using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Xml.Linq;

namespace VirtualKeyboard
{
  public partial class QwertzKeyboard : Form
  {
    public event EventHandler KeyBoardShown;
    public event EventHandler KeyBoardClosed;
    private TextBox targetTextBox;
    //private Button okBtn;
    private bool isNumeric = false;
    private bool isCalc = false;
    private bool isShift = false;
    private Screen screen = Screen.PrimaryScreen;
    // Erweiterte keys auf mehr Buttons (z.B. 14 pro Reihe)
    private Button[][] keys = new Button[5][] {
    new Button[14], new Button[14], new Button[14], new Button[14], new Button[8]};

    private Button[][] numkeys = new Button[4][] {
    new Button[4], new Button[4], new Button[4], new Button[4]};

    // **Echtes QWERTZ-Layout** (5 Reihen + Funktion/Steuerung)
    private string[] qwertzRows = {
    "?1234567890ß⌫↵",           // Ziffernreihe
    "↔qwertzuiopü+",          // Hauptbuchstaben 1 (versetzt)
    "  asdfghjklöä#",          // Hauptbuchstaben 2 (versetzt)
    "⇧<yxcvbnm,.-⇧",            // Hauptbuchstaben 3 (Y statt Z, versetzt)
    " _ "        // Untere Reihe: Shift (breit), Enter (hoch), Space (sehr breit)
    };
    private string[] numpadLayout;

    public QwertzKeyboard(TextBox target, string numeric)
    {
      if (numeric == "isNumeric")
      {
        isNumeric = true;
        numpadLayout = new string[] { "789", "456", "123", "⌫0↵" };
        InitializeNumPad();
      }
      if (numeric == "isCalc")
      {
        isCalc = true;
        numpadLayout = new string[] { "⌫/*-", "789+", "456", "123↵", "_0," };
        numkeys = new Button[5][] { new Button[4], new Button[4], new Button[4], new Button[4], new Button[4] };
        InitializeNumPad();
      }
      if (numeric == "isAlpha")
      {
        isNumeric = isCalc = false;
        InitializeKeyboard();
      }

      this.targetTextBox = target;
      this.FormBorderStyle = FormBorderStyle.None;
      this.BackColor = Color.FromArgb(1,53,101);
      this.StartPosition = FormStartPosition.Manual;
      this.TopMost = true;
      this.ShowInTaskbar = false;
      this.targetTextBox.Focus();
    }
    private void InitializeNumPad()
    {
      int y = 10, xBase = 10, btnWidth = 70, btnHeight = 55, spacing = 8;
      if (isCalc) this.Size = new Size((btnWidth + spacing) * 4 + xBase, (btnHeight + spacing) * 5 + xBase);
      if (isNumeric) this.Size = new Size((btnWidth + spacing) * 3 + xBase, (btnHeight + spacing) * 4 + xBase);

      for (int row = 0; row < numpadLayout.Length; row++)
      {
        string rowText = numpadLayout[row];
        int rowLength = rowText.Length;
        numkeys[row] = new Button[rowLength];
        xBase = 10;

        for (int col = 0;col < rowLength; col++)
        {
          char ch = rowText[col];
          if (ch == ' ') { xBase += btnWidth + spacing; continue; } // Leerspace für breiten 0
          if (ch == '↵')
          {
            Button okBtn = new Button
            {
              Text = "OK",
              Size = (isCalc) ? new Size(btnWidth, btnHeight * 2 + spacing) : new Size(btnWidth, btnHeight),
              Location = new Point(xBase, y),
              BackColor = Color.FromArgb(0, 192, 0),
              ForeColor = Color.White,
              Font = new Font("Arial", 14, FontStyle.Bold),
              FlatStyle = FlatStyle.Flat,
              Visible = true,
            };
            okBtn.FlatAppearance.BorderSize = 1;
            okBtn.FlatAppearance.BorderColor = Color.Green;
            okBtn.Click += OK_Click;
            this.Controls.Add(okBtn);

            // OK-Button rechts unten (NumPad-Enter-Stil)
            continue;
          }
          Button btn = new Button
          {
            Text = ch.ToString(),
            Tag = ch,
            Size = ch == '+' ? new Size(btnWidth, btnHeight * 2 + spacing) : new Size(btnWidth, btnHeight),
            Location = new Point(xBase, y),
            Font = new Font("Arial", 18, FontStyle.Bold),
            BackColor = Color.FromArgb(240, 240, 240),
            FlatStyle = FlatStyle.Flat,
            Visible = true,
            Enabled = true,
          };
          btn.Click += Key_Click;

          this.Controls.Add(btn);
          numkeys[row][col] = btn;

          xBase += btn.Width + spacing;
        }
        y += btnHeight + spacing;
      }
    }
    private void InitializeKeyboard()
    {
      int btnHeight = 60, spacing = 4;
      int startY = 10;

      for (int row = 0; row < qwertzRows.Length; row++)
      {
        string rowText = qwertzRows[row];
        int rowLength = rowText.Length;
        keys[row] = new Button[rowLength];
        int x = 10;

        for (int col = 0; col < rowLength; col++)
        {
          int btnWidth = 0; // Breiten anpassen
          char ch = rowText[col];
          string sch = ch.ToString();
          int btnH = (ch == '↵' ? (btnHeight + spacing) * 5 - 4 : btnHeight); // Hoher Enter

          Button btn = new Button
          {
            Text = sch,
            Size = new Size(btnWidth, btnH),
            Location = new Point(x, startY),
            Font = new Font(ch == ' ' ? "Arial" : "Arial", 18, FontStyle.Bold),
            Tag = ch,
            BackColor = Color.FromArgb(240, 240, 240),
            FlatStyle = FlatStyle.Flat,
            FlatAppearance = { BorderSize = 1, MouseOverBackColor = Color.LightGray },
          };

          btn.Click += Key_Click;

          switch (btn.Text)
          {
            case var t when t == " ":
              btn.Width = 58;
              btn.Enabled = false;
              break;
            case var t when t == "_":
              btn.Width = (btnHeight + spacing) * 12 - 4;
              btn.Text = "Leertaste";
              break;
            case var t when t == "⇧":
              btn.Width = (int)((double)btnHeight * 1.5);
              btn.Text = "Shift";
              break;
            case var t when t == "↔":
              btn.Width = (int)((double)btnHeight * 1.5);
              btn.Text = "Tab";
              break;
            case var t when t == "⌫":
              btn.Width = btnHeight * 2;
              break;
            case var t when t == "↵":
              btn.Width = 90;
              btn.Text = "OK";
              btn.BackColor = Color.FromArgb(0, 192, 0);
              btn.ForeColor = Color.White;
              btn.FlatAppearance.BorderSize = 1;
              btn.FlatAppearance.BorderColor = Color.Green;
              break;
            default:
              btn.Width = btnHeight;
              break;
          }

          this.Controls.Add(btn);
          keys[row][col] = btn;
          x += btn.Width + spacing;
        }
        startY += keys[row][0].Height + spacing;
      }

      this.Size = new Size((int)(screen.WorkingArea.Width * 0.80), (btnHeight + spacing) * 5 + 10);
      this.MaximumSize = new Size(1000, (btnHeight + spacing) * 5 + 10);
    }

    private void OK_Click(object sender, EventArgs e)
    {
      KeyBoardClosed?.Invoke(this, EventArgs.Empty);
      this.Close();
    }
    private void Tab_Click(object sender, EventArgs e)
    {
      if (targetTextBox.Parent?.SelectNextControl(targetTextBox, true, true, true, true) == true) this.Close();
    }
    private void Key_Click(object sender, EventArgs e)
    {
      Button btn = sender as Button;
      char ch = (char)btn.Tag;

      if (!string.IsNullOrWhiteSpace(targetTextBox.SelectedText)) targetTextBox.Clear();

      switch (btn.Text)
      {
        case var t when t == "Shift": Shift_Click(btn, null);
          break;
        case var t when t == "Tab": Tab_Click(btn, null);
          break;
        case var t when t == "OK": OK_Click(btn, null);
          break;
        case var t when t == "⌫":
          if (targetTextBox.Text.Length > 0)
            targetTextBox.Text = targetTextBox.Text.Substring(0, targetTextBox.Text.Length - 1);
          break;
        case var t when t == "Leertaste":
          targetTextBox.Text += " ";
          break;
        case var t when t == "_":
          targetTextBox.Text += " ";
          break;
        default: targetTextBox.Text += btn.Text;
          break;
      }
      if (isShift && char.IsLetter(ch)) ch = char.ToUpper(ch);

    }
    private void Shift_Click(object sender, EventArgs e)
    {
      Button shiftBtn = (Button)sender;
      isShift = !isShift;
      shiftBtn.BackColor = isShift ? Color.Yellow : Color.FromArgb(240, 240, 240);
      UpdateLayout();
    }
    private void UpdateLayout()
    {

      if (!isNumeric)
      {
        // Zeige ALLE QWERTZ-Buttons
        for (int row = 0; row < qwertzRows.Length; row++)
        {
          string rowText = qwertzRows[row];
          for (int col = 0; col < keys[row].Length && col < rowText.Length; col++)
          {
            char ch = rowText[col];
            if (keys[row][col].Text.Length > 1) continue;
            keys[row][col].Text = isShift && char.IsLetter(ch) ? char.ToUpper(ch).ToString() : ch.ToString();
            keys[row][col].Tag = ch;
            keys[row][col].Visible = true; // QWERTZ sichtbar
          }
        }
      }
      this.Refresh();
      targetTextBox.Focus();
    }
    protected override void OnShown(EventArgs e)
    {
      base.OnShown(e);
      this.Location = new Point((screen.WorkingArea.Width - this.Width) / 2, screen.WorkingArea.Height - this.Height);

      KeyBoardShown?.Invoke(this, EventArgs.Empty);
    }
  }
}