using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using TMPro;

// Clavier interne lettres + chiffres pour un TMP_InputField (code postal de SUPPLIERS).
// A poser sur le champ lui-meme.
//
// Sur mobile / WebGL, toucher un TMP_InputField donne le focus a un input HTML cache : le
// navigateur ouvre son clavier ET fait defiler la page pour amener cet input a l'ecran.
// On refuse donc le focus natif des la selection et on affiche ce clavier a la place.
[RequireComponent(typeof(TMP_InputField))]
public class PostalKeyboard : MonoBehaviour
{
    [Tooltip("Longueur maximale saisie, espace compris (ex: H2X 1Y4)")]
    public int MaxLength = 7;

    static readonly string[] Rows =
    {
        "1234567890",
        "QWERTYUIOP",
        "ASDFGHJKL",
        "ZXCVBNM"
    };

    const string PanelName = "POSTALKEYBOARD";
    const float RowHeight = 58f;
    const float RowSpacing = 6f;
    const float SideMargin = 10f;

    TMP_InputField Field;
    GameObject Panel;

    void Awake()
    {
        Field = GetComponent<TMP_InputField>();
        Field.onSelect.AddListener(_ => OnFieldSelected());
    }

    void OnDisable()
    {
        if (Panel != null) Panel.SetActive(false);
    }

    void OnFieldSelected()
    {
        // Sur poste de travail le clavier physique fait le travail : on ne change rien.
        if (!Application.isMobilePlatform && Application.platform != RuntimePlatform.WebGLPlayer)
            return;

        Field.DeactivateInputField();
        if (EventSystem.current != null) EventSystem.current.SetSelectedGameObject(null);

        Show(true);
    }

    void Show(bool On)
    {
        if (Panel == null)
        {
            if (!On) return;
            Panel = Build();
        }
        Panel.SetActive(On);
    }

    //--------------------------SAISIE----------------------------------------

    void Type(string Key)
    {
        string Value = Field.text ?? "";
        if (Value.Length >= MaxLength) return;
        Field.text = Value + Key;
    }

    void Back()
    {
        string Value = Field.text ?? "";
        if (Value.Length > 0) Field.text = Value[..^1];
    }

    //--------------------------CONSTRUCTION----------------------------------------

    // Le clavier est cree sous HIDER : c'est le dernier enfant du Canvas, donc dessine
    // par-dessus les panneaux, et il survit au changement de page.
    GameObject Build()
    {
        Transform Parent = Get.o1("HIDER") != null ? Get.o1("HIDER").transform
                                                   : Get.o1("Canvas").transform;

        GameObject Root = new(PanelName, typeof(RectTransform), typeof(CanvasRenderer), typeof(Image));
        Root.transform.SetParent(Parent, false);

        RectTransform Rt = (RectTransform)Root.transform;
        Rt.anchorMin = new Vector2(0f, 0f);
        Rt.anchorMax = new Vector2(1f, 0f);
        Rt.pivot = new Vector2(0.5f, 0f);
        Rt.anchoredPosition = Vector2.zero;
        Rt.sizeDelta = new Vector2(0f, Rows.Length * (RowHeight + RowSpacing) + RowHeight + RowSpacing * 2f);

        Root.GetComponent<Image>().color = new Color(0.12f, 0.12f, 0.12f, 0.95f);

        Font KeyFont = PanelFont();

        // Les touches sont ancrees en fractions de largeur : le clavier suit la taille de l'ecran.
        for (int r = 0; r < Rows.Length; r++)
        {
            string Row = Rows[r];
            float Y = -(r * (RowHeight + RowSpacing)) - RowSpacing;
            for (int k = 0; k < Row.Length; k++)
            {
                string Key = Row[k].ToString();
                AddKey(Root.transform, Key, Key, KeyFont,
                       k / (float)Row.Length, (k + 1) / (float)Row.Length, Y,
                       () => Type(Key));
            }
        }

        // Derniere rangee : espace, effacer, valider.
        float LastY = -(Rows.Length * (RowHeight + RowSpacing)) - RowSpacing;
        AddKey(Root.transform, "Space", "___", KeyFont, 0f, 0.5f, LastY, () => Type(" "));
        AddKey(Root.transform, "Back", "<", KeyFont, 0.5f, 0.75f, LastY, Back);
        AddKey(Root.transform, "Done", "OK", KeyFont, 0.75f, 1f, LastY, () => Show(false));

        return Root;
    }

    void AddKey(Transform Parent, string GoName, string Label, Font KeyFont,
                float XMin, float XMax, float Y, UnityEngine.Events.UnityAction OnClick)
    {
        GameObject Key = new(GoName, typeof(RectTransform), typeof(CanvasRenderer), typeof(Image), typeof(Button));
        Key.transform.SetParent(Parent, false);

        RectTransform Rt = (RectTransform)Key.transform;
        Rt.anchorMin = new Vector2(XMin, 1f);
        Rt.anchorMax = new Vector2(XMax, 1f);
        Rt.pivot = new Vector2(0.5f, 1f);
        Rt.sizeDelta = new Vector2(-2f * SideMargin, RowHeight);
        Rt.anchoredPosition = new Vector2(0f, Y);

        Key.GetComponent<Image>().color = Color.white;
        Key.GetComponent<Button>().onClick.AddListener(OnClick);

        GameObject TextGo = new("T", typeof(RectTransform), typeof(CanvasRenderer), typeof(Text));
        TextGo.transform.SetParent(Key.transform, false);

        RectTransform TRt = (RectTransform)TextGo.transform;
        TRt.anchorMin = Vector2.zero;
        TRt.anchorMax = Vector2.one;
        TRt.offsetMin = Vector2.zero;
        TRt.offsetMax = Vector2.zero;

        Text T = TextGo.GetComponent<Text>();
        T.text = Label;
        T.font = KeyFont;
        T.fontSize = 30;
        T.alignment = TextAnchor.MiddleCenter;
        T.color = Color.black;
        T.raycastTarget = false;
    }

    // Les Text crees a la main n'ont pas de police : on emprunte celle du panneau.
    static Font PanelFont()
    {
        GameObject Canvas = Get.o1("Canvas");
        if (Canvas != null)
        {
            Text Sample = Canvas.GetComponentInChildren<Text>(true);
            if (Sample != null && Sample.font != null) return Sample.font;
        }
        return Resources.GetBuiltinResource<Font>("LegacyRuntime.ttf");
    }
}