//===============================================================================
// Microsoft patterns & practices Enterprise Library
// Caching Application Block
//===============================================================================
// Copyright © Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===============================================================================

using System;
using Microsoft.Practices.EnterpriseLibrary.Caching.Cryptography.Configuration.Manageability.Properties;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Manageability;
using Microsoft.Practices.EnterpriseLibrary.Common.Configuration.Manageability.Adm;
using Microsoft.Practices.EnterpriseLibrary.Security.Cryptography.Configuration;

namespace Microsoft.Practices.EnterpriseLibrary.Caching.Cryptography.Configuration.Manageability
{
    /// <summary>
    /// Provides a default implementation for <see cref="SymmetricStorageEncryptionProviderData"/> that
    /// processes policy overrides, performing appropriate logging of 
    /// policy processing errors.
    /// </summary>
    public class SymmetricStorageEncryptionProviderDataManageabilityProvider
        : ConfigurationElementManageabilityProviderBase<SymmetricStorageEncryptionProviderData>
    {
        /// <summary>
        /// The name of the symmetric instance property.
        /// </summary>
        public const String SymmetricInstancePropertyName = "symmetricInstance";

        /// <summary>
        /// Initialize a new instance of the <see cref="SymmetricStorageEncryptionProviderDataManageabilityProvider"/> class.
        /// </summary>
        public SymmetricStorageEncryptionProviderDataManageabilityProvider()
        { }

        /// <summary>
        /// Gets the template for the name of the policy associated to the object.
        /// </summary>
        /// <remarks>
        /// Elements that override 
        /// <see cref="ConfigurationElementManageabilityProviderBase{T}.AddAdministrativeTemplateDirectives(AdmContentBuilder, T, IConfigurationSource, String)"/>
        /// to avoid creating a policy must still override this property.
        /// </remarks>
        protected override string ElementPolicyNameTemplate
        {
            get { return null; }
        }

        /// <summary>
        /// Adds the ADM instructions that describe the policies that can be used to override the properties of
        /// a specific instance of the configuration element type managed by the receiver.
        /// </summary>
        /// <param name="contentBuilder">The <see cref="AdmContentBuilder"/> to which the Adm instructions are to be appended.</param>
        /// <param name="configurationObject">The configuration object instance.</param>
        /// <param name="configurationSource">The configuration source from where to get additional configuration
        /// information, if necessary.</param>
        /// <param name="elementPolicyKeyName">The key for the element's policies.</param>
        /// <remarks>
        /// The default implementation for this method creates a policy, using 
        /// <see cref="ConfigurationElementManageabilityProviderBase{T}.ElementPolicyNameTemplate"/> to create the policy name and invoking
        /// <see cref="ConfigurationElementManageabilityProviderBase{T}.AddElementAdministrativeTemplateParts(AdmContentBuilder, T, IConfigurationSource, String)"/>
        /// to add the policy parts.
        /// Subclasses managing objects that must not create a policy must override this method to just add the parts.
        /// </remarks>
        protected override void AddAdministrativeTemplateDirectives(AdmContentBuilder contentBuilder,
                                                                    SymmetricStorageEncryptionProviderData configurationObject,
                                                                    IConfigurationSource configurationSource,
                                                                    String elementPolicyKeyName)
        {
            // parts for encryption providers are part of their cache manager's policies
            AddElementAdministrativeTemplateParts(contentBuilder, configurationObject, configurationSource, elementPolicyKeyName);
        }

        /// <summary>
        /// Adds the ADM parts that represent the properties of
        /// a specific instance of the configuration element type managed by the receiver.
        /// </summary>
        /// <param name="contentBuilder">The <see cref="AdmContentBuilder"/> to which the Adm instructions are to be appended.</param>
        /// <param name="configurationObject">The configuration object instance.</param>
        /// <param name="configurationSource">The configuration source from where to get additional configuration
        /// information, if necessary.</param>
        /// <param name="elementPolicyKeyName">The key for the element's policies.</param>
        /// <remarks>
        /// Subclasses managing objects that must not create a policy will likely need to include the elements' keys when creating the parts.
        /// </remarks>
        protected override void AddElementAdministrativeTemplateParts(AdmContentBuilder contentBuilder,
                                                                      SymmetricStorageEncryptionProviderData configurationObject,
                                                                      IConfigurationSource configurationSource,
                                                                      String elementPolicyKeyName)
        {
            CryptographySettings cryptographySection
                = configurationSource.GetSection("securityCryptographyConfiguration") as CryptographySettings;
            contentBuilder.AddDropDownListPartForNamedElementCollection<SymmetricProviderData>(Resources.SymmetricStorageEncryptionProviderSymmetricInstancePartName,
                                                                                               elementPolicyKeyName,
                                                                                               SymmetricInstancePropertyName,
                                                                                               cryptographySection.SymmetricCryptoProviders,
                                                                                               configurationObject.SymmetricInstance,
                                                                                               false);
        }

        /// <summary>
        /// Overrides the <paramref name="configurationObject"/>'s properties with the Group Policy values from the 
        /// registry.
        /// </summary>
        /// <param name="configurationObject">The configuration object for instances that must be managed.</param>
        /// <param name="policyKey">The <see cref="IRegistryKey"/> which holds the Group Policy overrides for the 
        /// configuration element.</param>
        /// <remarks>Subclasses implementing this method must retrieve all the override values from the registry
        /// before making modifications to the <paramref name="configurationObject"/> so any error retrieving
        /// the override values will cancel policy processing.</remarks>
        protected override void OverrideWithGroupPolicies(SymmetricStorageEncryptionProviderData configurationObject,
                                                          IRegistryKey policyKey)
        {
            String symmetricInstanceOverride = policyKey.GetStringValue(SymmetricInstancePropertyName);

            configurationObject.SymmetricInstance = symmetricInstanceOverride;
        }
    }
}
