// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
 
namespace Microsoft.Build.TaskHost.BackEnd;
 
/// <summary>
/// Reasons why the node shut down.
/// </summary>
internal enum NodeShutdownReason
{
    /// <summary>
    /// The node shut down because it was requested to shut down.
    /// </summary>
    Requested,
 
    /// <summary>
    /// The node shut down because of an error.
    /// </summary>
    Error,
 
    /// <summary>
    /// The node shut down because the connection failed.
    /// </summary>
    ConnectionFailed,
}
 
/// <summary>
/// Implementation of INodePacket for the packet informing the build manager than a node has shut down.
/// This is the last packet the BuildManager will receive from a Node, and as such can be used to trigger
/// any appropriate cleanup behavior.
/// </summary>
internal sealed class NodeShutdown : INodePacket
{
    /// <summary>
    /// The reason the node shut down.
    /// </summary>
    private NodeShutdownReason _reason;
 
    /// <summary>
    /// The exception - if any.
    /// </summary>
    private Exception? _exception;
 
    /// <summary>
    /// Constructor
    /// </summary>
    public NodeShutdown(NodeShutdownReason reason)
        : this(reason, exception: null)
    {
    }
 
    public NodeShutdown(NodeShutdownReason reason, Exception? exception)
    {
        _reason = reason;
        _exception = exception;
    }
 
    private NodeShutdown()
    {
    }
 
    /// <summary>
    /// Gets the packet type.
    /// </summary>
    public NodePacketType Type => NodePacketType.NodeShutdown;
 
    /// <summary>
    /// Gets the reason for shutting down.
    /// </summary>
    public NodeShutdownReason Reason => _reason;
 
    /// <summary>
    /// Gets the exception, if any.
    /// </summary>
    public Exception? Exception => _exception;
 
    /// <summary>
    /// Serializes or deserializes a packet.
    /// </summary>
    public void Translate(ITranslator translator)
    {
        translator.TranslateEnum(ref _reason, (int)_reason);
        translator.TranslateException(ref _exception);
    }
 
    internal static NodeShutdown FactoryForDeserialization(ITranslator translator)
    {
        var shutdown = new NodeShutdown();
        shutdown.Translate(translator);
        return shutdown;
    }
}