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::segmented::Segmented;
use gpui_native_theme::Theme;

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum Filter {
    All,
    Popular,
    Recent,
}

const FILTERS: [(Filter, &str); 3] = [
    (Filter::All, "All"),
    (Filter::Popular, "Popular"),
    (Filter::Recent, "Recent"),
];

type Changes = Rc<RefCell<Vec<Filter>>>;

struct Harness {
    filter: Filter,
    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(
            Segmented::new("filter", self.filter)
                .options(FILTERS)
                .on_change(move |next, _window, cx| {
                    changes.borrow_mut().push(next);
                    view.update(cx, |harness, cx| {
                        harness.filter = next;
                        cx.notify();
                    });
                }),
        )
    }
}

fn filter_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 {
        filter: Filter::All,
        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 strip hugs its labels in the `p_4` band: the three segments span
/// roughly `18..142` horizontally and `17.6..33.9` vertically (macOS's 13 pt
/// root font), so clicks land near `32` (All), `70` (Popular), and `118`
/// (Recent).
#[test]
fn clicking_a_segment_reports_it() {
    let (_cx, mut visual, changes) = filter_window();

    click(&mut visual, point(px(70.), px(27.)));
    assert_eq!(*changes.borrow(), vec![Filter::Popular]);

    click(&mut visual, point(px(118.), px(27.)));
    assert_eq!(*changes.borrow(), vec![Filter::Popular, Filter::Recent]);
}

#[test]
fn re_clicking_the_selected_segment_reports_nothing() {
    let (_cx, mut visual, changes) = filter_window();

    click(&mut visual, point(px(70.), px(27.)));
    assert_eq!(*changes.borrow(), vec![Filter::Popular]);

    click(&mut visual, point(px(70.), px(27.)));
    assert_eq!(*changes.borrow(), vec![Filter::Popular]);
}

#[test]
fn arrows_move_the_selection_when_the_strip_has_focus() {
    let (_cx, mut visual, changes) = filter_window();

    // Clicking a segment hands the strip the keyboard, like the list.
    click(&mut visual, point(px(32.), px(27.)));
    visual.simulate_keystrokes("right");
    assert_eq!(*changes.borrow(), vec![Filter::Popular]);

    visual.simulate_keystrokes("right");
    assert_eq!(*changes.borrow(), vec![Filter::Popular, Filter::Recent]);

    // The strip never wraps: right on the last segment reports nothing.
    visual.simulate_keystrokes("right");
    assert_eq!(*changes.borrow(), vec![Filter::Popular, Filter::Recent]);

    // Home and end jump to the ends.
    visual.simulate_keystrokes("home");
    assert_eq!(
        *changes.borrow(),
        vec![Filter::Popular, Filter::Recent, Filter::All]
    );

    visual.simulate_keystrokes("end");
    assert_eq!(
        *changes.borrow(),
        vec![Filter::Popular, Filter::Recent, Filter::All, Filter::Recent]
    );
}

/// The selected plate exists after a choice and settles on the chosen
/// segment's slot; without it the active background disappears entirely.
#[test]
fn the_plate_settles_on_the_chosen_segment() {
    let (_cx, mut visual, changes) = filter_window();

    click(&mut visual, point(px(70.), px(27.)));
    assert_eq!(*changes.borrow(), vec![Filter::Popular]);

    // Let the spring settle in real time (it steps on Instant::now()), then
    // check the plate landed in Popular's slot (~58..124).
    std::thread::sleep(std::time::Duration::from_millis(600));
    visual.update(|window, cx| {
        window.draw(cx).clear(cx);
    });
    let plate = visual
        .debug_bounds("segmented-plate")
        .expect("plate missing");
    assert!(
        plate.left() >= px(44.) && plate.left() <= px(94.),
        "plate settled at x {:?}",
        plate.origin
    );
}