//---------------------------------------------------------------------
// <copyright file="FunctionParameter.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// @owner       Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace System.Data.Metadata.Edm
{
    /// <summary>
    /// Class representing a function parameter
    /// </summary>
    public sealed class FunctionParameter : MetadataItem
    {
        internal static Func<FunctionParameter, SafeLink<EdmFunction>> DeclaringFunctionLinker = fp => fp._declaringFunction;
        
        #region Constructors
        /// <summary>
        /// The constructor for FunctionParameter taking in a name and a TypeUsage object
        /// </summary>
        /// <param name="name">The name of this FunctionParameter</param>
        /// <param name="typeUsage">The TypeUsage describing the type of this FunctionParameter</param>
        /// <param name="parameterMode">Mode of the parameter</param>
        /// <exception cref="System.ArgumentNullException">Thrown if name or typeUsage arguments are null</exception>
        /// <exception cref="System.ArgumentException">Thrown if name argument is empty string</exception>
        internal FunctionParameter(string name, TypeUsage typeUsage, ParameterMode parameterMode)
        {
            EntityUtil.CheckStringArgument(name, "name");
            EntityUtil.GenericCheckArgumentNull(typeUsage, "typeUsage");
            _name = name;            
            _typeUsage = typeUsage;
            SetParameterMode(parameterMode);
        }
        #endregion

        #region Fields
        private readonly TypeUsage _typeUsage;
        private readonly string _name;
        private readonly SafeLink<EdmFunction> _declaringFunction = new SafeLink<EdmFunction>();
        #endregion

        #region Properties
        /// <summary>
        /// Returns the kind of the type
        /// </summary>
        public override BuiltInTypeKind BuiltInTypeKind { get { return BuiltInTypeKind.FunctionParameter; } }

        /// <summary>
        /// Gets/Sets the mode of this parameter
        /// </summary>
        /// <exception cref="System.ArgumentNullException">Thrown if value passed into setter is null</exception>
        /// <exception cref="System.InvalidOperationException">Thrown if the FunctionParameter instance is in ReadOnly state</exception>
        [MetadataProperty(BuiltInTypeKind.ParameterMode, false)]
        public ParameterMode Mode
        {
            get
            {
                return GetParameterMode();
            }
        }

        /// <summary>
        /// Returns the identity of the member
        /// </summary>
        internal override string Identity
        {
            get
            {
                return _name;
            }
        }

        /// <summary>
        /// Returns the name of the member
        /// </summary>
        [MetadataProperty(PrimitiveTypeKind.String, false)]
        public String Name
        {
            get
            {
                return _name;
            }
        }

        /// <summary>
        /// Returns the TypeUsage object containing the type information and facets
        /// about the type
        /// </summary>
        [MetadataProperty(BuiltInTypeKind.TypeUsage, false)]
        public TypeUsage TypeUsage
        {
            get
            {
                return _typeUsage;
            }
        }

        /// <summary>
        /// Returns the declaring function of this parameter
        /// </summary>
        public EdmFunction DeclaringFunction
        {
            get
            {
                return _declaringFunction.Value;
            }
        }
        #endregion

        #region Methods
        /// <summary>
        /// Overriding System.Object.ToString to provide better String representation 
        /// for this type.
        /// </summary>
        public override string ToString()
        {
            return Name;
        }


        /// <summary>
        /// Sets the member to read only mode. Once this is done, there are no changes
        /// that can be done to this class
        /// </summary>
        internal override void SetReadOnly()
        {
            if (!IsReadOnly)
            {
                base.SetReadOnly();
                // TypeUsage is always readonly, no reason to set it
            }
        }
        #endregion
    }
}