import re

with open('WorkflowEngine.php', 'r') as f:
    content = f.read()

new_method = """
    public function getOrCreateInstanceBySubject(string $subjectType, int $subjectId, string $processCode, int $userId, string $mode='resume_or_create'): array {
        if (!in_array($subjectType, ['person', 'meeting', 'bni_group', 'organization'])) {
            throw new InvalidArgumentException("Invalid subjectType.");
        }
        if ($subjectId <= 0) {
            throw new InvalidArgumentException("subjectId must be > 0.");
        }
        if (empty($processCode)) {
            throw new InvalidArgumentException("processCode cannot be empty.");
        }

        $inTransaction = $this->pdo->inTransaction();
        if (!$inTransaction) { $this->pdo->beginTransaction(); }

        try {
            $sql = "SELECT * FROM process_definitions WHERE code = ? AND is_active = 1 AND subject_scope = ? ORDER BY version DESC, id DESC LIMIT 1";
            $stmt = $this->pdo->prepare($sql);
            $stmt->execute([$processCode, $subjectType]);
            $definition = $stmt->fetch(PDO::FETCH_ASSOC);

            if (!$definition) {
                $stmt = $this->pdo->prepare("SELECT * FROM process_definitions WHERE code = ? AND is_active = 1 ORDER BY version DESC, id DESC LIMIT 1");
                $stmt->execute([$processCode]);
                $definition = $stmt->fetch(PDO::FETCH_ASSOC);
                if (!$definition) {
                    throw new WorkflowNotFoundException("No active process definition found for code '$processCode'");
                }
            }

            $defId = $definition['id'];
            $defJson = json_decode($definition['definition_json'], true);
            $startNodeId = $defJson['start_node_id'] ?? null;
            if (!$startNodeId) {
                throw new Exception("Process definition missing start_node_id");
            }

            $instance = null;
            if ($mode === 'resume_or_create') {
                $stmt = $this->pdo->prepare(
                    "SELECT pi.* FROM process_instances pi\n                    JOIN process_definitions pd ON pi.process_definition_id = pd.id\n                    WHERE pi.subject_type = ? AND pi.subject_id = ? AND pd.code = ?\n                    ORDER BY pi.id DESC LIMIT 1"
                );
                $stmt->execute([$subjectType, $subjectId, $processCode]);
                $instance = $stmt->fetch(PDO::FETCH_ASSOC);
            }

            if (!$instance) {
                $stmt = $this->pdo->prepare(
                    "SELECT MAX(pi.run_number) \n                    FROM process_instances pi\n                    JOIN process_definitions pd ON pi.process_definition_id = pd.id\n                    WHERE pi.subject_type = ? AND pi.subject_id = ? AND pd.code = ?"
                );
                $stmt->execute([$subjectType, $subjectId, $processCode]);
                $maxRun = (int)$stmt->fetchColumn();
                $runNumber = $maxRun + 1;

                $personIdVal = ($subjectType === 'person') ? $subjectId : null;
                $status = $defJson['nodes'][$startNodeId]['ui_hints']['status'] ?? 'in_progress';
                $reason = $defJson['nodes'][$startNodeId]['ui_hints']['reason'] ?? '';
                $nextStep = $defJson['nodes'][$startNodeId]['ui_hints']['next_step'] ?? '';

                $stmt = $this->pdo->prepare(
                    "INSERT INTO process_instances \n                    (subject_type, subject_id, person_id, process_definition_id, current_node_id, current_status, current_reason, suggested_next_step, run_number, last_activity_at, data_json)\n                    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, NOW(), '{}')"
                );
                $stmt->execute([
                    $subjectType, $subjectId, $personIdVal, $defId, $startNodeId, $status, $reason, $nextStep, $runNumber
                ]);

                $instanceId = $this->pdo->lastInsertId();
                $this->addEvent($instanceId, 'system', 'Process started.', $startNodeId, [], $userId);

                $stmt = $this->pdo->prepare("SELECT * FROM process_instances WHERE id = ?");
                $stmt->execute([$instanceId]);
                $instance = $stmt->fetch(PDO::FETCH_ASSOC);
            }

            if (!$inTransaction) { $this->pdo->commit(); }

            return [
                'instance_id' => $instance['id'],
                'process_definition_id' => $instance['process_definition_id'],
                'process_code' => $processCode,
                'subject_type' => $instance['subject_type'],
                'subject_id' => $instance['subject_id'],
                'person_id' => $instance['person_id'],
                'current_node_id' => $instance['current_node_id'],
                'current_status' => $instance['current_status'],
                'last_activity_at' => $instance['last_activity_at'],
                'data_json' => $instance['data_json']
            ];

        } catch (Exception $e) {
            if (!$inTransaction) { $this->pdo->rollBack(); }
            throw $e;
        }
    }
"

if "function getOrCreateInstanceBySubject" not in content:
    last_brace_idx = content.rfind('}')
    content = content[:last_brace_idx] + new_method + "\n}\n"
    with open('WorkflowEngine.php', 'w') as f:
        f.write(content)
    print("Method added.")
else:
    print("Method already exists.")