package endly

import (
	"github.com/pkg/errors"
	"github.com/viant/toolbox/data"
)

// PredefinedUdfs represents a udf registry
var PredefinedUdfs = make(map[string]func(source interface{}, state data.Map) (interface{}, error))

// UdfRegistryProvider represents udf registry provider (i.e. to register parameterized udf dynamically)
var UdfRegistryProvider = make(map[string]func(args ...interface{}) (func(source interface{}, state data.Map) (interface{}, error), error))

type UdfProvider struct {
	ID       string        `description:"id for new udf registration"`
	Provider string        `description:"provider name"`
	Params   []interface{} `description:"provider parameters"`
}

// ServiceProvider represents a service provider
type ServiceProvider func() Service

// ServiceRegistry  represents a service registry
type ServiceRegistry []ServiceProvider

// Register register service provider.
func (r *ServiceRegistry) Register(serviceProvider ServiceProvider) error {
	if serviceProvider == nil {
		return errors.New("provider was empty")
	}
	*r = append(*r, serviceProvider)
	return nil
}

var registry ServiceRegistry = make([]ServiceProvider, 0)

// Registry global service provider registry
var Registry = &registry