feat: implement Translator class

tagstudio/src/qt/translations.py

@@ -0,0 +1,60 @@
+from pathlib import Path
+
+import ujson
+from PySide6.QtCore import QObject, Signal
+from PySide6.QtGui import QAction
+from PySide6.QtWidgets import QLabel, QPushButton
+
+DEFAULT_TRANSLATION = "en"
+
+
+class TranslatedString(QObject):
+    changed = Signal(str)
+
+    __default_value: str
+    __value: str | None = None
+
+    def __init__(self, value: str):
+        super().__init__()
+        self.__default_value = value
+
+    @property
+    def value(self) -> str:
+        return self.__value or self.__default_value
+
+    @value.setter
+    def value(self, value: str):
+        if self.__value != value:
+            self.__value = value
+            self.changed.emit(self.__value)
+
+
+class Translator:
+    _strings: dict[str, TranslatedString] = {}
+
+    def __init__(self):
+        for k, v in self.__get_translation_dict(DEFAULT_TRANSLATION).items():
+            self._strings[k] = TranslatedString(v)
+
+    def __get_translation_dict(self, lang: str) -> dict[str, str]:
+        with open(Path(__file__).parents[2] / "resources" / "translations" / f"{lang}.json") as f:
+            return ujson.loads(f.read())
+
+    def change_language(self, lang: str):
+        translated = self.__get_translation_dict(lang)
+        for k in self._strings:
+            self._strings[k].value = translated.get(k, None)
+
+    def translate_widget(self, widget: QObject, key: str):
+        if isinstance(widget, (QLabel, QAction, QPushButton)):
+            if key in self._strings:
+                self._strings[key].changed.connect(widget.setText)
+            widget.setText(self.translate(key))
+        else:
+            raise RuntimeError
+
+    def translate(self, key: str) -> str:
+        return self._strings[key].value if key in self._strings else "Not Translated"
+
+
+Translations = Translator()