feat(translate): keep translated subtitles next to the video so they load on reopen (#14)

Co-authored-by: Tri Vo Khac <git@trivk.dev>

src/translate/translationservice.h

@@ -18,8 +18,8 @@
 
 class QNetworkAccessManager;
 
-// Translates a whole subtitle track with an LLM, batch by batch, and caches the result
-// as an .srt file that mpv can load as a subtitle track.
+// Translates a whole subtitle track with an LLM, batch by batch, caches the result as an
+// .srt file and saves a copy next to the video (see TranslationStore).
 class TranslationService : public QObject
 {
     Q_OBJECT
@@ -62,6 +62,9 @@ public:
     Q_INVOKABLE void fetchModels();
     Q_INVOKABLE void clearError();
     Q_INVOKABLE void forgetTranslation();
+    // Path of the translation of \a videoUrl into the target language set in Settings,
+    // or an empty string when there is none.
+    Q_INVOKABLE QString savedTranslation(const QUrl &videoUrl) const;
     Q_INVOKABLE void loadGlossary(const QUrl &videoUrl);
     Q_INVOKABLE bool saveGlossary(const QVariantList &entries, const QStringList &episodes = {});
     Q_INVOKABLE void clearGlossary();
@@ -97,6 +100,8 @@ private:
     // something is missing.
     QCoro::Task<std::pair<LlmClient::Config, QString>> loadConfig();
     void fail(const std::shared_ptr<Job> &job, const QString &error);
+    // Saves the translation in \a cacheFile where players find it and announces it.
+    void finish(const std::shared_ptr<Job> &job, const QUrl &videoUrl, const QString &suffix, const QString &configKey, const QString &cacheFile, bool fromCache);
 
     void setBusy(bool busy);
     void setProgress(double progress);