//! The titlebar duties: traffic-light pads and window controls, asserted per
//! platform — macOS draws only pads, Windows/Linux only draw their controls.

use gpui::{
    AppContext as _, Entity, IntoElement, ParentElement as _, Pixels, Render, Styled as _,
    TestAppContext, VisualTestContext, Window, div, px,
};
use gpui_native_layout::dock::{Dock, DockState, PanelDescriptor};
use gpui_native_layout::window_controls::TRAFFIC_LIGHT_PAD;
use gpui_native_theme::Theme;

struct Panel {
    tag: &'static str,
}

impl Render for Panel {
    fn render(&mut self, _window: &mut Window, _cx: &mut gpui::Context<Self>) -> impl IntoElement {
        div().size_full().child(self.tag)
    }
}

fn descriptor(tag: &'static str) -> PanelDescriptor {
    PanelDescriptor::new(tag, tag, move |_, cx| cx.new(|_| Panel { tag }).into())
}

struct Harness {
    dock: Entity<DockState>,
    window_controls: bool,
    traffic_light_pad: bool,
}

impl Render for Harness {
    fn render(&mut self, _window: &mut Window, _cx: &mut gpui::Context<Self>) -> impl IntoElement {
        div().size_full().child(
            Dock::new("test-dock", self.dock.clone())
                .window_controls(self.window_controls)
                .traffic_light_pad(self.traffic_light_pad),
        )
    }
}

fn dock_window(
    window_controls: bool,
    traffic_light_pad: bool,
    cx: &mut TestAppContext,
) -> (Entity<DockState>, VisualTestContext) {
    cx.update(Theme::init);
    let dock = cx.update(DockState::new);
    let dock_for_window = dock.clone();
    let window = cx.add_window(move |_, _| Harness {
        dock: dock_for_window,
        window_controls,
        traffic_light_pad,
    });
    let mut visual = VisualTestContext::from_window(window.into(), cx);
    visual.update(|window, cx| window.draw(cx).clear(cx));
    (dock, visual)
}

fn bounds(visual: &mut VisualTestContext, selector: &str) -> Option<gpui::Bounds<Pixels>> {
    visual.debug_bounds(Box::leak(selector.to_string().into_boxed_str()))
}

fn open(visual: &mut VisualTestContext, dock: &Entity<DockState>, tag: &'static str) {
    visual.update(|window, cx| {
        dock.update(cx, |dock, cx| dock.open_panel(tag, window, cx));
    });
    visual.update(|window, cx| window.draw(cx).clear(cx));
}

#[cfg(target_os = "macos")]
#[test]
fn the_pill_bar_pads_for_traffic_lights_when_it_leads_the_window() {
    let mut cx = TestAppContext::single();
    let (dock, mut visual) = dock_window(false, false, &mut cx);
    cx.update(|cx| {
        dock.update(cx, |dock, cx| {
            dock.register_panel(descriptor("overview"), cx)
        });
    });
    open(&mut visual, &dock, "overview");

    let bar = bounds(&mut visual, "test-dock-pane-0-bar").expect("pill bar missing");
    let tab = bounds(&mut visual, "test-dock-pane-0-tabs-tab-overview").expect("tab missing");
    let bare_inset = tab.left() - bar.left();

    let (dock, mut visual) = dock_window(false, true, &mut cx);
    let _ = &dock;
    cx.update(|cx| {
        dock.update(cx, |dock, cx| {
            dock.register_panel(descriptor("overview"), cx)
        });
    });
    open(&mut visual, &dock, "overview");

    let padded_bar = bounds(&mut visual, "test-dock-pane-0-bar").expect("padded bar missing");
    let padded_tab =
        bounds(&mut visual, "test-dock-pane-0-tabs-tab-overview").expect("tab missing");
    let padded_inset = padded_tab.left() - padded_bar.left();

    assert!(
        padded_inset - bare_inset >= px(TRAFFIC_LIGHT_PAD) - px(1.),
        "the pad must clear the traffic lights (bare {bare_inset:?}, padded {padded_inset:?})"
    );
}

#[test]
fn window_controls_render_only_when_the_flag_is_set() {
    let mut cx = TestAppContext::single();
    let (dock, mut visual) = dock_window(false, false, &mut cx);
    cx.update(|cx| {
        dock.update(cx, |dock, cx| {
            dock.register_panel(descriptor("overview"), cx)
        });
    });
    open(&mut visual, &dock, "overview");

    // macOS: the system traffic lights own the controls — nothing renders;
    // the pad test above covers that mode.
    #[cfg(not(target_os = "macos"))]
    assert!(
        bounds(&mut visual, "window-control-close").is_none(),
        "controls must not render without the flag"
    );
    #[cfg(target_os = "macos")]
    let _ = (&dock, &mut visual);
}

#[cfg(not(target_os = "macos"))]
#[test]
fn the_flag_hosts_the_platform_controls_in_the_bar() {
    let mut cx = TestAppContext::single();
    let (dock, mut visual) = dock_window(true, false, &mut cx);
    cx.update(|cx| {
        dock.update(cx, |dock, cx| {
            dock.register_panel(descriptor("overview"), cx)
        });
    });
    open(&mut visual, &dock, "overview");

    // The maximize control exists once; its restore flip follows the
    // window's maximized state, not a separate control.
    assert!(bounds(&mut visual, "window-control-close").is_some());
    assert!(bounds(&mut visual, "window-control-maximize").is_some());
}