Move dynamic segments from Premium plugin

[MAILPOET-2382]

lib/DynamicSegments/Persistence/Loading/Loader.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace MailPoet\Premium\DynamicSegments\Persistence\Loading;
+
+use MailPoet\Premium\DynamicSegments\Mappers\DBMapper;
+use MailPoet\Premium\Models\DynamicSegment;
+use MailPoet\Premium\Models\DynamicSegmentFilter;
+
+class Loader {
+
+  /** @var DBMapper */
+  private $mapper;
+
+  public function __construct(DBMapper $mapper) {
+    $this->mapper = $mapper;
+  }
+
+  /**
+   * @return DynamicSegment[]
+   */
+  function load() {
+    $segments = DynamicSegment::findAll();
+    return $this->loadFilters($segments);
+  }
+
+  private function loadFilters(array $segments) {
+    $ids = array_map(function($segment) {
+      return $segment->id;
+    }, $segments);
+    $filters = DynamicSegmentFilter::getAllBySegmentIds($ids);
+
+    return $this->mapper->mapSegments($segments, $filters);
+  }
+
+}