package checker

import (
	"fmt"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

// Provider returns a new delegation observation provider.
func Provider() sdk.ObservationProvider {
	return &delegationProvider{}
}

type delegationProvider struct{}

func (p *delegationProvider) Key() sdk.ObservationKey {
	return ObservationKeyDelegation
}

// Definition implements sdk.CheckerDefinitionProvider so the SDK server can
// expose /definition without an extra argument.
func (p *delegationProvider) Definition() *sdk.CheckerDefinition {
	return Definition()
}

// ValidateOptions implements sdk.OptionsValidator. Option values cross all
// rules, so validating them once on the provider avoids duplicating the
// check in every rule.
func (p *delegationProvider) ValidateOptions(opts sdk.CheckerOptions) error {
	if v, ok := opts["minNameServers"]; ok {
		f, ok := v.(float64)
		if !ok {
			return fmt.Errorf("minNameServers must be a number")
		}
		if f < 1 {
			return fmt.Errorf("minNameServers must be >= 1")
		}
	}
	return nil
}