use gpui::{
    AppContext as _, Context, Entity, IntoElement, ParentElement as _, Render, SharedString,
    Styled as _, TestAppContext, VisualTestContext, Window, div,
};
use gpui_native_core::common::v_flex;
use gpui_native_core::field::Field;
use gpui_native_core::init;
use gpui_native_core::input::{Input, InputState};

struct FieldHost {
    url: Entity<InputState>,
}

impl Render for FieldHost {
    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        let url_error = self
            .url
            .read(cx)
            .value()
            .is_empty()
            .then_some("Required")
            .map(SharedString::from);

        div().size_full().p_4().child(
            v_flex().gap_3().child(
                Field::new("bench-url", "Server URL")
                    .description("Where your patches are sent.")
                    .error(url_error)
                    .child(Input::new("bench-url-input", self.url.clone())),
            ),
        )
    }
}

/// A field page in a real window; the url input is focused unless
/// `focus` is false, which leaves the page truly idle.
fn field_host(focus: bool) -> (TestAppContext, Entity<InputState>, VisualTestContext) {
    let cx = TestAppContext::single();
    cx.update(init);
    let (url, window) = cx.update(|cx| {
        let url = InputState::new(cx);
        let url_for_host = url.clone();
        let window = cx
            .open_window(gpui::WindowOptions::default(), |_, cx| {
                cx.new(|_| FieldHost { url: url_for_host })
            })
            .unwrap();
        (url, window)
    });
    let mut visual = VisualTestContext::from_window(window.into(), &cx);
    visual.update(|window, cx| {
        if focus {
            let focus = url.read(cx).focus_handle();
            window.focus(&focus, cx);
        }
        window.draw(cx).clear(cx);
    });
    (cx, url, visual)
}

#[test]
fn an_idle_field_page_schedules_no_frames() {
    let (_cx, _url, mut visual) = field_host(false);
    let frames = visual.update(|window, cx| window.simulate_next_frame(cx));
    assert_eq!(
        frames, 0,
        "an idle unfocused field page must not request animation frames"
    );
}

#[test]
fn a_focused_field_page_schedules_frames_for_its_blink() {
    let (_cx, _url, mut visual) = field_host(true);
    let frames = visual.update(|window, cx| window.simulate_next_frame(cx));
    assert!(
        frames > 0,
        "the focused caret's blink needs frames to redraw at the blink cadence"
    );
}