Translate: Add DeepL support (#2721)

Co-authored-by: v <vendicated@riseup.net>

src/plugins/translate/utils.ts

@@ -17,12 +17,18 @@
 */
 
 import { classNameFactory } from "@api/Styles";
+import { onlyOnce } from "@utils/onlyOnce";
+import { PluginNative } from "@utils/types";
+import { showToast, Toasts } from "@webpack/common";
 
-import { settings } from "./settings";
+import { DeeplLanguages, deeplLanguageToGoogleLanguage, GoogleLanguages } from "./languages";
+import { resetLanguageDefaults, settings } from "./settings";
 
 export const cl = classNameFactory("vc-trans-");
 
-interface TranslationData {
+const Native = VencordNative.pluginHelpers.Translate as PluginNative<typeof import("./native")>;
+
+interface GoogleData {
     src: string;
     sentences: {
         // 🏳️‍⚧️
@@ -30,15 +36,47 @@ interface TranslationData {
     }[];
 }
 
+interface DeeplData {
+    translations: {
+        detected_source_language: string;
+        text: string;
+    }[];
+}
+
 export interface TranslationValue {
-    src: string;
+    sourceLanguage: string;
     text: string;
 }
 
-export async function translate(kind: "received" | "sent", text: string): Promise<TranslationValue> {
-    const sourceLang = settings.store[kind + "Input"];
-    const targetLang = settings.store[kind + "Output"];
+export const getLanguages = () => IS_WEB || settings.store.service === "google"
+    ? GoogleLanguages
+    : DeeplLanguages;
 
+export async function translate(kind: "received" | "sent", text: string): Promise<TranslationValue> {
+    const translate = IS_WEB || settings.store.service === "google"
+        ? googleTranslate
+        : deeplTranslate;
+
+    try {
+        return await translate(
+            text,
+            settings.store[`${kind}Input`],
+            settings.store[`${kind}Output`]
+        );
+    } catch (e) {
+        const userMessage = typeof e === "string"
+            ? e
+            : "Something went wrong. If this issue persists, please check the console or ask for help in the support server.";
+
+        showToast(userMessage, Toasts.Type.FAILURE);
+
+        throw e instanceof Error
+            ? e
+            : new Error(userMessage);
+    }
+}
+
+async function googleTranslate(text: string, sourceLang: string, targetLang: string): Promise<TranslationValue> {
     const url = "https://translate.googleapis.com/translate_a/single?" + new URLSearchParams({
         // see https://stackoverflow.com/a/29537590 for more params
         // holy shidd nvidia
@@ -63,13 +101,69 @@ export async function translate(kind: "received" | "sent", text: string): Promis
             + `\n${res.status} ${res.statusText}`
         );
 
-    const { src, sentences }: TranslationData = await res.json();
+    const { src, sentences }: GoogleData = await res.json();
 
     return {
-        src,
+        sourceLanguage: GoogleLanguages[src] ?? src,
         text: sentences.
             map(s => s?.trans).
             filter(Boolean).
             join("")
     };
 }
+
+function fallbackToGoogle(text: string, sourceLang: string, targetLang: string): Promise<TranslationValue> {
+    return googleTranslate(
+        text,
+        deeplLanguageToGoogleLanguage(sourceLang),
+        deeplLanguageToGoogleLanguage(targetLang)
+    );
+}
+
+const showDeeplApiQuotaToast = onlyOnce(
+    () => showToast("Deepl API quota exceeded. Falling back to Google Translate", Toasts.Type.FAILURE)
+);
+
+async function deeplTranslate(text: string, sourceLang: string, targetLang: string): Promise<TranslationValue> {
+    if (!settings.store.deeplApiKey) {
+        showToast("DeepL API key is not set. Resetting to Google", Toasts.Type.FAILURE);
+
+        settings.store.service = "google";
+        resetLanguageDefaults();
+
+        return fallbackToGoogle(text, sourceLang, targetLang);
+    }
+
+    // CORS jumpscare
+    const { status, data } = await Native.makeDeeplTranslateRequest(
+        settings.store.service === "deepl-pro",
+        settings.store.deeplApiKey,
+        JSON.stringify({
+            text: [text],
+            target_lang: targetLang,
+            source_lang: sourceLang.split("-")[0]
+        })
+    );
+
+    switch (status) {
+        case 200:
+            break;
+        case -1:
+            throw "Failed to connect to DeepL API: " + data;
+        case 403:
+            throw "Invalid DeepL API key or version";
+        case 456:
+            showDeeplApiQuotaToast();
+            return fallbackToGoogle(text, sourceLang, targetLang);
+        default:
+            throw new Error(`Failed to translate "${text}" (${sourceLang} -> ${targetLang})\n${status} ${data}`);
+    }
+
+    const { translations }: DeeplData = JSON.parse(data);
+    const src = translations[0].detected_source_language;
+
+    return {
+        sourceLanguage: DeeplLanguages[src] ?? src,
+        text: translations[0].text
+    };
+}