[TUI] Implement hex view window for displaying image sectors

Aaru.Tui/ViewModels/Windows/HexViewWindowViewModel.cs

@@ -0,0 +1,115 @@
+using System.Collections.ObjectModel;
+using System.Windows.Input;
+using Aaru.CommonTypes.Interfaces;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace Aaru.Tui.ViewModels.Windows;
+
+public sealed partial class HexViewWindowViewModel : ViewModelBase
+{
+    private const int         BYTES_PER_LINE = 16;
+    readonly      IMediaImage _imageFormat;
+    readonly      Window      _parent;
+    readonly      Window      _view;
+    readonly      ulong       _currentSector;
+    [ObservableProperty]
+    string _filePath;
+    [ObservableProperty]
+    long _fileSize;
+    [ObservableProperty]
+    ObservableCollection<HexViewLine> _lines = [];
+
+    internal HexViewWindowViewModel(Window parent, Window view, IMediaImage imageFormat, string filePath)
+    {
+        ExitCommand = new RelayCommand(Exit);
+        BackCommand = new RelayCommand(Back);
+
+        _parent        = parent;
+        _view          = view;
+        _imageFormat   = imageFormat;
+        _currentSector = 0;
+        FilePath       = filePath;
+    }
+
+    public ICommand BackCommand { get; }
+    public ICommand ExitCommand { get; }
+
+    void Back()
+    {
+        _parent.Show();
+        _view.Close();
+    }
+
+    void Exit()
+    {
+        var lifetime = Application.Current!.ApplicationLifetime as IControlledApplicationLifetime;
+        lifetime!.Shutdown();
+    }
+
+    void LoadSector()
+    {
+        _imageFormat.ReadSector(_currentSector, out byte[]? sector);
+
+        using var stream = new MemoryStream(sector);
+        var       buffer = new byte[BYTES_PER_LINE];
+        long      offset = 0;
+
+        const int maxLines = 1000;
+
+        for(var lineCount = 0; stream.Position < stream.Length && lineCount < maxLines; lineCount++)
+        {
+            int bytesRead = stream.Read(buffer, 0, BYTES_PER_LINE);
+
+            if(bytesRead == 0) break;
+
+            var line = new HexViewLine
+            {
+                Offset = offset,
+                Bytes  = buffer.Take(bytesRead).ToArray()
+            };
+
+            Lines.Add(line);
+            offset += bytesRead;
+        }
+    }
+
+    public void LoadComplete()
+    {
+        LoadSector();
+    }
+}
+
+sealed class HexViewLine
+{
+    internal long   Offset { get; init; }
+    internal byte[] Bytes  { get; init; }
+
+    public string OffsetString => $"{Offset:X8}";
+
+    public string HexString
+    {
+        get
+        {
+            var hex = string.Join(" ", Bytes.Select(b => $"{b:X2}"));
+
+            // Pad to 16 bytes worth of hex (16 * 3 - 1 = 47 chars)
+            return hex.PadRight(47);
+        }
+    }
+
+    public string AsciiString
+    {
+        get
+        {
+            var ascii = new char[Bytes.Length];
+
+            for(var i = 0; i < Bytes.Length; i++) ascii[i] = Bytes[i] >= 32 && Bytes[i] < 127 ? (char)Bytes[i] : '.';
+
+            return new string(ascii).PadRight(16);
+        }
+    }
+}