// 
// Identifier.cs
//
// Author:
//       Mike Krüger <mkrueger@novell.com>
// 
// Copyright (c) 2009 Novell, Inc (http://www.novell.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;

namespace ICSharpCode.Decompiler.CSharp.Syntax
{
	public class Identifier : AstNode
	{
		public new static readonly Identifier Null = new NullIdentifier ();
		sealed class NullIdentifier : Identifier
		{
			public override bool IsNull {
				get {
					return true;
				}
			}
			
			public override void AcceptVisitor (IAstVisitor visitor)
			{
				visitor.VisitNullNode(this);
			}
			
			public override T AcceptVisitor<T> (IAstVisitor<T> visitor)
			{
				return visitor.VisitNullNode(this);
			}
			
			public override S AcceptVisitor<T, S> (IAstVisitor<T, S> visitor, T data)
			{
				return visitor.VisitNullNode(this, data);
			}
			
			protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
			{
				return other == null || other.IsNull;
			}
		}
		
		public override NodeType NodeType {
			get {
				return NodeType.Token;
			}
		}
		
		string name;
		public string Name {
			get { return this.name; }
			set {
				if (value == null)
					throw new ArgumentNullException(nameof(value));
				ThrowIfFrozen();
				this.name = value;
			}
		}
		
		TextLocation startLocation;
		public override TextLocation StartLocation {
			get {
				return startLocation;
			}
		}
		
		internal void SetStartLocation(TextLocation value)
		{
			ThrowIfFrozen();
			this.startLocation = value;
		}
		
		const uint verbatimBit = 1u << AstNodeFlagsUsedBits;
		
		public bool IsVerbatim {
			get {
				return (flags & verbatimBit) != 0;
			}
			set {
				ThrowIfFrozen();
				if (value)
					flags |= verbatimBit;
				else
					flags &= ~verbatimBit;
			}
		}
		
		public override TextLocation EndLocation {
			get {
				return new TextLocation (StartLocation.Line, StartLocation.Column + (Name ?? "").Length + (IsVerbatim ? 1 : 0));
			}
		}
		
		Identifier ()
		{
			this.name = string.Empty;
		}
		
		protected Identifier (string name, TextLocation location)
		{
			if (name == null)
				throw new ArgumentNullException(nameof(name));
			this.Name = name;
			this.startLocation = location;
		}

		public static Identifier Create (string name)
		{
			return Create (name, TextLocation.Empty);
		}

		public static Identifier Create (string name, TextLocation location)
		{
			if (string.IsNullOrEmpty(name))
				return Identifier.Null;
			if (name[0] == '@')
				return new Identifier (name.Substring (1), new TextLocation (location.Line, location.Column + 1)) { IsVerbatim = true };
			else
				return new Identifier (name, location);
		}
		
		public static Identifier Create (string name, TextLocation location, bool isVerbatim)
		{
			if (string.IsNullOrEmpty (name))
				return Identifier.Null;
			
			if (isVerbatim)
				return new Identifier (name, location) { IsVerbatim = true };
			return new Identifier (name, location);
		}
		
		public override void AcceptVisitor (IAstVisitor visitor)
		{
			visitor.VisitIdentifier (this);
		}
		
		public override T AcceptVisitor<T> (IAstVisitor<T> visitor)
		{
			return visitor.VisitIdentifier (this);
		}
		
		public override S AcceptVisitor<T, S> (IAstVisitor<T, S> visitor, T data)
		{
			return visitor.VisitIdentifier (this, data);
		}
		
		protected internal override bool DoMatch(AstNode other, PatternMatching.Match match)
		{
			Identifier o = other as Identifier;
			return o != null && !o.IsNull && MatchString(this.Name, o.Name);
		}
	}
}