// 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;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeGeneration;
using Microsoft.CodeAnalysis.Editing;
using Microsoft.CodeAnalysis.Options;
using Microsoft.CodeAnalysis.PickMembers;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.GenerateOverrides;

internal sealed partial class GenerateOverridesCodeRefactoringProvider
{
    private sealed class GenerateOverridesWithDialogCodeAction(
        GenerateOverridesCodeRefactoringProvider service,
        Document document,
        TextSpan textSpan,
        INamedTypeSymbol containingType,
        ImmutableArray<ISymbol> viableMembers) : CodeActionWithOptions
    {
        private readonly GenerateOverridesCodeRefactoringProvider _service = service;
        private readonly Document _document = document;
        private readonly INamedTypeSymbol _containingType = containingType;
        private readonly ImmutableArray<ISymbol> _viableMembers = viableMembers;
        private readonly TextSpan _textSpan = textSpan;

        public override string Title => FeaturesResources.Generate_overrides;

        internal override bool IsOptionServiceAvailable()
            => (_service._pickMembersService_forTestingPurposes ?? _document.Project.Solution.Services.GetService<IPickMembersService>()) is not null;

        public override object GetOptions(CancellationToken cancellationToken)
        {
            var services = _document.Project.Solution.Services;
            var pickMembersService = _service._pickMembersService_forTestingPurposes ?? services.GetRequiredService<IPickMembersService>();
            var globalOptionService = services.GetService<ILegacyGlobalOptionsWorkspaceService>();

            return pickMembersService.PickMembers(
                FeaturesResources.Pick_members_to_override,
                _viableMembers,
                selectAll: globalOptionService?.GenerateOverrides ?? true);
        }

        protected override async Task<IEnumerable<CodeActionOperation>> ComputeOperationsAsync(
            object options, IProgress<CodeAnalysisProgress> progressTracker, CancellationToken cancellationToken)
        {
            var result = (PickMembersResult)options;
            if (result.IsCanceled || result.Members.Length == 0)
                return [];

            var syntaxTree = await _document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
            RoslynDebug.AssertNotNull(syntaxTree);

            // If the user has selected just one member then we will insert it at the current
            // location.  Otherwise, if it's many members, then we'll auto insert them as appropriate.
            var afterThisLocation = result.Members.Length == 1
                ? syntaxTree.GetLocation(_textSpan)
                : null;

            var generator = SyntaxGenerator.GetGenerator(_document);
            var memberTasks = result.Members.SelectAsArray(
                m => GenerateOverrideAsync(generator, m, cancellationToken));

            var members = await Task.WhenAll(memberTasks).ConfigureAwait(false);

            var newDocument = await CodeGenerator.AddMemberDeclarationsAsync(
                new CodeGenerationSolutionContext(
                    _document.Project.Solution,
                    new CodeGenerationContext(
                        afterThisLocation: afterThisLocation,
                        contextLocation: syntaxTree.GetLocation(_textSpan))),
                _containingType,
                members,
                cancellationToken).ConfigureAwait(false);

            return new CodeActionOperation[]
                {
                    new ApplyChangesOperation(newDocument.Project.Solution),
                    new ChangeOptionValueOperation(result.SelectedAll),
                };
        }

        private Task<ISymbol> GenerateOverrideAsync(
            SyntaxGenerator generator, ISymbol symbol,
            CancellationToken cancellationToken)
        {
            return generator.OverrideAsync(
                symbol, _containingType, _document,
                cancellationToken: cancellationToken);
        }

        private sealed class ChangeOptionValueOperation(bool selectedAll) : CodeActionOperation
        {
            private readonly bool _selectedAll = selectedAll;

            public override void Apply(Workspace workspace, CancellationToken cancellationToken)
            {
                var service = workspace.Services.GetService<ILegacyGlobalOptionsWorkspaceService>();
                service?.GenerateOverrides = _selectedAll;
            }
        }
    }
}