feat[index]: Add support for inverted indexes

src/Collection/Index/Factory.php

@@ -38,6 +38,7 @@ public static function factory(array $attributes): IndexInterface
             'geo' => GeoSpatialIndex::class,
             'skiplist' => SkipListIndex::class,
             'ttl' => TTLIndex::class,
+            'inverted' => InvertedIndex::class
         ];
 
         if (!array_key_exists($attributes['type'], $indexes)) {
@@ -61,6 +62,10 @@ public static function factory(array $attributes): IndexInterface
             return new TTLIndex($attributes['fields'], $attributes['expireAfter'], $attributes);
         }
 
+        if ($attributes['type'] === 'inverted') {
+            return new InvertedIndex($attributes['fields'], $attributes);
+        }
+
         $class = $indexes[$attributes['type']];
         return new $class($attributes['fields'], $attributes);
     }

src/Collection/Index/HashIndex.php

@@ -11,6 +11,7 @@
  *
  * @package ArangoDB\Collection\Index
  * @author Lucas S. Vieira
+ * @deprecated
  */
 class HashIndex extends Index
 {

src/Collection/Index/Index.php

@@ -21,42 +21,42 @@ class Index implements IndexInterface
      *
      * @var string
      */
-    protected $id;
+    protected string $id;
 
     /**
      * Index name.
      *
      * @var string
      */
-    protected $name;
+    protected string $name;
 
     /**
      * Sparse
      *
      * @var bool
      */
-    protected $sparse;
+    protected bool $sparse;
 
     /**
      * Index type
      *
      * @var string
      */
-    protected $type;
+    protected string $type;
 
     /**
      * Unique constraint
      *
      * @var bool
      */
-    protected $unique;
+    protected bool $unique;
 
     /**
      * Fields of index
      *
      * @var array
      */
-    protected $fields;
+    protected array $fields;
 
     /**
      * Collection where the index belongs to
@@ -71,21 +71,21 @@ class Index implements IndexInterface
      *
      * @var bool
      */
-    protected $isNew;
+    protected bool $isNew;
 
     /**
      * Valid indexes types
      *
      * @var array
      */
-    protected static $indexTypes = [
-        'fulltext', 'general', 'geo', 'hash', 'persistent', 'skiplist', 'ttl', 'primary', 'edge'
+    protected static array $indexTypes = [
+        'fulltext', 'general', 'geo', 'hash', 'persistent', 'skiplist', 'ttl', 'primary', 'edge', 'inverted'
     ];
 
     /**
      * Index constructor.
      *
-     * @param string $type The index type. Must be one of following values: 'fulltext', 'general', 'geo', 'hash', 'persistent', 'skiplist' or 'ttl'
+     * @param string $type The index type. Must be one of following values: 'fulltext', 'general', 'geo', 'hash', 'persistent', 'skiplist', 'inverted' or 'ttl'
      * @param array $fields An array of attribute names. Normally with just one attribute.
      *
      * @param array $attributes
@@ -97,20 +97,30 @@ public function __construct(string $type, array $fields, array $attributes = [])
             throw new InvalidParameterException("type", $type);
         }
 
+        $fieldNames = [];
+
         foreach ($fields as $key => $field) {
-            if (!is_string($field)) {
-                throw new InvalidParameterException("fields[$key]", $field);
+            if (is_string($field)) {
+                array_push($fieldNames, $field);
+                continue;
+            }
+
+            if (is_array($field)) {
+                array_push($fieldNames, $field['name']);
+                continue;
             }
+
+            throw new InvalidParameterException("fields[$key]", $field);
         }
 
         $this->type = $type;
         $this->fields = $fields;
 
         // Default values;
-        $this->id = isset($attributes['id']) ? $attributes['id'] : '';
-        $this->name = isset($attributes['name']) ? $attributes['name'] : '';
-        $this->unique = isset($attributes['unique']) ? $attributes['unique'] : false;
-        $this->sparse = isset($attributes['sparse']) ? $attributes['sparse'] : false;
+        $this->id = $attributes['id'] ?? '';
+        $this->name = $attributes['name'] ?? '';
+        $this->unique = $attributes['unique'] ?? false;
+        $this->sparse = $attributes['sparse'] ?? false;
         $this->isNew = !isset($attributes['id']);
     }
 

src/Collection/Index/InvertedIndex.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace ArangoDB\Collection\Index;
+
+use ArangoDB\Validation\Exceptions\InvalidParameterException;
+
+/**
+* Inverted index representation
+*
+* @package ArangoDB\Collection\Index
+* @author Lucas S. Vieira
+*/
+final class InvertedIndex extends Index
+{
+    /**
+     * Default options for inverted index
+     *
+     * @var array
+     */
+    protected array $defaultOptions = [
+        'unique' => true,
+        'sparse' => true,
+        'analyzer' => "identity",
+        'inBackground' => true, // Keep the collection available for writes during the index creation
+        'parallelism' => 2,
+    ];
+
+    /**
+     * InvertedIndex constructor
+     *
+     * @param array $fields Fields for which the index applies to
+     * @param array $attributes Index $attributes
+     *
+     * @throws InvalidParameterException
+     */
+    public function __construct(array $fields, array $attributes = [])
+    {
+        parent::__construct('inverted', $fields, $attributes);
+    }
+}

src/Collection/Index/SkipListIndex.php

@@ -11,6 +11,7 @@
  *
  * @package ArangoDB\Collection\Index
  * @author Lucas S. Vieira
+ * @deprecated
  */
 final class SkipListIndex extends HashIndex
 {