package edgestack

import (
	"github.com/boltdb/bolt"
	portainer "github.com/portainer/portainer/api"
	"github.com/portainer/portainer/api/bolt/internal"
)

const (
	// BucketName represents the name of the bucket where this service stores data.
	BucketName = "edge_stack"
)

// Service represents a service for managing Edge stack data.
type Service struct {
	connection *internal.DbConnection
}

// NewService creates a new instance of a service.
func NewService(connection *internal.DbConnection) (*Service, error) {
	err := internal.CreateBucket(connection, BucketName)
	if err != nil {
		return nil, err
	}

	return &Service{
		connection: connection,
	}, nil
}

// EdgeStacks returns an array containing all edge stacks
func (service *Service) EdgeStacks() ([]portainer.EdgeStack, error) {
	var stacks = make([]portainer.EdgeStack, 0)

	err := service.connection.View(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(BucketName))

		cursor := bucket.Cursor()
		for k, v := cursor.First(); k != nil; k, v = cursor.Next() {
			var stack portainer.EdgeStack
			err := internal.UnmarshalObject(v, &stack)
			if err != nil {
				return err
			}
			stacks = append(stacks, stack)
		}

		return nil
	})

	return stacks, err
}

// EdgeStack returns an Edge stack by ID.
func (service *Service) EdgeStack(ID portainer.EdgeStackID) (*portainer.EdgeStack, error) {
	var stack portainer.EdgeStack
	identifier := internal.Itob(int(ID))

	err := internal.GetObject(service.connection, BucketName, identifier, &stack)
	if err != nil {
		return nil, err
	}

	return &stack, nil
}

// CreateEdgeStack assign an ID to a new Edge stack and saves it.
func (service *Service) CreateEdgeStack(edgeStack *portainer.EdgeStack) error {
	return service.connection.Update(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(BucketName))

		if edgeStack.ID == 0 {
			id, _ := bucket.NextSequence()
			edgeStack.ID = portainer.EdgeStackID(id)
		}

		data, err := internal.MarshalObject(edgeStack)
		if err != nil {
			return err
		}

		return bucket.Put(internal.Itob(int(edgeStack.ID)), data)
	})
}

// UpdateEdgeStack updates an Edge stack.
func (service *Service) UpdateEdgeStack(ID portainer.EdgeStackID, edgeStack *portainer.EdgeStack) error {
	identifier := internal.Itob(int(ID))
	return internal.UpdateObject(service.connection, BucketName, identifier, edgeStack)
}

// DeleteEdgeStack deletes an Edge stack.
func (service *Service) DeleteEdgeStack(ID portainer.EdgeStackID) error {
	identifier := internal.Itob(int(ID))
	return internal.DeleteObject(service.connection, BucketName, identifier)
}

// GetNextIdentifier returns the next identifier for an environment(endpoint).
func (service *Service) GetNextIdentifier() int {
	return internal.GetNextIdentifier(service.connection, BucketName)
}