// 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.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.Formatting.Rules;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.CodeCleanup.Providers;

internal sealed class FormatCodeCleanupProvider(ImmutableArray<AbstractFormattingRule> rules = default) : ICodeCleanupProvider
{
    public string Name => PredefinedCodeCleanupProviderNames.Format;

    public async Task<Document> CleanupAsync(Document document, ImmutableArray<TextSpan> spans, CodeCleanupOptions options, CancellationToken cancellationToken)
    {
        var formatter = document.GetRequiredLanguageService<ISyntaxFormattingService>();
        var root = await document.GetRequiredSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
        var result = formatter.GetFormattingResult(root, spans, options.FormattingOptions, rules, cancellationToken);

        // apply changes to an old text if it already exists
        return document.TryGetText(out var oldText)
            ? document.WithText(oldText.WithChanges(result.GetTextChanges(cancellationToken)))
            : document.WithSyntaxRoot(result.GetFormattedRoot(cancellationToken));
    }

    public Task<SyntaxNode> CleanupAsync(SyntaxNode root, ImmutableArray<TextSpan> spans, SyntaxFormattingOptions options, SolutionServices services, CancellationToken cancellationToken)
    {
        var formatter = services.GetRequiredLanguageService<ISyntaxFormattingService>(root.Language);
        var result = formatter.GetFormattingResult(root, spans, options, rules, cancellationToken);

        // apply changes to an old text if it already exists
        return (root.SyntaxTree != null && root.SyntaxTree.TryGetText(out var oldText))
            ? root.SyntaxTree.WithChangedText(oldText.WithChanges(result.GetTextChanges(cancellationToken))).GetRootAsync(cancellationToken)
            : Task.FromResult(result.GetFormattedRoot(cancellationToken));
    }
}