Implemented the composite aggregation feature

docs/searchclass.md

@@ -252,14 +252,28 @@ The `facet()` method allows you to add a facet (aggregation) to your search quer
 $search->facet($field, $group = null, $limit = null, $sortField = null, $sortDirection = 'desc');
 ```
 Parameters:
- * attribute name - This is a required parameter and can also be an expression name.
- * facet alias - If not provided, the attribute name will be utilized.
+ * field - name of the attribute to group by. This is a required parameter and can also be an expression name.
+ * group - Facet name. If not provided, the attribute name will be utilized.
  * limit - Defines the maximum number of facet values to return.
  * sortField - Field the facet values will be sorted by. Also, can be set as `COUNT(*)` or `FACET()`. For details, see [Ordering in facet result](https://manual.manticoresearch.com/Searching/Faceted_search#Ordering-in-facet-result).
  * sortDirection - Direction of sorting, `desc` by default
 
 Facets will be included in the result set and can be accessed using [ResultSet:getFacets()](searchresults.md#resultset-object).
 
+### multiFacet()
+
+The `multiFacet()` method allows you to add a facet (aggregation) composed by multiple fields to your search query.
+
+```php
+$search->multiFacet($group = null, $limit = null);
+```
+Parameters:
+ * group - Facet name. This is a required parameter.
+ * limit - Defines the maximum number of facet values to return.
+
+Multi field facets will be included in the result set and can be accessed using [ResultSet:getFacets()](searchresults.md#resultset-object).
+
+
 ### option()
 
 Pass options to the search query.

src/Manticoresearch/Search.php

@@ -258,22 +258,57 @@ public function maxMatches($maxmatches): self {
 		return $this;
 	}
 
-	public function facet($field, $group = null, $limit = null, $sortField = null, $sortDirection = 'desc') : self {
-		// reset facets
-		if ($field === false) {
-			$this->params['aggs'] = [];
-		}
+	public function facet(
+		$field,
+		$group = null,
+		$limit = null,
+		$sortField = null,
+		$sortDirection = 'desc',
+		$multiGroup = null
+	): self {
 		if ($group === null) {
 			$group = $field;
 		}
-			$terms = ['field' => $field];
+		$terms = ['field' => $field];
 		if ($limit !== null) {
 			$terms['size'] = $limit;
 		}
-		$this->params['aggs'][$group] = ['terms' => $terms];
+		$facet = ['terms' => $terms];
 		if ($sortField !== null) {
-			$this->params['aggs'][$group]['sort'] = [ [$sortField => $sortDirection] ];
+			$facet['sort'] = [ [$sortField => $sortDirection] ];
+		}
+		if ($multiGroup !== null && isset($this->params['aggs'], $this->params['aggs'][$multiGroup])) {
+			// reset facets
+			if ($field === false) {
+				$this->params['aggs'][$multiGroup]['sources'] = [];
+			}
+			$this->params['aggs'][$multiGroup]['composite']['sources'][] = [ $group => $facet ];
+		} else {
+			// reset facets
+			if ($field === false) {
+				$this->params['aggs'] = [];
+			}
+			$this->params['aggs'][$group] = $facet;
 		}
+
+		return $this;
+	}
+
+	public function multiFacet($group, $limit = null): self {
+		// reset multi facets
+		if ($group === false) {
+			$this->params['aggs'] = array_filter(
+				$this->params['aggs'],
+				function ($v) {
+					return isset($v['composite']);
+				}
+			);
+		}
+		$this->params['aggs'][$group] = [ 'composite' => [ 'sources' => [] ] ];
+		if ($limit !== null) {
+			$this->params['aggs'][$group]['composite']['size'] = $limit;
+		}
+
 		return $this;
 	}
 
@@ -332,6 +367,7 @@ public function profile(): self {
 	 */
 	public function get() {
 		$this->body = $this->compile();
+		print_r($this->body);
 		$resp = $this->client->search(['body' => $this->body], true);
 		return new ResultSet($resp);
 	}

test/Manticoresearch/SearchTest.php

@@ -849,6 +849,17 @@ public function testFacets() {
 		$this->assertCount(3, $facets['_year']['buckets']);
 	}
 
+	public function multiFacets() {
+		$results = static::$search->filter('_year', 'range', [1960,1992])->multiFacet('multi')
+			->facet('_year', null, null, null, 'desc', 'multi')
+			->facet('rating', null, null, null, 'desc', 'multi')
+			->get();
+		$facets = $results->getFacets();
+		$this->assertCount(1, $facets);
+		$this->assertArrayHasKey('_year', $facets);
+		$this->assertCount(3, $facets['_year']['buckets']);
+	}
+
 	public function testKnnSearchByDocId() {
 		$results = static::$search->knn('kind', 3, 5)->get();
 		$resultIds = [4,5,2,6,10];