using System;
using UnityEngine;

public class TextInput : MonoBehaviour, IControlable
{
    public event Action<string> OnComplete;

    [Header("Генерация")]
    [SerializeField] private LetterSlot _letterSlotPrefab;
    [SerializeField] private RectTransform _cellsRoot;

    [Header("Звуки")]
    [SerializeField] private AudioClip switchSlotSound;
    [SerializeField] private AudioClip switchLetterSound;
    [SerializeField] private AudioClip acceptSound;
    [SerializeField] private AudioClip openSound;

    [Header("Скорость переключения букв")]
    [SerializeField] private float MaxSpeedLetterPerSecond = 8;
    [SerializeField] private float MinSpeedLetterPerSecond = 3;
    [SerializeField] private float MaxSpeedTime = 3;
    [SerializeField] private float MinSpeedTime = 0.5f;

    private float switchButtonPressedTime = 0;
    private float letterSwitchSpeed = 0;
    private float switchDelayRest = 1;

    private int _slotIndex = 0;
    private LetterSlot[] _slots;
    private bool completionRequested = false;
    private bool completeUnpressed = false;

    public bool ControlsEnabled { get; set; } = true;
    private LetterSlot ActiveSlot => _slots[_slotIndex];

    public void Initialize(int cellsAmount, string alphabet, string initialString = "")
    {
        Generate(cellsAmount, alphabet);
        InitializeSlots(initialString);
    }

    public void UpdateControls()
    {
        int dir_h = In.GetAxis(JoystickSide.Both, InteractMode.Discrete).x;
        SwitchSlot(dir_h);

        int dir_v = In.GetAxis(JoystickSide.Both, InteractMode.Continious).y;
        SwitchLetter(dir_v);

        if(In.GetAction(JoystickSide.Both, InteractMode.Continious) == false)
            completeUnpressed = true;

        completionRequested = In.GetAction(JoystickSide.Both, InteractMode.Continious);
        if (completionRequested && completeUnpressed)
            Complete();
    }

    private void Complete()
    {
        string result = CollectText();
        OnComplete?.Invoke(result);
        Destroy(gameObject);
    }

    private void Generate(int cellsAmount, string alphabet)
    {
        ClearCells();
        _slots = new LetterSlot[cellsAmount];
        
        for (int i = 0; i < cellsAmount; i++)
        {
            var cell = Instantiate(_letterSlotPrefab, _cellsRoot);
            cell.Init(alphabet[0], alphabet);
            _slots[i] = cell;
        }

        _slotIndex = 0;
        _slots[_slotIndex].SetSelected(true);
    }

    private void InitializeSlots(string initialString)
    {
        for (int i = 0; i < _slots.Length; i++)
            _slots[i].SetSymbol(0);

        if (string.IsNullOrEmpty(initialString))
            return;

        int minLength = Mathf.Min(initialString.Length, _slots.Length);

        for (int i = 0; i < minLength; i++)
            _slots[i].SetSymbol(initialString[i]);
    }

    public void SwitchSlot(int dir)
    {
        if (dir == 0) return;

        ActiveSlot.SetSelected(false);
        _slotIndex = Mathf.Clamp(_slotIndex + dir, 0, _slots.Length);
        ActiveSlot.SetSelected(true);
    }

    public void SwitchLetter(int dir)
    {
        if (dir == 0)
        {
            switchDelayRest = 0;
            switchButtonPressedTime = 0;
            return;
        }

        if (switchDelayRest < 0)
        {
            ActiveSlot.ChangeSymbol(dir);
            recalculateRest();
        }

        switchDelayRest -= Time.deltaTime;
        switchButtonPressedTime += Time.deltaTime;


        void recalculateRest()
        {
            float k = (MaxSpeedLetterPerSecond - MinSpeedLetterPerSecond)
                      / (MaxSpeedTime - MinSpeedTime);
            float b = MinSpeedLetterPerSecond - k * MinSpeedTime;
            letterSwitchSpeed = k * switchButtonPressedTime + b;
            letterSwitchSpeed = Mathf.Clamp(letterSwitchSpeed,
                                            MinSpeedLetterPerSecond,
                                            MaxSpeedLetterPerSecond);
            switchDelayRest = 1 / letterSwitchSpeed;
        }
    }

    private void ClearCells()
    {
        for (int i = _cellsRoot.childCount - 1; i >= 0; i--)
        {
            var cell = _cellsRoot.GetChild(i).gameObject;
            Destroy(cell);
        }
        _slots = null;
    }

    public string CollectText()
    {
        System.Text.StringBuilder sb = new();
        foreach (var slot in _slots)
            sb.Append(slot.Symbol);
        return sb.ToString().Trim();
    }
}