using ClawdDotNet.Core.Instances;
using Shouldly;

namespace ClawdDotNet.Manager.Tests;

/// <summary>
/// <c>manager.json</c> and the log excerpt — the two places where the manager
/// talks to the file system (#528, stage 3).
/// </summary>
public sealed class ManagerSettingsTests : IDisposable
{
    private readonly string _dir = Path.Combine(
        Path.GetTempPath(), "clawd-tests", "mgr-" + Guid.NewGuid().ToString("N")[..8]);

    public ManagerSettingsTests() => Directory.CreateDirectory(_dir);

    public void Dispose()
    {
        try { Directory.Delete(_dir, recursive: true); }
        catch { /* A leftover test folder does not turn a run red. */ }
    }

    [Fact]
    public void A_missing_file_is_created_with_defaults()
    {
        var store = new ManagerSettingsStore(_dir);
        var settings = store.Load();

        File.Exists(store.SettingsPath).ShouldBeTrue("Der Ort soll sichtbar werden.");
        settings.WebUiPort.ShouldBe(7000);
        settings.UpdateChannel.ShouldBe("prod");
    }

    /// <summary>
    /// Master token and license key are not in plain text in the file — but they are at
    /// runtime, otherwise nobody could work with them.
    /// </summary>
    [Fact]
    public void Secrets_are_not_in_plaintext_in_the_file()
    {
        var store = new ManagerSettingsStore(_dir);
        store.Load();

        store.Settings.DeploymentcenterMasterToken = "dc_master_geheim_1234567890";
        store.Settings.LicenseKey = "LIZ-1234-5678";
        store.Save();

        File.ReadAllText(store.SettingsPath).ShouldNotContain("dc_master_geheim_1234567890");
        File.ReadAllText(store.SettingsPath).ShouldNotContain("LIZ-1234-5678");

        var again = new ManagerSettingsStore(_dir).Load();
        again.DeploymentcenterMasterToken.ShouldBe("dc_master_geheim_1234567890");
        again.LicenseKey.ShouldBe("LIZ-1234-5678");
    }

    /// <summary>
    /// A file written by hand or by PowerShell often has a byte order mark,
    /// and it must still apply.
    ///
    /// <para>In the acceptance run it looked as if it were ignored — the manager worked
    /// with defaults. This test clarifies whether that was due to the file.</para>
    /// </summary>
    [Fact]
    public void A_file_with_byte_order_mark_counts_too()
    {
        var path = Path.Combine(_dir, "manager.json");

        // Exactly as PowerShell writes it: with BOM, with double spaces after
        // the colon, and with doubled backslashes in the path.
        var content = """
            {
                "instanceExecutable":  "J:\\Programme\\ClawdDotNet.exe",
                "webUiPort":  7009,
                "deploymentcenterUrl":  ""
            }
            """;

        File.WriteAllText(path, content, new System.Text.UTF8Encoding(encoderShouldEmitUTF8Identifier: true));
        File.ReadAllBytes(path)[0].ShouldBe((byte)0xEF, "Der Test braucht das BOM.");

        var store = new ManagerSettingsStore(_dir);
        var settings = store.Load();

        store.LoadProblem.ShouldBeNull();
        settings.InstanceExecutable.ShouldBe(@"J:\Programme\ClawdDotNet.exe");
        settings.WebUiPort.ShouldBe(7009);
        settings.DeploymentcenterUrl.ShouldBe("");
    }

    /// <summary>
    /// An unreadable file must not prevent the manager from starting — then
    /// no instance would run at all, and that is the worse state.
    /// </summary>
    [Fact]
    public void A_broken_file_does_not_prevent_the_start()
    {
        File.WriteAllText(Path.Combine(_dir, "manager.json"), "{ das ist kein JSON");

        var store = new ManagerSettingsStore(_dir);

        store.Load().WebUiPort.ShouldBe(7000);

        // And the reason is recorded - otherwise the manager silently works with
        // defaults, and nobody can say why its instance directory is wrong.
        store.LoadProblem.ShouldNotBeNullOrWhiteSpace();
    }

    /// <summary>
    /// Nonsensical numbers can be in a hand-editable file. A
    /// probe interval of 0 would be an endless loop, an alarm after zero failed attempts an
    /// alarm at every hiccup.
    /// </summary>
    [Fact]
    public void Nonsensical_supervision_values_are_caught()
    {
        var settings = new ManagerSettings
        {
            ProbeIntervalSeconds = 0,
            StartTimeoutSeconds = -5,
            SilentChecksBeforeAlarm = 0,
            StopGraceSeconds = 99999
        };

        var options = settings.ToSupervisionOptions();

        options.ProbeInterval.ShouldBeGreaterThan(TimeSpan.Zero);
        options.StartTimeout.ShouldBeGreaterThan(TimeSpan.Zero);
        options.SilentChecksBeforeAlarm.ShouldBeGreaterThanOrEqualTo(1);
        options.StopGrace.ShouldBeLessThanOrEqualTo(TimeSpan.FromMinutes(10));
    }
}

/// <summary>The log excerpt that only gives a crash report its value.</summary>
public sealed class InstanceLogExcerptTests : IDisposable
{
    private readonly string _instance = Path.Combine(
        Path.GetTempPath(), "clawd-tests", "log-" + Guid.NewGuid().ToString("N")[..8]);

    public InstanceLogExcerptTests() => Directory.CreateDirectory(_instance);

    public void Dispose()
    {
        try { Directory.Delete(_instance, recursive: true); }
        catch { /* A leftover test folder does not turn a run red. */ }
    }

    private void Write(string tag, string module, params string[] lines)
    {
        var dir = Path.Combine(_instance, "Logs", tag);
        Directory.CreateDirectory(dir);
        File.WriteAllLines(Path.Combine(dir, module), lines);
    }

    [Fact]
    public void Without_log_nothing_comes_back()
    {
        // Not an error, but a finding: a process that was killed before its
        // write buffer was flushed leaves exactly nothing (#529).
        InstanceLogExcerpt.Read(_instance).ShouldBeEmpty();
    }

    /// <summary>
    /// Modules describe the same period. With a crash you want to know what
    /// happened at the same time — not first everything from one file, then everything from the
    /// next.
    /// </summary>
    [Fact]
    public void The_modules_are_merged_by_time()
    {
        Write("2026-09-08", "Startup.log",
            "[17:26:48.100] [INF] Instanz Test2 angelegt",
            "[17:26:50.900] [INF] Application is shutting down");

        Write("2026-09-08", "Web.log",
            "[17:26:49.500] [INF] Weboberfläche beendet");

        var lines = InstanceLogExcerpt.Read(_instance);

        lines.Count.ShouldBe(3);
        lines[0].ShouldContain("17:26:48");
        lines[1].ShouldContain("17:26:49");
        lines[2].ShouldContain("17:26:50");

        // Which file a line comes from is part of it.
        lines[1].ShouldStartWith("Web.log:");
    }

    [Fact]
    public void Only_the_most_recent_day_counts()
    {
        Write("2026-09-01", "Startup.log", "[10:00:00.000] [INF] uralt");
        Write("2026-09-08", "Startup.log", "[10:00:00.000] [INF] frisch");

        InstanceLogExcerpt.Read(_instance).ShouldHaveSingleItem().ShouldContain("frisch");
    }

    [Fact]
    public void Only_the_last_lines_are_taken()
    {
        Write("2026-09-08", "Startup.log",
            Enumerable.Range(0, 500).Select(i => $"[10:00:{i % 60:00}.000] [INF] Zeile {i}").ToArray());

        InstanceLogExcerpt.Read(_instance, lines: 10).Count.ShouldBeLessThanOrEqualTo(10);
    }

    /// <summary>
    /// The file may still be written to at exactly this moment — by an instance
    /// that is just ending. Whoever wanted to open it exclusively might get nothing at all.
    /// </summary>
    [Fact]
    public void A_file_open_for_writing_can_be_read()
    {
        Write("2026-09-08", "Startup.log", "[10:00:00.000] [INF] erste Zeile");

        var path = Path.Combine(_instance, "Logs", "2026-09-08", "Startup.log");

        using var open = new FileStream(
            path, FileMode.Append, FileAccess.Write, FileShare.ReadWrite);

        InstanceLogExcerpt.Read(_instance).ShouldNotBeEmpty();
    }

    [Fact]
    public void A_custom_log_directory_is_respected()
    {
        var own = Path.Combine(_instance, "AndereLogs");
        Directory.CreateDirectory(Path.Combine(own, "2026-09-08"));
        File.WriteAllLines(
            Path.Combine(own, "2026-09-08", "Startup.log"),
            ["[10:00:00.000] [INF] woanders"]);

        var config = new ClawdDotNet.Core.Config.InstanceConfig
        {
            WorkingDirectory = _instance,
            LogDirectory = "AndereLogs"
        };

        InstanceLogExcerpt.Read(_instance, config).ShouldHaveSingleItem().ShouldContain("woanders");
    }
}