Revert "Remove cache for now"

This reverts commit a804e6d.

src/main/kotlin/Translation.kt

@@ -10,6 +10,9 @@ class TranslationService(private val config: TranslationConfig?) {
 
     private val chatModel = config?.let { createChatModel(it) }
 
+    private val translationCache = mutableMapOf<String, String>()
+    private val translationCacheSize = 5
+
     @Synchronized
     fun translate(text: String): String {
         if (config == null) {
@@ -22,12 +25,24 @@ class TranslationService(private val config: TranslationConfig?) {
             return text
         }
 
+        var translated = translationCache[text]
+        if (translated != null) {
+            return translated
+        }
+
         try {
-            return chatModel.generate(config.prompt.replaceFirst("{}", config.model).replaceFirst("{}", text))
+            translated = chatModel.generate(config.prompt.replaceFirst("{}", config.model).replaceFirst("{}", text))
         } catch (e: Exception) {
             logger.error("Error while translating text: $text", e)
             return text
         }
+
+        if (translationCache.size >= translationCacheSize) {
+            translationCache.remove(translationCache.keys.first())
+        }
+        translationCache[text] = translated
+
+        return translated
     }
 
     private fun createChatModel(config: TranslationConfig): ChatLanguageModel {