package route

import (
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"net/netip"
)

// Windows has some limitation regarding metric size that differ from Unix-like systems.
// Because of that we are limiting the min and max metric size based on Windows limits:
// see based on info from https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/route_ws2008
const (
	// MinMetric max metric input
	MinMetric = 1
	// MaxMetric max metric input
	MaxMetric = 9999
	// MaxNetIDChar Max Network Identifier
	MaxNetIDChar = 40
)

const (
	// InvalidNetworkString invalid network type string
	InvalidNetworkString = "Invalid"
	// IPv4NetworkString IPv4 network type string
	IPv4NetworkString = "IPv4"
	// IPv6NetworkString IPv6 network type string
	IPv6NetworkString = "IPv6"
)

const (
	// InvalidNetwork invalid network type
	InvalidNetwork NetworkType = iota
	// IPv4Network IPv4 network type
	IPv4Network
	// IPv6Network IPv6 network type
	IPv6Network
)

// NetworkType route network type
type NetworkType int

// String returns prefix type string
func (p NetworkType) String() string {
	switch p {
	case IPv4Network:
		return IPv4NetworkString
	case IPv6Network:
		return IPv6NetworkString
	default:
		return InvalidNetworkString
	}
}

// ToPrefixType returns a prefix type
func ToPrefixType(prefix string) NetworkType {
	switch prefix {
	case IPv4NetworkString:
		return IPv4Network
	case IPv6NetworkString:
		return IPv6Network
	default:
		return InvalidNetwork
	}
}

// Route represents a route
type Route struct {
	ID          string
	Network     netip.Prefix
	NetID       string
	Description string
	Peer        string
	NetworkType NetworkType
	Masquerade  bool
	Metric      int
	Enabled     bool
}

// Copy copies a route object
func (r *Route) Copy() *Route {
	return &Route{
		ID:          r.ID,
		Description: r.Description,
		NetID:       r.NetID,
		Network:     r.Network,
		NetworkType: r.NetworkType,
		Peer:        r.Peer,
		Metric:      r.Metric,
		Masquerade:  r.Masquerade,
		Enabled:     r.Enabled,
	}
}

// IsEqual compares one route with the other
func (r *Route) IsEqual(other *Route) bool {
	return other.ID == r.ID &&
		other.Description == r.Description &&
		other.NetID == r.NetID &&
		other.Network == r.Network &&
		other.NetworkType == r.NetworkType &&
		other.Peer == r.Peer &&
		other.Metric == r.Metric &&
		other.Masquerade == r.Masquerade &&
		other.Enabled == r.Enabled
}

// ParseNetwork Parses a network prefix string and returns a netip.Prefix object and if is invalid, IPv4 or IPv6
func ParseNetwork(networkString string) (NetworkType, netip.Prefix, error) {
	prefix, err := netip.ParsePrefix(networkString)
	if err != nil {
		return InvalidNetwork, netip.Prefix{}, err
	}

	masked := prefix.Masked()

	if !masked.IsValid() {
		return InvalidNetwork, netip.Prefix{}, status.Errorf(codes.InvalidArgument, "invalid range %s", networkString)
	}

	if masked.Addr().Is6() {
		return IPv6Network, masked, nil
	}

	return IPv4Network, masked, nil
}