4 files changed, 302 insertions, 111 deletions
diff --git a/apps/web/src/components/editor/selection-box.tsx b/apps/web/src/components/editor/selection-box.tsx
new file mode 100644
index 00000000..5c452f7c
--- /dev/null
+++ b/apps/web/src/components/editor/selection-box.tsx
@@ -0,0 +1,58 @@
+"use client";
+
+import { useEffect, useRef } from "react";
+
+interface SelectionBoxProps {
+  startPos: { x: number; y: number } | null;
+  currentPos: { x: number; y: number } | null;
+  containerRef: React.RefObject<HTMLElement>;
+  isActive: boolean;
+}
+
+export function SelectionBox({
+  startPos,
+  currentPos,
+  containerRef,
+  isActive,
+}: SelectionBoxProps) {
+  const selectionBoxRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!isActive || !startPos || !currentPos || !containerRef.current) return;
+
+    const container = containerRef.current;
+    const containerRect = container.getBoundingClientRect();
+
+    // Calculate relative positions within the container
+    const startX = startPos.x - containerRect.left;
+    const startY = startPos.y - containerRect.top;
+    const currentX = currentPos.x - containerRect.left;
+    const currentY = currentPos.y - containerRect.top;
+
+    // Calculate the selection rectangle bounds
+    const left = Math.min(startX, currentX);
+    const top = Math.min(startY, currentY);
+    const width = Math.abs(currentX - startX);
+    const height = Math.abs(currentY - startY);
+
+    // Update the selection box position and size
+    if (selectionBoxRef.current) {
+      selectionBoxRef.current.style.left = `${left}px`;
+      selectionBoxRef.current.style.top = `${top}px`;
+      selectionBoxRef.current.style.width = `${width}px`;
+      selectionBoxRef.current.style.height = `${height}px`;
+    }
+  }, [startPos, currentPos, isActive, containerRef]);
+
+  if (!isActive || !startPos || !currentPos) return null;
+
+  return (
+    <div
+      ref={selectionBoxRef}
+      className="absolute pointer-events-none z-50"
+      style={{
+        backgroundColor: "hsl(var(--foreground) / 0.1)",
+      }}
+    />
+  );
+}
diff --git a/apps/web/src/components/editor/timeline-element.tsx b/apps/web/src/components/editor/timeline-element.tsx
index 1cd22c74..ee9445f3 100644
--- a/apps/web/src/components/editor/timeline-element.tsx
+++ b/apps/web/src/components/editor/timeline-element.tsx
@@ -339,6 +339,8 @@ export function TimelineElement({
             left: `${elementLeft}px`,
             width: `${elementWidth}px`,
           }}
+          data-element-id={element.id}
+          data-track-id={track.id}
           onMouseMove={resizing ? handleResizeMove : undefined}
           onMouseUp={resizing ? handleResizeEnd : undefined}
           onMouseLeave={resizing ? handleResizeEnd : undefined}
diff --git a/apps/web/src/components/editor/timeline.tsx b/apps/web/src/components/editor/timeline.tsx
index 53a7aacd..b250bda1 100644
--- a/apps/web/src/components/editor/timeline.tsx
+++ b/apps/web/src/components/editor/timeline.tsx
@@ -48,6 +48,8 @@ import {
   TimelinePlayhead,
   useTimelinePlayheadRuler,
 } from "./timeline-playhead";
+import { SelectionBox } from "./selection-box";
+import { useSelectionBox } from "@/hooks/use-selection-box";
 import type { DragData, TimelineTrack } from "@/types/timeline";
 import {
   getTrackHeight,
@@ -103,15 +105,7 @@ export function Timeline() {
     isInTimeline,
   });
 
-  // Marquee selection state
-  const [marquee, setMarquee] = useState<{
-    startX: number;
-    startY: number;
-    endX: number;
-    endY: number;
-    active: boolean;
-    additive: boolean;
-  } | null>(null);
+  // Old marquee selection removed - using new SelectionBox component instead
 
   // Dynamic timeline width calculation based on playhead position and duration
   const dynamicTimelineWidth = Math.max(
@@ -141,9 +135,40 @@ export function Timeline() {
     playheadRef,
   });
 
+  // Selection box functionality
+  const tracksContainerRef = useRef<HTMLDivElement>(null);
+  const {
+    selectionBox,
+    handleMouseDown: handleSelectionMouseDown,
+    isSelecting,
+    justFinishedSelecting,
+  } = useSelectionBox({
+    containerRef: tracksContainerRef,
+    playheadRef,
+    onSelectionComplete: (elements) => {
+      console.log(JSON.stringify({ onSelectionComplete: elements.length }));
+      setSelectedElements(elements);
+    },
+  });
+
   // Timeline content click to seek handler
   const handleTimelineContentClick = useCallback(
     (e: React.MouseEvent) => {
+      console.log(
+        JSON.stringify({
+          timelineClick: {
+            isSelecting,
+            justFinishedSelecting,
+            willReturn: isSelecting || justFinishedSelecting,
+          },
+        })
+      );
+
+      // Don't seek if this was a selection box operation
+      if (isSelecting || justFinishedSelecting) {
+        return;
+      }
+
       // Don't seek if clicking on timeline elements, but still deselect
       if ((e.target as HTMLElement).closest(".timeline-element")) {
         return;
@@ -161,6 +186,7 @@ export function Timeline() {
       }
 
       // Clear selected elements when clicking empty timeline area
+      console.log(JSON.stringify({ clearingSelectedElements: true }));
       clearSelectedElements();
 
       // Determine if we're clicking in ruler or tracks area
@@ -209,6 +235,8 @@ export function Timeline() {
       rulerScrollRef,
       tracksScrollRef,
       clearSelectedElements,
+      isSelecting,
+      justFinishedSelecting,
     ]
   );
 
@@ -283,107 +311,7 @@ export function Timeline() {
     return () => window.removeEventListener("keydown", handleKeyDown);
   }, [redo]);
 
-  // Mouse down on timeline background to start marquee
-  const handleTimelineMouseDown = (e: React.MouseEvent) => {
-    if (e.target === e.currentTarget && e.button === 0) {
-      setMarquee({
-        startX: e.clientX,
-        startY: e.clientY,
-        endX: e.clientX,
-        endY: e.clientY,
-        active: true,
-        additive: e.metaKey || e.ctrlKey || e.shiftKey,
-      });
-    }
-  };
-
-  // Mouse move to update marquee
-  useEffect(() => {
-    if (!marquee || !marquee.active) return;
-    const handleMouseMove = (e: MouseEvent) => {
-      setMarquee(
-        (prev) => prev && { ...prev, endX: e.clientX, endY: e.clientY }
-      );
-    };
-    const handleMouseUp = (e: MouseEvent) => {
-      setMarquee(
-        (prev) =>
-          prev && { ...prev, endX: e.clientX, endY: e.clientY, active: false }
-      );
-    };
-    window.addEventListener("mousemove", handleMouseMove);
-    window.addEventListener("mouseup", handleMouseUp);
-    return () => {
-      window.removeEventListener("mousemove", handleMouseMove);
-      window.removeEventListener("mouseup", handleMouseUp);
-    };
-  }, [marquee]);
-
-  // On marquee end, select elements in box
-  useEffect(() => {
-    if (!marquee || marquee.active) return;
-    const timeline = timelineRef.current;
-    if (!timeline) return;
-    const rect = timeline.getBoundingClientRect();
-    const x1 = Math.min(marquee.startX, marquee.endX) - rect.left;
-    const x2 = Math.max(marquee.startX, marquee.endX) - rect.left;
-    const y1 = Math.min(marquee.startY, marquee.endY) - rect.top;
-    const y2 = Math.max(marquee.startY, marquee.endY) - rect.top;
-    // Validation: skip if too small
-    if (Math.abs(x2 - x1) < 5 || Math.abs(y2 - y1) < 5) {
-      setMarquee(null);
-      return;
-    }
-    // Clamp to timeline bounds
-    const clamp = (val: number, min: number, max: number) =>
-      Math.max(min, Math.min(max, val));
-    const bx1 = clamp(x1, 0, rect.width);
-    const bx2 = clamp(x2, 0, rect.width);
-    const by1 = clamp(y1, 0, rect.height);
-    const by2 = clamp(y2, 0, rect.height);
-    let newSelection: { trackId: string; elementId: string }[] = [];
-    tracks.forEach((track, trackIdx) => {
-      track.elements.forEach((element) => {
-        const clipLeft =
-          element.startTime * TIMELINE_CONSTANTS.PIXELS_PER_SECOND * zoomLevel;
-        const clipTop = getCumulativeHeightBefore(tracks, trackIdx);
-        const clipBottom = clipTop + getTrackHeight(track.type);
-        const clipRight = clipLeft + getTrackHeight(track.type);
-        if (
-          bx1 < clipRight &&
-          bx2 > clipLeft &&
-          by1 < clipBottom &&
-          by2 > clipTop
-        ) {
-          newSelection.push({ trackId: track.id, elementId: element.id });
-        }
-      });
-    });
-    if (newSelection.length > 0) {
-      if (marquee.additive) {
-        const selectedSet = new Set(
-          selectedElements.map((c) => c.trackId + ":" + c.elementId)
-        );
-        newSelection = [
-          ...selectedElements,
-          ...newSelection.filter(
-            (c) => !selectedSet.has(c.trackId + ":" + c.elementId)
-          ),
-        ];
-      }
-      setSelectedElements(newSelection);
-    } else if (!marquee.additive) {
-      clearSelectedElements();
-    }
-    setMarquee(null);
-  }, [
-    marquee,
-    tracks,
-    zoomLevel,
-    selectedElements,
-    setSelectedElements,
-    clearSelectedElements,
-  ]);
+  // Old marquee system removed - using new SelectionBox component instead
 
   const handleDragEnter = (e: React.DragEvent) => {
     // When something is dragged over the timeline, show overlay
@@ -898,6 +826,7 @@ export function Timeline() {
           <div
             className="flex-1 relative overflow-hidden h-4"
             onWheel={handleWheel}
+            onMouseDown={handleSelectionMouseDown}
             onClick={handleTimelineContentClick}
             data-ruler-area
           >
@@ -1016,8 +945,16 @@ export function Timeline() {
           <div
             className="flex-1 relative overflow-hidden"
             onWheel={handleWheel}
+            onMouseDown={handleSelectionMouseDown}
             onClick={handleTimelineContentClick}
+            ref={tracksContainerRef}
           >
+            <SelectionBox
+              startPos={selectionBox?.startPos || null}
+              currentPos={selectionBox?.currentPos || null}
+              containerRef={tracksContainerRef}
+              isActive={selectionBox?.isActive || false}
+            />
             <ScrollArea className="w-full h-full" ref={tracksScrollRef}>
               <div
                 className="relative flex-1"
@@ -1025,7 +962,6 @@ export function Timeline() {
                   height: `${Math.max(200, Math.min(800, getTotalTracksHeight(tracks)))}px`,
                   width: `${dynamicTimelineWidth}px`,
                 }}
-                onMouseDown={handleTimelineMouseDown}
               >
                 {tracks.length === 0 ? (
                   <div></div>
diff --git a/apps/web/src/hooks/use-selection-box.ts b/apps/web/src/hooks/use-selection-box.ts
new file mode 100644
index 00000000..4caecf17
--- /dev/null
+++ b/apps/web/src/hooks/use-selection-box.ts
@@ -0,0 +1,195 @@
+import { useState, useEffect, useCallback } from "react";
+
+interface UseSelectionBoxProps {
+  containerRef: React.RefObject<HTMLElement>;
+  playheadRef?: React.RefObject<HTMLElement>;
+  onSelectionComplete: (
+    elements: { trackId: string; elementId: string }[]
+  ) => void;
+  isEnabled?: boolean;
+}
+
+interface SelectionBoxState {
+  startPos: { x: number; y: number };
+  currentPos: { x: number; y: number };
+  isActive: boolean;
+}
+
+export function useSelectionBox({
+  containerRef,
+  playheadRef,
+  onSelectionComplete,
+  isEnabled = true,
+}: UseSelectionBoxProps) {
+  const [selectionBox, setSelectionBox] = useState<SelectionBoxState | null>(
+    null
+  );
+  const [justFinishedSelecting, setJustFinishedSelecting] = useState(false);
+
+  // Mouse down handler to start selection
+  const handleMouseDown = useCallback(
+    (e: React.MouseEvent) => {
+      if (!isEnabled) return;
+
+      // Only start selection on empty space clicks
+      if ((e.target as HTMLElement).closest(".timeline-element")) {
+        return;
+      }
+      if (playheadRef?.current?.contains(e.target as Node)) {
+        return;
+      }
+      if ((e.target as HTMLElement).closest("[data-track-labels]")) {
+        return;
+      }
+
+      setSelectionBox({
+        startPos: { x: e.clientX, y: e.clientY },
+        currentPos: { x: e.clientX, y: e.clientY },
+        isActive: false, // Will become active when mouse moves
+      });
+    },
+    [isEnabled, playheadRef]
+  );
+
+  // Function to select elements within the selection box
+  const selectElementsInBox = useCallback(
+    (startPos: { x: number; y: number }, endPos: { x: number; y: number }) => {
+      if (!containerRef.current) return;
+
+      const container = containerRef.current;
+      const containerRect = container.getBoundingClientRect();
+
+      // Calculate selection rectangle in container coordinates
+      const startX = startPos.x - containerRect.left;
+      const startY = startPos.y - containerRect.top;
+      const endX = endPos.x - containerRect.left;
+      const endY = endPos.y - containerRect.top;
+
+      const selectionRect = {
+        left: Math.min(startX, endX),
+        top: Math.min(startY, endY),
+        right: Math.max(startX, endX),
+        bottom: Math.max(startY, endY),
+      };
+
+      // Find all timeline elements within the selection rectangle
+      const timelineElements = container.querySelectorAll(".timeline-element");
+
+      const selectedElements: { trackId: string; elementId: string }[] = [];
+
+      timelineElements.forEach((element) => {
+        const elementRect = element.getBoundingClientRect();
+        // Use absolute coordinates for more accurate intersection detection
+        const elementAbsolute = {
+          left: elementRect.left,
+          top: elementRect.top,
+          right: elementRect.right,
+          bottom: elementRect.bottom,
+        };
+
+        const selectionAbsolute = {
+          left: startPos.x,
+          top: startPos.y,
+          right: endPos.x,
+          bottom: endPos.y,
+        };
+
+        // Normalize selection rectangle (handle dragging in any direction)
+        const normalizedSelection = {
+          left: Math.min(selectionAbsolute.left, selectionAbsolute.right),
+          top: Math.min(selectionAbsolute.top, selectionAbsolute.bottom),
+          right: Math.max(selectionAbsolute.left, selectionAbsolute.right),
+          bottom: Math.max(selectionAbsolute.top, selectionAbsolute.bottom),
+        };
+
+        const elementId = element.getAttribute("data-element-id");
+        const trackId = element.getAttribute("data-track-id");
+
+        // Check if element intersects with selection rectangle (any overlap)
+        // Using absolute coordinates for more precise detection
+        const intersects = !(
+          elementAbsolute.right < normalizedSelection.left ||
+          elementAbsolute.left > normalizedSelection.right ||
+          elementAbsolute.bottom < normalizedSelection.top ||
+          elementAbsolute.top > normalizedSelection.bottom
+        );
+
+        if (intersects && elementId && trackId) {
+          selectedElements.push({ trackId, elementId });
+        }
+      });
+
+      // Always call the callback - with elements or empty array to clear selection
+      console.log(
+        JSON.stringify({ selectElementsInBox: selectedElements.length })
+      );
+      onSelectionComplete(selectedElements);
+    },
+    [containerRef, onSelectionComplete]
+  );
+
+  // Effect to track selection box movement
+  useEffect(() => {
+    if (!selectionBox) return;
+
+    const handleMouseMove = (e: MouseEvent) => {
+      const deltaX = Math.abs(e.clientX - selectionBox.startPos.x);
+      const deltaY = Math.abs(e.clientY - selectionBox.startPos.y);
+
+      // Start selection if mouse moved more than 5px
+      const shouldActivate = deltaX > 5 || deltaY > 5;
+
+      const newSelectionBox = {
+        ...selectionBox,
+        currentPos: { x: e.clientX, y: e.clientY },
+        isActive: shouldActivate || selectionBox.isActive,
+      };
+
+      setSelectionBox(newSelectionBox);
+
+      // Real-time visual feedback: update selection as we drag
+      if (newSelectionBox.isActive) {
+        selectElementsInBox(
+          newSelectionBox.startPos,
+          newSelectionBox.currentPos
+        );
+      }
+    };
+
+    const handleMouseUp = () => {
+      console.log(
+        JSON.stringify({ mouseUp: { wasActive: selectionBox?.isActive } })
+      );
+
+      // If we had an active selection, mark that we just finished selecting
+      if (selectionBox?.isActive) {
+        console.log(JSON.stringify({ settingJustFinishedSelecting: true }));
+        setJustFinishedSelecting(true);
+        // Clear the flag after a short delay to allow click events to check it
+        setTimeout(() => {
+          console.log(JSON.stringify({ clearingJustFinishedSelecting: true }));
+          setJustFinishedSelecting(false);
+        }, 50);
+      }
+
+      // Don't call selectElementsInBox again - real-time selection already handled it
+      // Just clean up the selection box visual
+      setSelectionBox(null);
+    };
+
+    window.addEventListener("mousemove", handleMouseMove);
+    window.addEventListener("mouseup", handleMouseUp);
+
+    return () => {
+      window.removeEventListener("mousemove", handleMouseMove);
+      window.removeEventListener("mouseup", handleMouseUp);
+    };
+  }, [selectionBox, selectElementsInBox]);
+
+  return {
+    selectionBox,
+    handleMouseDown,
+    isSelecting: selectionBox?.isActive || false,
+    justFinishedSelecting,
+  };
+}