package k8s

import (
	"fmt"
	"k8s.io/api/core/v1"
)

var (
	emptyPullPolicy = v1.PullPolicy("")
	// ValidPullPolicies is the set of pull policies that this package considers valid
	ValidPullPolicies = map[v1.PullPolicy]struct{}{
		v1.PullAlways:       {},
		v1.PullIfNotPresent: {},
		v1.PullNever:        {},
	}
)

// ErrInvalidPullPolicy is the error returned when trying to convert an unknown string to an api.PullPolicy
type ErrInvalidPullPolicy struct {
	str string
}

// Error is the error interface implementation
func (e ErrInvalidPullPolicy) Error() string {
	return fmt.Sprintf("%s is an invalid pull policy", e.str)
}

// PullPolicyFromString converts a string into an api.PullPolicy. returns an error if the string does not match a pull policy in ValidPullPolicies()
func PullPolicyFromString(ppStr string) (v1.PullPolicy, error) {
	candidatePP := v1.PullPolicy(ppStr)
	if _, ok := ValidPullPolicies[candidatePP]; !ok {
		return emptyPullPolicy, ErrInvalidPullPolicy{str: ppStr}
	}
	return candidatePP, nil
}