deskcrew 0.1.6

// How a drawn cursor gets from one place to another, and what colour it is.
pub type Point = (f32, f32);

use std::sync::atomic::{AtomicBool, Ordering};
use std::thread;
use std::time::{Duration, Instant};

// How far apart stroke points are, and how fast a stroke is drawn.
const STEP_PIXELS: f32 = 6.0;
#[cfg_attr(not(windows), allow(dead_code))]
const PIXELS_PER_SECOND: f32 = 1000.0;

const MIN_TRAVEL_MS: f32 = 90.0;
const MAX_TRAVEL_MS: f32 = 320.0;
const MS_PER_PIXEL: f32 = 0.16;
const BOW: f32 = 0.08;

pub fn travel_ms(from: Point, to: Point) -> u32 {
    let distance = (to.0 - from.0).hypot(to.1 - from.1);
    (MIN_TRAVEL_MS + distance * MS_PER_PIXEL).min(MAX_TRAVEL_MS) as u32
}

/// Starts and stops gently, with no speed jump at either end.
pub fn ease(t: f32) -> f32 {
    let t = t.clamp(0.0, 1.0);
    t * t * t * (t * (t * 6.0 - 15.0) + 10.0)
}

/// The middle of a slightly curved path, so travel never looks ruled.
pub fn bow(from: Point, to: Point, side: f32) -> Point {
    let (dx, dy) = (to.0 - from.0, to.1 - from.1);
    ((from.0 + to.0) / 2.0 - dy * BOW * side, (from.1 + to.1) / 2.0 + dx * BOW * side)
}

/// Where the cursor is at `t` along the curve from `from` to `to`.
pub fn along(from: Point, middle: Point, to: Point, t: f32) -> Point {
    let (p, q) = (1.0 - t, t);
    (
        p * p * from.0 + 2.0 * p * q * middle.0 + q * q * to.0,
        p * p * from.1 + 2.0 * p * q * middle.1 + q * q * to.1,
    )
}

pub type Rgb = (u8, u8, u8);

const PALETTE: [Rgb; 14] = [
    (255, 165, 31),
    (240, 48, 110),
    (21, 101, 240),
    (45, 190, 96),
    (138, 92, 246),
    (20, 184, 196),
    (132, 204, 22),
    (217, 70, 239),
    (220, 38, 38),
    (56, 189, 248),
    (250, 204, 21),
    (161, 98, 60),
    (148, 163, 184),
    (67, 56, 202),
];

/// Each coding agent's own place in the palette, by the first word of its name, so
/// "Claude Code" and "Claude" match and a second "Claude 2" starts from the same colour.
const AGENT_COLOURS: [(&str, usize); 16] = [
    ("claude", 0),
    ("cursor", 1),
    ("gemini", 2),
    ("fx", 2),
    ("codex", 3),
    ("copilot", 4),
    ("github", 4),
    ("windsurf", 5),
    ("aider", 6),
    ("amp", 7),
    ("roo", 8),
    ("continue", 9),
    ("cline", 10),
    ("goose", 11),
    ("opencode", 12),
    ("kiro", 13),
];

/// A colour from the agent's name, so it keeps its colour between runs, skipping
/// colours already on screen so two agents never look alike.
pub fn colour_for(name: &str, taken: &[Rgb]) -> Rgb {
    let lower = name.to_lowercase();
    let first = lower.split_whitespace().next().unwrap_or("");
    let known = AGENT_COLOURS.iter().find(|(agent, _)| *agent == first).map(|(_, at)| *at);
    let start = known.unwrap_or_else(|| name.bytes().fold(0x811C_9DC5_u32, |hash, byte| (hash ^ byte as u32).wrapping_mul(0x0100_0193)) as usize);
    (0..PALETTE.len())
        .map(|step| PALETTE[(start + step) % PALETTE.len()])
        .find(|colour| !taken.contains(colour))
        .unwrap_or(PALETTE[start % PALETTE.len()])
}

/// Points every few pixels along a stroke, through a smooth curve if asked for.
pub fn trace(points: &[(i32, i32)], smooth: bool) -> Vec<(f32, f32)> {
    let at = |i: isize| {
        let p = points[i.clamp(0, points.len() as isize - 1) as usize];
        (p.0 as f32, p.1 as f32)
    };
    let mut out = vec![at(0)];
    for i in 0..points.len().saturating_sub(1) as isize {
        let (a, b, c, d) = (at(i - 1), at(i), at(i + 1), at(i + 2));
        let steps = (((c.0 - b.0).hypot(c.1 - b.1) / STEP_PIXELS).ceil() as usize).max(1);
        for step in 1..=steps {
            let t = step as f32 / steps as f32;
            out.push(if smooth {
                let curve = |p0: f32, p1: f32, p2: f32, p3: f32| {
                    0.5 * (2.0 * p1
                        + (p2 - p0) * t
                        + (2.0 * p0 - 5.0 * p1 + 4.0 * p2 - p3) * t * t
                        + (3.0 * p1 - p0 - 3.0 * p2 + p3) * t * t * t)
                };
                (curve(a.0, b.0, c.0, d.0), curve(a.1, b.1, c.1, d.1))
            } else {
                (b.0 + (c.0 - b.0) * t, b.1 + (c.1 - b.1) * t)
            });
        }
    }
    out
}

/// Visit each point of a stroke on schedule, at a steady speed. False if stopped on the way.
#[cfg_attr(not(windows), allow(dead_code))]
pub fn pace(path: &[(f32, f32)], stop: &AtomicBool, mut visit: impl FnMut(usize, i32, i32)) -> bool {
    let started = Instant::now();
    for (at, point) in path.iter().enumerate() {
        if stop.load(Ordering::Relaxed) {
            return false;
        }
        let due = Duration::from_secs_f32(at as f32 * STEP_PIXELS / PIXELS_PER_SECOND);
        while let Some(left) = due.checked_sub(started.elapsed()) {
            if left > Duration::from_millis(2) {
                thread::sleep(left - Duration::from_millis(2));
            } else {
                std::hint::spin_loop();
            }
        }
        visit(at, point.0.round() as i32, point.1.round() as i32);
    }
    true
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn short_hops_are_quick_and_long_ones_are_capped() {
        assert_eq!(travel_ms((0.0, 0.0), (0.0, 0.0)), 90);
        assert_eq!(travel_ms((0.0, 0.0), (100.0, 0.0)), 106);
        assert_eq!(travel_ms((0.0, 0.0), (2560.0, 1600.0)), 320);
    }

    #[test]
    fn easing_starts_and_ends_still() {
        assert_eq!(ease(0.0), 0.0);
        assert_eq!(ease(1.0), 1.0);
        assert!((ease(0.5) - 0.5).abs() < 1e-6);
        assert!(ease(0.01) < 0.0001);
        assert!(ease(0.99) > 0.9999);
    }

    #[test]
    fn the_path_ends_exactly_on_target_and_bends_on_the_way() {
        let (from, to) = ((10.0, 20.0), (410.0, 20.0));
        let middle = bow(from, to, 1.0);
        assert_eq!(along(from, middle, to, 0.0), from);
        assert_eq!(along(from, middle, to, 1.0), to);
        assert!(along(from, middle, to, 0.5).1 > 20.0);
        assert!(bow(from, to, -1.0).1 < 20.0);
    }

    #[test]
    fn a_name_keeps_its_colour() {
        assert_eq!(colour_for("Claude Code", &[]), colour_for("Claude Code", &[]));
    }

    #[test]
    fn well_known_agents_have_their_own_colours() {
        assert_eq!(colour_for("Claude Code", &[]), PALETTE[0]);
        assert_eq!(colour_for("cursor", &[]), PALETTE[1]);
        assert_eq!(colour_for("Gemini CLI", &[]), PALETTE[2]);
        assert_eq!(colour_for("GitHub Copilot", &[]), colour_for("Copilot", &[]));
    }

    #[test]
    fn every_agent_differs_from_the_rest() {
        let names = ["Claude Code", "Cursor", "Gemini", "Codex", "Copilot", "Windsurf", "Aider", "Amp", "Roo Code", "Continue", "Cline", "Goose", "OpenCode", "Kiro"];
        let colours: Vec<Rgb> = names.iter().map(|name| colour_for(name, &[])).collect();
        assert!(colours.iter().enumerate().all(|(at, colour)| !colours[..at].contains(colour)));
    }

    #[test]
    fn a_second_copy_of_an_agent_gets_another_colour() {
        let first = colour_for("Claude 1", &[]);
        assert_eq!(first, PALETTE[0]);
        assert_ne!(colour_for("Claude 2", &[first]), first);
    }

    #[test]
    fn six_agents_on_screen_all_look_different() {
        let mut taken = Vec::new();
        for name in ["a", "b", "c", "d", "e", "f"] {
            let colour = colour_for(name, &taken);
            assert!(!taken.contains(&colour));
            taken.push(colour);
        }
    }
}