// 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.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.PooledObjects;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CodeFixes;
 
internal sealed partial class FixAllState
{
    /// <summary>
    /// Diagnostic provider to fetch document/project diagnostics to fix in a <see cref="FixAllContext"/>.
    /// </summary>
    internal sealed class FixMultipleDiagnosticProvider : FixAllContext.DiagnosticProvider
    {
        public ImmutableDictionary<Document, ImmutableArray<Diagnostic>> DocumentDiagnosticsMap { get; }
        public ImmutableDictionary<Project, ImmutableArray<Diagnostic>> ProjectDiagnosticsMap { get; }
 
        public FixMultipleDiagnosticProvider(ImmutableDictionary<Document, ImmutableArray<Diagnostic>> diagnosticsMap)
        {
            DocumentDiagnosticsMap = diagnosticsMap;
            ProjectDiagnosticsMap = ImmutableDictionary<Project, ImmutableArray<Diagnostic>>.Empty;
        }
 
        public FixMultipleDiagnosticProvider(ImmutableDictionary<Project, ImmutableArray<Diagnostic>> diagnosticsMap)
        {
            ProjectDiagnosticsMap = diagnosticsMap;
            DocumentDiagnosticsMap = ImmutableDictionary<Document, ImmutableArray<Diagnostic>>.Empty;
        }
 
        public override Task<IEnumerable<Diagnostic>> GetAllDiagnosticsAsync(Project project, CancellationToken cancellationToken)
        {
            var allDiagnosticsBuilder = ArrayBuilder<Diagnostic>.GetInstance();
            ImmutableArray<Diagnostic> diagnostics;
            if (!DocumentDiagnosticsMap.IsEmpty)
            {
                foreach (var document in project.Documents)
                {
                    if (DocumentDiagnosticsMap.TryGetValue(document, out diagnostics))
                    {
                        allDiagnosticsBuilder.AddRange(diagnostics);
                    }
                }
            }
 
            if (ProjectDiagnosticsMap.TryGetValue(project, out diagnostics))
            {
                allDiagnosticsBuilder.AddRange(diagnostics);
            }
 
            return Task.FromResult<IEnumerable<Diagnostic>>(allDiagnosticsBuilder.ToImmutableAndFree());
        }
 
        public override Task<IEnumerable<Diagnostic>> GetDocumentDiagnosticsAsync(Document document, CancellationToken cancellationToken)
        {
            if (DocumentDiagnosticsMap.TryGetValue(document, out var diagnostics))
            {
                return Task.FromResult<IEnumerable<Diagnostic>>(diagnostics);
            }
 
            return SpecializedTasks.EmptyEnumerable<Diagnostic>();
        }
 
        public override Task<IEnumerable<Diagnostic>> GetProjectDiagnosticsAsync(Project project, CancellationToken cancellationToken)
        {
            if (ProjectDiagnosticsMap.TryGetValue(project, out var diagnostics))
            {
                return Task.FromResult<IEnumerable<Diagnostic>>(diagnostics);
            }
 
            return SpecializedTasks.EmptyEnumerable<Diagnostic>();
        }
    }
}