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

using System;
using System.Diagnostics;
using System.Xml;
using System.Xml.XPath;

namespace System.Xml.Xsl.XsltOld
{
    internal sealed class ValueOfAction : CompiledAction
    {
        private const int ResultStored = 2;

        private int _selectKey = Compiler.InvalidQueryKey;
        private bool _disableOutputEscaping;

        private static readonly Action s_BuiltInRule = new BuiltInRuleTextAction();

        internal static Action BuiltInRule()
        {
            Debug.Assert(s_BuiltInRule != null);
            return s_BuiltInRule;
        }

        internal override void Compile(Compiler compiler)
        {
            CompileAttributes(compiler);
            CheckRequiredAttribute(_selectKey != Compiler.InvalidQueryKey, "select");
            CheckEmpty(compiler);
        }

        internal override bool CompileAttribute(Compiler compiler)
        {
            string name = compiler.Input.LocalName;
            string value = compiler.Input.Value;

            if (Ref.Equal(name, compiler.Atoms.Select))
            {
                _selectKey = compiler.AddQuery(value);
            }
            else if (Ref.Equal(name, compiler.Atoms.DisableOutputEscaping))
            {
                _disableOutputEscaping = compiler.GetYesNo(value);
            }
            else
            {
                return false;
            }

            return true;
        }

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

            switch (frame.State)
            {
                case Initialized:
                    Debug.Assert(frame != null);
                    Debug.Assert(frame.NodeSet != null);

                    string? value = processor.ValueOf(frame, _selectKey);

                    if (processor.TextEvent(value, _disableOutputEscaping))
                    {
                        frame.Finished();
                    }
                    else
                    {
                        frame.StoredOutput = value;
                        frame.State = ResultStored;
                    }
                    break;

                case ResultStored:
                    Debug.Assert(frame.StoredOutput != null);
                    processor.TextEvent(frame.StoredOutput);
                    frame.Finished();
                    break;

                default:
                    Debug.Fail("Invalid ValueOfAction execution state");
                    break;
            }
        }
    }

    internal sealed class BuiltInRuleTextAction : Action
    {
        private const int ResultStored = 2;
        internal override void Execute(Processor processor, ActionFrame frame)
        {
            Debug.Assert(processor != null && frame != null);

            switch (frame.State)
            {
                case Initialized:
                    Debug.Assert(frame != null);
                    Debug.Assert(frame.NodeSet != null);

                    string value = processor.ValueOf(frame.NodeSet.Current!);

                    if (processor.TextEvent(value, /*disableOutputEscaping:*/false))
                    {
                        frame.Finished();
                    }
                    else
                    {
                        frame.StoredOutput = value;
                        frame.State = ResultStored;
                    }
                    break;

                case ResultStored:
                    Debug.Assert(frame.StoredOutput != null);
                    processor.TextEvent(frame.StoredOutput);
                    frame.Finished();
                    break;

                default:
                    Debug.Fail("Invalid BuiltInRuleTextAction execution state");
                    break;
            }
        }
    }
}