1 files changed, 96 insertions, 0 deletions
diff --git a/azalea-core/src/difficulty.rs b/azalea-core/src/difficulty.rs
new file mode 100755
index 00000000..21e980ba
--- /dev/null
+++ b/azalea-core/src/difficulty.rs
@@ -0,0 +1,96 @@
+use std::fmt::{Debug, Error, Formatter};
+
+#[derive(Hash, Clone, Debug, PartialEq)]
+pub enum Difficulty {
+    PEACEFUL,
+    EASY,
+    NORMAL,
+    HARD,
+}
+
+pub enum Err {
+    InvalidDifficulty(String),
+}
+
+impl Debug for Err {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
+        match self {
+            Err::InvalidDifficulty(s) => write!(f, "Invalid difficulty: {}", s),
+        }
+    }
+}
+
+impl Difficulty {
+    pub fn name(&self) -> &'static str {
+        match self {
+            Difficulty::PEACEFUL => "peaceful",
+            Difficulty::EASY => "easy",
+            Difficulty::NORMAL => "normal",
+            Difficulty::HARD => "hard",
+        }
+    }
+
+    pub fn from_name(name: &str) -> Result<Difficulty, Err> {
+        match name {
+            "peaceful" => Ok(Difficulty::PEACEFUL),
+            "easy" => Ok(Difficulty::EASY),
+            "normal" => Ok(Difficulty::NORMAL),
+            "hard" => Ok(Difficulty::HARD),
+            _ => Err(Err::InvalidDifficulty(name.to_string())),
+        }
+    }
+
+    pub fn by_id(id: u8) -> Difficulty {
+        match id % 4 {
+            0 => Difficulty::PEACEFUL,
+            1 => Difficulty::EASY,
+            2 => Difficulty::NORMAL,
+            3 => Difficulty::HARD,
+            // this shouldn't be possible because of the modulo, so panicking is fine
+            _ => panic!("Unknown difficulty id: {}", id),
+        }
+    }
+
+    pub fn id(&self) -> u8 {
+        match self {
+            Difficulty::PEACEFUL => 0,
+            Difficulty::EASY => 1,
+            Difficulty::NORMAL => 2,
+            Difficulty::HARD => 3,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_difficulty_from_name() {
+        assert_eq!(
+            Difficulty::PEACEFUL,
+            Difficulty::from_name("peaceful").unwrap()
+        );
+        assert_eq!(Difficulty::EASY, Difficulty::from_name("easy").unwrap());
+        assert_eq!(Difficulty::NORMAL, Difficulty::from_name("normal").unwrap());
+        assert_eq!(Difficulty::HARD, Difficulty::from_name("hard").unwrap());
+        assert!(Difficulty::from_name("invalid").is_err());
+    }
+
+    #[test]
+    fn test_difficulty_id() {
+        assert_eq!(0, Difficulty::PEACEFUL.id());
+        assert_eq!(1, Difficulty::EASY.id());
+        assert_eq!(2, Difficulty::NORMAL.id());
+        assert_eq!(3, Difficulty::HARD.id());
+        assert_eq!(4, Difficulty::PEACEFUL.id());
+    }
+
+    #[test]
+    fn test_difficulty_name() {
+        assert_eq!("peaceful", Difficulty::PEACEFUL.name());
+        assert_eq!("easy", Difficulty::EASY.name());
+        assert_eq!("normal", Difficulty::NORMAL.name());
+        assert_eq!("hard", Difficulty::HARD.name());
+    }
+}