//------------------------------------------------------------------------------
// <copyright file="CopyAttributesAction.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>                                                                
// <owner current="true" primary="true">[....]</owner>
//------------------------------------------------------------------------------

namespace System.Xml.Xsl.XsltOld {
    using Res = System.Xml.Utils.Res;
    using System;
    using System.Diagnostics;
    using System.Xml;
    using System.Xml.XPath;

    internal sealed class CopyAttributesAction : Action {
        private const int BeginEvent    = 2;
        private const int TextEvent     = 3;
        private const int EndEvent      = 4;
        private const int Advance       = 5;

        private static CopyAttributesAction s_Action = new CopyAttributesAction();

        internal static CopyAttributesAction GetAction() {
            Debug.Assert(s_Action != null);
            return s_Action;
        }

        internal override void Execute(Processor processor, ActionFrame frame) {
            Debug.Assert(processor != null && frame != null);

            while (processor.CanContinue) {
                switch (frame.State) {
                case Initialized:
                    if (!frame.Node.HasAttributes || frame.Node.MoveToFirstAttribute() == false) {
                        frame.Finished();
                        break;
                    }

                    frame.State   = BeginEvent;
                    goto case BeginEvent;

                case BeginEvent:
                    Debug.Assert(frame.State == BeginEvent);
                    Debug.Assert(frame.Node.NodeType == XPathNodeType.Attribute);

                    if (SendBeginEvent(processor, frame.Node) == false) {
                        // This one wasn't output
                        break;
                    }
                    frame.State = TextEvent;
                    continue;

                case TextEvent:
                    Debug.Assert(frame.State == TextEvent);
                    Debug.Assert(frame.Node.NodeType == XPathNodeType.Attribute);

                    if (SendTextEvent(processor, frame.Node) == false) {
                        // This one wasn't output
                        break;
                    }
                    frame.State = EndEvent;
                    continue;

                case EndEvent:
                    Debug.Assert(frame.State == EndEvent);
                    Debug.Assert(frame.Node.NodeType == XPathNodeType.Attribute);

                    if (SendEndEvent(processor, frame.Node) == false) {
                        // This one wasn't output
                        break;
                    }
                    frame.State = Advance;
                    continue;

                case Advance:
                    Debug.Assert(frame.State == Advance);
                    Debug.Assert(frame.Node.NodeType == XPathNodeType.Attribute);

                    if (frame.Node.MoveToNextAttribute()) {
                        frame.State = BeginEvent;
                        continue;
                    }
                    else {
                        frame.Node.MoveToParent();
                        frame.Finished();
                        break;
                    }
                }
                break;
            }// while (processor.CanContinue)
        }

        private static bool SendBeginEvent(Processor processor, XPathNavigator node) {
            Debug.Assert(node.NodeType == XPathNodeType.Attribute);
            return processor.BeginEvent(XPathNodeType.Attribute, node.Prefix, node.LocalName, node.NamespaceURI, false);
        }

        private static bool SendTextEvent(Processor processor, XPathNavigator node) {
            Debug.Assert(node.NodeType == XPathNodeType.Attribute);
            return processor.TextEvent(node.Value);
        }

        private static bool SendEndEvent(Processor processor, XPathNavigator node) {
            Debug.Assert(node.NodeType == XPathNodeType.Attribute);
            return processor.EndEvent(XPathNodeType.Attribute);
        }
    }
}