Add addBottom function

Signed-off-by: David Arendsen <darendsen@gamepoint.com>

docs/04-functions.md

@@ -8,6 +8,7 @@ On this page you will find the methods you can use in the query builder.
 or [fromBucket()](functions/fromBucket.md)
 * [fromMeasurement()](functions/fromMeasurement.md)
 * [addAggregateWindow()](functions/addAggregateWindow.md)
+* [addBottom()](functions/addBottom.md)
 * [addCount()](functions/addCount.md)
 * [addDuplicate()](functions/addDuplicate.md)
 * [addFieldFilter()](functions/addFieldFilter.md)

docs/functions/addBottom.md

@@ -0,0 +1,45 @@
+# Flux Query Builder Docs
+
+## Functions » addBottom()
+
+### Parameters:
+
+<table>
+  <tbody>
+    <tr>
+      <th>Name</th>
+      <th>Required</th>
+      <th>Data type</th>
+      <th>Description</th>
+    </tr>
+    <tr>
+      <td>n</td>
+      <td>Yes</td>
+      <td>string</td>
+      <td>Number of rows to return from each input table.</td>
+    </tr>
+    <tr>
+      <td>columns</td>
+      <td>No</td>
+      <td>array</td>
+      <td>List of columns to sort by. Default is ["_value"].</td>
+    </tr>
+  </tbody>
+</table>
+
+
+### Example
+
+```php
+->addBottom(2, ['_value'])
+```
+
+This will result in the following Flux function part:
+
+```
+|> bottom(n: 2, columns: ["_value"])
+```
+
+### Extra resources
+
+* [Flux documentation](https://docs.influxdata.com/flux/v0.x/stdlib/universe/bottom/)

src/Builder/Universe.php

@@ -4,6 +4,7 @@ namespace Arendsen\FluxQueryBuilder\Builder;
 
 use Arendsen\FluxQueryBuilder\Builder\QueryBuilderInterface;
 use Arendsen\FluxQueryBuilder\Functions\AggregateWindow;
+use Arendsen\FluxQueryBuilder\Functions\Bottom;
 use Arendsen\FluxQueryBuilder\Functions\Count;
 use Arendsen\FluxQueryBuilder\Functions\Duplicate;
 use Arendsen\FluxQueryBuilder\Functions\First;
@@ -30,6 +31,12 @@ trait Universe
         return $this;
     }
 
+    public function addBottom(int $n, array $columns = []): QueryBuilderInterface
+    {
+        $this->addToQuery(new Bottom($n, $columns));
+        return $this;
+    }
+
     public function addCount(?string $column = null): QueryBuilderInterface
     {
         $this->addToQuery(

src/Functions/Bottom.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Arendsen\FluxQueryBuilder\Functions;
+
+use Arendsen\FluxQueryBuilder\Type\ArrayType;
+
+class Bottom extends Base
+{
+    /**
+     * @var int $n
+     */
+    private $n;
+
+    /**
+     * @var array $columns
+     */
+    private $columns;
+
+    public function __construct($n, array $columns = [])
+    {
+        $this->n = $n;
+        $this->columns = $columns;
+    }
+
+    public function __toString()
+    {
+        $input = new ArrayType(array_filter([
+            'n' => $this->n,
+            'columns' => $this->columns ?: null,
+        ]));
+        return '|> bottom(' . $input . ') ';
+    }
+}

tests/QueryBuilderTest.php

@@ -41,6 +41,11 @@ final class QueryBuilderTest extends TestCase
                 ['20s', 'mean', ['timeDst' => '_time']],
                 '|> aggregateWindow(every: 20s, fn: mean, timeDst: "_time") '
             ],
+            'addBottom' => [
+                'addBottom',
+                [2, ['_value']],
+                '|> bottom(n: 2, columns: ["_value"]) '
+            ],
             'addCount' => [
                 'addCount',
                 ['_value'],