// 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;
using System.Xml.XPath;

namespace MS.Internal.Xml.XPath
{
    internal sealed class IDQuery : CacheOutputQuery
    {
        public IDQuery(Query arg) : base(arg) { }
        private IDQuery(IDQuery other) : base(other) { }

        public override object Evaluate(XPathNodeIterator context)
        {
            object argVal = base.Evaluate(context);
            Debug.Assert(context.Current != null);
            XPathNavigator contextNode = context.Current.Clone();

            switch (GetXPathType(argVal))
            {
                case XPathResultType.NodeSet:
                    XPathNavigator? temp;
                    while ((temp = input.Advance()) != null)
                    {
                        ProcessIds(contextNode, temp.Value);
                    }
                    break;
                case XPathResultType.String:
                    ProcessIds(contextNode, (string)argVal);
                    break;
                case XPathResultType.Number:
                    ProcessIds(contextNode, StringFunctions.toString((double)argVal));
                    break;
                case XPathResultType.Boolean:
                    ProcessIds(contextNode, StringFunctions.toString((bool)argVal));
                    break;
                case XPathResultType_Navigator:
                    ProcessIds(contextNode, ((XPathNavigator)argVal).Value);
                    break;
            }
            return this;
        }

        private void ProcessIds(XPathNavigator contextNode, string val)
        {
            string[] ids = XmlConvert.SplitString(val);
            for (int idx = 0; idx < ids.Length; idx++)
            {
                if (contextNode.MoveToId(ids[idx]))
                {
                    Insert(outputBuffer, contextNode);
                }
            }
        }

        public override XPathNavigator? MatchNode(XPathNavigator? context)
        {
            Evaluate(new XPathSingletonIterator(context!, /*moved:*/true));
            XPathNavigator? result;
            while ((result = Advance()) != null)
            {
                if (result.IsSamePosition(context!))
                {
                    return context;
                }
            }
            return null;
        }

        public override XPathNodeIterator Clone() { return new IDQuery(this); }
    }
}