From 6336f9bca39420b2fa8d43f6100cb2e846af0afb Mon Sep 17 00:00:00 2001
From: Sebastian Franco <fransebas@google.com>
Date: Fri, 17 Nov 2023 10:47:00 -0600
Subject: [PATCH] Make sure ReorderAlgorithm only work on the logic layer and
 not on the view layer

The method isNearestDropLocationOccupied finds the NearestDrop location
using the view models (i.e. the CellLayoutLayoutParams) and the new
method isConfigurationRegionOccupied run over the logic models (i.e. the
CellAndSpan or ItemConfiguration) ensuring a separation between them.

Test: ReorderAlgorithmUnitTest
Flag: LEGACY FOLDABLE_SINGLE_PAGE DISABLED
Bug: 270395274
Change-Id: I0b3c6606ee6934ea3a5e41d110677c496d4a4330
---
 .../celllayout/ReorderAlgorithm.java          | 28 +++++++++++++++----
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/com/android/launcher3/celllayout/ReorderAlgorithm.java b/src/com/android/launcher3/celllayout/ReorderAlgorithm.java
index 5e5eefe602..17786f24fb 100644
--- a/src/com/android/launcher3/celllayout/ReorderAlgorithm.java
+++ b/src/com/android/launcher3/celllayout/ReorderAlgorithm.java
@@ -15,10 +15,13 @@
  */
 package com.android.launcher3.celllayout;
 
+import android.graphics.Rect;
 import android.view.View;
 
 import com.android.launcher3.CellLayout;
 
+import java.util.Map.Entry;
+
 /**
  * Contains the logic of a reorder.
  *
@@ -109,14 +112,16 @@ public class ReorderAlgorithm {
      */
     public CellLayout.ItemConfiguration dropInPlaceSolution(int pixelX, int pixelY, int spanX,
             int spanY, View dragView) {
-        int[] result = new int[2];
-        if (mCellLayout.isNearestDropLocationOccupied(pixelX, pixelY, spanX, spanY, dragView,
-                result)) {
-            result[0] = result[1] = -1;
-        }
+        int[] result = mCellLayout.findNearestAreaIgnoreOccupied(pixelX, pixelY, spanX, spanY,
+                new int[2]);
         CellLayout.ItemConfiguration solution = new CellLayout.ItemConfiguration();
         mCellLayout.copyCurrentStateToSolution(solution, false);
-        solution.isSolution = result[0] != -1;
+
+        solution.isSolution = !isConfigurationRegionOccupied(
+                new Rect(result[0], result[1], result[0] + spanX, result[1] + spanY),
+                solution,
+                dragView
+        );
         if (!solution.isSolution) {
             return solution;
         }
@@ -127,6 +132,17 @@ public class ReorderAlgorithm {
         return solution;
     }
 
+    private boolean isConfigurationRegionOccupied(Rect region,
+            CellLayout.ItemConfiguration configuration, View ignoreView) {
+        return configuration.map.entrySet()
+                .stream()
+                .filter(entry -> entry.getKey() != ignoreView)
+                .map(Entry::getValue)
+                .anyMatch(cellAndSpan -> region.intersect(cellAndSpan.cellX, cellAndSpan.cellY,
+                        cellAndSpan.cellX + cellAndSpan.spanX,
+                        cellAndSpan.cellY + cellAndSpan.spanY));
+    }
+
     /**
      * Returns a "reorder" where we simply drop the item in the closest empty space, without moving
      * any other item in the way.