package firewall

import (
	"context"
	"net"
	"sync"

	"github.com/qdm12/gluetun/internal/models"
	"github.com/qdm12/gluetun/internal/routing"
	"github.com/qdm12/golibs/command"
	"github.com/qdm12/golibs/files"
	"github.com/qdm12/golibs/logging"
)

// Configurator allows to change firewall rules and modify network routes.
type Configurator interface {
	Version(ctx context.Context) (string, error)
	SetEnabled(ctx context.Context, enabled bool) (err error)
	SetVPNConnection(ctx context.Context, connection models.OpenVPNConnection) (err error)
	SetAllowedPort(ctx context.Context, port uint16, intf string) (err error)
	RemoveAllowedPort(ctx context.Context, port uint16) (err error)
	SetDebug()
	// SetNetworkInformation is meant to be called only once
	SetNetworkInformation(defaultInterface string, defaultGateway net.IP, localSubnet net.IPNet)
}

type configurator struct { //nolint:maligned
	commander        command.Commander
	logger           logging.Logger
	routing          routing.Routing
	fileManager      files.FileManager // for custom iptables rules
	iptablesMutex    sync.Mutex
	debug            bool
	defaultInterface string
	defaultGateway   net.IP
	localSubnet      net.IPNet
	networkInfoMutex sync.Mutex

	// State
	enabled           bool
	vpnConnection     models.OpenVPNConnection
	allowedInputPorts map[uint16]string // port to interface mapping
	stateMutex        sync.Mutex
}

// NewConfigurator creates a new Configurator instance.
func NewConfigurator(logger logging.Logger, routing routing.Routing, fileManager files.FileManager) Configurator {
	return &configurator{
		commander:         command.NewCommander(),
		logger:            logger.WithPrefix("firewall: "),
		routing:           routing,
		fileManager:       fileManager,
		allowedInputPorts: make(map[uint16]string),
	}
}

func (c *configurator) SetDebug() {
	c.debug = true
}

func (c *configurator) SetNetworkInformation(defaultInterface string, defaultGateway net.IP, localSubnet net.IPNet) {
	c.networkInfoMutex.Lock()
	defer c.networkInfoMutex.Unlock()
	c.defaultInterface = defaultInterface
	c.defaultGateway = defaultGateway
	c.localSubnet = localSubnet
}