doom scroll touch edit

frontend/src/components/DoomScrollViewer/DoomScrollViewer.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 import { api, type MediaItem } from "../../api/client";
 
 interface Props {
@@ -12,10 +12,11 @@ export default function DoomScrollViewer({ items, onClose, onViewInLibrary }: Pr
   const [fading, setFading] = useState(false);
   const wheelLock = useRef(false);
   const touchStartY = useRef<number | null>(null);
+  const contentRef = useRef<HTMLDivElement>(null);
 
   const item = items[index];
 
-  function go(delta: 1 | -1) {
+  const go = useCallback((delta: 1 | -1) => {
     if (wheelLock.current) return;
     const next = index + delta;
     if (next < 0 || next >= items.length) return;
@@ -26,7 +27,7 @@ export default function DoomScrollViewer({ items, onClose, onViewInLibrary }: Pr
       setFading(false);
       wheelLock.current = false;
     }, 200);
-  }
+  }, [index, items.length]);
 
   useEffect(() => {
     const onWheel = (e: WheelEvent) => { e.deltaY > 0 ? go(1) : go(-1); };
@@ -35,24 +36,68 @@ export default function DoomScrollViewer({ items, onClose, onViewInLibrary }: Pr
       if (e.key === "ArrowUp") { e.preventDefault(); go(-1); }
       if (e.key === "Escape") onClose();
     };
-    const onTouchStart = (e: TouchEvent) => { touchStartY.current = e.touches[0].clientY; };
-    const onTouchEnd = (e: TouchEvent) => {
-      if (touchStartY.current === null) return;
-      const delta = touchStartY.current - e.changedTouches[0].clientY;
-      if (Math.abs(delta) > 50) delta > 0 ? go(1) : go(-1);
-      touchStartY.current = null;
-    };
     window.addEventListener("wheel", onWheel, { passive: true });
     window.addEventListener("keydown", onKey);
-    window.addEventListener("touchstart", onTouchStart);
-    window.addEventListener("touchend", onTouchEnd);
     return () => {
       window.removeEventListener("wheel", onWheel);
       window.removeEventListener("keydown", onKey);
+    };
+  }, [go, onClose]);
+
+  useEffect(() => {
+    const onTouchStart = (e: TouchEvent) => {
+      touchStartY.current = e.touches[0].clientY;
+      if (contentRef.current) contentRef.current.style.transition = "none";
+    };
+
+    const onTouchMove = (e: TouchEvent) => {
+      e.preventDefault();
+      if (touchStartY.current === null || !contentRef.current) return;
+      const offset = e.touches[0].clientY - touchStartY.current;
+      contentRef.current.style.transform = `translateY(${offset}px)`;
+      contentRef.current.style.opacity = String(Math.max(0.3, 1 - Math.abs(offset) / 300));
+    };
+
+    const onTouchEnd = (e: TouchEvent) => {
+      if (touchStartY.current === null) return;
+      const delta = touchStartY.current - e.changedTouches[0].clientY;
+      touchStartY.current = null;
+
+      if (Math.abs(delta) > 80) {
+        // Hand off to the fading animation
+        if (contentRef.current) {
+          contentRef.current.style.transition = "";
+          contentRef.current.style.transform = "";
+          contentRef.current.style.opacity = "";
+        }
+        go(delta > 0 ? 1 : -1);
+      } else {
+        // Snap back to center
+        if (contentRef.current) {
+          const el = contentRef.current;
+          el.style.transition = "opacity 0.25s ease, transform 0.25s ease";
+          el.style.transform = "translateY(0)";
+          el.style.opacity = "1";
+          setTimeout(() => {
+            if (contentRef.current) {
+              contentRef.current.style.transition = "";
+              contentRef.current.style.transform = "";
+              contentRef.current.style.opacity = "";
+            }
+          }, 260);
+        }
+      }
+    };
+
+    window.addEventListener("touchstart", onTouchStart);
+    window.addEventListener("touchmove", onTouchMove, { passive: false });
+    window.addEventListener("touchend", onTouchEnd);
+    return () => {
       window.removeEventListener("touchstart", onTouchStart);
+      window.removeEventListener("touchmove", onTouchMove);
       window.removeEventListener("touchend", onTouchEnd);
     };
-  }, [index, fading]);
+  }, [go]);
 
   return (
     <>
@@ -61,6 +106,7 @@ export default function DoomScrollViewer({ items, onClose, onViewInLibrary }: Pr
 
       {/* Media area */}
       <div
+        ref={contentRef}
         style={{
           position: "fixed", inset: 0, zIndex: 201,
           display: "flex", flexDirection: "column", alignItems: "center", justifyContent: "center",