Added support for a forced position on new object (old position returns null)

Author: Martin Kluska

src/Commands/RecalculatePositionCommand.php

@@ -64,9 +64,6 @@ public function handle()
         $modelClass::sorted()->chunk(200, function (Collection $collection) use ($groups, &$positionsByGroup) {
             /** @var PositionTrait|Model $model */
             foreach ($collection as $model) {
-                // Prevent the move action and force the position we set
-                $model->setDisablePositionUpdateAttribute(true);
-
                 // Builds the group key to get position
                 $groupKey = $this->buildGroupKeyForPosition($model, $groups);
 

src/PositionObserver.php

@@ -1,9 +1,11 @@
 <?php
+
 namespace Pion\Support\Eloquent\Position;
 
 use Pion\Support\Eloquent\Position\Query\AbstractPositionQuery;
 use Pion\Support\Eloquent\Position\Query\LastPositionQuery;
 use Pion\Support\Eloquent\Position\Query\PositionQuery;
+use Pion\Support\Eloquent\Position\Query\MoveQuery;
 use Pion\Support\Eloquent\Position\Traits\PositionTrait;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Contracts\Events\Dispatcher;
@@ -50,12 +52,30 @@ public function saving($model)
             // Check if the position is set
             if (is_null($position) || $position == '') {
                 $this->appendLast($model, $oldPosition);
+            } else if (is_null($oldPosition)) {
+                $this->forcedPosition($model, $position);
             } else {
                 $this->move($model, $position, $oldPosition);
             }
         }
     }
 
+    /**
+     * Forces the new position, will be overriden if it's out of maximum bounds.
+     *
+     * @param Model|PositionTrait $model
+     * @param int                 $position
+     * @param int|null            $oldPosition
+     */
+    protected function forcedPosition($model, $position, $oldPosition = null)
+    {
+        // Build the new position
+        $query = new PositionQuery($model, $position);
+
+        // Run the query
+        $query->runQuery($query, $oldPosition);
+    }
+
     /**
      * Setups the position to be at the end
      *
@@ -83,7 +103,7 @@ protected function move($model, $position, $oldPosition)
         // Check if the position has change and we need to recalculate
         if ($oldPosition != $position) {
             // Build the position query
-            $query = new PositionQuery($model, $position, $oldPosition);
+            $query = new MoveQuery($model, $position, $oldPosition);
 
             // Run the position query
             $this->runQuery($query, $oldPosition);

src/Query/LastPositionQuery.php

@@ -15,7 +15,6 @@
  */
 class LastPositionQuery extends AbstractPositionQuery
 {
-
     /**
      * Creates the base query and builds the query
      *

src/Query/MoveQuery.php

@@ -0,0 +1,119 @@
+<?php
+namespace Pion\Support\Eloquent\Position\Query;
+
+use Pion\Support\Eloquent\Position\Traits\PositionTrait;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+
+class MoveQuery extends AbstractPositionQuery
+{
+    /**
+     * @var bool
+     */
+    protected $increment = false;
+
+    /**
+     * @var string
+     */
+    protected $positionColumn = null;
+
+    /**
+     * @var int
+     */
+    protected $position;
+
+    /**
+     * Comparision condition for old position value.
+     * In default is for decrement.
+     * @var string
+     */
+    protected $oldComparisionCondition = '>';
+    /**
+     * Comparision condition for new position value.
+     * In default is for decrement.
+     * @var string
+     */
+    protected $newComparisionCondition = '<=';
+
+
+    /**
+     * PositionQuery constructor.
+     *
+     * @param Model|PositionTrait $model
+     * @param int                 $position
+     * @param int|null            $oldPosition
+     */
+    public function __construct($model, $position, $oldPosition)
+    {
+        parent::__construct($model, $oldPosition, false);
+
+        $this->position = $position;
+
+        // Indicate if si the increment/decrement
+        $this->increment = $position < $oldPosition;
+
+        // Get the column for position to build correct query
+        $this->positionColumn = $model->getPositionColumn();
+
+        // Build the comparision condition
+        $this->buildComparisionCondition();
+
+        // Prepare the query
+        $this->query = $this->buildQuery();
+    }
+
+    //region Query
+
+    /**
+     * Runs the increment/decrement query
+     *
+     * @param Builder $query
+     *
+     * @return int
+     */
+    public function runQuery($query)
+    {
+        if ($this->increment) {
+            return $query->increment($this->positionColumn);
+        } else {
+            return $query->decrement($this->positionColumn);
+        }
+    }
+
+    /**
+     * Builds the basic query with where condition (includes the position conditions)
+     * @return Builder
+     */
+    protected function buildQuery()
+    {
+        // Create query
+        $query = parent::buildQuery();
+
+        // Build the where condition for the position. This will ensure to update only required rows
+        return $query->where($this->positionColumn, $this->oldComparisionCondition, $this->oldPosition)
+                    ->where($this->positionColumn, $this->newComparisionCondition, $this->position);
+    }
+
+    /**
+     * Builds the correct comparision condition
+     */
+    protected function buildComparisionCondition()
+    {
+        if ($this->increment) {
+            $this->oldComparisionCondition = '<';
+            $this->newComparisionCondition = '>=';
+        }
+    }
+    //endregion
+
+    //region Getters
+
+    /**
+     * @return mixed
+     */
+    public function position()
+    {
+        return $this->position;
+    }
+    //endregion
+}

src/Query/PositionQuery.php

@@ -1,119 +1,87 @@
 <?php
 namespace Pion\Support\Eloquent\Position\Query;
 
-use Pion\Support\Eloquent\Position\Traits\PositionTrait;
-use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Model;
+use Pion\Support\Eloquent\Position\Traits\PositionTrait;
 
-class PositionQuery extends AbstractPositionQuery
-{
+class PositionQuery extends AbstractPositionQuery {
     /**
-     * @var bool
+     * @var string
      */
-    protected $increment = false;
+    protected $position = null;
 
     /**
      * @var string
      */
     protected $positionColumn = null;
 
     /**
-     * @var int
-     */
-    protected $position;
-
-    /**
-     * Comparision condition for old position value.
-     * In default is for decrement.
-     * @var string
-     */
-    protected $oldComparisionCondition = '>';
-    /**
-     * Comparision condition for new position value.
-     * In default is for decrement.
-     * @var string
+     * When only the new model is updated, we don`t need to run query
+     * @var bool
      */
-    protected $newComparisionCondition = '<=';
-
+    protected $shouldRunQuery = false;
 
     /**
-     * PositionQuery constructor.
+     * Creates the base query and builds the query
      *
      * @param Model|PositionTrait $model
-     * @param int                 $position
-     * @param int                 $oldPosition
      */
-    public function __construct($model, $position, $oldPosition)
+    public function __construct($model, $position)
     {
-        parent::__construct($model, $oldPosition, false);
-
+        // Store the new position
         $this->position = $position;
 
-        // Indicate if si the increment/decrement
-        $this->increment = $position < $oldPosition;
-
-        // Get the column for position to build correct query
+        // Get the position column
         $this->positionColumn = $model->getPositionColumn();
 
-        // Build the comparision condition
-        $this->buildComparisionCondition();
-
-        // Prepare the query
-        $this->query = $this->buildQuery();
-    }
-
-    //region Query
-
-    /**
-     * Runs the increment/decrement query
-     *
-     * @param Builder $query
-     *
-     * @return int
-     */
-    public function runQuery($query)
-    {
-        if ($this->increment) {
-            return $query->increment($this->positionColumn);
-        } else {
-            return $query->decrement($this->positionColumn);
-        }
+        // Build the query
+        parent::__construct($model, null, true);
     }
 
     /**
-     * Builds the basic query with where condition (includes the position conditions)
+     * Builds the basic query and appends a where conditions for group is set
      * @return Builder
      */
     protected function buildQuery()
     {
         // Create query
         $query = parent::buildQuery();
 
-        // Build the where condition for the position. This will ensure to update only required rows
-        return $query->where($this->positionColumn, $this->oldComparisionCondition, $this->oldPosition)
-                    ->where($this->positionColumn, $this->newComparisionCondition, $this->position);
-    }
+        // Get the last position and move the position
+        $lastPosition = $query->max($this->positionColumn);
 
-    /**
-     * Builds the correct comparision condition
-     */
-    protected function buildComparisionCondition()
-    {
-        if ($this->increment) {
-            $this->oldComparisionCondition = '<';
-            $this->newComparisionCondition = '>=';
+        // If the new position is last position, just update the position or if
+        // new position is out of bounds
+        if ($this->position >= $lastPosition) {
+            $this->model()->setPosition($lastPosition + 1);
+        } else {
+            $this->shouldRunQuery = true;
+
+            // Set the forced position
+            $this->model()->setPosition($this->position);
+
+            // Move other models
+            $query->where($this->positionColumn, '>=', $this->position);
         }
+
+        return $query;
     }
-    //endregion
 
-    //region Getters
 
     /**
-     * @return mixed
+     * Runs the query for last position and sets the model position if the position has
+     * changed
+     *
+     * @param Builder $query
+     *
+     * @return int the last position returned
      */
-    public function position()
+    public function runQuery($query)
     {
-        return $this->position;
+        if ($this->shouldRunQuery) {
+            return $query->increment($this->positionColumn);
+        }
+
+        return $this->model()->getPosition();
     }
-    //endregion
-}
+}

src/Traits/BasePositionTrait.php

@@ -128,26 +128,20 @@ protected function resetPositionOptionCache()
      * Enables setting disablePositionUpdate option in runtime
      *
      * @param boolean $value
-     *
-     * @return $this
      */
     public function setDisablePositionUpdateAttribute($value)
     {
         $this->optionCache['disablePositionUpdate'] = $value;
-        return $this;
     }
 
     /**
      * Enables setting positionColumn option in runtime
      *
      * @param string $value
-     *
-     * @return $this
      */
     public function setPositionColumnAttribute($value)
     {
         $this->optionCache['positionColumn'] = $value;
-        return $this;
     }
     //endregion
 }