//
// EntityTagHeaderValue.cs
//
// Authors:
//	Marek Safar  <marek.safar@gmail.com>
//
// Copyright (C) 2011 Xamarin Inc (http://www.xamarin.com)
//
// 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.
//

using System.Collections.Generic;

namespace System.Net.Http.Headers
{
	public class EntityTagHeaderValue : ICloneable
	{
		static readonly EntityTagHeaderValue any = new EntityTagHeaderValue () { Tag = "*" };

		public EntityTagHeaderValue (string tag)
		{
			Parser.Token.CheckQuotedString (tag);
			Tag = tag;
		}

		public EntityTagHeaderValue (string tag, bool isWeak)
			: this (tag)
		{
			IsWeak = isWeak;
		}

		internal EntityTagHeaderValue ()
		{
		}

		public static EntityTagHeaderValue Any {
			get {
				return any;
			}
		}

		public bool IsWeak { get; internal set; }
		public string Tag { get; internal set; }

		object ICloneable.Clone ()
		{
			return MemberwiseClone ();
		}

		public override bool Equals (object obj)
		{
			var source = obj as EntityTagHeaderValue;
			return source != null && source.Tag == Tag &&
				string.Equals (source.Tag, Tag, StringComparison.Ordinal);
		}

		public override int GetHashCode ()
		{
			return IsWeak.GetHashCode () ^ Tag.GetHashCode ();
		}

		public static EntityTagHeaderValue Parse (string input)
		{
			EntityTagHeaderValue value;
			if (TryParse (input, out value))
				return value;

			throw new FormatException (input);
		}

		public static bool TryParse (string input, out EntityTagHeaderValue parsedValue)
		{
			var lexer = new Lexer (input);
			Token token;
			if (TryParseElement (lexer, out parsedValue, out token) && token == Token.Type.End)
				return true;

			parsedValue = null;
			return false;
		}

		static bool TryParseElement (Lexer lexer, out EntityTagHeaderValue parsedValue, out Token t)
		{
			parsedValue = null;

			t = lexer.Scan ();
			bool is_weak = false;

			if (t == Token.Type.Token) {
				var s = lexer.GetStringValue (t);
				if (s == "*") {
					parsedValue = any;

					t = lexer.Scan ();
					return true;
				}

				if (s != "W" || lexer.PeekChar () != '/')
					return false;

				is_weak = true;
				lexer.EatChar ();
				t = lexer.Scan ();
			}

			if (t != Token.Type.QuotedString)
				return false;

			parsedValue = new EntityTagHeaderValue ();
			parsedValue.Tag = lexer.GetStringValue (t);
			parsedValue.IsWeak = is_weak;

			t = lexer.Scan ();

			return true;
		}

		internal static bool TryParse (string input, int minimalCount, out List<EntityTagHeaderValue> result)
		{
			return CollectionParser.TryParse (input, minimalCount, TryParseElement, out result);
		}

		public override string ToString ()
		{
			return IsWeak ?
				"W/" + Tag :
				Tag;
		}
	}
}