Add function to get random nature, add shiny rate to library settings

src/static_data/libraries/library_settings.rs

@@ -6,6 +6,10 @@ use std::fmt::Debug;
 pub trait LibrarySettings: Debug + ValueIdentifiable {
     /// The highest level a Pokemon can be.
     fn maximum_level(&self) -> LevelInt;
+
+    /// The chance of a Pokemon being shiny, as the denominator of a fraction, where the nominator
+    /// is 1. For example, if this is 1000, then the chance of a Pokemon being shiny is 1/1000.
+    fn shiny_rate(&self) -> u32;
 }
 
 /// This library holds several misc settings for the library.
@@ -15,23 +19,35 @@ pub struct LibrarySettingsImpl {
     identifier: ValueIdentifier,
     /// The highest level a Pokemon can be.
     maximum_level: LevelInt,
+    /// The chance of a Pokemon being shiny, as the denominator of a fraction, where the nominator
+    /// is 1. For example, if this is 1000, then the chance of a Pokemon being shiny is 1/1000.
+    shiny_rate: u32,
 }
 
 impl LibrarySettingsImpl {
     /// Creates a new settings library.
-    pub fn new(maximum_level: LevelInt) -> Self {
+    /// - `maximum_level` is the highest level a Pokemon can be.
+    /// - `shiny_rate` is the chance of a Pokemon being shiny, as the denominator of a fraction, where
+    /// the nominator is 1. For example, if this is 1000, then the chance of a Pokemon being shiny is
+    /// 1/1000.
+    pub fn new(maximum_level: LevelInt, shiny_rate: u32) -> Self {
+        assert!(shiny_rate >= 1);
+        assert!(maximum_level >= 1);
         Self {
             identifier: Default::default(),
             maximum_level,
+            shiny_rate,
         }
     }
 }
 
 impl LibrarySettings for LibrarySettingsImpl {
-    /// The highest level a Pokemon can be.
     fn maximum_level(&self) -> LevelInt {
         self.maximum_level
     }
+    fn shiny_rate(&self) -> u32 {
+        self.shiny_rate
+    }
 }
 
 impl ValueIdentifiable for LibrarySettingsImpl {

src/static_data/libraries/nature_library.rs

@@ -1,6 +1,6 @@
 use crate::static_data::Nature;
-use crate::{StringKey, ValueIdentifiable, ValueIdentifier};
-use hashbrown::HashMap;
+use crate::{Random, StringKey, ValueIdentifiable, ValueIdentifier};
+use indexmap::IndexMap;
 use std::fmt::Debug;
 use std::sync::Arc;
 
@@ -10,6 +10,8 @@ pub trait NatureLibrary: Debug + ValueIdentifiable {
     fn load_nature(&mut self, name: StringKey, nature: Arc<dyn Nature>);
     /// Gets a nature by name.
     fn get_nature(&self, key: &StringKey) -> Option<Arc<dyn Nature>>;
+    /// Gets a random nature.
+    fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature>;
     /// Finds a nature name by nature.
     fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey;
 }
@@ -20,7 +22,7 @@ pub struct NatureLibraryImpl {
     /// A unique identifier so we know what value this is.
     identifier: ValueIdentifier,
     /// The underlying data structure.
-    map: HashMap<StringKey, Arc<dyn Nature>>,
+    map: IndexMap<StringKey, Arc<dyn Nature>>,
 }
 
 impl NatureLibraryImpl {
@@ -28,7 +30,7 @@ impl NatureLibraryImpl {
     pub fn new(capacity: usize) -> Self {
         Self {
             identifier: Default::default(),
-            map: HashMap::with_capacity(capacity),
+            map: IndexMap::with_capacity(capacity),
         }
     }
 }
@@ -44,6 +46,11 @@ impl NatureLibrary for NatureLibraryImpl {
         self.map.get(key).cloned()
     }
 
+    fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature> {
+        let i = rand.get_between(0, self.map.len() as i32);
+        return self.map.get_index(i as usize).unwrap().1.clone();
+    }
+
     /// Finds a nature name by nature.
     fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey {
         for kv in &self.map {
@@ -87,6 +94,7 @@ pub mod tests {
             fn load_nature(&mut self, name: StringKey, nature: Arc<dyn Nature>);
             fn get_nature(&self, key: &StringKey) -> Option<Arc<dyn Nature>>;
             fn get_nature_name(&self, nature: &Arc<dyn Nature>) -> StringKey;
+            fn get_random_nature(&self, rand: &mut Random) -> Arc<dyn Nature>;
         }
         impl ValueIdentifiable for NatureLibrary {
             fn value_identifier(&self) -> ValueIdentifier{

src/static_data/libraries/static_data.rs

@@ -199,7 +199,7 @@ pub mod test {
     pub fn build() -> StaticDataImpl {
         StaticDataImpl {
             identifier: Default::default(),
-            settings: Box::new(LibrarySettingsImpl::new(100)),
+            settings: Box::new(LibrarySettingsImpl::new(100, 100)),
             species: crate::static_data::libraries::species_library::tests::build(),
             moves: crate::static_data::libraries::move_library::tests::build(),
             items: crate::static_data::libraries::item_library::tests::build(),