refactor(web): extract timeline range selection helpers

apps/web/src/hooks/useTimelineDrag.ts

@@ -17,6 +17,7 @@ import {
   finalizeMultiSelectDraft,
   updateMultiSelectDraft,
 } from "./timelineMultiSelect.js";
+import { finalizeRangeSelection, updateRangeSelectionDraft } from "./timelineRangeSelection.js";
 import { getTouchPoint, resolveTouchDragDecision } from "./timelineTouch.js";
 
 const DRAG_CLICK_THRESHOLD_PX = 5;
@@ -893,18 +894,8 @@ export function useTimelineDrag({
 
       // Range select
       const range = rangeStateRef.current;
-      if (range.isSelecting && range.startDate) {
-        const deltaX = e.clientX - range.startClientX;
-        const daysDelta = pixelsToDays(deltaX, cellWidthRef.current);
-        const currentDate = new Date(range.startDate);
-        currentDate.setDate(currentDate.getDate() + daysDelta);
-
-        const prevDelta = range.currentDate
-          ? Math.round((range.currentDate.getTime() - range.startDate.getTime()) / 86400000)
-          : 0;
-        if (daysDelta === prevDelta) return;
-
-        const updated: RangeState = { ...range, currentDate };
+      const updated = updateRangeSelectionDraft(range, e.clientX, cellWidthRef.current);
+      if (updated) {
         rangeStateRef.current = updated;
         setRangeState(updated);
       }
@@ -927,19 +918,9 @@ export function useTimelineDrag({
 
       // Range select
       const range = rangeStateRef.current;
-      if (range.isSelecting && range.resourceId && range.startDate) {
-        const endDate = range.currentDate ?? range.startDate;
-        const [startDate, finalEnd] =
-          range.startDate <= endDate ? [range.startDate, endDate] : [endDate, range.startDate];
-
-        onRangeSelected?.({
-          resourceId: range.resourceId,
-          startDate,
-          endDate: finalEnd,
-          suggestedProjectId: range.suggestedProjectId,
-          anchorX: e.clientX,
-          anchorY: e.clientY,
-        });
+      const selection = finalizeRangeSelection(range, e.clientX, e.clientY);
+      if (selection) {
+        onRangeSelected?.(selection);
 
         rangeStateRef.current = INITIAL_RANGE_STATE;
         setRangeState(INITIAL_RANGE_STATE);