fix half block dragging (#6135)

web/ce/store/timeline/base-timeline.store.ts

@@ -44,7 +44,11 @@ export interface IBaseTimelineStore {
   updateActiveBlockId: (blockId: string | null) => void;
   updateRenderView: (data: any) => void;
   updateAllBlocksOnChartChangeWhileDragging: (addedWidth: number) => void;
-  getUpdatedPositionAfterDrag: (id: string, ignoreDependencies?: boolean) => IBlockUpdateDependencyData[];
+  getUpdatedPositionAfterDrag: (
+    id: string,
+    shouldUpdateHalfBlock: boolean,
+    ignoreDependencies?: boolean
+  ) => IBlockUpdateDependencyData[];
   updateBlockPosition: (id: string, deltaLeft: number, deltaWidth: number, ignoreDependencies?: boolean) => void;
   getNumberOfDaysFromPosition: (position: number | undefined) => number | undefined;
   setIsDragging: (isDragging: boolean) => void;
@@ -271,24 +275,30 @@ export class BaseTimeLineStore implements IBaseTimelineStore {
   /**
    * returns updates dates of blocks post drag.
    * @param id
+   * @param shouldUpdateHalfBlock if is a half block then update the incomplete block only if this is true
    * @returns
    */
-  getUpdatedPositionAfterDrag = action((id: string) => {
+  getUpdatedPositionAfterDrag = action((id: string, shouldUpdateHalfBlock: boolean) => {
     const currBlock = this.blocksMap[id];
 
     if (!currBlock?.position || !this.currentViewData) return [];
 
-    return [
-      {
-        id,
-        start_date: renderFormattedPayloadDate(
-          getDateFromPositionOnGantt(currBlock.position.marginLeft, this.currentViewData)
-        ),
-        target_date: renderFormattedPayloadDate(
-          getDateFromPositionOnGantt(currBlock.position.marginLeft + currBlock.position.width, this.currentViewData, -1)
-        ),
-      },
-    ] as IBlockUpdateDependencyData[];
+    const updatePayload: IBlockUpdateDependencyData = { id };
+
+    // If shouldUpdateHalfBlock or the start date is available then update start date
+    if (shouldUpdateHalfBlock || currBlock.start_date) {
+      updatePayload.start_date = renderFormattedPayloadDate(
+        getDateFromPositionOnGantt(currBlock.position.marginLeft, this.currentViewData)
+      );
+    }
+    // If shouldUpdateHalfBlock or the target date is available then update target date
+    if (shouldUpdateHalfBlock || currBlock.target_date) {
+      updatePayload.target_date = renderFormattedPayloadDate(
+        getDateFromPositionOnGantt(currBlock.position.marginLeft + currBlock.position.width, this.currentViewData, -1)
+      );
+    }
+
+    return [updatePayload];
   });
 
   /**

web/core/components/gantt-chart/helpers/blockResizables/use-gantt-resizable.ts

@@ -4,7 +4,7 @@ import { setToast } from "@plane/ui";
 // hooks
 import { useTimeLineChartStore } from "@/hooks/use-timeline-chart";
 //
-import { SIDEBAR_WIDTH } from "../../constants";
+import { DEFAULT_BLOCK_WIDTH, SIDEBAR_WIDTH } from "../../constants";
 import { IBlockUpdateDependencyData, IGanttBlock } from "../../types";
 
 export const useGanttResizable = (
@@ -75,10 +75,19 @@ export const useGanttResizable = (
         const prevWidth = parseFloat(resizableDiv.style.width.slice(0, -2));
         // calculate new width
         const marginDelta = prevMarginLeft - marginLeft;
-        width = prevWidth + marginDelta;
+        // If target date does not exist while dragging with left handle the revert to default width
+        width = block.target_date ? prevWidth + marginDelta : DEFAULT_BLOCK_WIDTH;
       } else if (dragDirection === "right") {
         // calculate new width and update the initialMarginLeft using +=
         width = Math.round(mouseX / dayWidth) * dayWidth - marginLeft;
+
+        // If start date does not exist while dragging with right handle the revert to default width and adjust marginLeft accordingly
+        if (!block.start_date) {
+          // calculate new right and update the marginLeft to the newly calculated one
+          const marginRight = Math.round(mouseX / dayWidth) * dayWidth;
+          marginLeft = marginRight - DEFAULT_BLOCK_WIDTH;
+          width = DEFAULT_BLOCK_WIDTH;
+        }
       } else if (dragDirection === "move") {
         // calculate new marginLeft and update the initial marginLeft using -=
         marginLeft = Math.round((mouseX - initialPositionRef.current.offsetX) / dayWidth) * dayWidth;
@@ -105,8 +114,12 @@ export const useGanttResizable = (
       ganttContainerElement.removeEventListener("scroll", handleOnScroll);
       document.removeEventListener("mouseup", handleMouseUp);
 
+      // update half blocks only when the missing side of the block is directly dragged
+      const shouldUpdateHalfBlock =
+        (dragDirection === "left" && !block.start_date) || (dragDirection === "right" && !block.target_date);
+
       try {
-        const blockUpdates = getUpdatedPositionAfterDrag(block.id, dragDirection !== "move");
+        const blockUpdates = getUpdatedPositionAfterDrag(block.id, shouldUpdateHalfBlock, dragDirection !== "move");
         updateBlockDates && updateBlockDates(blockUpdates);
       } catch (e) {
         setToast;

web/core/components/gantt-chart/views/helpers.ts

@@ -99,7 +99,7 @@ export const getItemPositionWidth = (chartData: ChartDataType, itemData: IGanttB
   // get scroll position from the number of days and width of each day
   scrollPosition = itemStartDate
     ? getPositionFromDate(chartData, itemStartDate, 0)
-    : getPositionFromDate(chartData, itemTargetDate!, -1 * DEFAULT_BLOCK_WIDTH);
+    : getPositionFromDate(chartData, itemTargetDate!, -1 * DEFAULT_BLOCK_WIDTH + chartData.data.dayWidth);
 
   if (itemStartDate && itemTargetDate) {
     // get width of block