//! Layout, hit testing and task updates, driven without a window.

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

use iris::harness::Harness;
use iris::prelude::*;

/// `PixelRegion` neither compares nor prints.
fn corners(h: &Harness, id: &impl IdLike) -> (f32, f32, f32, f32) {
    let region = h.region(id).expect("widget drew nothing");
    (
        region.top_left.x,
        region.top_left.y,
        region.bot_right.x,
        region.bot_right.y,
    )
}

/// A fixed 100 wide, and the rest of the 400 to its neighbour.
fn two_rects(h: &mut Harness) -> (WidgetId, WidgetId) {
    let left = rect(Color::RED).width(100).add(&mut h.rsc);
    let right = rect(Color::BLUE).add(&mut h.rsc);
    h.set_root((left, right).span(Dir::RIGHT));
    (left.id(), right.id())
}

#[test]
fn a_span_gives_each_child_the_width_it_asked_for() {
    let mut h = Harness::new((400, 200));
    let (left, right) = two_rects(&mut h);

    assert_eq!(corners(&h, &left), (0.0, 0.0, 100.0, 200.0));
    assert_eq!(corners(&h, &right), (100.0, 0.0, 400.0, 200.0));
}

#[test]
fn resizing_relays_out_against_the_new_output() {
    let mut h = Harness::new((400, 200));
    let (left, right) = two_rects(&mut h);

    h.resize((800, 100));
    assert!(h.needs_redraw());
    h.frame();

    assert_eq!(corners(&h, &left), (0.0, 0.0, 100.0, 100.0));
    assert_eq!(corners(&h, &right), (100.0, 0.0, 800.0, 100.0));
}

#[test]
fn a_press_reaches_only_the_widget_under_the_cursor() {
    let mut h = Harness::new((400, 200));
    let clicks = Rc::new(RefCell::new(Vec::new()));

    let (on_left, on_right) = (clicks.clone(), clicks.clone());
    let left = rect(Color::RED)
        .width(100)
        .on(CursorSense::click(), move |_, _| {
            on_left.borrow_mut().push("left")
        })
        .add(&mut h.rsc);
    let right = rect(Color::BLUE)
        .on(CursorSense::click(), move |_, _| {
            on_right.borrow_mut().push("right")
        })
        .add(&mut h.rsc);
    h.set_root((left, right).span(Dir::RIGHT));

    h.click((50, 100));
    assert_eq!(*clicks.borrow(), ["left"]);

    h.click((300, 100));
    assert_eq!(*clicks.borrow(), ["left", "right"]);
}

#[test]
fn hover_ends_when_the_cursor_leaves_the_window() {
    let mut h = Harness::new((400, 200));
    let hovered = Rc::new(RefCell::new(0));
    let ended = Rc::new(RefCell::new(0));

    let (h_count, e_count) = (hovered.clone(), ended.clone());
    let widget = rect(Color::RED)
        .on(CursorSense::HoverStart, move |_, _| {
            *h_count.borrow_mut() += 1
        })
        .on(CursorSense::HoverEnd, move |_, _| {
            *e_count.borrow_mut() += 1
        })
        .add(&mut h.rsc);
    h.set_root(widget);

    h.move_to((200, 100));
    assert_eq!((*hovered.borrow(), *ended.borrow()), (1, 0));

    // A second sample inside the same widget is not a second hover.
    h.move_to((210, 100));
    assert_eq!((*hovered.borrow(), *ended.borrow()), (1, 0));

    h.leave();
    assert_eq!((*hovered.borrow(), *ended.borrow()), (1, 1));
}

#[test]
fn a_task_update_reaches_the_tree() {
    let mut h = Harness::new((400, 200));
    let widget = rect(Color::RED).add(&mut h.rsc);
    h.set_root(widget.task_on(CursorSense::click(), async move |mut ctx| {
        ctx.update(move |_, rsc| widget(rsc).color = Color::BLUE);
    }));

    h.click((200, 100));

    assert!(
        h.await_update(Duration::from_secs(5)),
        "the task sent no update"
    );
    assert_eq!(h.rsc[widget].color, Color::BLUE);
}

#[test]
fn a_wheel_scrolls_the_content_and_stops_at_its_end() {
    let mut h = Harness::new((400, 200));
    // Twice the window's height, so there is 200 to scroll.
    let top = rect(Color::RED).height(200).add(&mut h.rsc);
    let bottom = rect(Color::BLUE).height(200).add(&mut h.rsc);
    h.set_root((top, bottom).span(Dir::DOWN).scrollable());
    h.move_to((200, 100));

    // `Scroll` starts snapped to the end.
    assert_eq!(corners(&h, &top).1, -200.0);

    // The handler scales a wheel line by 50.
    h.scroll((0, 1));
    h.frame();
    assert_eq!(corners(&h, &top).1, -150.0);

    h.scroll((0, 10));
    h.frame();
    assert_eq!(corners(&h, &top).1, 0.0);
}