use gpui::{
    AppContext as _, IntoElement, ParentElement as _, Render, Styled as _, TestAppContext,
    VisualTestContext, Window, div,
};
use gpui_native_core::button::{Button, ButtonVariant};
use gpui_native_core::field::{Field, FieldVariant};
use gpui_native_theme::Theme;

struct FieldHost {
    variant: FieldVariant,
    with_error: bool,
}

impl Render for FieldHost {
    fn render(&mut self, _window: &mut Window, _cx: &mut gpui::Context<Self>) -> impl IntoElement {
        let mut field = Field::new("test-field", "Server URL")
            .description("Where patches are sent.")
            .variant(self.variant)
            .child(
                Button::new("test-field-button")
                    .label("Edit")
                    .variant(ButtonVariant::Ghost),
            );
        if self.with_error {
            field = field.error(Some("Required"));
        }

        div().size_full().p_4().child(field)
    }
}

fn field_window(
    variant: FieldVariant,
    with_error: bool,
) -> (TestAppContext, gpui::AnyWindowHandle) {
    let mut cx = TestAppContext::single();
    cx.update(Theme::init);
    let window = cx.add_window(move |_, _| FieldHost {
        variant,
        with_error,
    });
    let window: gpui::AnyWindowHandle = window.into();
    cx.update_window(window, |_, window, cx| {
        window.draw(cx).clear(cx);
    })
    .unwrap();
    (cx, window)
}

#[test]
fn block_stacks_the_label_above_the_control() {
    let (cx, window) = field_window(FieldVariant::Block, false);
    let mut visual = VisualTestContext::from_window(window, &cx);
    let label = visual
        .debug_bounds("test-field-label")
        .expect("label missing");
    let control = visual
        .debug_bounds("test-field-control")
        .expect("control missing");

    assert!(
        label.bottom() <= control.top(),
        "label must sit above the control: {label:?} vs {control:?}"
    );
    assert!(
        (label.left() - control.left()).abs() < gpui::px(1.),
        "label and control must share the left edge"
    );
}

#[test]
fn row_leads_with_the_label_and_trails_the_control() {
    let (cx, window) = field_window(FieldVariant::Row, false);
    let mut visual = VisualTestContext::from_window(window, &cx);
    let label = visual
        .debug_bounds("test-field-label")
        .expect("label missing");
    let control = visual
        .debug_bounds("test-field-control")
        .expect("control missing");

    assert!(
        control.left() >= label.right(),
        "the control must trail the label: {label:?} vs {control:?}"
    );
    let label_center = (label.top() + label.bottom()) / 2.;
    let control_center = (control.top() + control.bottom()) / 2.;
    assert!(
        (label_center - control_center).abs() < gpui::px(1.5),
        "the control must center on the title line: {label:?} vs {control:?}"
    );
}

#[test]
fn the_error_renders_under_the_control_only_when_set() {
    let (cx, window) = field_window(FieldVariant::Block, false);
    let mut visual = VisualTestContext::from_window(window, &cx);
    assert!(
        visual.debug_bounds("test-field-error").is_none(),
        "no error must render when none is set"
    );

    let (cx, window) = field_window(FieldVariant::Block, true);
    let mut visual = VisualTestContext::from_window(window, &cx);
    let error = visual
        .debug_bounds("test-field-error")
        .expect("error missing");
    let control = visual
        .debug_bounds("test-field-control")
        .expect("control missing");
    assert!(
        error.top() >= control.bottom(),
        "the error must sit under the control: {control:?} vs {error:?}"
    );
}