//---------------------------------------------------------------------
// <copyright file="IgnorePropertiesAttribute.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <summary>
//      CLR attribute to be annotated on types which indicate the list of properties
//      to ignore.
// </summary>
//
// @owner  Microsoft
//---------------------------------------------------------------------
 
namespace System.Data.Services
{
    using System;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Diagnostics;
    using System.Reflection;
 
    /// <summary>Attribute to be annotated on types with ETags.</summary>
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1019:DefineAccessorsForAttributeArguments", Justification = "Processed values are available.")]
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
    public sealed class IgnorePropertiesAttribute : System.Attribute
    {
        /// <summary>Name of the properties that form the ETag.</summary>
        private readonly ReadOnlyCollection<string> propertyNames;
 
        // This constructor was added since string[] is not a CLS-compliant type and
        // compiler gives a warning as error saying this attribute doesn't have any
        // constructor that takes CLS-compliant type
 
        /// <summary>
        /// Initializes a new instance of IgnoreProperties attribute with the property name
        /// that needs to be ignored
        /// </summary>
        /// <param name='propertyName'>Name of the property that form the ETag for the current type.</param>
        public IgnorePropertiesAttribute(string propertyName)
        {
            WebUtil.CheckArgumentNull(propertyName, "propertyName");
            this.propertyNames = new ReadOnlyCollection<string>(new List<string>(new string[1] { propertyName }));
        }
 
        /// <summary>
        /// Initializes a new instance of IgnoreProperties attribute with the list of property names
        /// that need to be ignored
        /// </summary>
        /// <param name='propertyNames'>Name of the properties that form the ETag for the current type.</param>
        public IgnorePropertiesAttribute(params string[] propertyNames)
        {
            WebUtil.CheckArgumentNull(propertyNames, "propertyNames");
            if (propertyNames.Length == 0)
            {
                throw new ArgumentException(Strings.ETagAttribute_MustSpecifyAtleastOnePropertyName, "propertyNames");
            }
 
            this.propertyNames = new ReadOnlyCollection<string>(new List<string>(propertyNames));
        }
 
        /// <summary>Name of the properties that needs to be ignored for the current type.</summary>
        public ReadOnlyCollection<string> PropertyNames
        {
            get
            {
                return this.propertyNames;
            }
        }
 
        /// <summary>
        /// Validate and get the list of properties specified by this attribute on the given type.
        /// </summary>
        /// <param name="type">clr type on which this attribute must have defined.</param>
        /// <param name="inherit">whether we need to inherit this attribute or not.
        /// For context types,we need to, since we can have one context dervied from another, and we want to ignore all the properties on the base ones too.
        /// For resource types, we don't need to, since we don't want derived types to know about ignore properties of the base type. Also
        /// from derived type, you cannot change the definition of the base type.</param>
        /// <param name="bindingFlags">binding flags to be used for validating property names.</param>
        /// <returns>list of property names specified on IgnoreProperties on the given type.</returns>
        internal static IEnumerable<string> GetProperties(Type type, bool inherit, BindingFlags bindingFlags)
        {
            IgnorePropertiesAttribute[] attributes = (IgnorePropertiesAttribute[])type.GetCustomAttributes(typeof(IgnorePropertiesAttribute), inherit);
            Debug.Assert(attributes.Length == 0 || attributes.Length == 1, "There should be atmost one IgnoreProperties specified");
            if (attributes.Length == 1)
            {
                foreach (string propertyName in attributes[0].PropertyNames)
                {
                    if (String.IsNullOrEmpty(propertyName))
                    {
                        throw new InvalidOperationException(Strings.IgnorePropertiesAttribute_PropertyNameCannotBeNullOrEmpty);
                    }
 
                    PropertyInfo property = type.GetProperty(propertyName, bindingFlags);
                    if (property == null)
                    {
                        throw new InvalidOperationException(Strings.IgnorePropertiesAttribute_InvalidPropertyName(propertyName, type.FullName));
                    }
                }
 
                return attributes[0].PropertyNames;
            }
 
            return WebUtil.EmptyStringArray;
        }
    }
}