namespace Nancy.Extensions

{

using System;

using System.Diagnostics;

using System.Text.RegularExpressions;

using Nancy.ErrorHandling;

/// <summary>

/// Containing extensions for <see cref="INancyModule"/> implementations.

/// </summary>

public static class ModuleExtensions

{

/// <summary>

/// A regular expression used to manipulate parameterized route segments.

/// </summary>

/// <value>A <see cref="Regex"/> object.</value>

[DebuggerBrowsable(DebuggerBrowsableState.Never)]

private static readonly Regex ModuleNameExpression =

new Regex(@"(?<name>[\w]+)Module$", RegexOptions.Compiled);

/// <summary>

/// Extracts the friendly name of a Nancy module given its type.

/// </summary>

/// <param name="module">The module instance</param>

/// <returns>A string containing the name of the parameter.</returns>

/// <exception cref="FormatException"></exception>

public static string GetModuleName(this INancyModule module)

{

var typeName = module.GetType().Name;

var nameMatch =

ModuleNameExpression.Match(typeName);

if (nameMatch.Success)

{

return nameMatch.Groups["name"].Value;

}

return typeName;

}

/// <summary>

/// Returns a boolean indicating whether the route is executing, or whether the module is

/// being constructed.

/// </summary>

/// <param name="module">The module instance</param>

/// <returns>True if the route is being executed, false if the module is being constructed</returns>

public static bool RouteExecuting(this INancyModule module)

{

return module.Context != null;

}

/// <summary>

/// Adds the before delegate to the Before pipeline if the module is not currently executing,

/// or executes the delegate directly and returns any response returned if it is.

/// Uses <see cref="RouteExecutionEarlyExitException"/>

/// </summary>

/// <param name="module">Current module</param>

/// <param name="beforeDelegate">Delegate to add or execute</param>

/// <param name="earlyExitReason">Optional reason for the early exit (if necessary)</param>

public static void AddBeforeHookOrExecute(this INancyModule module, Func<NancyContext, Response> beforeDelegate, string earlyExitReason = null)

{

if (module.RouteExecuting())

{

var result = beforeDelegate.Invoke(module.Context);

if (result != null)

{

throw new RouteExecutionEarlyExitException(result, earlyExitReason);

}

}

else

{

module.Before.AddItemToEndOfPipeline(beforeDelegate);

}

}

}

}