Moving i18n to sepparate module

locales/src/lib.rs

@@ -0,0 +1,97 @@
+//! This modules contains the parts for making the app translatable.
+use std::sync::Arc;
+
+use fluent::{FluentArgs, FluentBundle, FluentResource};
+use pslink_shared::datatypes::Lang;
+use unic_langid::LanguageIdentifier;
+
+/// A struct containing the data, functions and the current language to query the localized strings.
+#[derive(Clone)]
+pub struct I18n {
+    lang: Lang,
+    ftl_bundle: Arc<FluentBundle<FluentResource>>,
+}
+
+impl std::fmt::Debug for I18n {
+    /// On debug print skip the bundle
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{:?}", self.lang)
+    }
+}
+
+impl I18n {
+    /// Create a new translator struct
+    #[must_use]
+    pub fn new(lang: Lang) -> Self {
+        let ftl_bundle = Arc::new(Self::create_ftl_bundle(lang));
+        Self { lang, ftl_bundle }
+    }
+
+    /// Get the current language
+    #[must_use]
+    pub const fn lang(&self) -> &Lang {
+        &self.lang
+    }
+
+    /// Set the current language
+    pub fn set_lang(&mut self, lang: Lang) {
+        self.lang = lang;
+        self.ftl_bundle = Arc::new(Self::create_ftl_bundle(lang));
+    }
+
+    /// Get a localized string. Optionally with parameters provided in `args`.
+    pub fn translate(&self, key: impl AsRef<str>, args: Option<&FluentArgs>) -> String {
+        // log!(key.as_ref());
+        let msg = self
+            .ftl_bundle
+            .get_message(key.as_ref())
+            .expect("Failed to get fluent message for key {}");
+
+        let pattern = msg.value().expect("Failed to parse pattern");
+
+        self.ftl_bundle
+            .format_pattern(pattern, args, &mut vec![])
+            .to_string()
+    }
+
+    /// Prettyprint the language name
+    #[must_use]
+    pub const fn label(&self) -> &'static str {
+        match self.lang {
+            Lang::EnUS => "English (US)",
+            Lang::DeDE => "Deutsch (Deutschland)",
+        }
+    }
+
+    /// include the fluent messages into the binary
+    #[must_use]
+    pub const fn ftl_messages(lang: Lang) -> &'static str {
+        macro_rules! include_ftl_messages {
+            ( $lang_id:literal ) => {
+                include_str!(concat!("../", $lang_id, "/main.ftl"))
+            };
+        }
+        match lang {
+            Lang::EnUS => include_ftl_messages!("en"),
+            Lang::DeDE => include_ftl_messages!("de"),
+        }
+    }
+
+    #[must_use]
+    pub fn language_identifier(lang: Lang) -> LanguageIdentifier {
+        lang.as_ref()
+            .parse()
+            .expect("parse Lang to LanguageIdentifier")
+    }
+
+    /// Create and initialize a fluent bundle.
+    #[must_use]
+    pub fn create_ftl_bundle(lang: Lang) -> FluentBundle<FluentResource> {
+        let ftl_resource = FluentResource::try_new(Self::ftl_messages(lang).to_owned())
+            .expect("parse FTL messages");
+
+        let mut bundle = FluentBundle::new(vec![Self::language_identifier(lang)]);
+        bundle.add_resource(ftl_resource).expect("add FTL resource");
+        bundle
+    }
+}