using System.Diagnostics;

namespace Azaion.Missions.E2E.Fixtures;

/// <summary>
/// Stop/start helper for the postgres-test compose service. Used by FT-P-17
/// to prove that <c>/health</c> does not ping the database — the fixture
/// stops postgres-test, the test asserts /health still returns 200, and the
/// fixture restarts postgres-test in teardown.
/// </summary>
/// <remarks>
/// Like <see cref="ComposeRestartFixture"/>, this fixture only runs when
/// <c>COMPOSE_RESTART_ENABLED=1</c>. The e2e-consumer image needs the
/// docker CLI on PATH and a docker socket bind to actually drive compose.
/// Tests using the fixture must skip with a clear reason when disabled.
/// </remarks>
public sealed class PostgresStopStartFixture
{
    public bool Enabled => Environment.GetEnvironmentVariable("COMPOSE_RESTART_ENABLED") == "1";

    public string ComposeFile =>
        Environment.GetEnvironmentVariable("COMPOSE_FILE_PATH") ?? "/workspace/docker-compose.test.yml";

    public string ServiceName =>
        Environment.GetEnvironmentVariable("POSTGRES_SERVICE_NAME") ?? "postgres-test";

    public void Stop()
    {
        EnsureEnabled();
        Run("docker", $"compose -f {ComposeFile} stop {ServiceName}");
    }

    public void Start()
    {
        EnsureEnabled();
        Run("docker", $"compose -f {ComposeFile} start {ServiceName}");
        // Wait for the service to report healthy via pg_isready before
        // returning — otherwise the next test would hit ConnectionRefused.
        WaitUntilHealthy();
    }

    private void WaitUntilHealthy()
    {
        var deadline = DateTime.UtcNow.AddSeconds(30);
        while (DateTime.UtcNow < deadline)
        {
            try
            {
                Run("docker",
                    $"compose -f {ComposeFile} exec -T {ServiceName} pg_isready -U postgres -d azaion");
                return;
            }
            catch (InvalidOperationException)
            {
                Thread.Sleep(500);
            }
        }
        throw new InvalidOperationException(
            $"postgres service '{ServiceName}' did not become ready within 30s after start");
    }

    private void EnsureEnabled()
    {
        if (!Enabled)
            throw new InvalidOperationException(
                "PostgresStopStartFixture is disabled; set COMPOSE_RESTART_ENABLED=1 to use it.");
    }

    private static void Run(string file, string args)
    {
        var psi = new ProcessStartInfo(file, args)
        {
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false
        };
        using var p = Process.Start(psi)
            ?? throw new InvalidOperationException($"Failed to launch {file} {args}");
        p.WaitForExit();
        if (p.ExitCode != 0)
        {
            var err = p.StandardError.ReadToEnd();
            throw new InvalidOperationException($"`{file} {args}` exited {p.ExitCode}: {err}");
        }
    }
}