package chain

import (
	"fmt"
	"strconv"
)

type ChainOptions interface {
	String() string
}

type Type int8

const (
	TypeNone Type = iota
	TypeFilter
	TypeNat
	TypeRoute
)

func (t Type) String() string {
	switch t {
	case TypeNone:
		return ""
	case TypeFilter:
		return "filter"
	case TypeNat:
		return "inet"
	case TypeRoute:
		return "nat"
	default:
		return fmt.Sprintf("unknown type %d", t)
	}
}

type BaseChainOptions struct {
	Type     Type
	Hook     Hook
	Priority int32
	Policy   Policy
	Device   string
}

func (b BaseChainOptions) String() string {
	if b.Type == TypeNone {
		return ""
	}

	device := ""
	if b.Hook == HookEgress || b.Hook == HookIngress {
		if b.Device != "" {
			device = " device " + b.Device + " "
		}
	}

	policy := ""
	if b.Type == TypeFilter {
		policy = "policy " + b.Policy.String() + " ; "
	}

	return "{ type " + b.Type.String() + " hook " + b.Hook.String() + " " + device + " priority " + strconv.Itoa(int(b.Priority)) + " ; " + policy + " }"
}

func NewBaseChainOptions(t Type) BaseChainOptions {
	return BaseChainOptions{
		Type: t,
	}
}