package zones

import (
	"bytes"
	"fmt"
	"os"

	"darvaza.org/core"

	"git.jpi.io/amery/jpictl/pkg/wireguard"
)

// GetWireguardConfig reads a wgN.conf file
func (m *Machine) GetWireguardConfig(ring int) (*wireguard.Config, error) {
	data, err := m.ReadFile("wg%v.conf", ring)
	if err != nil {
		return nil, err
	}

	r := bytes.NewReader(data)
	return wireguard.NewConfigFromReader(r)
}

func (m *Machine) tryApplyWireguardConfig(ring int) error {
	wg, err := m.GetWireguardConfig(ring)
	switch {
	case os.IsNotExist(err):
		return nil
	case err != nil:
		return err
	default:
		return m.applyWireguardConfig(ring, wg)
	}
}

func (m *Machine) applyWireguardConfig(ring int, wg *wireguard.Config) error {
	addr := wg.GetAddress()
	zoneID, nodeID, ok := Rings[ring].Decode(addr)
	if !ok {
		return fmt.Errorf("%s: invalid wg%v address: %s", m.Name, ring, addr)
	}

	if err := m.applyZoneNodeID(zoneID, nodeID); err != nil {
		err = core.Wrapf(err, "%s: wg%v:%s", m.Name, ring, addr)
		return err
	}

	return nil
}

func (m *Machine) applyZoneNodeID(zoneID, nodeID int) error {
	switch {
	case zoneID == 0:
		return fmt.Errorf("invalid %s", "zoneID")
	case nodeID == 0:
		return fmt.Errorf("invalid %s", "nodeID")
	case m.ID() != nodeID:
		return fmt.Errorf("invalid %s: %v ≠ %v", "zoneID", m.ID(), nodeID)
	case m.zone.ID != 0 && m.zone.ID != zoneID:
		return fmt.Errorf("invalid %s: %v ≠ %v", "zoneID", m.zone.ID, zoneID)
	case m.zone.ID == 0:
		m.zone.ID = zoneID
	}

	return nil
}