Initial work on TextPath widget

src/Spectre.Console/Widgets/TextPath.cs

@@ -0,0 +1,107 @@
+namespace Spectre.Console;
+
+/// <summary>
+/// Representation of a file system path.
+/// </summary>
+public sealed class TextPath : IRenderable
+{
+    private readonly string[] _parts;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="TextPath"/> class.
+    /// </summary>
+    /// <param name="path">The path to render.</param>
+    public TextPath(string path)
+    {
+        // Normalize the path
+        path ??= string.Empty;
+        path = path.Replace('\\', '/');
+        path = path.TrimEnd('/').Trim();
+
+        // Get the distinct parts
+        _parts = path.Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries);
+    }
+
+    /// <inheritdoc/>
+    public Measurement Measure(RenderContext context, int maxWidth)
+    {
+        var fitted = Fit(context, maxWidth);
+        var length = fitted.Sum(f => f.Length) + fitted.Length - 1;
+
+        return new Measurement(
+            Math.Min(length, maxWidth),
+            Math.Max(length, maxWidth));
+    }
+
+    /// <inheritdoc/>
+    public IEnumerable<Segment> Render(RenderContext context, int maxWidth)
+    {
+        var fitted = Fit(context, maxWidth);
+
+        var parts = new List<Segment>();
+        foreach (var (_, _, last, item) in fitted.Enumerate())
+        {
+            parts.Add(new Segment(item));
+
+            if (!last)
+            {
+                parts.Add(new Segment("/", new Style(Color.Grey)));
+            }
+        }
+
+        return parts;
+    }
+
+    private string[] Fit(RenderContext context, int maxWidth)
+    {
+        // No parts?
+        if (_parts.Length == 0)
+        {
+            return _parts;
+        }
+
+        // Will it fit as is?
+        if (_parts.Sum(p => Cell.GetCellLength(p)) + (_parts.Length - 1) < maxWidth)
+        {
+            return _parts;
+        }
+
+        var ellipsis = context.Unicode ? "…" : "...";
+        var ellipsisLength = Cell.GetCellLength(ellipsis);
+
+        if (_parts.Length >= 2)
+        {
+            // Try popping parts until it fits
+            var queue = new Queue<string>(_parts.Skip(1).Take(_parts.Length - 2));
+            while (queue.Count > 0)
+            {
+                // Remove the first item
+                queue.Dequeue();
+
+                // Get the current queue width in cells
+                var queueWidth =
+                        Cell.GetCellLength(_parts[0]) // First
+                        + ellipsisLength // Ellipsis
+                        + queue.Sum(p => Cell.GetCellLength(p)) // Middle
+                        + Cell.GetCellLength(_parts.Last()) // Last
+                        + queue.Count + 2; // Separators
+
+                // Will it fit?
+                if (maxWidth >= queueWidth)
+                {
+                    var result = new List<string>();
+                    result.Add(_parts[0]);
+                    result.Add(ellipsis);
+                    result.AddRange(queue);
+                    result.Add(_parts.Last());
+                    return result.ToArray();
+                }
+            }
+        }
+
+        // Just trim the last part so it fits
+        var last = _parts.Last();
+        var take = Math.Max(0, maxWidth - ellipsisLength);
+        return new[] { string.Concat(ellipsis, last.Substring(last.Length - take, take)) };
+    }
+}