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

use gpui::{
    Context, IntoElement, Modifiers, MouseButton, ParentElement as _, Render, Styled as _,
    TestAppContext, VisualTestContext, Window, WindowHandle, div, point, px,
};
use gpui_native_core::menu::{Menu, MenuItem};
use gpui_native_theme::Theme;

struct Harness {
    open: bool,
    changes: Rc<RefCell<Vec<bool>>>,
    activated: Rc<RefCell<Vec<&'static str>>>,
}

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();
        let activated = self.activated.clone();
        div().size_full().child(
            Menu::new("test-menu")
                .open(self.open)
                .on_change(move |next, _, cx| {
                    changes.borrow_mut().push(next);
                    view.update(cx, |harness, cx| {
                        harness.open = next;
                        cx.notify();
                    });
                })
                .trigger(|_, _| {
                    div()
                        .w(px(100.))
                        .h(px(32.))
                        .bg(gpui::black())
                        .into_any_element()
                })
                .items(move |_, _| {
                    vec![
                        cut_item(activated.clone()),
                        MenuItem::separator(),
                        copy_item(activated.clone()),
                        MenuItem::new("Unavailable").disabled(true).handler({
                            let activated = activated.clone();
                            move |_, _| record(&activated, "unavailable")
                        }),
                        delete_item(activated.clone()),
                    ]
                }),
        )
    }
}

fn cut_item(activated: Rc<RefCell<Vec<&'static str>>>) -> MenuItem {
    MenuItem::new("Cut")
        .shortcut("cmd-x")
        .handler(move |_, _| record(&activated, "cut"))
}

fn copy_item(activated: Rc<RefCell<Vec<&'static str>>>) -> MenuItem {
    MenuItem::new("Copy").handler(move |_, _| record(&activated, "copy"))
}

fn delete_item(activated: Rc<RefCell<Vec<&'static str>>>) -> MenuItem {
    MenuItem::new("Delete")
        .destructive(true)
        .handler(move |_, _| record(&activated, "delete"))
}

fn record(sink: &Rc<RefCell<Vec<&'static str>>>, what: &'static str) {
    sink.borrow_mut().push(what);
}

type Changes = Rc<RefCell<Vec<bool>>>;
type Activated = Rc<RefCell<Vec<&'static str>>>;

fn menu_window(
    open: bool,
) -> (
    TestAppContext,
    VisualTestContext,
    WindowHandle<Harness>,
    Changes,
    Activated,
) {
    let mut cx = TestAppContext::single();
    cx.update(Theme::init);
    let changes = Rc::new(RefCell::new(Vec::new()));
    let activated = Rc::new(RefCell::new(Vec::new()));
    let harness_changes = changes.clone();
    let harness_activated = activated.clone();
    let window = cx.add_window(move |_, _| Harness {
        open,
        changes: harness_changes,
        activated: harness_activated,
    });
    let mut visual = VisualTestContext::from_window(window.into(), &cx);
    visual.update(|window, cx| {
        window.draw(cx).clear(cx);
    });
    (cx, visual, window, changes, activated)
}

fn draw(visual: &mut VisualTestContext) {
    visual.update(|window, cx| {
        window.draw(cx).clear(cx);
    });
}

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

#[test]
fn arrow_navigation_skips_separators_and_disabled_items() {
    let (_cx, mut visual, _window, changes, activated) = menu_window(true);

    // Selection starts on the first item; down moves to the next
    // selectable item (Copy, past the separator), and enter activates it,
    // closing the menu.
    visual.simulate_keystrokes("down");
    visual.simulate_keystrokes("enter");
    draw(&mut visual);
    assert_eq!(*activated.borrow(), vec!["copy"]);
    assert_eq!(*changes.borrow(), vec![false]);

    // Reopen: the selection starts over on the first item, and end jumps
    // straight to the last selectable item, over the separator and the
    // disabled row.
    click(&mut visual, point(px(10.), px(16.)));
    draw(&mut visual);
    visual.simulate_keystrokes("end");
    visual.simulate_keystrokes("enter");
    assert_eq!(*activated.borrow(), vec!["copy", "delete"]);
    assert_eq!(*changes.borrow(), vec![false, true, false]);
}

#[test]
fn escape_dismisses_without_activating() {
    let (_cx, mut visual, _window, changes, activated) = menu_window(true);

    visual.simulate_keystrokes("escape");
    assert_eq!(*changes.borrow(), vec![false]);
    assert!(activated.borrow().is_empty());

    // A closed menu is inert.
    draw(&mut visual);
    visual.simulate_keystrokes("escape");
    assert_eq!(*changes.borrow(), vec![false]);
}

#[test]
fn clicking_outside_dismisses_and_swallows_the_click() {
    let (_cx, mut visual, _window, changes, activated) = menu_window(true);

    click(&mut visual, point(px(600.), px(600.)));
    assert_eq!(*changes.borrow(), vec![false]);
    assert!(activated.borrow().is_empty());

    draw(&mut visual);
    click(&mut visual, point(px(600.), px(600.)));
    assert_eq!(*changes.borrow(), vec![false]);
}

#[test]
fn clicking_the_trigger_toggles() {
    let (_cx, mut visual, _window, changes, _activated) = menu_window(false);

    click(&mut visual, point(px(10.), px(16.)));
    assert_eq!(*changes.borrow(), vec![true]);
}

#[test]
fn clicking_an_item_activates_and_closes() {
    let (_cx, mut visual, _window, changes, activated) = menu_window(true);

    // The first row hangs just below the trigger's panel padding.
    click(&mut visual, point(px(60.), px(50.)));
    assert_eq!(*activated.borrow(), vec!["cut"]);
    assert_eq!(*changes.borrow(), vec![false]);
}

#[test]
fn enter_activates_the_selected_item_and_closes() {
    let (_cx, mut visual, _window, changes, activated) = menu_window(true);

    visual.simulate_keystrokes("enter");
    assert_eq!(*activated.borrow(), vec!["cut"]);
    assert_eq!(*changes.borrow(), vec![false]);
}