solidcraft-upstream/crates/ui-egui/src/sketch_drag_ui_tests.rs

//! Dragging sketch geometry in the viewport: live frames re-solve the sketch only, letting go
//! brings the model up to date in the drag's one undo step, and the grab stays on the geometry.

use serde_json::{Value, json};
use solvecraft_engine::geom::Vec2;

use crate::scenario::Harness;

fn run(h: &mut Harness, id: &str, p: Value) {
    if let Err(e) = h.app.run(id, p.clone()) {
        panic!("{id} {p}: {e}");
    }
}

fn screen(h: &mut Harness, x: f64, y: f64) -> egui::Pos2 {
    let [sx, sy] = h.at(&json!({"sketch": [x, y]})).expect("on screen");
    egui::pos2(sx as f32, sy as f32)
}

fn point(h: &Harness, id: &str) -> Vec2 {
    let sid = h.app.session.active_sketch.expect("sketch mode");
    let st = h.app.session.world_state();
    let sk = &st.sketch(sid).expect("the sketch").sketch;
    sk.resolve_point(id).and_then(|i| sk.point(i)).unwrap_or_else(|| panic!("no point {id}"))
}

/// Press at `path[0]` and move through the rest, one frame per event.
fn press_and_move(h: &mut Harness, path: &[egui::Pos2]) {
    let Some(&a) = path.first() else { return };
    h.app.synthetic.push(egui::Event::PointerMoved(a));
    h.app.synthetic.push(egui::Event::PointerButton { pos: a, button: egui::PointerButton::Primary, pressed: true, modifiers: Default::default() });
    h.app.synthetic.extend(path.iter().skip(1).map(|&p| egui::Event::PointerMoved(p)));
    play(h);
}

fn release(h: &mut Harness, at: egui::Pos2) {
    h.app.synthetic.push(egui::Event::PointerButton { pos: at, button: egui::PointerButton::Primary, pressed: false, modifiers: Default::default() });
    play(h);
}

fn play(h: &mut Harness) {
    while !h.app.synthetic.is_empty() {
        h.frame();
    }
    h.frames(2);
}

/// Points from `a` to `b` in `n` equal moves (without `a`).
fn steps(a: egui::Pos2, b: egui::Pos2, n: usize) -> Vec<egui::Pos2> {
    (1..=n).map(|k| a + (b - a) * (k as f32 / n as f32)).collect()
}

#[test]
fn a_viewport_drag_solves_the_sketch_live_and_rebuilds_the_model_on_release() {
    let mut h = Harness::new();
    run(&mut h, "sketch.create", json!({"plane": "XY"}));
    run(&mut h, "sketch.rectangle.two_point", json!({"p0": [5, 5], "p1": [25, 20]}));
    run(&mut h, "sketch.dimension", json!({"entities": ["l1"], "value": 20}));
    run(&mut h, "sketch.dimension", json!({"entities": ["l2"], "value": 15}));
    run(&mut h, "sketch.finish", json!({}));
    run(&mut h, "solid.extrude", json!({"distance": 5}));
    let sketch = h.app.session.doc.features.first().map(|f| f.id).expect("the sketch");
    h.app.edit_sketch(sketch);
    h.settle();
    let undo = h.app.session.undo.len();
    let a = screen(&mut h, 5.0, 5.0);
    let b = screen(&mut h, -3.0, -6.0);
    let mut path = vec![a];
    path.extend(steps(a, b, 8));
    press_and_move(&mut h, &path);
    assert!(h.app.viewport.point_drag.is_some(), "the drag is under way");
    assert!(h.app.session.model.is_stale(), "the frames updated the sketch only");
    assert!(point(&h, "l1.start").dist(Vec2::new(-3.0, -6.0)) < 0.1, "{:?}", point(&h, "l1.start"));
    release(&mut h, b);
    assert!(h.app.viewport.point_drag.is_none());
    assert!(!h.app.session.model.is_stale(), "letting go evaluated the model");
    assert_eq!(h.app.session.undo.len(), undo + 1, "one undo step for the drag");
    assert!(point(&h, "l1.start").dist(Vec2::new(-3.0, -6.0)) < 0.1);
    run(&mut h, "edit.undo", json!({}));
    assert!(point(&h, "l1.start").dist(Vec2::new(5.0, 5.0)) < 1e-9);
}

#[test]
fn a_dragged_line_that_stops_short_stays_under_the_cursor_when_it_can_follow_again() {
    let mut h = Harness::new();
    run(&mut h, "sketch.create", json!({"plane": "XY"}));
    // Two 10 mm links from the origin hold the start of a horizontal 10 mm line: the line can
    // slide right until its start is 20 mm from the origin (3 mm).
    let (x, y) = (15.0, 75f64.sqrt());
    run(&mut h, "sketch.line", json!({"points": [[0, 0], [10, 0], [x, y], [x + 10.0, y]]}));
    for l in ["l1", "l2", "l3"] {
        run(&mut h, "sketch.dimension", json!({"entities": [l], "value": 10}));
    }
    run(&mut h, "sketch.constraint.horizontal_vertical", json!({"line": "l3"}));
    let grab = screen(&mut h, x + 5.0, y);
    let far = screen(&mut h, x + 11.0, y);
    let back = screen(&mut h, x + 7.0, y);
    let mut path = vec![grab];
    path.extend(steps(grab, far, 8));
    path.extend(steps(far, back, 4));
    press_and_move(&mut h, &path);
    release(&mut h, back);
    // The cursor went 6 mm right, the line only 3; back at 2 mm right it is under it again.
    let start = point(&h, "l3.start");
    assert!(start.dist(Vec2::new(x + 2.0, y)) < 0.1, "{start:?}");
    assert!(!h.app.session.model.is_stale());
}