package headscale

import (
	"encoding/json"
	"fmt"
	"strconv"

	"github.com/pterm/pterm"
	"gorm.io/datatypes"
	"inet.af/netaddr"
)

// GetAdvertisedNodeRoutes returns the subnet routes advertised by a node (identified by
// namespace and node name)
func (h *Headscale) GetAdvertisedNodeRoutes(namespace string, nodeName string) (*[]netaddr.IPPrefix, error) {
	m, err := h.GetMachine(namespace, nodeName)
	if err != nil {
		return nil, err
	}

	hostInfo, err := m.GetHostInfo()
	if err != nil {
		return nil, err
	}
	return &hostInfo.RoutableIPs, nil
}

// GetEnabledNodeRoutes returns the subnet routes enabled by a node (identified by
// namespace and node name)
func (h *Headscale) GetEnabledNodeRoutes(namespace string, nodeName string) ([]netaddr.IPPrefix, error) {
	m, err := h.GetMachine(namespace, nodeName)
	if err != nil {
		return nil, err
	}

	data, err := m.EnabledRoutes.MarshalJSON()
	if err != nil {
		return nil, err
	}

	routesStr := []string{}
	err = json.Unmarshal(data, &routesStr)
	if err != nil {
		return nil, err
	}

	routes := make([]netaddr.IPPrefix, len(routesStr))
	for index, routeStr := range routesStr {
		route, err := netaddr.ParseIPPrefix(routeStr)
		if err != nil {
			return nil, err
		}
		routes[index] = route
	}

	return routes, nil
}

func (h *Headscale) IsNodeRouteEnabled(namespace string, nodeName string, routeStr string) bool {
	route, err := netaddr.ParseIPPrefix(routeStr)
	if err != nil {
		return false
	}

	enabledRoutes, err := h.GetEnabledNodeRoutes(namespace, nodeName)
	if err != nil {
		return false
	}

	for _, enabledRoute := range enabledRoutes {
		if route == enabledRoute {
			return true
		}
	}
	return false
}

// EnableNodeRoute enables a subnet route advertised by a node (identified by
// namespace and node name)
func (h *Headscale) EnableNodeRoute(namespace string, nodeName string, routeStr string) error {
	m, err := h.GetMachine(namespace, nodeName)
	if err != nil {
		return err
	}

	route, err := netaddr.ParseIPPrefix(routeStr)
	if err != nil {
		return err
	}

	availableRoutes, err := h.GetAdvertisedNodeRoutes(namespace, nodeName)
	if err != nil {
		return err
	}

	enabledRoutes, err := h.GetEnabledNodeRoutes(namespace, nodeName)
	if err != nil {
		return err
	}

	available := false
	for _, availableRoute := range *availableRoutes {
		// If the route is available, and not yet enabled, add it to the new routing table
		if route == availableRoute {
			available = true
			if !h.IsNodeRouteEnabled(namespace, nodeName, routeStr) {
				enabledRoutes = append(enabledRoutes, route)
			}
		}
	}

	if !available {
		return fmt.Errorf("route (%s) is not available on node %s", nodeName, routeStr)
	}

	routes, err := json.Marshal(enabledRoutes)
	if err != nil {
		return err
	}

	m.EnabledRoutes = datatypes.JSON(routes)
	h.db.Save(&m)

	err = h.RequestMapUpdates(m.NamespaceID)
	if err != nil {
		return err
	}

	return nil
}

func (h *Headscale) RoutesToPtables(namespace string, nodeName string, availableRoutes []netaddr.IPPrefix) pterm.TableData {
	d := pterm.TableData{{"Route", "Enabled"}}

	for _, route := range availableRoutes {
		enabled := h.IsNodeRouteEnabled(namespace, nodeName, route.String())

		d = append(d, []string{route.String(), strconv.FormatBool(enabled)})
	}
	return d
}