private void RenderHelp(ApplicationSchema applicationSchema, CommandSchema command)
{
var column = 0;
var row = 0;
var childCommands = applicationSchema.GetChildCommands(command.Name);
bool IsEmpty() => column == 0 && row == 0;
void Render(string text)
{
_console.Output.Write(text);
column += text.Length;
}
void RenderNewLine()
{
_console.Output.WriteLine();
column = 0;
row++;
}
void RenderMargin(int lines = 1)
{
if (!IsEmpty())
{
for (var i = 0; i < lines; i++)
{
RenderNewLine();
}
}
}
void RenderIndent(int spaces = 2)
{
Render(' '.Repeat(spaces));
}
void RenderColumnIndent(int spaces = 20, int margin = 2)
{
if (column + margin < spaces)
{
RenderIndent(spaces - column);
}
else
{
Render(" ");
}
}
void RenderWithColor(string text, ConsoleColor foregroundColor)
{
_console.WithForegroundColor(foregroundColor, () => Render(text));
}
void RenderHeader(string text)
{
RenderWithColor(text, ConsoleColor.Magenta);
RenderNewLine();
}
void RenderApplicationInfo()
{
if (!command.IsDefault)
{
return;
}
// Title and version
RenderWithColor(_metadata.Title, ConsoleColor.Yellow);
Render(" ");
RenderWithColor(_metadata.VersionText, ConsoleColor.Yellow);
RenderNewLine();
// Description
if (!string.IsNullOrWhiteSpace(_metadata.Description))
{
Render(_metadata.Description);
RenderNewLine();
}
}
void RenderDescription()
{
if (string.IsNullOrWhiteSpace(command.Description))
{
return;
}
RenderMargin();
RenderHeader("Description");
RenderIndent();
Render(command.Description);
RenderNewLine();
}
void RenderUsage()
{
RenderMargin();
RenderHeader("Usage");
// Exe name
RenderIndent();
Render(_metadata.ExecutableName);
// Command name
if (!string.IsNullOrWhiteSpace(command.Name))
{
Render(" ");
RenderWithColor(command.Name, ConsoleColor.Cyan);
}
// Child command placeholder
if (childCommands.Any())
{
Render(" ");
RenderWithColor("[command]", ConsoleColor.Cyan);
}
// Parameters
foreach (var parameter in command.Parameters)
{
Render(" ");
Render(parameter.IsScalar
? $"<{parameter.DisplayName}>"
: $"<{parameter.DisplayName}...>");
}
// Required options
var requiredOptionSchemas = command.Options
.Where(o => o.IsRequired)
.ToArray();
foreach (var option in requiredOptionSchemas)
{
Render(" ");
if (!string.IsNullOrWhiteSpace(option.Name))
{
RenderWithColor($"--{option.Name}", ConsoleColor.White);
Render(" ");
Render(option.IsScalar
? "<value>"
: "<values...>");
}
else
{
RenderWithColor($"-{option.ShortName}", ConsoleColor.White);
Render(" ");
Render(option.IsScalar
? "<value>"
: "<values...>");
}
}
// Options placeholder
if (command.Options.Count != requiredOptionSchemas.Length)
{
Render(" ");
RenderWithColor("[options]", ConsoleColor.White);
}
RenderNewLine();
}
void RenderParameters()
{
if (!command.Parameters.Any())
{
return;
}
RenderMargin();
RenderHeader("Parameters");
var parameters = command.Parameters
.OrderBy(p => p.Order)
.ToArray();
foreach (var parameter in parameters)
{
RenderWithColor("* ", ConsoleColor.Red);
RenderWithColor($"{parameter.DisplayName}", ConsoleColor.White);
RenderColumnIndent();
// Description
if (!string.IsNullOrWhiteSpace(parameter.Description))
{
Render(parameter.Description);
}
RenderNewLine();
}
}
void RenderOptions()
{
RenderMargin();
RenderHeader("Options");
var options = command.Options
.OrderByDescending(o => o.IsRequired)
.ToList();
// Add built-in options
options.Add(CommandOptionSchema.HelpOption);
if (command.IsDefault)
{
options.Add(CommandOptionSchema.VersionOption);
}
foreach (var option in options)
{
if (option.IsRequired)
{
RenderWithColor("* ", ConsoleColor.Red);
}
else
{
RenderIndent();
}
// Short name
if (option.ShortName != null)
{
RenderWithColor($"-{option.ShortName}", ConsoleColor.White);
}
// Delimiter
if (!string.IsNullOrWhiteSpace(option.Name) && option.ShortName != null)
{
Render("|");
}
// Name
if (!string.IsNullOrWhiteSpace(option.Name))
{
RenderWithColor($"--{option.Name}", ConsoleColor.White);
}
RenderColumnIndent();
// Description
if (!string.IsNullOrWhiteSpace(option.Description))
{
Render(option.Description);
Render(" ");
}
// Environment variable
if (!string.IsNullOrWhiteSpace(option.EnvironmentVariableName))
{
Render($"(Environment variable: {option.EnvironmentVariableName}).");
Render(" ");
}
RenderNewLine();
}
}
void RenderChildCommands()
{
if (!childCommands.Any())
{
return;
}
RenderMargin();
RenderHeader("Commands");
foreach (var childCommand in childCommands)
{
var relativeCommandName =
string.IsNullOrWhiteSpace(childCommand.Name) || string.IsNullOrWhiteSpace(command.Name)
? childCommand.Name
: childCommand.Name.Substring(command.Name.Length + 1);
// Name
RenderIndent();
RenderWithColor(relativeCommandName, ConsoleColor.Cyan);
// Description
if (!string.IsNullOrWhiteSpace(childCommand.Description))
{
RenderColumnIndent();
Render(childCommand.Description);
}
RenderNewLine();
}
RenderMargin();
// Child command help tip
Render("You can run `");
Render(_metadata.ExecutableName);
if (!string.IsNullOrWhiteSpace(command.Name))
{
Render(" ");
RenderWithColor(command.Name, ConsoleColor.Cyan);
}
Render(" ");
RenderWithColor("[command]", ConsoleColor.Cyan);
Render(" ");
RenderWithColor("--help", ConsoleColor.White);
Render("` to show help on a specific command.");
RenderNewLine();
}
_console.ResetColor();
RenderApplicationInfo();
RenderDescription();
RenderUsage();
RenderParameters();
RenderOptions();
RenderChildCommands();
}