// 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.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using Microsoft.CodeAnalysis.Text;
 
namespace Microsoft.CodeAnalysis;
 
/* This is the static API on Workspace that lets you associate text containers with workspace instances */
public abstract partial class Workspace
{
    private static readonly ConditionalWeakTable<SourceTextContainer, WorkspaceRegistration> s_bufferToWorkspaceRegistrationMap = new();
 
    /// <summary>
    /// Gets the workspace associated with the specific text container.
    /// </summary>
    public static bool TryGetWorkspace(SourceTextContainer textContainer, [NotNullWhen(true)] out Workspace? workspace)
    {
        if (textContainer == null)
        {
            throw new ArgumentNullException(nameof(textContainer));
        }
 
        var registration = GetWorkspaceRegistration(textContainer);
        workspace = registration.Workspace;
 
        return workspace != null;
    }
 
    /// <summary>
    /// Register a correspondence between a text container and a workspace.
    /// </summary>
    protected void RegisterText(SourceTextContainer textContainer)
    {
        if (textContainer == null)
        {
            throw new ArgumentNullException(nameof(textContainer));
        }
 
        var registration = GetWorkspaceRegistration(textContainer);
        registration.SetWorkspace(this);
        this.ScheduleTask(registration.RaiseEvents, "Workspace.RegisterText");
    }
 
    /// <summary>
    /// Unregister a correspondence between a text container and a workspace.
    /// </summary>
    protected void UnregisterText(SourceTextContainer textContainer)
    {
        if (textContainer == null)
        {
            throw new ArgumentNullException(nameof(textContainer));
        }
 
        var registration = GetWorkspaceRegistration(textContainer);
 
        if (registration.Workspace == this)
        {
            registration.SetWorkspaceAndRaiseEvents(null);
        }
    }
 
    /// <summary>
    /// Returns a <see cref="WorkspaceRegistration" /> for a given text container.
    /// </summary>
    public static WorkspaceRegistration GetWorkspaceRegistration(SourceTextContainer textContainer)
    {
        if (textContainer == null)
        {
            throw new ArgumentNullException(nameof(textContainer));
        }
 
        return s_bufferToWorkspaceRegistrationMap.GetValue(textContainer, static _ => new WorkspaceRegistration());
    }
}