From 5e8fb145097db6a29e7ed797e3d9d0dee1d4ce9d Mon Sep 17 00:00:00 2001
From: Ebube Chuba <ebube97@me.com>
Date: Mon, 18 Nov 2024 16:11:24 -0500
Subject: [PATCH] chore: clean up ts to check for supported languages

---
 src/controllers/translation.ts | 80 ++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 29 deletions(-)

diff --git a/src/controllers/translation.ts b/src/controllers/translation.ts
index 43738ce1..d55a5116 100644
--- a/src/controllers/translation.ts
+++ b/src/controllers/translation.ts
@@ -5,28 +5,50 @@ import { z } from 'zod';
 import { fromError } from 'zod-validation-error';
 import LanguageEnum from '../shared/constants/LanguageEnum';
 
-const TranslationRequestBody = z.object({
-  text: z.string(),
-  sourceLanguageCode: z.nativeEnum(LanguageEnum),
-  destinationLanguageCode: z.nativeEnum(LanguageEnum),
-});
 
 export interface Translation {
   translation: string;
 }
 
-// TODO: move this information to remote config
-const SUPPORTED_TRANSLATIONS = {
-  [`${LanguageEnum.IGBO}to${LanguageEnum.ENGLISH}`]: {
-    maxInputLength: 120,
-    translationAPI: IGBO_TO_ENGLISH_API,
+export type LanguageCode = `${LanguageEnum}`
+
+type SupportedLanguage = {
+  [key in LanguageCode]?: {
+    maxInputLength: number,
+    translationAPI: string,
+  }
+}
+const SUPPORTED_TRANSLATIONS: { [key in LanguageCode]: SupportedLanguage} = {
+  [LanguageEnum.IGBO]: {
+    [LanguageEnum.ENGLISH]: {
+      maxInputLength: 120,
+      translationAPI: IGBO_TO_ENGLISH_API,
+    },
   },
-  [`${LanguageEnum.ENGLISH}to${LanguageEnum.IGBO}`]: {
-    maxInputLength: 150,
-    translationAPI: ENGLIGH_TO_IGBO_API,
+  [LanguageEnum.ENGLISH]: {
+    [LanguageEnum.IGBO]: {
+      maxInputLength: 150,
+      translationAPI: ENGLIGH_TO_IGBO_API,
+    },
   },
-} as const;
-type SupportedTranslationCodes = keyof typeof SUPPORTED_TRANSLATIONS;
+  [LanguageEnum.YORUBA]: {},
+  [LanguageEnum.HAUSA]: {},
+  [LanguageEnum.UNSPECIFIED]: {},
+};
+
+const TranslationRequestBody = z.object({
+  text: z.string(),
+  sourceLanguageCode: z.nativeEnum(LanguageEnum),
+  destinationLanguageCode: z.nativeEnum(LanguageEnum),
+});
+
+const PayloadKeyMap = {
+  [LanguageEnum.IGBO]: 'igbo',
+  [LanguageEnum.ENGLISH]: 'english',
+  [LanguageEnum.YORUBA]: 'yoruba',
+  [LanguageEnum.HAUSA]: 'hausa',
+  [LanguageEnum.UNSPECIFIED]: 'unspecified',
+}
 
 /**
  * Talks to Igbo-to-English translation model to translate the provided text.
@@ -43,42 +65,42 @@ export const getTranslation: MiddleWare = async (req, res, next) => {
     }
 
     const requestBody = requestBodyValidation.data;
+    const sourceLanguage = requestBody.sourceLanguageCode
+    const destinationLanguage = requestBody.destinationLanguageCode
 
-    if (requestBody.sourceLanguageCode === requestBody.destinationLanguageCode) {
+    if (sourceLanguage === destinationLanguage) {
       throw new Error('Source and destination languages must be different');
     }
 
     if (
-      !(
-        `${requestBody.sourceLanguageCode}to${requestBody.destinationLanguageCode}` in
-        SUPPORTED_TRANSLATIONS
-      )
+      !(sourceLanguage in SUPPORTED_TRANSLATIONS &&
+      destinationLanguage in SUPPORTED_TRANSLATIONS[sourceLanguage])
     ) {
       throw new Error(
-        `${requestBody.sourceLanguageCode} to ${requestBody.destinationLanguageCode} translation is not yet supported`
+        `${sourceLanguage} to ${destinationLanguage} translation is not yet supported`
       );
     }
     const textToTranslate = requestBody.text;
+    const maxInputLength = SUPPORTED_TRANSLATIONS[sourceLanguage][destinationLanguage]!.maxInputLength
     if (!textToTranslate) {
       throw new Error('Cannot translate empty string');
     }
-    const translationKey =
-      `${requestBody.sourceLanguageCode}to${requestBody.destinationLanguageCode}` as SupportedTranslationCodes;
-    // TODO: update this use map based on language
-    if (textToTranslate.length > SUPPORTED_TRANSLATIONS[translationKey].maxInputLength) {
+
+    if (textToTranslate.length > maxInputLength) {
       throw new Error(
-        `Cannot translate text greater than ${SUPPORTED_TRANSLATIONS[translationKey].maxInputLength} characters`
+        `Cannot translate text greater than ${maxInputLength} characters`
       );
     }
 
     // TODO: joint model will standardize request
-    const payload =
-      translationKey == 'ibotoeng' ? { igbo: textToTranslate } : { english: textToTranslate };
+    const payload = {
+      [PayloadKeyMap[sourceLanguage]]: textToTranslate
+    }
 
     // Talks to translation endpoint
     const { data: response } = await axios.request<Translation>({
       method: 'POST',
-      url: SUPPORTED_TRANSLATIONS[translationKey].translationAPI,
+      url: SUPPORTED_TRANSLATIONS[sourceLanguage][destinationLanguage]!.translationAPI,
       headers: {
         'Content-Type': 'application/json',
         'X-API-Key': MAIN_KEY,