using System.Text;
using System.Text.Json.Nodes;
using Fleet.Core;
using Monitor.Probe;

namespace Monitor.Backend.Tests;

/// <summary>进程内的真实 Probe：用后端生成的身份文件（和面板下载的 probe.json 同一份）启动 <see cref="ProbeApp"/>。</summary>
public sealed class ProbeHarness : IAsyncDisposable
{
    private readonly CancellationTokenSource _stop = new();
    private readonly string _directory;
    private readonly Task _run;

    private ProbeHarness(string directory, ProbeApp app)
    {
        _directory = directory;
        App = app;
        _run = Task.Run(() => app.RunAsync(_stop.Token), CancellationToken.None);
    }

    public ProbeApp App { get; }

    public string Directory => _directory;

    public string ProbeId { get; init; } = "";

    /// <summary>向后端申请身份（<c>POST /api/admin/probe/identity</c>），写成 <c>probe.json</c> 并启动。</summary>
    public static async Task<ProbeHarness> StartAsync(BackendFixture backend, Action<ProbeFile>? configure = null)
    {
        JsonNode created = await backend.CreateProbeAsync();
        string json = created.ToJsonString();

        string directory = Path.Combine(Path.GetTempPath(), "monitor-probe-" + Guid.NewGuid().ToString("N"));
        System.IO.Directory.CreateDirectory(directory);
        string path = Path.Combine(directory, "probe.json");
        await File.WriteAllTextAsync(path, json, Encoding.UTF8);

        ProbeFile file = Fleet.Hosting.NodeConfig.Load(path, ProbeConfigContext.Default.ProbeFile);
        configure?.Invoke(file);
        var app = new ProbeApp(file, directory, TimeProvider.System, new Fleet.Hosting.ConsoleNodeLog(TimeProvider.System, Console.Out));
        return new ProbeHarness(directory, app) { ProbeId = created["probe_id"]!.GetValue<string>() };
    }

    public async ValueTask DisposeAsync()
    {
        await _stop.CancelAsync();
        try
        {
            await _run.WaitAsync(TimeSpan.FromSeconds(15));
        }
        catch (Exception ex) when (ex is OperationCanceledException or TimeoutException)
        {
            // 停止中
        }

        App.Dispose();
        _stop.Dispose();
        try
        {
            System.IO.Directory.Delete(_directory, recursive: true);
        }
        catch (IOException)
        {
            // 临时目录清理失败不影响测试结果
        }
    }
}