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

namespace VirtualKeyboard
{
  public partial class QwertzKeyboard : Form
  {
    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]};
    // **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)
    };
    // NumPad-Positionen: Standard-Rechner-Layout
    // Zeile 1: 7 8 9 /
    // Zeile 2: 4 5 6 *
    // Zeile 3: 1 2 3 -
    // Zeile 4: 0 00 , +
    // Rechts: OK
    //string[] numpadLayout = {
    //    "⌫/*-",
    //    "789+",
    //    "456",
    //    "123↵",
    //    "0," // 0 breit, Komma, Plus
    //  };
    // Numeric-Reihen
    private string[] numpadLayout;

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

      // OK wird in Reihen integriert
      this.Size = new Size((int)(screen.WorkingArea.Width * 0.80), (btnHeight + spacing) * 5 + 10);
      this.MaximumSize = new Size(1000, (btnHeight + spacing) * 5 + 10);
      UpdateLayout();
    }

    private void OK_Click(object sender, EventArgs e)
    {
      this.Close();
    }

    private void Tab_Click(object sender, EventArgs e)
    {
      DialogResult result = DialogResult.None;
      if (targetTextBox.Parent?.SelectNextControl(targetTextBox, true, true, true, true) == true)    result = DialogResult.OK;
      else result = DialogResult.Cancel;
      this.Close();
    }

    private void Key_Click(object sender, EventArgs e)
    {
      Button btn = sender as Button;
      char ch = (char)btn.Tag;

      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;
        default: targetTextBox.Text += btn.Text;
          break;
      }
      if (isShift && char.IsLetter(ch)) ch = char.ToUpper(ch);

      //targetTextBox.Focus();
      //targetTextBox.SelectionStart = targetTextBox.Text.Length;
    }

    private void ToggleMode_Click()
    {
      isNumeric = !isNumeric;
      UpdateLayout();
    }

    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
          }
        }
      }
      else
      {
        // **VERSTECKE ALLE QWERTZ-Buttons** und zeige nur NumPad
        HideAllQwertzButtons();
        SetupRealNumPad();
      }
      this.Refresh();
      targetTextBox.Focus();
    }
    private void HideAllQwertzButtons()
    {
      // Blende ALLE Keys aus (QWERTZ komplett weg)
      foreach (var row in keys)
      {
        foreach (var btn in row.Where(b => b != null))
        {
          btn.Visible = false;
        }
      }
    }
    private void SetupRealNumPad()
    {
      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);
      // NumPad-Grids füllen (erste 4 Reihen)
      for (int row = 0; row < numpadLayout.Length; row++)
      {
        string rowText = numpadLayout[row];

        btnHeight = 55;
        xBase = 10;
        for (int col = 0; col < rowText.Length; col++)
        {
          char ch = rowText[col];
          if (ch == ' ') { xBase += btnWidth + spacing; continue; } // Leerspace für breiten 0
          if (ch == '↵')
          {
            Button okBtn = keys[row][col];
            // OK-Button rechts unten (NumPad-Enter-Stil)
            okBtn.Text = "OK";
            okBtn.Size = (isCalc) ? new Size(btnWidth, btnHeight * 2 + spacing) : new Size(btnWidth, btnHeight);
            okBtn.Location = new Point(xBase, y);
            okBtn.BackColor = Color.FromArgb(0, 192, 0);
            okBtn.ForeColor = Color.White;
            okBtn.Font = new Font("Arial", 14, FontStyle.Bold);
            okBtn.FlatStyle = FlatStyle.Flat;
            okBtn.FlatAppearance.BorderSize = 1;
            okBtn.FlatAppearance.BorderColor = Color.Green;
            okBtn.Visible = true;
            okBtn.Click += OK_Click;
            continue;
          }
          if (ch == '+') { btnHeight = btnHeight * 2 + spacing; }
          Button btn = keys[row][col];
          btn.Text = ch.ToString();
          btn.Tag = ch;
          btn.Size = (row == 4 && col == 0) ? new Size(btnWidth * 2 + spacing, btnHeight) : new Size(btnWidth, btnHeight); // Breiter 0
          btn.Location = new Point(xBase, y);
          btn.Font = new Font("Arial", 18, FontStyle.Bold);
          btn.BackColor = Color.FromArgb(240, 240, 240); // NumPad-Look
          btn.FlatStyle = FlatStyle.Flat;
          btn.FlatAppearance.BorderSize = 1;
          btn.Visible = true;
          btn.Enabled = true;

          xBase += btn.Width + spacing;
        }
        y += (btnHeight > 55) ? (btnHeight / 2) + (spacing / 2) : btnHeight + spacing;
      }


      // Verstecke ungenutzte Keys (Reihen 4+)
      for (int row = 5; row < keys.Length; row++)
        for (int col = 0; col < keys[row].Length; col++)
          keys[row][col].Visible = false;
    }

    protected override void OnShown(EventArgs e)
    {
      base.OnShown(e);
      this.Location = new Point((screen.WorkingArea.Width - this.Width) / 2, screen.WorkingArea.Height - this.Height);
    }
  }
}