Refactor facets handling

lib/Alchemy/Phrasea/SearchEngine/Elastic/Search/FacetsResponse.php

@@ -0,0 +1,67 @@
+<?php
+
+namespace Alchemy\Phrasea\SearchEngine\Elastic\Search;
+
+use Alchemy\Phrasea\Exception\RuntimeException;
+use JsonSerializable;
+
+class FacetsResponse implements JsonSerializable
+{
+    private $facets = array();
+
+    public function __construct(array $response)
+    {
+        if (!isset($response['aggregations'])) {
+            return;
+        }
+        foreach ($response['aggregations'] as $name => $aggregation) {
+            if (!isset($aggregation['buckets'])) {
+                $this->throwAggregationResponseError();
+            }
+            $values = $this->buildBucketsValues($name, $aggregation['buckets']);
+            if ($values) {
+                $this->facets[] = array(
+                    'name' => $name,
+                    'values' => $values,
+                );
+            }
+        }
+    }
+
+    private function buildBucketsValues($name, $buckets)
+    {
+        $values = array();
+        foreach ($buckets as $bucket) {
+            if (!isset($bucket['key']) || !isset($bucket['doc_count'])) {
+                $this->throwAggregationResponseError();
+            }
+            $values[] = array(
+                'value' => $bucket['key'],
+                'count' => $bucket['doc_count'],
+                'query' => $this->buildQuery($name, $bucket['key']),
+            );
+        }
+
+        return $values;
+    }
+
+    private function buildQuery($name, $value)
+    {
+        // Strip double quotes from values to prevent broken queries
+        $value = str_replace('/"/u', ' ', $value);
+        // TODO escape value when escaping is supported in query parser
+        return ($name === 'Collection') ?
+            sprintf('collection:"%s"', $value) :
+            sprintf('"%s" IN %s', $value, $name);
+    }
+
+    private function throwAggregationResponseError()
+    {
+        throw new RuntimeException('Invalid aggregation response');
+    }
+
+    public function jsonSerialize()
+    {
+        return $this->facets;
+    }
+}