// 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.Collections.Generic;
using System.Composition;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.ExternalAccess.Razor;
using Microsoft.CodeAnalysis.Razor.CodeActions;
using Microsoft.CodeAnalysis.Razor.ProjectSystem;
using Microsoft.CodeAnalysis.Remote.Razor.ProjectSystem;
using Microsoft.CodeAnalysis.Text;
using ExternalHandlers = Microsoft.CodeAnalysis.ExternalAccess.Razor.Cohost.Handlers;
 
namespace Microsoft.CodeAnalysis.Remote.Razor;
 
[Export(typeof(IRoslynCodeActionHelpers)), Shared]
internal sealed class RoslynCodeActionHelpers : IRoslynCodeActionHelpers
{
    public Task<string> GetFormattedNewFileContentsAsync(IProjectSnapshot projectSnapshot, Uri csharpFileUri, string newFileContent, CancellationToken cancellationToken)
    {
        Debug.Assert(projectSnapshot is RemoteProjectSnapshot);
        var project = ((RemoteProjectSnapshot)projectSnapshot).Project;
 
        var filePath = RazorUri.GetDocumentFilePathFromUri(csharpFileUri);
        var source = SourceText.From(newFileContent, Encoding.UTF8, checksumAlgorithm: SourceHashAlgorithm.Sha256);
        var document = project.AddDocument(filePath, source, filePath: filePath);
 
        return ExternalHandlers.CodeActions.GetFormattedNewFileContentAsync(document, cancellationToken);
    }
 
    public async Task<TextEdit[]?> GetSimplifiedTextEditsAsync(DocumentContext documentContext, Uri? codeBehindUri, TextEdit edit, CancellationToken cancellationToken)
    {
        Debug.Assert(documentContext is RemoteDocumentContext);
        var context = (RemoteDocumentContext)documentContext;
 
        Document document;
        if (codeBehindUri is null)
        {
            // Edit is for inserting into the generated document
            document = await context.Snapshot.GetGeneratedDocumentAsync(cancellationToken).ConfigureAwait(false);
        }
        else
        {
            // Edit is for inserting into a C# document
            var solution = context.TextDocument.Project.Solution;
            var documentIds = solution.GetDocumentIdsWithUri(codeBehindUri);
            if (documentIds.Length == 0)
            {
                return null;
            }
 
            document = solution.GetRequiredDocument(documentIds.First(d => d.ProjectId == context.TextDocument.Project.Id));
        }
 
        return await ExternalHandlers.CodeActions.GetSimplifiedEditsAsync(document, edit, cancellationToken).ConfigureAwait(false);
    }
}