rust-java-functional-programming/src/geometry.rs

use std::ops::Add;

#[derive(Debug, Copy, Clone)]
pub struct Point {
    x: u32,
    y: u32,
}

#[derive(Debug, Copy, Clone)]
pub struct Rectangle {
    x: u32,
    y: u32,
    width: u32,
    height: u32,
}

impl Point {
    pub fn new(x: u32, y: u32) -> Self {
        Self { x, y }
    }

    pub fn origin() -> Self {
        Self { x: 0, y: 0 }
    }

    pub fn with_x(&self, x: u32) -> Self {
        Self { x, y: self.y }
    }

    pub fn with_y(&self, y: u32) -> Self {
        Self { x: self.x, y }
    }

    pub fn x(&self) -> u32 {
        self.x
    }

    pub fn y(&self) -> u32 {
        self.y
    }

    pub fn left_of(&self, other: &Self) -> bool {
        self.x < other.x
    }

    pub fn right_of(&self, other: &Self) -> bool {
        self.x > other.x
    }

    pub fn above(&self, other: &Self) -> bool {
        self.y < other.y
    }

    pub fn below(&self, other: &Self) -> bool {
        self.y > other.y
    }
}

impl Add for Point {
    type Output = Point;

    fn add(self, other: Point) -> Point {
        Point {
            x: self.x + other.x,
            y: self.y + other.y,
        }
    }
}

impl PartialEq for Point {
    fn eq(&self, other: &Self) -> bool {
        self.x == other.x && self.y == other.y
    }
}

impl Eq for Point {}

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

    #[test]
    fn test_point_get_x() {
        assert_eq!(Point::new(42, 52).x(), 42);
    }

    #[test]
    fn test_point_get_y() {
        assert_eq!(Point::new(42, 52).y(), 52);
    }

    #[test]
    fn test_point_set_x() {
        assert_eq!(Point::new(42, 52).with_x(12), Point::new(12, 52));
    }

    #[test]
    fn test_point_set_y() {
        assert_eq!(Point::new(42, 52).with_y(12), Point::new(42, 12));
    }

    #[test]
    fn test_point_left_of() {
        assert!(Point::new(10, 20).left_of(&Point::new(20, 20)));
        assert!(!Point::new(10, 11).left_of(&Point::new(10, 11)));
        assert!(!Point::new(10, 11).left_of(&Point::new(8, 11)));
    }

    #[test]
    fn test_point_right_of() {
        assert!(Point::new(10, 20).right_of(&Point::new(0, 20)));
        assert!(!Point::new(10, 11).right_of(&Point::new(10, 11)));
        assert!(!Point::new(10, 11).right_of(&Point::new(12, 11)));
    }

    #[test]
    fn test_point_above() {
        assert!(Point::new(1, 1).above(&Point::new(1, 2)));
        assert!(!Point::new(10, 11).above(&Point::origin()));
    }

    #[test]
    fn test_point_below() {
        assert!(Point::new(1, 1).below(&Point::new(1, 0)));
        assert!(!Point::new(10, 11).below(&Point::new(12, 11)));
    }

    #[test]
    fn test_point_add() {
        assert_eq!(Point::new(1, 1) + Point::new(10, 10), Point::new(11, 11));
        assert_eq!(
            Point::new(10, 0) + Point::new(0, 10),
            Point::new(0, 10) + Point::new(10, 0)
        );
    }
}