// 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;
using System.Xml.Schema;

namespace System.Xml
{
    // Contains information associated with the document type declaration.
    public class XmlDocumentType : XmlLinkedNode
    {
        private readonly string _name;
        private readonly string? _publicId;
        private readonly string? _systemId;
        private readonly string? _internalSubset;
        private bool _namespaces;

        // parsed DTD
        private SchemaInfo? _schemaInfo;

        protected internal XmlDocumentType(string name, string? publicId, string? systemId, string? internalSubset, XmlDocument doc) : base(doc)
        {
            _name = name;
            _publicId = publicId;
            _systemId = systemId;
            _namespaces = true;
            _internalSubset = internalSubset;
            Debug.Assert(doc != null);
            if (!doc.IsLoading)
            {
                doc.IsLoading = true;
                XmlLoader loader = new XmlLoader();
                loader.ParseDocumentType(this); // will edit notation nodes, etc.
                doc.IsLoading = false;
            }
        }

        // Gets the name of the node.
        public override string Name
        {
            get { return _name; }
        }

        // Gets the name of the current node without the namespace prefix.
        public override string LocalName
        {
            get { return _name; }
        }

        // Gets the type of the current node.
        public override XmlNodeType NodeType
        {
            get { return XmlNodeType.DocumentType; }
        }

        // Creates a duplicate of this node.
        public override XmlNode CloneNode(bool deep)
        {
            Debug.Assert(OwnerDocument != null);
            return OwnerDocument.CreateDocumentType(_name, _publicId, _systemId, _internalSubset);
        }

        //
        // Microsoft extensions
        //

        //  Gets a value indicating whether the node is read-only.
        public override bool IsReadOnly
        {
            get
            {
                return true;        // Make entities and notations readonly
            }
        }

        // Gets the collection of XmlEntity nodes declared in the document type declaration.
        public XmlNamedNodeMap Entities => field ??= new XmlNamedNodeMap(this);

        // Gets the collection of XmlNotation nodes present in the document type declaration.
        public XmlNamedNodeMap Notations => field ??= new XmlNamedNodeMap(this);

        //
        // DOM Level 2
        //

        // Gets the value of the public identifier on the DOCTYPE declaration.
        public string? PublicId
        {
            get { return _publicId; }
        }

        // Gets the value of
        // the system identifier on the DOCTYPE declaration.
        public string? SystemId
        {
            get { return _systemId; }
        }

        // Gets the entire value of the DTD internal subset
        // on the DOCTYPE declaration.
        public string? InternalSubset
        {
            get { return _internalSubset; }
        }

        internal bool ParseWithNamespaces
        {
            get { return _namespaces; }
            set { _namespaces = value; }
        }

        // Saves the node to the specified XmlWriter.
        public override void WriteTo(XmlWriter w)
        {
            w.WriteDocType(_name, _publicId, _systemId, _internalSubset);
        }

        // Saves all the children of the node to the specified XmlWriter.
        public override void WriteContentTo(XmlWriter w)
        {
            // Intentionally do nothing
        }

        internal SchemaInfo? DtdSchemaInfo
        {
            get
            {
                return _schemaInfo;
            }
            set
            {
                _schemaInfo = value;
            }
        }
    }
}