//---------------------------------------------------------------------
// <copyright file="ProjectionPath.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <summary>
// Provides a class to represent an annotated path of segments
// (each of which is a step in the parsed tree).
// </summary>
//---------------------------------------------------------------------
 
namespace System.Data.Services.Client
{
    #region Namespaces.
 
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Linq.Expressions;
    using System.Text;
 
    #endregion Namespaces.
 
    /// <summary>Use this class to represent an annotated list of path segments.</summary>
    [DebuggerDisplay("{ToString()}")]
    internal class ProjectionPath : List<ProjectionPathSegment>
    {
        #region Constructors.
 
        /// <summary>Initializes a new <see cref="ProjectionPath"/> instance.</summary>
        internal ProjectionPath() : base()
        {
        }
 
        /// <summary>Initializes a new <see cref="ProjectionPath"/> instance.</summary>
        /// <param name="root">Root parameter for this path.</param>
        /// <param name="expectedRootType">Expression to get the expected root type in the target tree.</param>
        /// <param name="rootEntry">Expression for the root entry.</param>
        internal ProjectionPath(ParameterExpression root, Expression expectedRootType, Expression rootEntry)
            : base()
        {
            this.Root = root;
            this.RootEntry = rootEntry;
            this.ExpectedRootType = expectedRootType;
        }
 
        /// <summary>Initializes a new <see cref="ProjectionPath"/> instance.</summary>
        /// <param name="root">Root parameter for this path.</param>
        /// <param name="expectedRootType">Expression to get the expected root type in the target tree.</param>
        /// <param name="rootEntry">Expression for the root entry.</param>
        /// <param name="members">Member to initialize the path with.</param>
        internal ProjectionPath(ParameterExpression root, Expression expectedRootType, Expression rootEntry, IEnumerable<Expression> members)
            : this(root, expectedRootType, rootEntry)
        {
            Debug.Assert(members != null, "members != null");
 
            foreach (Expression member in members)
            {
                this.Add(new ProjectionPathSegment(this, ((MemberExpression)member).Member.Name, member.Type));
            }
        }
 
        #endregion Constructors.
 
        #region Internal properties.
 
        /// <summary>Parameter expression in the source tree.</summary>
        internal ParameterExpression Root 
        { 
            get; 
            private set; 
        }
 
        /// <summary>Expression to get the entry for <see cref="Root"/> in the target tree.</summary>
        internal Expression RootEntry 
        { 
            get; 
            private set; 
        }
 
        /// <summary>Expression to get the expected root type in the target tree.</summary>
        internal Expression ExpectedRootType 
        { 
            get; 
            private set; 
        }
 
        #endregion Internal properties.
 
        #region Methods.
 
        /// <summary>Provides a string representation of this object.</summary>
        /// <returns>A string representation of this object, suitable for debugging.</returns>
        public override string ToString()
        {
            StringBuilder builder = new StringBuilder();
            builder.Append(this.Root.ToString());
            builder.Append("->");
            for (int i = 0; i < this.Count; i++)
            {
                if (i > 0)
                {
                    builder.Append('.');
                }
 
                builder.Append(this[i].Member == null ? "*" : this[i].Member);
            }
 
            return builder.ToString();
        }
 
        #endregion Methods.
    }
}