feat: chat reactions

internal/handler/chat.go

@@ -38,6 +38,8 @@ func writeChatError(w http.ResponseWriter, err error) {
 		response.Error(w, http.StatusNotFound, err.Error())
 	case errors.Is(err, service.ErrChatBadEntity):
 		response.Error(w, http.StatusBadRequest, err.Error())
+	case errors.Is(err, service.ErrChatBadEmoji):
+		response.Error(w, http.StatusBadRequest, err.Error())
 	case errors.Is(err, service.ErrChatBadQuote):
 		response.Error(w, http.StatusBadRequest, err.Error())
 	case errors.Is(err, service.ErrChatBadAvatarKey):
@@ -648,6 +650,78 @@ func (h *ChatHandler) SetMute(w http.ResponseWriter, r *http.Request) {
 	response.JSON(w, http.StatusOK, map[string]any{"muted_until": until})
 }
 
+// Message — GET /chat/conversations/{id}/messages/{messageID}
+func (h *ChatHandler) Message(w http.ResponseWriter, r *http.Request) {
+	msg, err := h.svc.Message(r.Context(), middleware.UserID(r.Context()),
+		chi.URLParam(r, "id"), chi.URLParam(r, "messageID"))
+	if err != nil {
+		writeChatError(w, err)
+		return
+	}
+	response.JSON(w, http.StatusOK, msg)
+}
+
+// MessageReactions — GET /chat/conversations/{id}/messages/{messageID}/reactions
+//
+// Only read when someone opens the list; the thread itself renders from the
+// grouped counts that ride along with each message.
+func (h *ChatHandler) MessageReactions(w http.ResponseWriter, r *http.Request) {
+	list, err := h.svc.MessageReactions(r.Context(),
+		middleware.UserID(r.Context()), chi.URLParam(r, "messageID"))
+	if err != nil {
+		writeChatError(w, err)
+		return
+	}
+	response.JSON(w, http.StatusOK, list)
+}
+
+// Typing — POST /chat/conversations/{id}/typing
+//
+// Fire-and-forget: nothing is stored and the response carries nothing, because
+// a typing indicator is stale within seconds of being sent.
+func (h *ChatHandler) Typing(w http.ResponseWriter, r *http.Request) {
+	if err := h.svc.Typing(r.Context(),
+		middleware.UserID(r.Context()), chi.URLParam(r, "id")); err != nil {
+		writeChatError(w, err)
+		return
+	}
+	response.NoContent(w)
+}
+
+type reactReq struct {
+	Emoji string `json:"emoji"`
+}
+
+// React — PUT /chat/conversations/{id}/messages/{messageID}/reaction.
+// Replaces any previous choice.
+func (h *ChatHandler) React(w http.ResponseWriter, r *http.Request) {
+	var req reactReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		response.Error(w, http.StatusBadRequest, "invalid JSON body")
+		return
+	}
+	// The message id is authoritative: React re-derives the conversation from
+	// it and authorizes there, so the id in the path can't be used to react
+	// into a thread the caller isn't in.
+	if err := h.svc.React(r.Context(), middleware.UserID(r.Context()),
+		chi.URLParam(r, "messageID"), req.Emoji); err != nil {
+		writeChatError(w, err)
+		return
+	}
+	response.NoContent(w)
+}
+
+// Unreact — DELETE /chat/conversations/{id}/messages/{messageID}/reaction.
+// Idempotent.
+func (h *ChatHandler) Unreact(w http.ResponseWriter, r *http.Request) {
+	if err := h.svc.Unreact(r.Context(), middleware.UserID(r.Context()),
+		chi.URLParam(r, "messageID")); err != nil {
+		writeChatError(w, err)
+		return
+	}
+	response.NoContent(w)
+}
+
 // Receipts — GET /chat/conversations/{id}/receipts
 func (h *ChatHandler) Receipts(w http.ResponseWriter, r *http.Request) {
 	rc, err := h.svc.Receipts(r.Context(), middleware.UserID(r.Context()), chi.URLParam(r, "id"))