// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics.CodeAnalysis;
using System.Xml;

namespace System.Security.Cryptography.Xml
{
    public sealed class EncryptedData : EncryptedType
    {
        [RequiresDynamicCode(CryptoHelpers.XsltRequiresDynamicCodeMessage)]
        [RequiresUnreferencedCode(CryptoHelpers.CreateFromNameUnreferencedCodeMessage)]
        public override void LoadXml(XmlElement value)
        {
            ArgumentNullException.ThrowIfNull(value);

            IncrementLoadXmlCurrentThreadDepth();
            try
            {
                XmlNamespaceManager nsm = new XmlNamespaceManager(value.OwnerDocument.NameTable);
                nsm.AddNamespace("enc", EncryptedXml.XmlEncNamespaceUrl);
                nsm.AddNamespace("ds", SignedXml.XmlDsigNamespaceUrl);

                Id = Utils.GetAttribute(value, "Id", EncryptedXml.XmlEncNamespaceUrl);
                Type = Utils.GetAttribute(value, "Type", EncryptedXml.XmlEncNamespaceUrl);
                MimeType = Utils.GetAttribute(value, "MimeType", EncryptedXml.XmlEncNamespaceUrl);
                Encoding = Utils.GetAttribute(value, "Encoding", EncryptedXml.XmlEncNamespaceUrl);

                XmlNode? encryptionMethodNode = value.SelectSingleNode("enc:EncryptionMethod", nsm);

                // EncryptionMethod
                EncryptionMethod = new EncryptionMethod();
                if (encryptionMethodNode != null)
                    EncryptionMethod.LoadXml((encryptionMethodNode as XmlElement)!);

                // Key Info
                KeyInfo = new KeyInfo();
                XmlNode? keyInfoNode = value.SelectSingleNode("ds:KeyInfo", nsm);
                if (keyInfoNode != null)
                    KeyInfo.LoadXml((keyInfoNode as XmlElement)!);

                // CipherData
                XmlNode? cipherDataNode = value.SelectSingleNode("enc:CipherData", nsm);
                if (cipherDataNode == null)
                    throw new CryptographicException(SR.Cryptography_Xml_MissingCipherData);

                CipherData = new CipherData();
                CipherData.LoadXml((cipherDataNode as XmlElement)!);

                // EncryptionProperties
                XmlNode? encryptionPropertiesNode = value.SelectSingleNode("enc:EncryptionProperties", nsm);
                if (encryptionPropertiesNode != null)
                {
                    // Select the EncryptionProperty elements inside the EncryptionProperties element
                    XmlNodeList? encryptionPropertyNodes = encryptionPropertiesNode.SelectNodes("enc:EncryptionProperty", nsm);
                    if (encryptionPropertyNodes != null)
                    {
                        foreach (XmlNode node in encryptionPropertyNodes)
                        {
                            EncryptionProperty ep = new EncryptionProperty();
                            ep.LoadXml((node as XmlElement)!);
                            EncryptionProperties.Add(ep);
                        }
                    }
                }

                // Save away the cached value
                _cachedXml = value;
            }
            finally
            {
                DecrementLoadXmlCurrentThreadDepth();
            }
        }

        public override XmlElement GetXml()
        {
            if (CacheValid) return _cachedXml;

            XmlDocument document = new XmlDocument();
            document.PreserveWhitespace = true;
            return GetXml(document);
        }

        internal XmlElement GetXml(XmlDocument document)
        {
            // Create the EncryptedData element
            XmlElement encryptedDataElement = (XmlElement)document.CreateElement("EncryptedData", EncryptedXml.XmlEncNamespaceUrl);

            // Deal with attributes
            if (!string.IsNullOrEmpty(Id))
                encryptedDataElement.SetAttribute("Id", Id);
            if (!string.IsNullOrEmpty(Type))
                encryptedDataElement.SetAttribute("Type", Type);
            if (!string.IsNullOrEmpty(MimeType))
                encryptedDataElement.SetAttribute("MimeType", MimeType);
            if (!string.IsNullOrEmpty(Encoding))
                encryptedDataElement.SetAttribute("Encoding", Encoding);

            // EncryptionMethod
            if (EncryptionMethod != null)
                encryptedDataElement.AppendChild(EncryptionMethod.GetXml(document));

            // KeyInfo
            if (KeyInfo.Count > 0)
                encryptedDataElement.AppendChild(KeyInfo.GetXml(document));

            // CipherData is required.
            if (CipherData == null)
                throw new CryptographicException(SR.Cryptography_Xml_MissingCipherData);
            encryptedDataElement.AppendChild(CipherData.GetXml(document));

            // EncryptionProperties
            if (EncryptionProperties.Count > 0)
            {
                XmlElement encryptionPropertiesElement = document.CreateElement("EncryptionProperties", EncryptedXml.XmlEncNamespaceUrl);
                for (int index = 0; index < EncryptionProperties.Count; index++)
                {
                    EncryptionProperty ep = EncryptionProperties.Item(index);
                    encryptionPropertiesElement.AppendChild(ep.GetXml(document));
                }
                encryptedDataElement.AppendChild(encryptionPropertiesElement);
            }
            return encryptedDataElement;
        }
    }
}