<UserControl xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vm="using:DodoSSH.Client.Shell.ViewModels"
             x:Class="DodoSSH.Client.App.Views.TerminalTabs"
             x:DataType="vm:MainWindowViewModel">

  <!--
    The window's tab strip: three fixed tabs, then one per open terminal.

    ── IT IS NOT ONLY TERMINALS ANY MORE, and the type is still called TerminalTabs. ─────────────────────
    Vaults, SFTP and S3 sit at the head of the strip and are always there. The name stays because the strip
    is named in MainWindow, in the layout harness's height budget and in its own suite, and renaming a type
    to track what it grew into is a rename across four files that leaves the product identical. What the
    name now under-describes is written here instead.

    ── THE THREE FIXED TABS ─────────────────────────────────────────────────────────────────────────────
    None of the three can be closed, and that is the difference between them and a terminal rather than a
    styling choice. A terminal tab owns a shell and closing it ends that shell; these three own nothing —
    they are three places this window goes, and a close box on one would be asking whether to destroy a
    destination.

    Vaults is first and is the only one with anything under it: the nav rail, and whichever of its screens
    the rail points at. SFTP and S3 were rail entries until this strip existed, and they moved because they
    are the two destinations you *stay in* while something runs. The rail is drawn only under Vaults; see
    MainWindowViewModel.IsVaultsTab for why that is expressed as a page test rather than as a surface.

    S3 carries no count although the rail entry it replaces did. There is room for one, and a number on two
    of five tabs reads as a fact about those two rather than as the tab's own state — a terminal tab has
    nothing to count, and the eye reads the strip left to right expecting the same shape.

    ── THE TERMINAL TABS ────────────────────────────────────────────────────────────────────────────────
    Every one is one pane in the one WebView, so switching is a single frame telling the page which pane to
    show — nothing is created, nothing is destroyed, and the shell behind a hidden pane goes on running and
    goes on producing output. That is what makes tabs cost almost nothing here, and it is also why closing
    one is the only thing in this application that deliberately ends a session.

    The strip spans the whole window rather than one screen, which is what it is for: a connection you
    opened stays visible and one click away while you are looking at a transfer, a key, or preferences.
    Clicking a tab switches the window's surface to that terminal — see MainWindowViewModel.ShellSurface.

    Two of the design's header controls are still absent: SPLIT and FORWARDS. Splits would need a second
    pane geometry the renderer does not have, and port forwarding does not exist in the SSH layer. Two
    disabled buttons would teach nobody anything; see docs/design-import-gaps.md.

    An ItemsControl of buttons rather than a TabStrip, because the selection lives on the shell — a tab
    outlives the vault that opened it — and a strip that owned its own selection would be a second copy of
    that state.

    ── v2 ────────────────────────────────────────────────────────────────────────────────────────────────
    Tabs became pills: taller, rounded, each with its own outline, on the sidebar's surface rather than the
    chrome's. The design puts a "Hosts" pill at the head of this strip and hides the sidebar while a session
    is showing, so that pill is the only way back. The three fixed tabs are that idea taken at its word and
    one step further: the rail is not hidden, but it belongs to the Vaults tab, and the head of the strip is
    where you go to get back to it.
  -->

  <Border Height="42" Background="{StaticResource Sidebar}"
          BorderBrush="{StaticResource Border}" BorderThickness="0,0,0,1">

    <!--
      Everything in one scrolling row: the three fixed tabs, a rule, the terminals, the button that opens
      another, then the sentence for when there are none. The strip stays rather than collapsing — a row of
      chrome that appears and disappears would move every screen up and down by 42 pixels each time the last
      tab closed.
    -->
    <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
      <StackPanel Orientation="Horizontal" Margin="8,0,0,0">

        <!--
          The three that are always here. Buttons with no close box, marked active from the shell's own
          state rather than holding a selection of their own — the same reason the terminal tabs below are
          buttons and not a TabStrip.

          Each is lit by a different property and the three are exclusive by construction: IsVaultsTab is
          "a page, and not one of these two", and the other two are the existing IsTransfersShowing and
          IsBucketsShowing that both heads already use. Nothing here can light two at once.
        -->
        <Button Classes="flat tab fixed" Classes.active="{Binding IsVaultsTab}"
                Command="{Binding ShowVaultsCommand}"
                ToolTip.Tip="Your keychain: hosts, keys, pins, snippets and logs">
          <StackPanel Orientation="Horizontal" Spacing="7" VerticalAlignment="Center">
            <TextBlock Text="▦" FontSize="13" VerticalAlignment="Center" />
            <TextBlock Text="Vaults" VerticalAlignment="Center" />
          </StackPanel>
        </Button>

        <Button Classes="flat tab fixed" Classes.active="{Binding IsTransfersShowing}"
                Command="{Binding ShowFilesCommand}"
                CommandParameter="{x:Static vm:RemoteKind.Host}"
                ToolTip.Tip="Move files to and from a host over SFTP">
          <StackPanel Orientation="Horizontal" Spacing="7" VerticalAlignment="Center">
            <TextBlock Text="⇅" FontSize="13" VerticalAlignment="Center" />
            <TextBlock Text="SFTP" VerticalAlignment="Center" />
          </StackPanel>
        </Button>

        <!--
          The same screen as SFTP over the same view model — an object store and an SFTP host are both an
          IRemoteFileStore — and a separate tab anyway, because which picker is offered is decided by the
          destination rather than by a toggle inside the screen. See ShowFiles, which also explains why
          pressing this while an SFTP session is open refuses instead of arriving.
        -->
        <Button Classes="flat tab fixed" Classes.active="{Binding IsBucketsShowing}"
                Command="{Binding ShowFilesCommand}"
                CommandParameter="{x:Static vm:RemoteKind.Bucket}"
                ToolTip.Tip="Objects in an S3-compatible bucket from your keychain">
          <StackPanel Orientation="Horizontal" Spacing="7" VerticalAlignment="Center">
            <TextBlock Text="◳" FontSize="13" VerticalAlignment="Center" />
            <TextBlock Text="S3" VerticalAlignment="Center" />
          </StackPanel>
        </Button>

        <!--
          What separates the fixed tabs from the terminals. Without it the strip is five pills of the same
          shape and the user has to read all five to learn that three of them are places and two are
          machines. It is a rule rather than a gap because a gap at this width reads as the strip having
          been laid out carelessly.
        -->
        <Border Width="1" Height="18" Margin="6,0,10,0" VerticalAlignment="Center"
                Background="{StaticResource Border}" />

        <ItemsControl ItemsSource="{Binding Tabs}">
          <ItemsControl.ItemsPanel>
            <ItemsPanelTemplate>
              <StackPanel Orientation="Horizontal" />
            </ItemsPanelTemplate>
          </ItemsControl.ItemsPanel>
          <ItemsControl.ItemTemplate>
            <DataTemplate x:DataType="vm:TerminalTabViewModel">

              <!--
                The close box is inside the tab, not beside it. Beside it, the two were siblings in a grid:
                the cross was as tall as the strip and sat outside the tab's own background, so it read as a
                divider between tabs rather than as part of one, and the tab it belonged to was ambiguous
                for the tab to its right.

                Nested buttons work, and it is worth knowing why rather than assuming. Avalonia's
                Button.OnPointerPressed checks IsLeftButtonPressed, takes the pointer capture and marks the
                event handled — so a left press on the cross does not also select the tab. It deliberately
                does not handle any other button, which is exactly what lets a middle press bubble out of
                the cross and reach the handler below.

                Marked active on IsShowing rather than on IsSelected, which are not the same question. The
                selection survives navigating away — that is what makes the strip a way back to a terminal —
                so a tab lit while preferences filled the window would be a second "you are here" mark
                pointing at something nobody can see. See TerminalTabViewModel.IsShowing.
              -->
              <Button Classes="flat tab"
                      Classes.active="{Binding IsShowing}"
                      Command="{Binding $parent[ItemsControl].((vm:MainWindowViewModel)DataContext).SelectTabCommand}"
                      CommandParameter="{Binding}"
                      PointerPressed="OnTabPointerPressed"
                      ToolTip.Tip="{Binding Address}">
                <StackPanel Orientation="Horizontal" Spacing="7" VerticalAlignment="Center">
                  <!--
                    Green while the shell behind this tab is running, grey while it is connecting and once
                    it has ended. The pane keeps its scrollback either way, which is usually why somebody is
                    still looking at a tab whose dot has gone out.
                  -->
                  <Ellipse Classes="dot" Width="5" Height="5" Classes.live="{Binding IsLive}"
                           VerticalAlignment="Center" />
                  <TextBlock Text="{Binding Label}" VerticalAlignment="Center" />

                  <!--
                    What a tab with no pane has to say for itself: "connecting…" while the handshake runs,
                    and the refusal once one has failed. It is here rather than only on the card because the
                    whole point of not blocking the window is that the user is somewhere else — the strip is
                    the one piece of chrome that is on screen wherever that is.
                  -->
                  <TextBlock Text="{Binding Status}" VerticalAlignment="Center" FontSize="10.5"
                             MaxWidth="180" TextTrimming="CharacterEllipsis"
                             Foreground="{StaticResource TextFaint}"
                             IsVisible="{Binding !HasSession}" />

                  <!--
                    Always drawn, never on hover only. The strip has no other close affordance, and one
                    that appears when the pointer is already over the tab cannot be found by somebody
                    looking for it.
                  -->
                  <Button Classes="flat close inline" Width="16" Height="16" Padding="0"
                          VerticalAlignment="Center"
                          Command="{Binding $parent[ItemsControl].((vm:MainWindowViewModel)DataContext).CloseTabCommand}"
                          CommandParameter="{Binding}"
                          ToolTip.Tip="Closes this terminal and ends its shell. Middle-click the tab does the same.">
                    <TextBlock Text="✕" FontSize="10" HorizontalAlignment="Center"
                               VerticalAlignment="Center" />
                  </Button>
                </StackPanel>
              </Button>

            </DataTemplate>
          </ItemsControl.ItemTemplate>
        </ItemsControl>

        <!--
          Opens the quick-connect palette, which is also what Ctrl+K does — so the tooltip can say that
          honestly, and there is one way to start a connection rather than two that have to agree.

          Not a MenuFlyout offering "SSH" and "local shell", which is the nicer-looking answer and is not
          verifiably safe here: this strip sits directly above the WebView's rectangle, and whether a popup
          dropping into it composites above a native child window depends on whether Avalonia gives it its
          own platform window. docs/platform-flags.md records what this project already paid for treating a
          rendering claim as settled without a screenshot. The palette has no such question — opening it
          collapses the terminal outright.
        -->
        <Button Classes="flat tab plus" Width="30"
                Command="{Binding ToggleSearchCommand}"
                ToolTip.Tip="Open a connection  ·  Ctrl+K">
          <TextBlock Text="+" FontSize="15" HorizontalAlignment="Center" VerticalAlignment="Center" />
        </Button>

        <!--
          Nothing open, and this is where that is said. It is also the only place near the terminal that can
          carry a sentence at all: the rectangle below is a native child window, and anything Avalonia draws
          in it is drawn underneath.
        -->
        <TextBlock Classes="mono" FontSize="10.5"
                   Text="no terminals open · press + or Ctrl+K, or choose a host and press Connect"
                   Foreground="{StaticResource TextFaint}" VerticalAlignment="Center" Margin="12,0"
                   TextTrimming="CharacterEllipsis"
                   IsVisible="{Binding !HasTabs}" />

      </StackPanel>
    </ScrollViewer>
  </Border>

</UserControl>
