package specgen

import (
	"github.com/pkg/errors"
)

type NamespaceMode string

const (
	// Default indicates the spec generator should determine
	// a sane default
	Default NamespaceMode = "default"
	// Host means the the namespace is derived from
	// the host
	Host NamespaceMode = "host"
	// Path is the path to a namespace
	Path NamespaceMode = "path"
	// FromContainer means namespace is derived from a
	// different container
	FromContainer NamespaceMode = "container"
	// FromPod indicates the namespace is derived from a pod
	FromPod NamespaceMode = "pod"
	// Private indicates the namespace is private
	Private NamespaceMode = "private"
	// NoNetwork indicates no network namespace should
	// be joined.  loopback should still exists
	NoNetwork NamespaceMode = "none"
	// Bridge indicates that a CNI network stack
	// should be used
	Bridge NamespaceMode = "bridge"
	// Slirp indicates that a slirp4ns network stack should
	// be used
	Slirp NamespaceMode = "slirp4ns"
)

// Namespace describes the namespace
type Namespace struct {
	NSMode NamespaceMode `json:"nsmode,omitempty"`
	Value  string        `json:"string,omitempty"`
}

// IsHost returns a bool if the namespace is host based
func (n *Namespace) IsHost() bool {
	return n.NSMode == Host
}

// IsPath indicates via bool if the namespace is based on a path
func (n *Namespace) IsPath() bool {
	return n.NSMode == Path
}

// IsContainer indicates via bool if the namespace is based on a container
func (n *Namespace) IsContainer() bool {
	return n.NSMode == FromContainer
}

// IsPod indicates via bool if the namespace is based on a pod
func (n *Namespace) IsPod() bool {
	return n.NSMode == FromPod
}

// IsPrivate indicates the namespace is private
func (n *Namespace) IsPrivate() bool {
	return n.NSMode == Private
}

func validateNetNS(n *Namespace) error {
	if n == nil {
		return nil
	}
	switch n.NSMode {
	case Host, Path, FromContainer, FromPod, Private, NoNetwork, Bridge, Slirp:
		break
	default:
		return errors.Errorf("invalid network %q", n.NSMode)
	}
	return nil
}

// Validate perform simple validation on the namespace to make sure it is not
// invalid from the get-go
func (n *Namespace) validate() error {
	if n == nil {
		return nil
	}
	// Path and From Container MUST have a string value set
	if n.NSMode == Path || n.NSMode == FromContainer {
		if len(n.Value) < 1 {
			return errors.Errorf("namespace mode %s requires a value", n.NSMode)
		}
	} else {
		// All others must NOT set a string value
		if len(n.Value) > 0 {
			return errors.Errorf("namespace value %s cannot be provided with namespace mode %s", n.Value, n.NSMode)
		}
	}
	return nil
}