Separate workspace item finding logic

Extract the item finding logic from AddWorkspaceItemsTask
to a separate class and write tests.

Test: AddWorkspaceItemsTaskTest.kt , WorkspaceItemSpaceFinderTest.kt
Bug: 199160559
Change-Id: Ie1bc4fcd4f94cd7cb0601c21bbdf273452b9dd1f

src/com/android/launcher3/model/WorkspaceItemSpaceFinder.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.launcher3.model;
+
+import static com.android.launcher3.WorkspaceLayoutManager.FIRST_SCREEN_ID;
+
+import android.util.LongSparseArray;
+
+import com.android.launcher3.InvariantDeviceProfile;
+import com.android.launcher3.LauncherAppState;
+import com.android.launcher3.LauncherSettings;
+import com.android.launcher3.config.FeatureFlags;
+import com.android.launcher3.model.data.ItemInfo;
+import com.android.launcher3.util.GridOccupancy;
+import com.android.launcher3.util.IntArray;
+import com.android.launcher3.util.IntSet;
+
+import java.util.ArrayList;
+
+/**
+ * Utility class to help find space for new workspace items
+ */
+public class WorkspaceItemSpaceFinder {
+
+    /**
+     * Find a position on the screen for the given size or adds a new screen.
+     *
+     * @return screenId and the coordinates for the item in an int array of size 3.
+     */
+    public int[] findSpaceForItem(LauncherAppState app, BgDataModel dataModel,
+            IntArray workspaceScreens, IntArray addedWorkspaceScreensFinal, int spanX, int spanY) {
+        LongSparseArray<ArrayList<ItemInfo>> screenItems = new LongSparseArray<>();
+
+        // Use sBgItemsIdMap as all the items are already loaded.
+        synchronized (dataModel) {
+            for (ItemInfo info : dataModel.itemsIdMap) {
+                if (info.container == LauncherSettings.Favorites.CONTAINER_DESKTOP) {
+                    ArrayList<ItemInfo> items = screenItems.get(info.screenId);
+                    if (items == null) {
+                        items = new ArrayList<>();
+                        screenItems.put(info.screenId, items);
+                    }
+                    items.add(info);
+                }
+            }
+        }
+
+        // Find appropriate space for the item.
+        int screenId = 0;
+        int[] coordinates = new int[2];
+        boolean found = false;
+
+        int screenCount = workspaceScreens.size();
+        // First check the preferred screen.
+        IntSet screensToExclude = new IntSet();
+        if (FeatureFlags.QSB_ON_FIRST_SCREEN) {
+            screensToExclude.add(FIRST_SCREEN_ID);
+        }
+
+        for (int screen = 0; screen < screenCount; screen++) {
+            screenId = workspaceScreens.get(screen);
+            if (!screensToExclude.contains(screenId) && findNextAvailableIconSpaceInScreen(
+                    app, screenItems.get(screenId), coordinates, spanX, spanY)) {
+                // We found a space for it
+                found = true;
+                break;
+            }
+        }
+
+        if (!found) {
+            // Still no position found. Add a new screen to the end.
+            screenId = LauncherSettings.Settings.call(app.getContext().getContentResolver(),
+                    LauncherSettings.Settings.METHOD_NEW_SCREEN_ID)
+                    .getInt(LauncherSettings.Settings.EXTRA_VALUE);
+
+            // Save the screen id for binding in the workspace
+            workspaceScreens.add(screenId);
+            addedWorkspaceScreensFinal.add(screenId);
+
+            // If we still can't find an empty space, then God help us all!!!
+            if (!findNextAvailableIconSpaceInScreen(
+                    app, screenItems.get(screenId), coordinates, spanX, spanY)) {
+                throw new RuntimeException("Can't find space to add the item");
+            }
+        }
+        return new int[]{screenId, coordinates[0], coordinates[1]};
+    }
+
+    private boolean findNextAvailableIconSpaceInScreen(
+            LauncherAppState app, ArrayList<ItemInfo> occupiedPos,
+            int[] xy, int spanX, int spanY) {
+        InvariantDeviceProfile profile = app.getInvariantDeviceProfile();
+
+        GridOccupancy occupied = new GridOccupancy(profile.numColumns, profile.numRows);
+        if (occupiedPos != null) {
+            for (ItemInfo r : occupiedPos) {
+                occupied.markCells(r, true);
+            }
+        }
+        return occupied.findVacantCell(xy, spanX, spanY);
+    }
+}