using System;
using System.Configuration;
using System.Web.Services;
using ZetaLib.Core.Common;
using ZetaLib.Core.Collections;

/// <summary>
/// Base class for web services that protect their functions with
/// an API key.
/// </summary>
public class ApiKeyProtectedWebServiceBase :
	WebService
{
	/// <summary>
	/// 
	/// </summary>
	private static string[] validApiKeys
	{
		get
		{
			if ( _validApiKeys == null )
			{
				lock ( typeLock )
				{
					Set<string> result = new Set<string>();

					result.AddRange( ConvertHelper.ToString(
						ConfigurationManager.AppSettings[
						apiKeyConfigName], string.Empty ).Split(
						new char[] { ';' },
						StringSplitOptions.RemoveEmptyEntries ) );

					_validApiKeys = result.ToArray();
				}
			}

			return _validApiKeys;
		}
	}

	/// <summary>
	/// Checks whether the API key is valid.
	/// </summary>
	protected static void CheckApiKey(
		string apiKey )
	{
		if ( validApiKeys.Length > 0 )
		{
			foreach ( string validApiKey in validApiKeys )
			{
				if ( string.Compare( apiKey, validApiKey, true ) == 0 )
				{
					return;
				}
			}

			// Invalue.
			throw new ApplicationException(
				string.Format(
				"Invalid API key '{0}'.",
				apiKey ) );
		}
	}

	private static string apiKeyConfigName = @"apiKey";

	/// <summary>
	/// Allows for changing the app settings key.
	/// </summary>
	protected static string ApiKeyConfigName
	{
		get
		{
			lock ( typeLock )
			{
				return apiKeyConfigName;
			}
		}
		set
		{
			lock ( typeLock )
			{
				if ( apiKeyConfigName != value )
				{
					apiKeyConfigName = value;
					_validApiKeys = null;
				}
			}
		}
	}

	private static string[] _validApiKeys;

	private static object typeLock = new object();
}