Add Direction type

Author: fwcd

lighthouse-protocol/src/utils/direction.rs

@@ -0,0 +1,56 @@
+use std::fmt::Debug;
+
+use rand::{prelude::Distribution, distributions::Standard};
+use serde::{Deserialize, Serialize};
+
+use super::{Delta, Unity, Zero};
+
+/// One of the four cardinal directions.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+pub enum Direction {
+    Up,
+    Down,
+    Left,
+    Right,
+}
+
+impl<T> TryFrom<Delta<T>> for Direction where T: Zero + Unity + PartialEq + Debug {
+    type Error = String;
+
+    fn try_from(delta: Delta<T>) -> Result<Self, Self::Error> {
+        if delta == Delta::UP {
+            Ok(Direction::Up)
+        } else if delta == Delta::DOWN {
+            Ok(Direction::Down)
+        } else if delta == Delta::LEFT {
+            Ok(Direction::Left)
+        } else if delta == Delta::RIGHT {
+            Ok(Direction::Right)
+        } else {
+            Err(format!("Not a direction: {:?}", delta))
+        }
+    }
+}
+
+impl<T> From<Direction> for Delta<T> where T: Zero + Unity {
+    fn from(direction: Direction) -> Self {
+        match direction {
+            Direction::Up => Delta::UP,
+            Direction::Down => Delta::DOWN,
+            Direction::Left => Delta::LEFT,
+            Direction::Right => Delta::RIGHT,
+        }
+    }
+}
+
+impl Distribution<Direction> for Standard {
+    fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> Direction {
+        match rng.gen_range(0..4) {
+            0 => Direction::Up,
+            1 => Direction::Down,
+            2 => Direction::Left,
+            3 => Direction::Right,
+            _ => unreachable!(),
+        }
+    }
+}

lighthouse-protocol/src/utils/mod.rs

@@ -1,4 +1,5 @@
 mod color;
+mod direction;
 mod rect;
 mod rem_euclid;
 mod rotation;
@@ -7,6 +8,7 @@ mod vec2;
 mod zero;
 
 pub use color::*;
+pub use direction::*;
 pub use rect::*;
 pub use rem_euclid::*;
 pub use rotation::*;