namespace DodoSSH.Client.Terminal.Tests;

/// <summary>
/// The renderer page's right button: a copy, a paste, and never a menu.
/// </summary>
/// <remarks>
/// <para>
/// The gesture every terminal has had since the Windows console got QuickEdit — select and right-click to
/// copy, right-click with nothing selected to paste. It lives in the page because that is the only place it
/// can: the selection is drawn into a canvas the host never sees, and once a terminal has focus the host's
/// window receives no input events at all.
/// </para>
/// <para>
/// What is asserted here is which frame the page sends, addressed to which session, and which of xterm's two
/// insertion routes it takes on the way back. What is deliberately <em>not</em> asserted is anything about
/// xterm itself — whether <c>paste()</c> really brackets, whether a selection really loses its right
/// padding — because the fake terminal in the harness is a stub with a memory and not an emulator. That
/// boundary is where <c>docs/manual-checks.md</c> 1.11 picks up.
/// </para>
/// </remarks>
public sealed class RendererClipboardTests
{
    /// <summary>The session every single-pane test here opens.</summary>
    private const uint SessionId = 7;

    [Fact]
    public void ARightClickOverASelection_CopiesIt()
    {
        var page = Attached();

        page.Do("select(7, 'error: nothing was written')");
        page.Do("rightClick(7)");

        page.Sent.ShouldContain("5/7/error: nothing was written");
    }

    /// <remarks>
    /// The console's behaviour, and load-bearing rather than cosmetic. Dropping the selection is the only
    /// acknowledgement of the copy there is — nothing else on screen moves — and it is what makes the next
    /// right-click a paste rather than a second copy of something forgotten about.
    /// </remarks>
    [Fact]
    public void ARightClickOverASelection_DropsTheSelectionAfterCopyingIt()
    {
        var page = Attached();

        page.Do("select(7, 'systemctl status sshd')");
        page.Do("rightClick(7)");

        page.Selection(SessionId).ShouldBeEmpty();
    }

    [Fact]
    public void ARightClickWithNothingSelected_AsksTheHostForTheClipboard()
    {
        var page = Attached();

        page.Do("rightClick(7)");

        // No payload: the page has nothing to send, which is the whole reason it has to ask.
        page.Sent.ShouldContain("6/7/");
    }

    /// <remarks>
    /// The composite property, and the one a user would describe: copy, then paste. It passes only if the
    /// copy dropped the selection — a page that left it standing sends a second copy frame here and never a
    /// paste request, which is the failure that reads as "paste is broken".
    /// </remarks>
    [Fact]
    public void ASecondRightClick_PastesBecauseTheFirstOneCopied()
    {
        var page = Attached();

        page.Do("select(7, 'df -h')");
        page.Do("rightClick(7)");
        page.Do("rightClick(7)");

        page.Sent.ShouldContain("5/7/df -h");
        page.Sent.ShouldContain("6/7/");
    }

    /// <remarks>
    /// <para>
    /// <c>preventDefault</c> is the WebView's own context menu, which is what this whole change is about.
    /// </para>
    /// <para>
    /// <c>stopPropagation</c> is xterm's, and it is the half that is easy to leave out. xterm registers its
    /// own <c>contextmenu</c> handler on the element inside the pane, which parks a 20-pixel textarea under
    /// the pointer at z-index 1000 and leaves the selection sitting in it, selected — both of which exist to
    /// serve the native menu and are litter without one. The page takes the event in the capture phase to
    /// get ahead of it; a listener that forgot the third argument to <c>addEventListener</c> would still
    /// suppress the menu and would fail here.
    /// </para>
    /// </remarks>
    [Fact]
    public void ARightClick_TakesTheEventFromTheBrowserAndFromXterm()
    {
        var page = Attached();

        page.Do("rightClick(7)");

        page.Prevented.ShouldBe(1);
        page.Stopped.ShouldBe(1);
    }

    /// <remarks>
    /// The panes cover the page — they are positioned at inset 0 — so the only right-click that misses one is
    /// on the status banner, which is drawn over the bottom of the pane while it has something to say. That
    /// used to be the one place in a terminal window that still opened a browser menu.
    /// </remarks>
    [Fact]
    public void ARightClickThatMissesEveryPane_StillOpensNoMenu()
    {
        var page = Attached();

        page.Do("rightClickOffAPane()");

        page.Prevented.ShouldBe(1);

        // And nothing is stopped, because there is nothing below the document to stop it from — nor any
        // frame sent, because a click that is on no pane is a click about no session.
        page.Stopped.ShouldBe(0);
    }

    /// <remarks>
    /// A right-click over a pane with a selection sends one frame and not two: the branch is exclusive, and a
    /// page that asked for the clipboard as well would paste over the selection it had just copied.
    /// </remarks>
    [Fact]
    public void ARightClickOverASelection_DoesNotAlsoAskForTheClipboard()
    {
        var page = Attached();

        page.Do("select(7, 'uname -a')");
        page.Do("rightClick(7)");

        page.Sent.ShouldNotContain("6/7/");
    }

    /// <remarks>
    /// Two panes, because the session id on a clipboard frame is the whole of what puts the text where the
    /// pointer was. They agree with the host's own idea of the active tab in every arrangement that exists
    /// today; the page is what knows, so this is what proves the page says.
    /// </remarks>
    [Fact]
    public void ARightClick_IsAddressedToThePaneItHappenedIn()
    {
        var page = Attached();

        page.Do("openSession(9)");
        page.Do("select(7, 'the first pane'); select(9, 'the second pane')");

        page.Do("rightClick(9)");

        page.Sent.ShouldContain("5/9/the second pane");
        page.Sent.ShouldNotContain("5/7/the first pane");
    }

    /// <remarks>
    /// The other half of the round trip. <c>paste()</c> rather than <c>input()</c>, because this text came
    /// off the system clipboard and that is the case bracketed paste exists for: a shell that receives a
    /// multi-line command inside the markers treats every newline as text rather than as "run this".
    /// </remarks>
    [Fact]
    public void TheClipboardComingBack_IsPastedRatherThanTyped()
    {
        var page = Attached();

        page.Do("deliverClipboard(7, 'sudo systemctl restart sshd')");

        page.Pasted(SessionId).ShouldBe("sudo systemctl restart sshd");
        page.Typed(SessionId).ShouldBeEmpty();
    }

    /// <remarks>
    /// No Enter, ever. A clipboard paste inserts and stops; pressing Enter for somebody is what the sidebar's
    /// RUN does, and that is a thing they asked for by name.
    /// </remarks>
    [Fact]
    public void TheClipboardComingBack_DoesNotPressEnter()
    {
        var page = Attached();

        page.Do("deliverClipboard(7, 'rm -rf /var/tmp/build')");

        page.Typed(SessionId).ShouldBeEmpty();
    }

    /// <summary>The caret follows the paste, so the next keystroke lands where the text did.</summary>
    [Fact]
    public void TheClipboardComingBack_LeavesTheCaretInThatPane()
    {
        var page = Attached();

        var before = page.Focuses(SessionId);
        page.Do("deliverClipboard(7, 'whoami')");

        page.Focuses(SessionId).ShouldBe(before + 1);
    }

    /// <remarks>
    /// Multi-byte, because both directions run through the page's own <c>TextEncoder</c> and
    /// <c>TextDecoder</c> and a character that straddles nothing is not a test of either. The harness's codec
    /// is a real UTF-8 one for this reason; see its remark.
    /// </remarks>
    [Fact]
    public void TheTextSurvivesTheRoundTrip_WhenItIsNotAscii()
    {
        var page = Attached();

        page.Do("select(7, 'échec — 90° · λ')");
        page.Do("rightClick(7)");
        page.Do("deliverClipboard(7, 'échec — 90° · λ')");

        page.Sent.ShouldContain("5/7/échec — 90° · λ");
        page.Pasted(SessionId).ShouldBe("échec — 90° · λ");
    }

    /// <remarks>
    /// The distinction the new opcode exists to keep, asserted from the other side: a snippet off the sidebar
    /// is still <em>typed</em> when it is a single line, because bash marks a bracketed paste as an active
    /// region and a snippet should read as though it had been typed. Sharing one opcode with the clipboard
    /// would have meant choosing one of these two behaviours for both.
    /// </remarks>
    [Fact]
    public void ASingleLineSnippet_IsStillTypedRatherThanPasted()
    {
        var page = Attached();

        page.Do("deliverSnippet(7, 'tail -f /var/log/syslog', false)");

        page.Typed(SessionId).ShouldBe("tail -f /var/log/syslog");
        page.Pasted(SessionId).ShouldBeEmpty();
    }

    /// <inheritdoc cref="ASingleLineSnippet_IsStillTypedRatherThanPasted" />
    [Fact]
    public void AMultiLineSnippet_IsStillPastedRatherThanTyped()
    {
        var page = Attached();

        page.Do("deliverSnippet(7, 'cd /srv\\nmake\\nmake install', false)");

        page.Pasted(SessionId).ShouldBe("cd /srv\nmake\nmake install");
        page.Typed(SessionId).ShouldBeEmpty();
    }

    /// <remarks>
    /// And the Enter goes through the typed route even for a multi-line snippet, deliberately outside the
    /// bracketing: a <c>\r</c> inside the wrapper arrives at the shell as a literal carriage return and
    /// nothing runs.
    /// </remarks>
    [Fact]
    public void ASnippetWithRun_PressesEnterOutsideTheBrackets()
    {
        var page = Attached();

        page.Do("deliverSnippet(7, 'cd /srv\\nmake', true)");

        page.Pasted(SessionId).ShouldBe("cd /srv\nmake");
        page.Typed(SessionId).ShouldBe("\r");
    }

    /// <summary>A page with an open socket and one pane, which is where every test here starts.</summary>
    private static RendererPage Attached()
    {
        var page = RendererPage.Load();

        // The socket has to be open before anything is sent: send() drops a frame when it is not, which
        // would make every assertion here pass or fail on the transport rather than on the gesture.
        page.Do("accept(0)");
        page.Do("openSession(7)");

        return page;
    }
}