using UnityEngine;
using TMPro;

[RequireComponent(typeof(TMP_InputField))]
public class PostalCodeFormatter : MonoBehaviour
{
    private TMP_InputField input;
    private bool isUpdating = false;
    private int pendingCaret = -1;

    // Format: L C L   C L C
    // Index:  0 1 2 3 4 5 6
    // Sans espace: L C L C L C (0 1 2 3 4 5)

    private void Awake()
    {
        input = GetComponent<TMP_InputField>();
        input.characterLimit = 7;
        input.onValueChanged.AddListener(OnValueChanged);
    }

    private void OnDestroy()
    {
        if (input != null)
            input.onValueChanged.RemoveListener(OnValueChanged);
    }

    private void LateUpdate()
    {
        if (pendingCaret >= 0)
        {
            input.caretPosition = pendingCaret;
            input.selectionAnchorPosition = pendingCaret;
            input.selectionFocusPosition = pendingCaret;
            pendingCaret = -1;
            isUpdating = false;
        }
    }

    private void OnValueChanged(string raw)
    {
        if (isUpdating || string.IsNullOrEmpty(raw))
            return;

        // Enlever espaces et mettre en majuscules
        string clean = raw.ToUpper().Replace(" ", "");

        // Filtrer selon le format L C L C L C
        string valid = "";
        for (int i = 0; i < clean.Length && i < 6; i++)
        {
            char c = clean[i];
            
            if (IsLetterPosition(i))
            {
                // Position lettre : accepter seulement A-Z
                if (char.IsLetter(c))
                    valid += c;
            }
            else
            {
                // Position chiffre : accepter seulement 0-9
                if (char.IsDigit(c))
                    valid += c;
            }
        }

        // Insérer espace après 3 caractères
        string formatted = valid;
        if (valid.Length > 3)
            formatted = valid.Insert(3, " ");

        if (formatted != raw)
        {
            isUpdating = true;
            input.text = formatted;
            pendingCaret = formatted.Length;
        }
    }

    private bool IsLetterPosition(int index)
    {
        // Format sans espace: L C L C L C
        // Index:              0 1 2 3 4 5
        // Lettres aux positions 0, 2, 4
        return index == 0 || index == 2 || index == 4;
    }
}