Servers/MoonlightServers.Daemon/ServerSystem/Docker/DockerRuntime.cs

using Docker.DotNet;
using Docker.DotNet.Models;
using MoonCore.Events;
using MoonlightServers.Daemon.Mappers;
using MoonlightServers.Daemon.ServerSystem.Interfaces;
using MoonlightServers.Daemon.ServerSystem.Models;
using MoonlightServers.Daemon.Services;

namespace MoonlightServers.Daemon.ServerSystem.Docker;

public class DockerRuntime : IRuntime
{
    private readonly DockerClient DockerClient;
    private readonly ServerContext Context;
    private readonly ServerConfigurationMapper Mapper;
    private readonly DockerEventService DockerEventService;
    private readonly DockerImageService ImageService;
    private readonly EventSource<int> ExitEventSource = new();

    private IReporter Reporter => Context.Server.Reporter;
    private IAsyncDisposable ContainerEventSubscription;
    private string ContainerId;

    public DockerRuntime(
        DockerClient dockerClient,
        ServerContext context,
        ServerConfigurationMapper mapper,
        DockerEventService dockerEventService,
        DockerImageService imageService
    )
    {
        DockerClient = dockerClient;
        Context = context;
        Mapper = mapper;
        DockerEventService = dockerEventService;
        ImageService = imageService;
    }

    public async Task InitializeAsync()
    {
        ContainerEventSubscription = await DockerEventService.SubscribeContainerAsync(OnContainerEvent);
    }

    private async ValueTask OnContainerEvent(Message message)
    {
        // Only handle events for our own container
        if (message.ID != ContainerId)
            return;

        // Only handle die events
        if (message.Action != "die")
            return;

        int exitCode;

        if (message.Actor.Attributes.TryGetValue("exitCode", out var exitCodeStr))
        {
            if (!int.TryParse(exitCodeStr, out exitCode))
                exitCode = 0;
        }
        else
            exitCode = 0;


        await ExitEventSource.InvokeAsync(exitCode);
    }

    public async Task<bool> CheckExistsAsync()
    {
        try
        {
            var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

            await DockerClient.Containers.InspectContainerAsync(
                containerName
            );

            return true;
        }
        catch (DockerContainerNotFoundException)
        {
            return false;
        }
    }

    public async Task CreateAsync(string path)
    {
        var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

        var parameters = Mapper.ToRuntimeParameters(
            Context.Configuration,
            path,
            containerName
        );

        // Docker image
        await Reporter.StatusAsync("Downloading docker image");

        await ImageService.DownloadAsync(
            Context.Configuration.DockerImage,
            async status => { await Reporter.StatusAsync(status); }
        );

        await Reporter.StatusAsync("Downloaded docker image");
        
        //
        
        var response = await DockerClient.Containers.CreateContainerAsync(parameters);
        ContainerId = response.ID;

        await Reporter.StatusAsync("Created container");
    }

    public async Task StartAsync()
    {
        var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

        await DockerClient.Containers.StartContainerAsync(containerName, new());
    }

    public Task UpdateAsync()
    {
        return Task.CompletedTask;
    }

    public async Task KillAsync()
    {
        var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

        await DockerClient.Containers.KillContainerAsync(containerName, new());
    }

    public async Task DestroyAsync()
    {
        var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

        try
        {
            var container = await DockerClient.Containers.InspectContainerAsync(containerName);

            if (container.State.Running)
                await DockerClient.Containers.KillContainerAsync(containerName, new());

            await DockerClient.Containers.RemoveContainerAsync(containerName, new()
            {
                Force = true
            });
        }
        catch (DockerContainerNotFoundException)
        {
            // Ignored
        }
    }

    public async Task<IAsyncDisposable> SubscribeExitedAsync(Func<int, ValueTask> callback)
        => await ExitEventSource.SubscribeAsync(callback);

    public async Task RestoreAsync()
    {
        try
        {
            var containerName = string.Format(DockerConstants.RuntimeNameTemplate, Context.Configuration.Id);

            var container = await DockerClient.Containers.InspectContainerAsync(containerName);
            ContainerId = container.ID;
        }
        catch (DockerContainerNotFoundException)
        {
            // Ignore
        }
    }

    public async ValueTask DisposeAsync()
    {
        await ContainerEventSubscription.DisposeAsync();
    }
}