class LogToReportMigration

abstract class LogToReportMigration implements Migration {
    
    /**
     * @throws MigrationException
     */
    public function migrate(DOMDocument $document) : void {
        $coverage = $document->getElementsByTagName('coverage')
            ->item(0);
        if (!$coverage instanceof DOMElement) {
            throw new MigrationException('Unexpected state - No coverage element');
        }
        $logNode = $this->findLogNode($document);
        if ($logNode === null) {
            return;
        }
        $reportChild = $this->toReportFormat($logNode);
        $report = $coverage->getElementsByTagName('report')
            ->item(0);
        if ($report === null) {
            $report = $coverage->appendChild($document->createElement('report'));
        }
        $report->appendChild($reportChild);
        $logNode->parentNode
            ->removeChild($logNode);
    }
    protected function migrateAttributes(DOMElement $src, DOMElement $dest, array $attributes) : void {
        foreach ($attributes as $attr) {
            if (!$src->hasAttribute($attr)) {
                continue;
            }
            $dest->setAttribute($attr, $src->getAttribute($attr));
            $src->removeAttribute($attr);
        }
    }
    protected abstract function forType() : string;
    protected abstract function toReportFormat(DOMElement $logNode) : DOMElement;
    private function findLogNode(DOMDocument $document) : ?DOMElement {
        $logNode = (new DOMXPath($document))->query(sprintf('//logging/log[@type="%s"]', $this->forType()))
            ->item(0);
        if (!$logNode instanceof DOMElement) {
            return null;
        }
        return $logNode;
    }

}