// 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.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.CodeFixes;

/// <summary>
/// Context for "Fix all occurrences" code fixes provided by a <see cref="FixAllProvider"/>.
/// </summary>
public partial class FixAllContext
{
    /// <summary>
    /// Diagnostic provider to fetch document/project diagnostics to fix in a <see cref="FixAllContext"/>,
    /// which supports a <see cref="GetDocumentSpanDiagnosticsAsync(Document, TextSpan, CancellationToken)"/>
    /// method to compute diagnostics for a given span within a document.
    /// We need to compute diagnostics for a span when applying a fix all operation in <see cref="FixAllScope.ContainingMember"/>
    /// and <see cref="FixAllScope.ContainingType"/> scopes.
    /// A regular <see cref="DiagnosticProvider"/> will compute diagnostics for the entire document and filter out
    /// diagnostics outside the span as a post-filtering step.
    /// A <see cref="SpanBasedDiagnosticProvider"/> can do this more efficiently by implementing the
    /// <see cref="GetDocumentSpanDiagnosticsAsync(Document, TextSpan, CancellationToken)"/> method to compute
    /// the diagnostics only for the given 'fixAllSpan' upfront.
    /// </summary>
    internal abstract class SpanBasedDiagnosticProvider : DiagnosticProvider
    {
        /// <summary>
        /// Gets all the diagnostics to fix for the given <paramref name="fixAllSpan"/> in the given <paramref name="document"/> in a <see cref="FixAllContext"/>.
        /// </summary>
        public abstract Task<IEnumerable<Diagnostic>> GetDocumentSpanDiagnosticsAsync(Document document, TextSpan fixAllSpan, CancellationToken cancellationToken);
    }
}