package synchronizator

import "slices"

type PlatformClass interface {
	// How to transform the struct into a node. It needs to return the class,
	// name and a []byte representation of the metadata.
	//
	// - name: A user friendly name
	// - metadata: Arbitrary data. This will be stored as a jsonb in the database
	//
	ToNode() (string, []byte, error)

	// How to transform a node into the struct. This method should modify the
	// struct directly as it receives a pointer.
	//
	// - name: A user friendly name
	// - metadata: Arbitrary data. This is stored as a jsonb in the database
	FromNode(string, []byte) error
}

// Utility struct to represent a collection of nodes, it's a [Node] itself so all
// the node's functionality is available.
type Platform struct {
	Node                      // Underlaying node info
	Collections []*Collection // Child nodes
}

type Fetcher = func(pagination Pagination) ([]*Collection, Pagination, error)

type Pagination struct {
	Total   int
	HasMore bool
	Limit   int
	Offset  int
}

var StartPagination = Pagination{
	Total:   0,
	HasMore: false,
	Limit:   10,
	Offset:  0,
}

func (platform *Platform) FetchCollections(fetcher Fetcher, start_pagination Pagination) error {
	collections, pagination, err := fetcher(start_pagination)
	if err != nil {
		return err
	}
	platform.Collections = slices.Concat(platform.Collections, collections)

	if pagination.HasMore {
		return platform.FetchCollections(fetcher, pagination)
	}

	err = BulkCreateNode(platform._conn, platform.Collections)

	return nil
}