using System.Net;
using System.Text;
using DodoSSH.Client.Import;
using DodoSSH.Client.Shell.ViewModels;

namespace DodoSSH.Client.App.Tests;

/// <summary>
/// The Hetzner Cloud wizard, from a token to hosts on the server.
/// </summary>
/// <remarks>
/// <para>
/// What this establishes beyond <c>HetznerCloudClientTests</c> is the half that suite cannot reach: that
/// reading a project stores nothing, that importing goes through the ordinary create-and-push path every
/// other write uses, that a server the keychain already points at arrives unticked rather than silently
/// duplicated, and that the token does not outlive the request it was typed for.
/// </para>
/// <para>
/// Hetzner is a stubbed <c>HttpMessageHandler</c>. Everything else — the vault, the cache, the server — is
/// this fixture's real one, which is the point: the assertion that matters most is that the imported hosts
/// reached the server without anything pressing Sync.
/// </para>
/// </remarks>
public sealed partial class ShellFlowTests
{
    private const string HetznerToken =
        "abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789";

    /// <summary>
    /// The whole wizard.
    /// </summary>
    /// <remarks>
    /// One server already in the keychain and one not, so the two halves of the default are both exercised:
    /// the new one arrives ticked, the known one does not, and only the ticked one is stored.
    /// </remarks>
    [Fact]
    public async Task ImportingFromHetzner_ShowsTheProjectFirstAndThenStoresWhatWasTicked()
    {
        await UnlockedAsync();
        var vault = shell.Vault!;

        // db.internal:deploy is what AddHostAsync creates, so the first server is one the keychain has.
        await AddHostAsync(vault, "prod-db");

        var wizard = Wizard(Project("""
            {
              "id": 1,
              "name": "already-here",
              "status": "running",
              "public_net": { "ipv4": { "ip": "db.internal" } }
            }
            """,
            """
            {
              "id": 2,
              "name": "web-01",
              "status": "running",
              "public_net": { "ipv4": { "ip": "203.0.113.10" } },
              "server_type": { "name": "cx22" },
              "datacenter": { "name": "fsn1-dc14", "location": { "name": "fsn1", "city": "Falkenstein", "country": "DE" } },
              "image": { "name": "ubuntu-24.04" }
            }
            """));

        wizard.Step.ShouldBe(HetznerImportStep.Token, "it opens on the box, having sent nothing");

        wizard.Token = HetznerToken;
        wizard.Username = "deploy";

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.Step.ShouldBe(HetznerImportStep.Choose);
        wizard.Rows.Count.ShouldBe(2);
        vault.Hosts.Count.ShouldBe(1, "reading the project stores nothing");

        var known = wizard.Rows.Single(row => string.Equals(row.Name, "already-here", StringComparison.Ordinal));

        known.AlreadyPresent.ShouldBeTrue("it points at a machine the keychain already has");
        known.IsSelected.ShouldBeFalse("a duplicate takes a click rather than being the default");

        var fresh = wizard.Rows.Single(row => string.Equals(row.Name, "web-01", StringComparison.Ordinal));

        fresh.IsSelected.ShouldBeTrue();
        fresh.Address.ShouldBe("203.0.113.10");

        await wizard.ImportCommand.ExecuteAsync(null);

        wizard.Step.ShouldBe(HetznerImportStep.Done);

        var imported = vault.Hosts.Single(row => string.Equals(row.Label, "web-01", StringComparison.Ordinal));

        imported.Address.ShouldBe("deploy@203.0.113.10:22");
        imported.Host.SshKeyId.ShouldBeNull("Hetzner has no private key to hand over");
        imported.Host.Notes.ShouldNotBeNull().ShouldContain("cx22");

        vault.Hosts.Count.ShouldBe(2, "only the ticked one was stored");

        // Through the ordinary path, which is the point of routing it through the vault: it reached the
        // server without anything pressing Sync.
        server.LiveRowCount.ShouldBe(2);
    }

    /// <summary>
    /// The token does not outlive the request it was typed for.
    /// </summary>
    /// <remarks>
    /// This is the whole of what makes pasting a credential capable of listing somebody's estate into a text
    /// box acceptable: it is used once and dropped. Asserted on the success path deliberately — a wizard
    /// that cleared the box only when something went wrong would leave the token sitting there for the
    /// entire time somebody spends reading a list of forty servers.
    /// </remarks>
    [Fact]
    public async Task TheTokenIsForgottenAsSoonAsTheProjectHasBeenRead()
    {
        await UnlockedAsync();

        var wizard = Wizard(Project(WebServer));

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.Token.ShouldBeEmpty();
        wizard.Rows.ShouldHaveSingleItem();
    }

    /// <remarks>
    /// A refused token is the failure this meets most often, and the recovery is to type a different one —
    /// so it stays on the step that has the box, with a message that says where tokens come from.
    /// </remarks>
    [Fact]
    public async Task ARefusedToken_StaysOnTheTokenStepAndStoresNothing()
    {
        await UnlockedAsync();

        var wizard = Wizard(new StubHetznerResponse(
            HttpStatusCode.Unauthorized,
            """{ "error": { "code": "unauthorized", "message": "unable to authenticate" } }"""));

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.Step.ShouldBe(HetznerImportStep.Token);
        wizard.Status.ShouldContain("API tokens");
        wizard.Rows.ShouldBeEmpty();
        wizard.Token.ShouldBeEmpty("a refused token is retyped rather than corrected in place");
        shell.Vault!.Hosts.ShouldBeEmpty();
    }

    /// <remarks>
    /// An empty project is a correct answer to a correct token, so it is not an error — and it is not a step
    /// forward either, because a list screen with nothing on it says less than the sentence does.
    /// </remarks>
    [Fact]
    public async Task AnEmptyProject_SaysSoWithoutMovingOn()
    {
        await UnlockedAsync();

        var wizard = Wizard(Project());

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.Step.ShouldBe(HetznerImportStep.Token);
        wizard.Status.ShouldContain("no servers");
    }

    /// <summary>
    /// Choosing the private network does not quietly put a public address in the keychain.
    /// </summary>
    /// <remarks>
    /// The one asymmetry in how addresses resolve, and the reason for it: falling back between v4 and v6
    /// reaches the same machine over the same internet, where falling back from a private address to a
    /// public one would put an address on the open internet into a bookmark that was asked to stay off it.
    /// So the row loses its tick and cannot get it back while that choice stands.
    /// </remarks>
    [Fact]
    public async Task ChoosingThePrivateNetwork_LeavesAServerWithoutOneUnimportable()
    {
        await UnlockedAsync();

        var wizard = Wizard(Project(WebServer, """
            {
              "id": 3,
              "name": "db-01",
              "status": "running",
              "public_net": { "ipv4": { "ip": "203.0.113.20" } },
              "private_net": [ { "ip": "10.0.0.4" } ]
            }
            """));

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.SelectedCount.ShouldBe(2);

        wizard.UseAddressCommand.Execute(HetznerAddressKind.Private);

        var public_ = wizard.Rows.Single(row => string.Equals(row.Name, "web-01", StringComparison.Ordinal));
        var inside = wizard.Rows.Single(row => string.Equals(row.Name, "db-01", StringComparison.Ordinal));

        public_.CanImport.ShouldBeFalse("it is on no private network");
        public_.IsSelected.ShouldBeFalse();
        public_.Address.ShouldBe("—");

        inside.CanImport.ShouldBeTrue();
        inside.Address.ShouldBe("10.0.0.4");

        wizard.SelectedCount.ShouldBe(1);

        // Neither direction of "tick everything" can reach it, which is what "not importable" has to mean.
        wizard.ToggleAllCommand.Execute(null);

        public_.IsSelected.ShouldBeFalse();
        inside.IsSelected.ShouldBeFalse("that press was the untick, since everything reachable was ticked");

        wizard.ToggleAllCommand.Execute(null);

        public_.IsSelected.ShouldBeFalse();
        inside.IsSelected.ShouldBeTrue();

        await wizard.ImportCommand.ExecuteAsync(null);

        shell.Vault!.Hosts.ShouldHaveSingleItem().Host.Hostname.ShouldBe("10.0.0.4");
    }

    /// <remarks>
    /// Changing the address choice must not throw away ticks somebody set — but changing the login user has
    /// to re-ask "is this already here", because the user is half of what that is decided on.
    /// </remarks>
    [Fact]
    public async Task ChangingTheLoginUser_ReasksWhetherTheKeychainAlreadyHasIt()
    {
        await UnlockedAsync();
        var vault = shell.Vault!;

        await AddHostAsync(vault, "prod-db");

        var wizard = Wizard(Project("""
            {
              "id": 1,
              "name": "db",
              "status": "running",
              "public_net": { "ipv4": { "ip": "db.internal" } }
            }
            """));

        wizard.Token = HetznerToken;
        wizard.Username = "deploy";

        await wizard.ScanCommand.ExecuteAsync(null);

        wizard.Rows.ShouldHaveSingleItem().AlreadyPresent.ShouldBeTrue();

        wizard.Username = "ubuntu";

        wizard.Rows[0].AlreadyPresent.ShouldBeFalse("a different account on that machine is a different host");
    }

    /// <summary>
    /// A server with no public IPv4 still imports, and the row says what was assumed to reach it.
    /// </summary>
    /// <remarks>
    /// IPv6-only is a whole Hetzner price tier rather than an edge case. The address is the first in the
    /// routed /64 — the API reports a network, which nothing can dial — and that is a convention of
    /// Hetzner's own images rather than a fact, so it is on the row and in the stored note.
    /// </remarks>
    [Fact]
    public async Task AnIPv6OnlyServer_ImportsWithWhatWasAssumedWrittenDown()
    {
        await UnlockedAsync();

        var wizard = Wizard(Project("""
            {
              "id": 5,
              "name": "v6-only",
              "status": "running",
              "public_net": { "ipv4": null, "ipv6": { "ip": "2a01:4f8:1c17:d00::/64" } }
            }
            """));

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);

        var row = wizard.Rows.ShouldHaveSingleItem();

        row.Address.ShouldBe("2a01:4f8:1c17:d00::1");
        row.HasWarning.ShouldBeTrue();
        row.Meaning.ShouldContain("No public IPv4");

        await wizard.ImportCommand.ExecuteAsync(null);

        var host = shell.Vault!.Hosts.ShouldHaveSingleItem();

        host.Host.Hostname.ShouldBe("2a01:4f8:1c17:d00::1");
        host.Host.Notes.ShouldNotBeNull().ShouldContain("No public IPv4");
    }

    /// <remarks>
    /// After an import the list is asked again rather than cleared, so a row that was just stored says
    /// "already here" — which is what makes coming back and importing the rest of the project harmless and
    /// visible rather than harmless and confusing.
    /// </remarks>
    [Fact]
    public async Task AfterImporting_TheListSaysWhichOnesAreNowHere()
    {
        await UnlockedAsync();

        var wizard = Wizard(Project(WebServer));

        wizard.Token = HetznerToken;

        await wizard.ScanCommand.ExecuteAsync(null);
        await wizard.ImportCommand.ExecuteAsync(null);

        wizard.ReviewCommand.Execute(null);

        wizard.Step.ShouldBe(HetznerImportStep.Choose);

        var row = wizard.Rows.ShouldHaveSingleItem();

        row.AlreadyPresent.ShouldBeTrue();
        row.IsSelected.ShouldBeFalse("importing it twice takes a click");
    }

    // ---- Where it lives in the shell ----

    /// <remarks>
    /// The wizard is drawn over the Preferences page inside settings mode, exactly as the ssh_config
    /// importer is: the nav stays lit on Preferences and the titlebar offers "Back to preferences". What
    /// would silently come apart is the content column — two importers and one page beneath them.
    /// </remarks>
    [Fact]
    public async Task TheHetznerWizardOpensOverPreferencesAndBacksOutToIt()
    {
        await UnlockedAsync();

        shell.ShowScreenCommand.Execute(ShellScreen.HetznerImport);

        shell.IsHetznerImportOpen.ShouldBeTrue();
        shell.IsImporterOpen.ShouldBeTrue("the titlebar's back button asks this one");
        shell.IsSettingsPreferencesPage.ShouldBeTrue("the nav stays lit on Preferences");
        shell.IsSettingsPreferencesContentShowing.ShouldBeFalse("the wizard is what the column draws");

        shell.CloseImportCommand.Execute(null);

        shell.IsHetznerImportOpen.ShouldBeFalse();
        shell.IsSettingsMode.ShouldBeTrue("back to preferences, not out of settings");
        shell.IsSettingsPreferencesContentShowing.ShouldBeTrue();
    }

    /// <remarks>
    /// Opening one closes the other. They share a content column, and two importers drawn over each other
    /// would leave whichever was on top looking like the one the back button belongs to.
    /// </remarks>
    [Fact]
    public async Task OpeningOneImporterClosesTheOther()
    {
        await UnlockedAsync();

        shell.ShowScreenCommand.Execute(ShellScreen.Import);
        shell.IsImportOpen.ShouldBeTrue();

        shell.ShowScreenCommand.Execute(ShellScreen.HetznerImport);

        shell.IsImportOpen.ShouldBeFalse();
        shell.IsHetznerImportOpen.ShouldBeTrue();

        shell.ShowScreenCommand.Execute(ShellScreen.Import);

        shell.IsHetznerImportOpen.ShouldBeFalse();
        shell.IsImportOpen.ShouldBeTrue();
    }

    /// <summary>
    /// Reopening the wizard puts it back on step one.
    /// </summary>
    /// <remarks>
    /// A decision rather than an omission. The first step holds a credential this deliberately does not
    /// keep, so a "resumed" second step would be a list nothing on screen has the means to refresh — and it
    /// would go on looking current for as long as somebody left the application open.
    /// </remarks>
    [Fact]
    public async Task ReopeningTheWizard_StartsAtTheTokenAgain()
    {
        await UnlockedAsync();

        var wizard = shell.HetznerImportScreen.ShouldNotBeNull();

        // Driven through the shell's own view model rather than the one this file builds, because what is
        // being checked is what OpenHetznerImport does to the screen the shell is holding.
        wizard.Token = HetznerToken;
        wizard.Step = HetznerImportStep.Choose;

        shell.ShowScreenCommand.Execute(ShellScreen.HetznerImport);

        wizard.Step.ShouldBe(HetznerImportStep.Token);
        wizard.Rows.ShouldBeEmpty();
    }

    // ---- Helpers ----

    /// <summary>A server carrying enough to be imported, used wherever the shape is not what is being tested.</summary>
    private const string WebServer = """
        {
          "id": 2,
          "name": "web-01",
          "status": "running",
          "public_net": { "ipv4": { "ip": "203.0.113.10" } }
        }
        """;

    /// <summary>The wizard, over a Hetzner that answers with exactly this.</summary>
    private HetznerImportViewModel Wizard(StubHetznerResponse response) =>
        new(shell.Vault!, new HetznerCloudClient(new HttpClient(new StubHetzner(response))));

    /// <summary>One page holding these servers and saying there are no more.</summary>
    private static StubHetznerResponse Project(params string[] servers) =>
        new(
            HttpStatusCode.OK,
            $$"""
            {
              "servers": [ {{string.Join(",", servers)}} ],
              "meta": { "pagination": { "page": 1, "per_page": 50, "next_page": null } }
            }
            """);

    private sealed record StubHetznerResponse(HttpStatusCode Status, string Body);

    /// <summary>Answers every request the same way. What varies between these tests is the body, not the sequence.</summary>
    private sealed class StubHetzner(StubHetznerResponse response) : HttpMessageHandler
    {
        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request,
            CancellationToken cancellationToken) =>
            Task.FromResult(new HttpResponseMessage(response.Status)
            {
                Content = new StringContent(response.Body, Encoding.UTF8, "application/json"),
            });
    }
}