fix: ensure timeline clips can be extended to longer than 5s

apps/web/src/components/editor/timeline-element.tsx

@@ -45,6 +45,7 @@ export function TimelineElement({
   const { mediaItems } = useMediaStore();
   const {
     updateElementTrim,
+    updateElementDuration,
     removeElementFromTrack,
     dragState,
     splitElement,
@@ -67,6 +68,7 @@ export function TimelineElement({
     track,
     zoomLevel,
     onUpdateTrim: updateElementTrim,
+    onUpdateDuration: updateElementDuration,
   });
 
   const effectiveDuration =

apps/web/src/hooks/use-timeline-element-resize.ts

@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { ResizeState, TimelineElement, TimelineTrack } from "@/types/timeline";
+import { useMediaStore } from "@/stores/media-store";
 
 interface UseTimelineElementResizeProps {
   element: TimelineElement;
@@ -11,6 +12,11 @@ interface UseTimelineElementResizeProps {
     trimStart: number,
     trimEnd: number
   ) => void;
+  onUpdateDuration: (
+    trackId: string,
+    elementId: string,
+    duration: number
+  ) => void;
 }
 
 export function useTimelineElementResize({
@@ -18,8 +24,10 @@ export function useTimelineElementResize({
   track,
   zoomLevel,
   onUpdateTrim,
+  onUpdateDuration,
 }: UseTimelineElementResizeProps) {
   const [resizing, setResizing] = useState<ResizeState | null>(null);
+  const { mediaItems } = useMediaStore();
 
   // Set up document-level mouse listeners during resize (like proper drag behavior)
   useEffect(() => {
@@ -60,6 +68,30 @@ export function useTimelineElementResize({
     });
   };
 
+  const canExtendElementDuration = () => {
+    // Text elements can always be extended
+    if (element.type === "text") {
+      return true;
+    }
+
+    // Media elements - check the media type
+    if (element.type === "media") {
+      const mediaItem = mediaItems.find((item) => item.id === element.mediaId);
+      if (!mediaItem) return false;
+
+      // Images can be extended (static content)
+      if (mediaItem.type === "image") {
+        return true;
+      }
+
+      // Videos and audio cannot be extended beyond their natural duration
+      // (no additional content exists)
+      return false;
+    }
+
+    return false;
+  };
+
   const updateTrimFromMouseMove = (e: { clientX: number }) => {
     if (!resizing) return;
 
@@ -68,19 +100,48 @@ export function useTimelineElementResize({
     const deltaTime = deltaX / (50 * zoomLevel);
 
     if (resizing.side === "left") {
+      // Left resize - only trim within original duration
       const maxAllowed = element.duration - resizing.initialTrimEnd - 0.1;
       const calculated = resizing.initialTrimStart + deltaTime;
       const newTrimStart = Math.max(0, Math.min(maxAllowed, calculated));
 
       onUpdateTrim(track.id, element.id, newTrimStart, resizing.initialTrimEnd);
     } else {
-      // For right resize (expanding element), allow trimEnd to go to 0 but cap at element duration
+      // Right resize - can extend duration for supported element types
       const calculated = resizing.initialTrimEnd - deltaTime;
-      // Prevent negative trim AND prevent trimEnd from exceeding element duration
-      const maxTrimEnd = element.duration - resizing.initialTrimStart - 0.1; // Leave at least 0.1s visible
-      const newTrimEnd = Math.max(0, Math.min(maxTrimEnd, calculated));
 
-      onUpdateTrim(track.id, element.id, resizing.initialTrimStart, newTrimEnd);
+      if (calculated < 0) {
+        // We're trying to extend beyond original duration
+        if (canExtendElementDuration()) {
+          // Extend the duration instead of reducing trimEnd further
+          const extensionNeeded = Math.abs(calculated);
+          const newDuration = element.duration + extensionNeeded;
+          const newTrimEnd = 0; // Reset trimEnd to 0 since we're extending
+
+          // Update duration first, then trim
+          onUpdateDuration(track.id, element.id, newDuration);
+          onUpdateTrim(
+            track.id,
+            element.id,
+            resizing.initialTrimStart,
+            newTrimEnd
+          );
+        } else {
+          // Can't extend - just set trimEnd to 0 (maximum possible extension)
+          onUpdateTrim(track.id, element.id, resizing.initialTrimStart, 0);
+        }
+      } else {
+        // Normal trimming within original duration
+        const maxTrimEnd = element.duration - resizing.initialTrimStart - 0.1; // Leave at least 0.1s visible
+        const newTrimEnd = Math.max(0, Math.min(maxTrimEnd, calculated));
+
+        onUpdateTrim(
+          track.id,
+          element.id,
+          resizing.initialTrimStart,
+          newTrimEnd
+        );
+      }
     }
   };
 

apps/web/src/stores/timeline-store.ts

@@ -87,6 +87,11 @@ interface TimelineStore {
     trimStart: number,
     trimEnd: number
   ) => void;
+  updateElementDuration: (
+    trackId: string,
+    elementId: string,
+    duration: number
+  ) => void;
   updateElementStartTime: (
     trackId: string,
     elementId: string,
@@ -284,7 +289,9 @@ export const useTimelineStore = create<TimelineStore>((set, get) => {
 
     removeTrack: (trackId) => {
       get().pushHistory();
-      updateTracksAndSave(get()._tracks.filter((track) => track.id !== trackId));
+      updateTracksAndSave(
+        get()._tracks.filter((track) => track.id !== trackId)
+      );
     },
 
     addElementToTrack: (trackId, elementData) => {
@@ -439,6 +446,22 @@ export const useTimelineStore = create<TimelineStore>((set, get) => {
       );
     },
 
+    updateElementDuration: (trackId, elementId, duration) => {
+      get().pushHistory();
+      updateTracksAndSave(
+        get()._tracks.map((track) =>
+          track.id === trackId
+            ? {
+                ...track,
+                elements: track.elements.map((element) =>
+                  element.id === elementId ? { ...element, duration } : element
+                ),
+              }
+            : track
+        )
+      );
+    },
+
     updateElementStartTime: (trackId, elementId, startTime) => {
       get().pushHistory();
       updateTracksAndSave(