Delete and rename conversations

internal/service/conversations.go

@@ -6,6 +6,10 @@ import (
 	"errors"
 	"log/slog"
 	"net/http"
+	"strings"
+	"unicode/utf8"
+
+	"code.chimeric.al/chimerical/odidere/internal/db"
 )
 
 func (svc *Service) listConversations(w http.ResponseWriter, r *http.Request) {
@@ -125,6 +129,103 @@ func (svc *Service) getConversationHandler(
 	}
 }
 
+// maxTitleLength is the most characters, counted as Unicode code
+// points, that a conversation title may hold. It keeps a title
+// short enough for the picker and small in storage.
+const maxTitleLength = 256
+
+// updateConversation renames one conversation. The handler trims
+// the title, then rejects an empty title or a title longer than
+// maxTitleLength with 400. A conversation that does not exist, or
+// belongs to another user, returns 404. The rename is allowed while
+// inference runs: a title is not a message, and a concurrent
+// inference does not read or write it.
+func (svc *Service) updateConversation(w http.ResponseWriter, r *http.Request) {
+	var (
+		ctx = r.Context()
+		log = ctx.Value(logKey).(*slog.Logger)
+		id  = r.PathValue("id")
+		req struct {
+			Title string `json:"title"`
+		}
+	)
+
+	r.Body = http.MaxBytesReader(w, r.Body, 32<<20)
+	if err := json.UnmarshalRead(r.Body, &req); err != nil {
+		log.ErrorContext(
+			ctx, "failed to decode request",
+			slog.Any("error", err),
+		)
+		http.Error(w, "invalid request", http.StatusBadRequest)
+		return
+	}
+
+	req.Title = strings.TrimSpace(req.Title)
+	if req.Title == "" {
+		http.Error(w, "invalid request", http.StatusBadRequest)
+		return
+	}
+	if utf8.RuneCountInString(req.Title) > maxTitleLength {
+		http.Error(w, "invalid request", http.StatusBadRequest)
+		return
+	}
+
+	// Load the conversation first, so a rename of a conversation
+	// that does not belong to the user reports 404, not a silent
+	// no-op.
+	if _, err := svc.dbr.SelectConversationIdUserId(
+		ctx, id, "default",
+	); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			http.NotFound(w, r)
+			return
+		}
+		log.ErrorContext(
+			ctx, "failed to load conversation",
+			slog.Any("error", err),
+		)
+		http.Error(
+			w,
+			http.StatusText(http.StatusInternalServerError),
+			http.StatusInternalServerError,
+		)
+		return
+	}
+
+	saved, err := svc.dbw.UpdateConversationTitle(
+		ctx,
+		db.UpdateConversationTitleParams{
+			Id:    id,
+			Title: req.Title,
+		},
+	)
+	if err != nil {
+		// The conversation was deleted after the load above.
+		if errors.Is(err, sql.ErrNoRows) {
+			http.NotFound(w, r)
+			return
+		}
+		log.ErrorContext(
+			ctx, "failed to rename conversation",
+			slog.Any("error", err),
+		)
+		http.Error(
+			w,
+			http.StatusText(http.StatusInternalServerError),
+			http.StatusInternalServerError,
+		)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.MarshalWrite(w, saved); err != nil {
+		log.ErrorContext(
+			ctx, "failed to encode conversation response",
+			slog.Any("error", err),
+		)
+	}
+}
+
 func (svc *Service) deleteConversation(w http.ResponseWriter, r *http.Request) {
 	var (
 		ctx = r.Context()