Terminal abstractions and widgets for console applications - IConsole, ITerminal, panels, tables, rules, and ANSI color support

Install

dotnet add package TimeWarp.Terminal --prerelease

NuGet · Source

TimeWarp.Terminal

Terminal abstractions and widgets for console applications - IConsole, ITerminal, panels, tables, rules, and ANSI color support.

Installation

dotnet add package TimeWarp.Terminal

Quick Start

using TimeWarp.Terminal;

// Use the static Terminal class (Console-compatible API)
Terminal.WriteLine("Hello, World!".Green());
Terminal.WriteLine("Warning!".Yellow().Bold());

// Or get a terminal instance — all Write methods return ITerminal for fluent chaining
ITerminal terminal = TimeWarpTerminal.Default;
terminal
  .WritePanel("Important message", "Notice")
  .WriteRule("Section")
  .WriteTable(t => t
    .AddColumn("Name")
    .AddColumn("Value")
    .AddRow("Status", "OK".Green()))
  .WriteLine("Done!");

Static Terminal API

The Terminal static class provides a Console-compatible API for easy migration:

using static TimeWarp.Terminal.Terminal;

// Direct replacement for Console methods
WriteLine("Hello, World!");
WriteErrorLine("Error occurred!");
string? input = ReadLine();
Clear();

// Properties
int width = WindowWidth;
bool interactive = IsInteractive;
bool colorSupport = SupportsColor;

// Cursor operations
SetCursorPosition(10, 5);
var (left, top) = GetCursorPosition();

Testing with Static Terminal

// Replace Instance for testing
using TestTerminal testTerminal = new();
Terminal.Instance = testTerminal;

Terminal.WriteLine("test output");

Assert.Contains("test output", testTerminal.Output);

// Restore after test
Terminal.Instance = TimeWarpTerminal.Default;

Interfaces

IConsole

Basic console I/O abstraction for testable console applications.

public interface IConsole
{
    IConsole Write(string message);
    IConsole WriteLine(string? message = null);
    Task WriteLineAsync(string? message = null);
    IConsole WriteErrorLine(string? message = null);
    Task WriteErrorLineAsync(string? message = null);
    string? ReadLine();
}

ITerminal

Extended terminal interface with cursor control, colors, and hyperlinks.

public interface ITerminal : IConsole
{
    new ITerminal Write(string message);
    new ITerminal WriteLine(string? message = null);
    new ITerminal WriteErrorLine(string? message = null);
    ConsoleKeyInfo ReadKey(bool intercept);
    void SetCursorPosition(int left, int top);
    (int Left, int Top) GetCursorPosition();
    int WindowWidth { get; }
    bool IsInteractive { get; }
    bool SupportsColor { get; }
    bool SupportsHyperlinks { get; }
    void Clear();
}

Implementations

Testing Example

using TestTerminal terminal = new();

// Queue input for ReadLine
terminal = new TestTerminal("line1\nline2");

// Queue keys for ReadKey
terminal.QueueKey(ConsoleKey.Enter);
terminal.QueueKeys("hello");
terminal.QueueLine("complete line");

// Run code that uses ITerminal
myCommand.Execute(terminal);

// Verify output
Assert.Contains("expected text", terminal.Output);
Assert.Contains("error message", terminal.ErrorOutput);

Widgets

Panel

Bordered panel with optional header and content.

// Simple panel
terminal.WritePanel("This is important information");

// Panel with header
terminal.WritePanel("Content here", "Notice");

// Fluent builder with full options
terminal.WritePanel
( 
  panel => 
    panel
    .Header("Configuration".Cyan().Bold())
    .Content("Setting: value")
    .Border(BorderStyle.Rounded)
    .BorderColor(AnsiColors.Cyan)
    .Padding(2, 1)
    .Width(60)
    .WordWrap(true)
);

Border Styles: Rounded, Square, Doubled, Heavy, None

Table

Formatted table with columns, alignment, and styling.

// Simple table
terminal.WriteTable
( 
  t => t
    .AddColumn("Name")
    .AddColumn("Value", Alignment.Right)
    .AddRow("CPU", "45%")
    .AddRow("Memory", "2.1 GB")
);

// Full-featured table
terminal.WriteTable(t => t
    .AddColumn("Package")
    .AddColumn("Downloads", Alignment.Right)
    .AddColumn(new TableColumn("Path") { TruncateMode = TruncateMode.Start })
    .AddRow("GuardClauses", "12M", "/home/user/packages/guard")
    .Border(BorderStyle.Rounded)
    .BorderColor(AnsiColors.Cyan)
    .Expand()
    .Shrink());

terminal.WriteTable(table);

Alignment: Left (default), Right, Center

TruncateMode: End (default), Start, Middle

Rule

Horizontal rule with optional centered title.

// Simple rule
terminal.WriteRule();

// Rule with title
terminal.WriteRule("Section Title");

// Styled rule
terminal.WriteRule("Results".Cyan().Bold());

// Fluent builder
terminal.WriteRule(rule => rule
    .Title("Configuration")
    .Style(LineStyle.Doubled)
    .Color(AnsiColors.Cyan));

Line Styles: Thin, Doubled, Heavy

ANSI Colors

Extension methods for colored and styled console output.

// Foreground colors
terminal.WriteLine("Success!".Green());
terminal.WriteLine("Warning!".Yellow());
terminal.WriteLine("Error!".Red());

// Chained styles
terminal.WriteLine("Important".Red().Bold().Underline());

// Background colors
terminal.WriteLine("Highlighted".OnYellow());
terminal.WriteLine("Inverted".Black().OnWhite());

Available Colors

Standard: Black, Red, Green, Yellow, Blue, Magenta, Cyan, White, Gray

Bright: BrightRed, BrightGreen, BrightYellow, BrightBlue, BrightMagenta, BrightCyan, BrightWhite

Styles

Bold(), Dim(), Italic(), Underline(), Strikethrough()

Background Colors

OnBlack(), OnRed(), OnGreen(), OnYellow(), OnBlue(), OnMagenta(), OnCyan(), OnWhite()

ConsoleColor Support

Use ConsoleColor enum values for color output without needing ANSI escape codes directly. This provides a Console-compatible API for colored output.

// Single foreground color
Terminal.WriteLine("Error!", ConsoleColor.Red);
Terminal.WriteLine("Success!", ConsoleColor.Green);
Terminal.WriteLine("Warning!", ConsoleColor.Yellow);

// Foreground and background colors
Terminal.WriteLine("Highlighted", ConsoleColor.Black, ConsoleColor.Yellow);
Terminal.WriteLine("Inverted", ConsoleColor.White, ConsoleColor.Black);

// Error output with color
Terminal.WriteErrorLine("Error: File not found", ConsoleColor.Red);

// Write without newline
Terminal.Write("Loading...", ConsoleColor.Cyan);

// Widgets with colors
Terminal.WriteTable(table => table
    .AddColumn("Name")
    .AddColumn("Value")
    .AddRow("Status", "OK"),
  ConsoleColor.White, ConsoleColor.DarkBlue);

Terminal.WritePanel("Important content", "Notice",
  ConsoleColor.White, ConsoleColor.DarkBlue);

Supported Colors

All ConsoleColor values are mapped to their ANSI equivalents:

Foreground: Black, Red, Green, Yellow, Blue, Magenta, Cyan, White, Gray, DarkGray, DarkRed, DarkGreen, DarkYellow, DarkBlue, DarkMagenta, DarkCyan

Background: Maps to corresponding ANSI background codes (BgBlack, BgRed, etc.)

Hyperlinks

OSC 8 hyperlinks for supported terminals (Windows Terminal, iTerm2, VS Code, etc.).

// Write a clickable link
terminal.WriteLink("https://github.com", "GitHub");
terminal.WriteLinkLine("https://example.com", "Click here");

// String extension method
string link = "Click here".Link("https://example.com");
terminal.WriteLine(link);

// Styled hyperlink
terminal.WriteLine("Visit us".Link("https://example.com").Cyan().Underline());

// Check terminal support
if (terminal.SupportsHyperlinks)
    terminal.WriteLinkLine("https://docs.com", "View docs");
else
    terminal.WriteLine("View docs at https://docs.com");

AnsiStringUtils

Utilities for working with ANSI-styled strings.

// Get visible length (excludes ANSI codes)
int length = AnsiStringUtils.GetVisibleLength("Hello".Red()); // 5

// Strip all ANSI codes
string plain = AnsiStringUtils.StripAnsiCodes("\x1b[31mError\x1b[0m"); // "Error"

// Pad accounting for ANSI codes
string padded = AnsiStringUtils.PadRightVisible("Hi".Red(), 10);
string centered = AnsiStringUtils.CenterVisible("Title".Bold(), 40);

// Wrap text preserving ANSI codes
string[] lines = AnsiStringUtils.WrapText(longStyledText, maxWidth: 80);