// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System.Collections.Immutable;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.MakeTypePartial
{
    internal abstract class AbstractMakeTypePartialCodeFixProvider : SyntaxEditorBasedCodeFixProvider
    {
        protected AbstractMakeTypePartialCodeFixProvider()
            : base(supportsFixAll: false)
        {
        }
 
        public override Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            RegisterCodeFix(context, CodeFixesResources.Make_type_partial, nameof(CodeFixesResources.Make_type_partial));
            return Task.CompletedTask;
        }
 
        protected override async Task FixAllAsync(Document document, ImmutableArray<Diagnostic> diagnostics, SyntaxEditor editor, CodeActionOptionsProvider fallbackOptions, CancellationToken cancellationToken)
        {
            var syntaxRoot = editor.OriginalRoot;
            var generator = editor.Generator;
            var semanticModel = await document.GetRequiredSemanticModelAsync(cancellationToken).ConfigureAwait(false);
 
            foreach (var diagnostic in diagnostics)
            {
                var declaration = syntaxRoot.FindNode(diagnostic.Location.SourceSpan);
                var symbol = semanticModel.GetDeclaredSymbol(declaration, cancellationToken);
 
                if (symbol is null)
                {
                    Debug.Fail("Declared symbol must never be null here");
                    continue;
                }
 
                foreach (var reference in symbol.DeclaringSyntaxReferences)
                {
                    var node = await reference.GetSyntaxAsync(cancellationToken).ConfigureAwait(false);
                    var modifiers = generator.GetModifiers(node);
 
                    if (!modifiers.IsPartial)
                    {
                        var fixedModifiers = modifiers.WithPartial(true);
                        editor.ReplaceNode(node, generator.WithModifiers(node, fixedModifiers));
                    }
                }
            }
        }
    }
}