/// <summary>
/// ## GetStrategyAliasMap
///
/// Returns a mapping of all alias => class names for classes that implement the strategy.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static Dictionary <string, string> GetStrategyAliasMap <T>()
{
Dictionary <string, string> map = new Dictionary <string, string>();
// iterate over all strategy implementations
// and pull alias from class attribute
List <TypeInfo> types = GetStrategyImplementations <T>();
foreach (TypeInfo ti in types)
{
// then pull in from the attribute
CommandAlias alias = ti.GetCustomAttribute <CommandAlias>();
if (alias != null)
{
foreach (string s in alias.Aliases)
{
if (map.ContainsKey(s))
{
throw new Exception($"Duplicate alias defined for the type {ti.Name}: {s}");
}
map[s] = ti.Name;
}
}
else
{
// add the class name as the default "alias"
map[ti.Name] = ti.Name;
}
}
return(map);
}
/// <summary>
/// ## AddOption
///
/// Adds a new option to the option set.
/// </summary>
/// <param name="options">OptionSet to add to.</param>
/// <param name="strategies">List of strategy types to use for this option.</param>
/// <param name="option">The option name.</param>
/// <param name="action">The delegate to call for the option.</param>
private void AddOption(OptionSet options, List <TypeInfo> strategies, string option, OptionAction <string, string> action)
{
/*
* The terminology here is a bit confusing, so here is quick explanation:
* - Option is the overall argument provided and the bit of text right after the hypen(s): --foo or -f
* - Command is the part after the colon following the option: --foo:bar
* This ties back directly to a strategy.
*
* So for the CLI argument `--select:regex=^foo\.txt$`, we get:
* - option: select
* - command: regex (refers to the RegexSelectionStrategy)
* - command parameters: ^foo\.txt$
*
* We are also using the first character of the command as a short alias,
* so we can use `-s` instead of `--select` for example.
*/
// Let's use class attributes for each stategy to set the option command name
// and build the option command description text.
StringBuilder buffer = new StringBuilder($"The {option} strategy to use and any parameters to provide.");
foreach (TypeInfo ti in strategies)
{
// default command alias for strategy is the class name
string alias = ti.Name;
string description = "(no description)";
CommandAlias commandAlias = ti.GetCustomAttribute <CommandAlias>();
if (commandAlias != null && commandAlias.Aliases.Count > 0)
{
alias = String.Join(", ", commandAlias.Aliases);
}
DescriptionAttribute descriptionAttr = ti.GetCustomAttribute <DescriptionAttribute>();
if (descriptionAttr != null)
{
description = descriptionAttr.Description;
}
// final constuct should look like: - foo, bar: My foobar description.
buffer.Append($"\n - {alias}: {description}");
}
// add the option:
// f|foo:
// The foo strategy to use...
// delegate to call
options.Add($"{option[0]}|{option}:", buffer.ToString(), action);
}