[core] Random Number Generator

Implement a random number generator as a thin wrapper around rand::StdRng. Provide
some default seed data to get consistent random numbers.

core/Cargo.toml

@@ -6,4 +6,5 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+rand = "0.9.1"
 thiserror = "2"

core/src/lib.rs

@@ -3,6 +3,7 @@
 pub mod colors;
 pub mod coordinates;
 pub mod pieces;
+pub mod random;
 pub mod shapes;
 
 mod macros;

core/src/random.rs

@@ -0,0 +1,44 @@
+// Eryn Wells <eryn@erynwells.me>
+
+use rand::{rngs::StdRng, RngCore, SeedableRng};
+
+pub struct RandomNumberGenerator {
+    rng: StdRng,
+}
+
+impl RandomNumberGenerator {
+    /// A default value for hashing chess games.
+    ///
+    /// This value is the SHA-256 hash of a PGN I downloaded from the internet
+    /// of the six games Kasparov played against Deep Blue in 1996.
+    #[rustfmt::skip]
+    const DEFAULT_SEED_VALUE: [u8; 32] = [
+        0x22, 0x0b, 0xae, 0xd5, 0xc5, 0xb8, 0x20, 0xb1,
+        0xee, 0x05, 0x4b, 0x72, 0x73, 0x4c, 0x1a, 0xf9,
+        0xc2, 0xb7, 0x5d, 0x87, 0xc8, 0xa9, 0x44, 0x87,
+        0x01, 0xda, 0xdb, 0xe0, 0x8e, 0xf8, 0xe8, 0x77,
+    ];
+
+    #[must_use]
+    pub fn new(seed: <StdRng as SeedableRng>::Seed) -> Self {
+        let rng = StdRng::from_seed(seed);
+
+        Self { rng }
+    }
+
+    #[must_use]
+    pub fn rand(&mut self) -> &mut StdRng {
+        &mut self.rng
+    }
+
+    pub fn next_u64(&mut self) -> u64 {
+        self.rng.next_u64()
+    }
+}
+
+impl Default for RandomNumberGenerator {
+    fn default() -> Self {
+        let rng = StdRng::from_seed(Self::DEFAULT_SEED_VALUE);
+        Self { rng }
+    }
+}