNumberPressed(3);
                else if (keyboard.digit4Key.wasPressedThisFrame || keyboard.numpad4Key.wasPressedThisFrame) OnNumberPressed(4);
                else if (keyboard.digit5Key.wasPressedThisFrame || keyboard.numpad5Key.wasPressedThisFrame) OnNumberPressed(5);
                else if (keyboard.digit6Key.wasPressedThisFrame || keyboard.numpad6Key.wasPressedThisFrame) OnNumberPressed(6);
                else if (keyboard.digit7Key.wasPressedThisFrame || keyboard.numpad7Key.wasPressedThisFrame) OnNumberPressed(7);
                else if (keyboard.digit8Key.wasPressedThisFrame || keyboard.numpad8Key.wasPressedThisFrame) OnNumberPressed(8);
                else if (keyboard.digit9Key.wasPressedThisFrame || keyboard.numpad9Key.wasPressedThisFrame) OnNumberPressed(9);

                if (keyboard.backspaceKey.wasPressedThisFrame || keyboard.deleteKey.wasPressedThisFrame || keyboard.cKey.wasPressedThisFrame)
                {
                    OnBackspacePressed();
                }

                if (keyboard.enterKey.wasPressedThisFrame || keyboard.numpadEnterKey.wasPressedThisFrame)
                {
                    OnEnterPressed();
                }
            }
        }

#if ENABLE_LEGACY_INPUT_MANAGER
        if (Input.GetKeyDown(KeyCode.Escape))
        {
            CloseKeypad();
            return;
        }
#endif
    }

    public void OpenKeypad()
    {
        openFrame = Time.frameCount;

        if (!gameObject.activeSelf) gameObject.SetActive(true);
        if (keypadPanelRoot != null && !keypadPanelRoot.activeSelf)
            keypadPanelRoot.SetActive(true);

        isOpen = true;
        Time.timeScale = 0f;
        Cursor.lockState = CursorLockMode.None;
        Cursor.visible = true;

        enteredCode = "";
        UpdateDisplay();
        SetStatus("ВВЕДИТЕ 4-ЗНАЧНЫЙ КОД ДОСТУПА", normalStatusColor);

        GameAudioSynthesizer.PlayKeypadBeep();
    }

    public void CloseKeypad()
    {
        if (!isOpen) return;

        isOpen = false;
        if (keypadPanelRoot != null)
            keypadPanelRoot.SetActive(false);

        Time.timeScale = 1f;
        Cursor.lockState = CursorLockMode.Locked;
        Cursor.visible = false;

        GameAudioSynthesizer.PlayKeypadClear();
    }

    public void OnNumberPressed(int number)
    {
        if (isLockedSuccess) return;

        if (enteredCode.Length < 4)
        {
            enteredCode += number.ToString();
            GameAudioSynthesizer.PlayKeypadBeep();
            UpdateDisplay();

            if (enteredCode.Length == 4)
            {
                SetStatus("НАЖМИТЕ [ВВОД / ENTER] ДЛЯ ПРОВЕРКИ", normalStatusColor);
            }
        }
    }

    public void OnBackspacePressed()
    {
        if (isLockedSuccess) return;

        if (enteredCode.Length > 0)
        {
            enteredCode = enteredCode.Substring(0, enteredCode.Length - 1);
            GameAudioSynthesizer.PlayKeypadClear();
            UpdateDisplay();
            SetStatus("ВВЕДИТЕ 4-ЗНАЧНЫЙ КОД ДОСТУПА", normalStatusColor);
        }
    }

    public void OnClearPressed()
    {
        if (isLockedSuccess) return;

        enteredCode = "";
        GameAudioSynthesizer.PlayKeypadClear();
        UpdateDisplay();
        SetStatus("КОД СБРОШЕН. ВВЕДИТЕ ЗАНОВО", normalStatusColor);
    }

    public void OnEnterPressed()
    {
        if (isLockedSuccess) return;

        if (enteredCode.Length != 4)
        {
            SetStatus("ОШИБКА: ТРЕБУЕТСЯ 4 ЦИФРЫ!", errorStatusColor);
            GameAudioSynthesizer.PlayErrorCode();
            return;
        }

        if (LevelCodeManager.Instance != null && LevelCodeManager.Instance.ValidateCode(enteredCode))
        {
            isLockedSuccess = true;
            SetStatus("ДОСТУП РАЗРЕШЕН! ЗАПУСК ЛИФТА НА УРОВЕНЬ 2...", successStatusColor);
            GameAudioSynthesizer.PlaySuccessChime();
            StartCoroutine(RoutineSuccessTransition());
        }
        else
        {
            SetStatus("ОТКАЗ В ДОСТУПЕ! НЕВЕРНЫЙ КОД", errorStatusColor);
            GameAudioSynthesizer.PlayErrorCode();
            StartCoroutine(RoutineWrongCodeShake());
        }
    }

    private IEnumerator RoutineWrongCodeShake()
    {
        yield return new WaitForSecondsRealtime(0.8f);
        enteredCode = "";
        UpdateDisplay();
        SetStatus("ВВЕДИТЕ 4-ЗНАЧНЫЙ КОД ДОСТУПА", normalStatusColor);
    }

    private IEnumerator RoutineSuccessTransition()
    {
        SetStatus("ДОСТУП РАЗРЕШЕН! СПУСК НА УРОВЕНЬ 2...", successStatusColor);
        yield return new WaitForSecondsRealtime(1.2f);

        if (LevelSuccessUI.Instance != null)
        {
            LevelSuccessUI.Instance.ShowSuccessScreen();
        }

        yield return new WaitForSecondsRealtime(1.2f);

        Time.timeScale = 1f;
        UnityEngine.SceneManagement.SceneManager.LoadScene("Level2");
    }

    private void UpdateDisplay()
    {
        for (int i = 0; i < 4; i++)
        {
            if (digitSlots != null && i < digitSlots.Length && digitSlots[i] != null)
            {
                if (i < enteredCode.Length)
                {
                    digitSlots[i].text = enteredCode[i].ToString();
                    digitSlots[i].color = new Color(1.0f, 0.85f, 0.1f, 1.0f);
                }
                else
                {
                    digitSlots[i].text = "_";
                    digitSlots[i].color = new Color(0.4f, 0.4f, 0.4f, 0.7f);
                }
            }
        }
    }

    private void SetStatus(string text, Color color)
    {
        if (statusText != null)
        {
            statusText.text = text;
            statusText.color = color;
        }
    }
}