wgui: basic i18n support, refactoring: use LayoutState, translation framework (LLM-based generator)

wgui/src/i18n.rs

@@ -0,0 +1,110 @@
+use std::rc::Rc;
+
+use crate::assets::AssetProvider;
+
+// a string which optionally has translation key in it
+// it will hopefully support dynamic language changing soon
+// for now it's just a simple string container
+#[derive(Default)]
+pub struct Translation {
+	text: Rc<str>,
+	translated: bool, // if true, `text` is a translation key
+}
+
+impl PartialEq for Translation {
+	fn eq(&self, other: &Self) -> bool {
+		*self.text == *other.text && self.translated == other.translated
+	}
+}
+
+impl Translation {
+	pub fn generate(&self, i18n: &mut I18n) -> Rc<str> {
+		if self.translated {
+			i18n.translate(&self.text)
+		} else {
+			self.text.clone()
+		}
+	}
+
+	pub fn from_raw_text(text: &str) -> Self {
+		Self {
+			text: Rc::from(text),
+			translated: false,
+		}
+	}
+
+	pub fn from_translation_key(translated: &str) -> Self {
+		Self {
+			text: Rc::from(translated),
+			translated: true,
+		}
+	}
+}
+
+pub struct I18n {
+	json_root_translated: serde_json::Value, // any language
+
+	// TODO
+	json_root_fallback: serde_json::Value, // english
+}
+
+fn find_translation<'a>(translation: &str, mut val: &'a serde_json::Value) -> Option<&'a str> {
+	for part in translation.split('.') {
+		if let Some(sub) = val.get(part) {
+			val = sub;
+		}
+	}
+
+	val.as_str()
+}
+
+fn guess_lang() -> String {
+	if let Ok(lang) = std::env::var("LANG") {
+		if let Some((first, _)) = lang.split_once('_') {
+			String::from(first)
+		} else {
+			lang
+		}
+	} else {
+		log::warn!("LANG is not set, defaulting to \"en\".");
+		String::from("en")
+	}
+}
+
+impl I18n {
+	pub fn new(provider: &mut Box<dyn AssetProvider>) -> anyhow::Result<Self> {
+		let mut lang = guess_lang();
+		log::info!("Guessed system language: {lang}");
+
+		match lang.as_str() {
+			"en" | "pl" | "it" | "ja" | "es" => {}
+			_ => {
+				log::warn!(
+					"Unsupported language \"{}\", defaulting to \"en\".",
+					lang.as_str()
+				);
+
+				lang = String::from("en");
+			}
+		}
+
+		let data_english = provider.load_from_path(&format!("lang/{lang}.json"))?;
+		let data_translated = provider.load_from_path(&format!("lang/{lang}.json"))?;
+
+		let json_root_fallback = serde_json::from_str(str::from_utf8(&data_english)?)?;
+		let json_root_translated = serde_json::from_str(str::from_utf8(&data_translated)?)?;
+
+		Ok(Self {
+			json_root_fallback,
+			json_root_translated,
+		})
+	}
+
+	pub fn translate(&mut self, translation_key: &str) -> Rc<str> {
+		if let Some(translated) = find_translation(translation_key, &self.json_root_translated) {
+			Rc::from(translated)
+		} else {
+			Rc::from(translation_key) // show translation key as a fallback
+		}
+	}
+}