// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#nullable disable
 
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Razor.Language.Legacy;
using Microsoft.AspNetCore.Razor.Language.Syntax;
using Microsoft.AspNetCore.Razor.PooledObjects;
using Xunit;
 
namespace Microsoft.AspNetCore.Razor.Language.Test;
 
public class DirectiveTokenEditHandlerTest
{
    [Theory]
    [InlineData(0, 4, "")] // "Namespace"
    [InlineData(4, 0, "Other")] // "SomeOtherNamespace"
    [InlineData(0, 4, "Other")] // "OtherNamespace"
    public void CanAcceptChange_ProvisionallyAcceptsNonWhitespaceChanges(int index, int length, string newText)
    {
        // Arrange
        var directiveTokenHandler = new TestDirectiveTokenEditHandler()
        {
            AcceptedCharacters = AcceptedCharactersInternal.NonWhitespace,
            Tokenizer = TestDirectiveTokenEditHandler.TestTokenizer
        };
 
        var target = GetSyntaxNode(directiveTokenHandler, "SomeNamespace");
 
        var sourceChange = new SourceChange(index, length, newText);
 
        // Act
        var result = directiveTokenHandler.CanAcceptChange(target, sourceChange);
 
        // Assert
        Assert.Equal(PartialParseResultInternal.Accepted | PartialParseResultInternal.Provisional, result);
    }
 
    [Theory]
    [InlineData(4, 1, "")] // "SomeNamespace"
    [InlineData(9, 0, " ")] // "Some Name space"
    [InlineData(9, 5, " Space")] // "Some Name Space"
    public void CanAcceptChange_RejectsWhitespaceChanges(int index, int length, string newText)
    {
        // Arrange
        var directiveTokenHandler = new TestDirectiveTokenEditHandler()
        {
            AcceptedCharacters = AcceptedCharactersInternal.NonWhitespace,
            Tokenizer = TestDirectiveTokenEditHandler.TestTokenizer
        };
 
        var target = GetSyntaxNode(directiveTokenHandler, "Some Namespace");
 
        var sourceChange = new SourceChange(index, length, newText);
 
        // Act
        var result = directiveTokenHandler.CanAcceptChange(target, sourceChange);
 
        // Assert
        Assert.Equal(PartialParseResultInternal.Rejected, result);
    }
 
    private static CSharpStatementLiteralSyntax GetSyntaxNode(DirectiveTokenEditHandler editHandler, string content)
    {
        using PooledArrayBuilder<SyntaxToken> builder = [];
 
        var tokens = NativeCSharpLanguageCharacteristics.Instance.TokenizeString(content).ToArray();
        foreach (var token in tokens)
        {
            builder.Add(new SyntaxToken(token));
        }
 
        return SyntaxFactory.CSharpStatementLiteral(builder.ToList(), SpanChunkGenerator.Null, editHandler);
    }
 
    private class TestDirectiveTokenEditHandler : DirectiveTokenEditHandler
    {
        public new PartialParseResultInternal CanAcceptChange(SyntaxNode target, SourceChange change)
            => base.CanAcceptChange(target, change);
 
        internal static IEnumerable<Syntax.InternalSyntax.SyntaxToken> TestTokenizer(string str)
        {
            yield return Syntax.InternalSyntax.SyntaxFactory.Token(SyntaxKind.Marker, str);
        }
    }
}