use std::{cell::RefCell, rc::Rc};

use gpui::{
    Context, IntoElement, MouseButton, ParentElement as _, Render, Styled as _, TestAppContext,
    VisualTestContext, Window, div, point, px,
};
use gpui_native_core::select::Select;
use gpui_native_theme::Theme;

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum Level {
    Low,
    Mid,
    High,
}

const LEVELS: [(Level, &str); 3] = [
    (Level::Low, "Low"),
    (Level::Mid, "Mid"),
    (Level::High, "High"),
];

type Changes = Rc<RefCell<Vec<Option<Level>>>>;

struct Harness {
    value: Option<Level>,
    changes: Changes,
}

impl Render for Harness {
    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        let changes = self.changes.clone();
        let view = cx.entity();
        div().size_full().p_4().child(
            Select::new("level")
                .options(LEVELS)
                .selected(self.value)
                .on_change(move |next, _window, cx| {
                    changes.borrow_mut().push(next);
                    view.update(cx, |harness, cx| {
                        harness.value = next;
                        cx.notify();
                    });
                }),
        )
    }
}

fn level_window() -> (TestAppContext, VisualTestContext, Changes) {
    let mut cx = TestAppContext::single();
    cx.update(Theme::init);
    let changes = Rc::new(RefCell::new(Vec::new()));
    let harness_changes = changes.clone();
    let window = cx.add_window(move |_, _| Harness {
        value: None,
        changes: harness_changes,
    });
    let mut visual = VisualTestContext::from_window(window.into(), &cx);
    visual.update(|window, cx| {
        window.draw(cx).clear(cx);
    });
    (cx, visual, changes)
}

fn click(visual: &mut VisualTestContext, position: gpui::Point<gpui::Pixels>) {
    visual.simulate_mouse_down(position, MouseButton::Left, gpui::Modifiers::default());
    visual.simulate_mouse_up(position, MouseButton::Left, gpui::Modifiers::default());
}

/// The trigger band is `16..46`; the panel hangs 4 px below it with a 4 px
/// inner padding, so the three rows ride `~58..90`, `~90..122`, `~122..154`.
/// Every option must answer a pointer press — a popup that clips its last
/// item never does.
#[test]
fn every_option_row_answers_the_pointer() {
    let (_cx, mut visual, changes) = level_window();

    let expected = [
        (px(74.), Level::Low),
        (px(106.), Level::Mid),
        (px(138.), Level::High),
    ];
    for (y, value) in expected {
        click(&mut visual, point(px(100.), px(31.)));
        visual.update(|window, cx| {
            window.draw(cx).clear(cx);
        });
        click(&mut visual, point(px(100.), y));
        visual.update(|window, cx| {
            window.draw(cx).clear(cx);
        });
        assert_eq!(
            changes.borrow().last(),
            Some(&Some(value)),
            "pressing {value:?}'s row must choose it"
        );
    }
}