add reading settings sync

internal/handler/user.go

@@ -53,6 +53,51 @@ func (h *UserHandler) UpdateProfile(w http.ResponseWriter, r *http.Request) {
 	response.JSON(w, http.StatusOK, u)
 }
 
+// GetReadingPrefs returns the caller's saved reading prefs blob (always
+// well-formed JSON; an empty object when the user has never written).
+// The frontend treats the response as the source of truth on first
+// sign-in for this device.
+func (h *UserHandler) GetReadingPrefs(w http.ResponseWriter, r *http.Request) {
+	uid := middleware.UserID(r.Context())
+	raw, err := h.svc.GetReadingPrefs(r.Context(), uid)
+	if err != nil {
+		response.Error(w, http.StatusInternalServerError, "could not load reading prefs")
+		return
+	}
+	// Round-trip the JSONB as the data field directly. We use a raw
+	// json.RawMessage so the body is `{"data": {...}}` not a re-encoded
+	// string. The envelope wrapper keeps shape parity with the rest of
+	// the API.
+	response.JSON(w, http.StatusOK, json.RawMessage(raw))
+}
+
+// UpdateReadingPrefs replaces the caller's reading-prefs blob with the
+// request body (which must itself be a JSON object — we re-marshal a
+// decoded map to enforce that without imposing a fixed schema on a
+// payload the frontend owns).
+func (h *UserHandler) UpdateReadingPrefs(w http.ResponseWriter, r *http.Request) {
+	uid := middleware.UserID(r.Context())
+
+	// Decode into map[string]any to guarantee the body is an object (not
+	// an array, number, or string). Re-marshal before persisting so the
+	// stored JSON is canonicalised and any duplicate keys are dropped.
+	var body map[string]any
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		response.Error(w, http.StatusBadRequest, "invalid JSON body (expect an object)")
+		return
+	}
+	prefsJSON, err := json.Marshal(body)
+	if err != nil {
+		response.Error(w, http.StatusBadRequest, "could not re-encode prefs")
+		return
+	}
+	if err := h.svc.UpdateReadingPrefs(r.Context(), uid, prefsJSON); err != nil {
+		response.Error(w, http.StatusInternalServerError, "could not save reading prefs")
+		return
+	}
+	response.JSON(w, http.StatusOK, json.RawMessage(prefsJSON))
+}
+
 type presignReq struct {
 	ContentType string `json:"content_type"`
 }