// 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.Immutable;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.Shared.Extensions;

internal static partial class ISolutionExtensions
{
    public static async Task<ImmutableArray<INamespaceSymbol>> GetGlobalNamespacesAsync(
        this Solution solution,
        CancellationToken cancellationToken)
    {
        var results = ArrayBuilder<INamespaceSymbol>.GetInstance();

        foreach (var projectId in solution.ProjectIds)
        {
            var project = solution.GetProject(projectId)!;
            if (project.SupportsCompilation)
            {
                var compilation = await project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
#nullable disable // Can 'compilation' be null here?
                results.Add(compilation.Assembly.GlobalNamespace);
#nullable enable
            }
        }

        return results.ToImmutableAndFree();
    }

    public static TextDocumentKind? GetDocumentKind(this Solution solution, DocumentId documentId)
        => solution.GetTextDocument(documentId)?.Kind;

    public static Solution WithTextDocumentText(this Solution solution, DocumentId documentId, SourceText text, PreservationMode mode = PreservationMode.PreserveIdentity)
    {
        var documentKind = solution.GetDocumentKind(documentId);
        switch (documentKind)
        {
            case TextDocumentKind.Document:
                return solution.WithDocumentText(documentId, text, mode);

            case TextDocumentKind.AnalyzerConfigDocument:
                return solution.WithAnalyzerConfigDocumentText(documentId, text, mode);

            case TextDocumentKind.AdditionalDocument:
                return solution.WithAdditionalDocumentText(documentId, text, mode);

            case null:
                throw CreateDocumentNotFoundException(documentId);

            default:
                throw ExceptionUtilities.UnexpectedValue(documentKind);
        }
    }

    public static Workspace? TryGetWorkspace(this Solution solution)
        => solution.WorkspaceKind == WorkspaceKind.RemoteWorkspace
            ? null
            : solution.Workspace;
}