new language manager that loads strings from compiled json file

src/language_manager.rs

@@ -0,0 +1,48 @@
+use std::collections::HashMap;
+
+use serde::Deserialize;
+use serde_json::from_reader;
+use serenity::prelude::TypeMapKey;
+use std::error::Error;
+use std::fs::File;
+use std::io::BufReader;
+use std::path::Path;
+
+#[derive(Deserialize)]
+pub struct LanguageManager {
+    languages: HashMap<String, String>,
+    strings: HashMap<String, HashMap<String, String>>,
+}
+
+impl LanguageManager {
+    pub(crate) fn from_compiled<P>(path: P) -> Result<Self, Box<dyn Error + Send + Sync>>
+    where
+        P: AsRef<Path>,
+    {
+        let file = File::open(path)?;
+        let reader = BufReader::new(file);
+
+        let new: Self = from_reader(reader)?;
+
+        Ok(new)
+    }
+
+    pub(crate) fn get(&self, language: &str, name: &'static str) -> &str {
+        self.strings
+            .get(language)
+            .map(|sm| sm.get(name))
+            .expect(&format!(r#"Language does not exist: "{}""#, language))
+            .expect(&format!(r#"String does not exist: "{}""#, name))
+    }
+
+    fn all_languages(&self) -> Vec<(&str, &str)> {
+        self.languages
+            .iter()
+            .map(|(k, v)| (k.as_str(), v.as_str()))
+            .collect()
+    }
+}
+
+impl TypeMapKey for LanguageManager {
+    type Value = Self;
+}