/* ****************************************************************************
 *
 * Copyright (c) Microsoft Corporation. 
 *
 * This source code is subject to terms and conditions of the Apache License, Version 2.0. A 
 * copy of the license can be found in the License.html file at the root of this distribution. If 
 * you cannot locate the  Apache License, Version 2.0, please send an email to 
 * dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound 
 * by the terms of the Apache License, Version 2.0.
 *
 * You must not remove this notice, or any other, from this software.
 *
 *
 * ***************************************************************************/
 
using System;
using System.Dynamic.Utils;
 
#if CLR2
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
 
    /// <summary>
    /// Used to denote the target of a <see cref="GotoExpression"/>.
    /// </summary>
    public sealed class LabelTarget {
        private readonly Type _type;
        private readonly string _name;
 
        internal LabelTarget(Type type, string name) {
            _type = type;
            _name = name;
        }
 
        /// <summary>
        /// Gets the name of the label.
        /// </summary>
        /// <remarks>The label's name is provided for information purposes only.</remarks>
        public string Name {
            get { return _name; }
        }
 
        /// <summary>
        /// The type of value that is passed when jumping to the label
        /// (or System.Void if no value should be passed).
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1721:PropertyNamesShouldNotMatchGetMethods")]
        public Type Type {
            get { return _type; }
        }
 
        /// <summary>
        /// Returns a <see cref="String"/> that represents the current <see cref="Object"/>. 
        /// </summary>
        /// <returns>A <see cref="String"/> that represents the current <see cref="Object"/>. </returns>
        public override string ToString() {
            return String.IsNullOrEmpty(this.Name) ? "UnamedLabel" : this.Name;
        }
    }
 
    public partial class Expression {
        /// <summary>
        /// Creates a <see cref="LabelTarget"/> representing a label with void type and no name.
        /// </summary>
        /// <returns>The new <see cref="LabelTarget"/>.</returns>
        public static LabelTarget Label() {
            return Label(typeof(void), null);
        }
 
        /// <summary>
        /// Creates a <see cref="LabelTarget"/> representing a label with void type and the given name.
        /// </summary>
        /// <param name="name">The name of the label.</param>
        /// <returns>The new <see cref="LabelTarget"/>.</returns>
        public static LabelTarget Label(string name) {
            return Label(typeof(void), name);
        }
 
        /// <summary>
        /// Creates a <see cref="LabelTarget"/> representing a label with the given type.
        /// </summary>
        /// <param name="type">The type of value that is passed when jumping to the label.</param>
        /// <returns>The new <see cref="LabelTarget"/>.</returns>
        public static LabelTarget Label(Type type) {
            return Label(type, null);
        }
 
        /// <summary>
        /// Creates a <see cref="LabelTarget"/> representing a label with the given type and name.
        /// </summary>
        /// <param name="type">The type of value that is passed when jumping to the label.</param>
        /// <param name="name">The name of the label.</param>
        /// <returns>The new <see cref="LabelTarget"/>.</returns>
        public static LabelTarget Label(Type type, string name) {
            ContractUtils.RequiresNotNull(type, "type");
            TypeUtils.ValidateType(type);
            return new LabelTarget(type, name);
        }
    }
}