From 5d0fedac8cb6ec720c35c06684b3e3938a21f9cf Mon Sep 17 00:00:00 2001
From: CoCoSol007 <solois.corentin@gmail.com>
Date: Tue, 13 Feb 2024 19:08:42 +0100
Subject: [PATCH] add hex utils

---
 crates/border-wars/src/hex.rs | 99 +++++++++++++++++++++++++++++++++++
 crates/border-wars/src/lib.rs |  1 +
 2 files changed, 100 insertions(+)
 create mode 100644 crates/border-wars/src/hex.rs

diff --git a/crates/border-wars/src/hex.rs b/crates/border-wars/src/hex.rs
new file mode 100644
index 0000000..a5523b0
--- /dev/null
+++ b/crates/border-wars/src/hex.rs
@@ -0,0 +1,99 @@
+//! This file contains utilities for working with hex coordinates.
+
+use std::collections::HashSet;
+
+/// Contains all ``HexPosition`` neighbors of a ``HexPosition``
+pub struct GroupHexPosition(HashSet<HexPosition>);
+
+impl GroupHexPosition {
+    /// Return an intersection of two ``GroupHexPosition``
+    ///
+    /// ## example
+    /// ```
+    /// use border_wars::hex::GroupHexPosition;
+    ///
+    /// let vec1 = GroupHexPosition(
+    ///     vec![HexPosition { q: 0, r: 0 }, HexPosition { q: 1, r: -1 }]
+    /// );
+    /// let vec2 = GroupHexPosition(
+    ///     vec![HexPosition { q: 0, r: 0 }, HexPosition { q: 0, r: -1 }]
+    /// );
+    /// let iter = vec1.iter_with(&vec2);
+    /// assert_eq!(iter, vec![HexPosition { q: 0, r: 0 }]);
+    pub fn iter_with(&self, other: &GroupHexPosition) -> Vec<HexPosition> {
+        let mut result = Vec::new();
+        for pos_1 in self.0.iter() {
+            if other.0.contains(pos_1) {
+                result.push(*pos_1);
+            }
+        }
+        result
+    }
+
+    /// Removes the origin (``HexPosition { q: 0, r: 0 }``) of a
+    /// ``GroupHexPosition``
+    ///
+    /// ## example
+    /// ```
+    /// use border_wars::hex::GroupHexPosition;
+    ///
+    /// let mut vec = GroupHexPosition(vec![
+    ///     HexPosition { q: 0, r: 0 },
+    ///     HexPosition { q: 1, r: -1 },
+    /// ]);
+    /// vec.remove_origin();
+    /// assert_eq!(vec.0, vec![HexPosition { q: 1, r: -1 }]);
+    /// ```
+    pub fn remove_origin(&mut self) -> &mut Self {
+        self.0.remove(&HexPosition { q: 0, r: 0 });
+        self
+    }
+}
+
+/// Hex position (in a hexagonal grid).
+///
+/// usnig this doc : https://www.redblobgames.com/grids/hexagons/
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub struct HexPosition {
+    /// Q coordinate
+    pub q: i32,
+
+    /// R coordinate
+    pub r: i32,
+}
+
+impl HexPosition {
+    /// Returns the distance between two ``HexPosition``
+    ///
+    /// ## example
+    /// ```
+    /// let hex1 = HexPosition { q: 0, r: 0 };
+    /// let hex2 = HexPosition { q: 1, r: 1 };
+    /// let distance = hex1.distance_to(&hex2);
+    /// assert_eq!(distance, 2);
+    /// ```
+    pub fn distance_to(&self, other: &HexPosition) -> f32 {
+        (((self.q - other.q).abs()
+            + (self.r - other.r).abs()
+            + (self.q + self.r - other.q - other.r).abs())
+            / 2) as f32
+    }
+
+    /// Returns all positions in a given range
+    ///
+    /// ## example
+    /// ```
+    /// let hex = HexPosition { q: 0, r: 0 };
+    /// let positions = hex.range(1);
+    /// assert_eq!(positions.len(), 6);
+    /// ```
+    pub fn range(&self, range: i32) -> GroupHexPosition {
+        let mut positions = HashSet::new();
+        for q in (-range)..=range {
+            for r in (-range).max(-q - range)..=range.min(-q + range) {
+                positions.insert(HexPosition { q, r });
+            }
+        }
+        GroupHexPosition(positions)
+    }
+}
diff --git a/crates/border-wars/src/lib.rs b/crates/border-wars/src/lib.rs
index c85940e..e475a9e 100644
--- a/crates/border-wars/src/lib.rs
+++ b/crates/border-wars/src/lib.rs
@@ -2,6 +2,7 @@
 
 use bevy::prelude::*;
 
+pub mod hex;
 pub mod scenes;
 
 /// The current scene of the game.