Add language support

src/language/__init__.py

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+from .lang import TranslationProvider, LANGUAGES

src/language/lang.py

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+
+# from data import AppSettings
+
+import json
+from pathlib import Path
+from typing import Dict, Optional
+
+
+LANGUAGES = { "DE": "Deutsch", "EN": "English", "FR": "Francais" }
+LANGUAGE_FOLDER = Path('res', "lang")
+
+
+class TranslationProvider:
+    last_language_key: Optional[str] = None
+    last_language_dict: Optional[Dict[str,str]] = None
+
+    @classmethod
+    def get_language_file(cls, language: str) -> Dict[str, str]:
+        if language not in list(LANGUAGES.keys()):
+            raise ValueError('invalid language key: "{language}"')
+        
+        if cls.last_language_key == language and cls.last_language_dict is not None:
+            return cls.last_language_dict
+            
+        path = Path(LANGUAGE_FOLDER, f'{language}.json' )
+        try:
+            with open(path, 'r', encoding='utf-8') as f:
+                result = json.load(f)
+                cls.last_language_key = language
+                cls.last_language_dict = result
+                return result
+            
+        except FileNotFoundError:
+            print(f'Language not found: "{language}"')
+            raise
+
+    @classmethod
+    def get_translated(cls, key:str, language:str) -> str:
+
+        lang_dict = cls.get_language_file(language)
+        result = lang_dict.get(key, None)
+        if result:
+            return result
+
+        print(f'unsuccesful try to get {key} in language {language}')
+        return f'key not found for language: \nkey:"{key}"\nlanguage:"{language}"'