Add rotation functions and diagonal/orthogonal check functions to Direction

CHANGELOG.md

@@ -1,7 +1,13 @@
 Unreleased
 ==========
 
+### Additions:
+
+- Add new geometry helper functions to `Direction`: `is_diagonal()`, `is_orthogonal()`,
+  `multi_rot()`, `rot_cw()`, and `rot_ccw()`
+
 ### Bugfixes:
+
 - Fix incorrect setter name on `visualize_path_style` causing the setting to not work
 - `OwnedStructure`, `OwnedStructureObject`, and `OwnedStructureProperties`'s `my` method now
   correctly handles the value being undefined.

src/constants/small_enums.rs

@@ -4,6 +4,7 @@ use std::{borrow::Cow, fmt};
 use enum_iterator::Sequence;
 use js_sys::JsString;
 use num_derive::FromPrimitive;
+use num_traits::FromPrimitive;
 use serde::{
     de::{Error as _, Unexpected},
     Deserialize, Serialize,
@@ -115,6 +116,85 @@ pub enum Direction {
     TopLeft = 8,
 }
 
+impl Direction {
+    /// Whether the direction is orthogonal.
+    ///
+    /// Example usage:
+    ///
+    /// ```
+    /// use screeps::Direction::*;
+    ///
+    /// assert_eq!(Top.is_orthogonal(), true);
+    /// assert_eq!(TopRight.is_orthogonal(), false);
+    /// ```
+    pub fn is_orthogonal(self) -> bool {
+        use Direction::*;
+
+        matches!(self, Top | Right | Bottom | Left)
+    }
+
+    /// Whether the direction is diagonal.
+    ///
+    /// Example usage:
+    ///
+    /// ```
+    /// use screeps::Direction::*;
+    ///
+    /// assert_eq!(Top.is_diagonal(), false);
+    /// assert_eq!(TopRight.is_diagonal(), true);
+    /// ```
+    pub fn is_diagonal(self) -> bool {
+        !self.is_orthogonal()
+    }
+
+    /// Rotate the direction by a specified number of steps clockwise if
+    /// positive or counter-clockwise if negative.
+    ///
+    /// Example usage:
+    ///
+    /// ```
+    /// use screeps::Direction::*;
+    ///
+    /// assert_eq!(Top.multi_rot(1), TopRight);
+    /// assert_eq!(Top.multi_rot(2), Right);
+    /// assert_eq!(Top.multi_rot(-1), TopLeft);
+    /// assert_eq!(Top.multi_rot(-2), Left);
+    /// assert_eq!(Top.multi_rot(64), Top);
+    /// ```
+    pub fn multi_rot(self, times: i8) -> Self {
+        let raw_dir = ((self as u8) - 1).wrapping_add_signed(times) % 8 + 1;
+        // unwrap should be optimized away, as the integer we ended up with
+        // is always a valid value
+        Self::from_u8(raw_dir).unwrap()
+    }
+
+    /// Rotate the direction clockwise by one step.
+    ///
+    /// Example usage:
+    ///
+    /// ```
+    /// use screeps::Direction::*;
+    ///
+    /// assert_eq!(Top.rot_cw(), TopRight);
+    /// ```
+    pub fn rot_cw(self) -> Self {
+        self.multi_rot(1)
+    }
+
+    /// Rotate the direction counter-clockwise by one step.
+    ///
+    /// Example usage:
+    ///
+    /// ```
+    /// use screeps::Direction::*;
+    ///
+    /// assert_eq!(Top.rot_ccw(), TopLeft);
+    /// ```
+    pub fn rot_ccw(self) -> Self {
+        self.multi_rot(-1)
+    }
+}
+
 impl From<Direction> for (i32, i32) {
     /// Returns the change in (x, y) when moving in each direction.
     #[inline]