#region License

// The MIT License
//
// Copyright (c) 2006-2008 DevDefined Limited.
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#endregion

using System;
using DevDefined.OAuth.Framework;
using DevDefined.OAuth.Utility;

namespace DevDefined.OAuth.Provider.Inspectors
{
	public class TimestampRangeInspector : IContextInspector
	{
		readonly Func<DateTime> _nowFunc;
		TimeSpan _maxAfterNow;
		TimeSpan _maxBeforeNow;

		public TimestampRangeInspector(TimeSpan window)
			: this(new TimeSpan(window.Ticks/2), new TimeSpan(window.Ticks/2))
		{
		}

		public TimestampRangeInspector(TimeSpan maxBeforeNow, TimeSpan maxAfterNow)
			: this(maxBeforeNow, maxAfterNow, () => Clock.Now)
		{
		}

		public TimestampRangeInspector(TimeSpan maxBeforeNow, TimeSpan maxAfterNow, Func<DateTime> nowFunc)
		{
			_maxBeforeNow = maxBeforeNow;
			_maxAfterNow = maxAfterNow;
			_nowFunc = nowFunc;
		}

		public void InspectContext(ProviderPhase phase, IOAuthContext context)
		{
			DateTime timestamp = DateTimeUtility.FromEpoch(Convert.ToInt32(context.Timestamp));
			DateTime now = _nowFunc();

			if (now.Subtract(_maxBeforeNow) > timestamp)
			{
				throw new OAuthException(context, OAuthProblems.TimestampRefused,
				                         string.Format(
				                         	"The timestamp is to old, it must be at most {0} seconds before the servers current date and time",
				                         	_maxBeforeNow.TotalSeconds));
			}
			if (now.Add(_maxAfterNow) < timestamp)
			{
				throw new OAuthException(context, OAuthProblems.TimestampRefused,
				                         string.Format(
				                         	"The timestamp is to far in the future, if must be at most {0} seconds after the server current date and time",
				                         	_maxAfterNow.TotalSeconds));
			}
		}
	}
}