touch media viewer fixes

frontend/src/components/MediaViewer/MediaViewer.tsx

@@ -13,6 +13,9 @@ interface Props {
 export default function MediaViewer({ mediaId, siblings, onClose, onNavigate }: Props) {
   const [showTags, setShowTags] = useState(() => window.innerWidth >= 768);
   const touchStartX = useRef<number | null>(null);
+  const touchStartY = useRef<number | null>(null);
+  const swipeAxis = useRef<"horizontal" | "vertical" | null>(null);
+  const contentRef = useRef<HTMLDivElement>(null);
 
   const { data: item } = useQuery<MediaItem>({
     queryKey: ["media", mediaId],
@@ -24,28 +27,105 @@ export default function MediaViewer({ mediaId, siblings, onClose, onNavigate }:
   const prevId = currentIndex > 0 ? mediaSiblings[currentIndex - 1].media_item_id : null;
   const nextId = currentIndex < mediaSiblings.length - 1 ? mediaSiblings[currentIndex + 1].media_item_id : null;
 
+  // Clear inline styles when a new item loads so the card appears cleanly
+  useEffect(() => {
+    if (contentRef.current) {
+      contentRef.current.style.transition = "";
+      contentRef.current.style.transform = "";
+      contentRef.current.style.opacity = "";
+    }
+  }, [mediaId]);
+
   useEffect(() => {
     function onKey(e: KeyboardEvent) {
       if (e.key === "Escape") onClose();
       if (e.key === "ArrowLeft" && prevId) onNavigate(prevId);
       if (e.key === "ArrowRight" && nextId) onNavigate(nextId);
     }
-    const onTouchStart = (e: TouchEvent) => { touchStartX.current = e.touches[0].clientX; };
+
+    const onTouchStart = (e: TouchEvent) => {
+      touchStartX.current = e.touches[0].clientX;
+      touchStartY.current = e.touches[0].clientY;
+      swipeAxis.current = null;
+      if (contentRef.current) contentRef.current.style.transition = "none";
+    };
+
+    const onTouchMove = (e: TouchEvent) => {
+      if (touchStartX.current === null || touchStartY.current === null) return;
+      const dx = e.touches[0].clientX - touchStartX.current;
+      const dy = e.touches[0].clientY - touchStartY.current;
+
+      // Commit to an axis on the first significant movement
+      if (swipeAxis.current === null && (Math.abs(dx) > 8 || Math.abs(dy) > 8)) {
+        swipeAxis.current = Math.abs(dx) >= Math.abs(dy) ? "horizontal" : "vertical";
+      }
+
+      // Vertical gestures (tag panel scroll, etc.) pass through untouched
+      if (swipeAxis.current !== "horizontal") return;
+
+      e.preventDefault();
+      if (!contentRef.current) return;
+      contentRef.current.style.transform = `translate(calc(-50% + ${dx}px), -50%)`;
+      contentRef.current.style.opacity = String(Math.max(0.4, 1 - Math.abs(dx) / 400));
+    };
+
     const onTouchEnd = (e: TouchEvent) => {
       if (touchStartX.current === null) return;
       const delta = touchStartX.current - e.changedTouches[0].clientX;
-      if (Math.abs(delta) > 50) {
-        if (delta > 0 && nextId) onNavigate(nextId);
-        if (delta < 0 && prevId) onNavigate(prevId);
-      }
       touchStartX.current = null;
+      touchStartY.current = null;
+
+      // Non-horizontal gesture: just reset the transition we disabled on touchstart
+      if (swipeAxis.current !== "horizontal") {
+        swipeAxis.current = null;
+        if (contentRef.current) {
+          contentRef.current.style.transition = "";
+          contentRef.current.style.transform = "";
+          contentRef.current.style.opacity = "";
+        }
+        return;
+      }
+      swipeAxis.current = null;
+
+      const targetId = delta > 0 ? nextId : prevId;
+
+      if (Math.abs(delta) > 80 && targetId) {
+        const el = contentRef.current;
+        if (el) {
+          const slideX = delta > 0 ? -120 : 120;
+          el.style.transition = "opacity 0.2s ease, transform 0.2s ease";
+          el.style.transform = `translate(calc(-50% + ${slideX}px), -50%)`;
+          el.style.opacity = "0";
+          setTimeout(() => onNavigate(targetId), 200);
+        } else {
+          onNavigate(targetId);
+        }
+      } else {
+        // Snap back to center
+        const el = contentRef.current;
+        if (el) {
+          el.style.transition = "opacity 0.25s ease, transform 0.25s ease";
+          el.style.transform = "translate(-50%, -50%)";
+          el.style.opacity = "1";
+          setTimeout(() => {
+            if (contentRef.current) {
+              contentRef.current.style.transition = "";
+              contentRef.current.style.transform = "";
+              contentRef.current.style.opacity = "";
+            }
+          }, 260);
+        }
+      }
     };
+
     window.addEventListener("keydown", onKey);
     window.addEventListener("touchstart", onTouchStart);
+    window.addEventListener("touchmove", onTouchMove, { passive: false });
     window.addEventListener("touchend", onTouchEnd);
     return () => {
       window.removeEventListener("keydown", onKey);
       window.removeEventListener("touchstart", onTouchStart);
+      window.removeEventListener("touchmove", onTouchMove);
       window.removeEventListener("touchend", onTouchEnd);
     };
   }, [prevId, nextId, onClose, onNavigate]);
@@ -78,6 +158,7 @@ export default function MediaViewer({ mediaId, siblings, onClose, onNavigate }:
 
       {/* Media card */}
       <div
+        ref={contentRef}
         onClick={(e) => e.stopPropagation()}
         style={{ position: "fixed", top: "50%", left: "50%", transform: "translate(-50%, -50%)", zIndex: 101, background: "#1a1a1a", borderRadius: 8, padding: 16, display: "flex", flexDirection: "column", alignItems: "center", gap: 12, maxWidth: "80vw", maxHeight: "90vh", overflow: "auto" }}
       >