using System.Diagnostics;
using SQLInsight.Servers.Synthetic;

namespace SQLInsight.Servers.Tests;

/// <summary>The process the AX logon runs in: its output is bounded, and it never outlives the agent.</summary>
public class ProcessRunnerTests
{
    [Fact]
    public async Task Process_output_is_capped_but_read_to_the_end()
    {
        using var reader = new StringReader(new string('x', ProcessRunner.MaxOutputChars * 3) + "end");

        var text = await ProcessRunner.ReadBoundedAsync(reader, ProcessRunner.MaxOutputChars);

        Assert.Equal(ProcessRunner.MaxOutputChars, text.Length);
        Assert.Equal(-1, reader.Peek()); // everything was read, so a process never blocks on a full pipe
    }

    [Fact]
    public async Task A_process_is_killed_when_the_agent_stops()
    {
        if (!OperatingSystem.IsWindows())
        {
            return;
        }

        var marker = Path.Combine(Path.GetTempPath(), "sqlinsight-kill-" + Guid.NewGuid().ToString("N") + ".txt");
        var powershell = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.System), @"WindowsPowerShell\v1.0\powershell.exe");
        using var stop = new CancellationTokenSource(TimeSpan.FromMinutes(2));
        var started = Stopwatch.StartNew();
        try
        {
            // Writes its process id, then would wait for a minute; the agent stops as soon as it has started.
            var stopWhenStarted = Task.Run(async () =>
            {
                while (!File.Exists(marker) && started.Elapsed < TimeSpan.FromMinutes(1))
                {
                    await Task.Delay(100);
                }

                await Task.Delay(500);
                await stop.CancelAsync();
            });
            await Assert.ThrowsAnyAsync<OperationCanceledException>(() => new ProcessRunner().RunAsync(powershell,
                ["-NoProfile", "-NonInteractive", "-Command", $"Set-Content -LiteralPath '{marker}' -Value $PID; Start-Sleep -Seconds 60"],
                new Dictionary<string, string>(), TimeSpan.FromMinutes(5), stop.Token));
            await stopWhenStarted;
            Assert.True(started.Elapsed < TimeSpan.FromSeconds(55), $"The process was waited for ({started.Elapsed}).");

            var pid = int.Parse((await File.ReadAllTextAsync(marker)).Trim(), System.Globalization.CultureInfo.InvariantCulture);
            var gone = Stopwatch.StartNew();
            while (IsRunning(pid))
            {
                Assert.True(gone.Elapsed < TimeSpan.FromSeconds(10), $"PowerShell ({pid}) was left running.");
                await Task.Delay(100);
            }
        }
        finally
        {
            File.Delete(marker);
        }

        static bool IsRunning(int pid)
        {
            try
            {
                using var process = Process.GetProcessById(pid);
                return !process.HasExited;
            }
            catch (ArgumentException)
            {
                return false;
            }
        }
    }
}