package zones

import (
	"io/fs"
	"os"
)

var (
	_ machineRinger = (*Zone)(nil)
	_ machineRinger = (*Zones)(nil)
)

type machineRinger interface {
	MachineIterator

	SyncWireguardConfig(ring int) error
	PruneWireguardConfig(ring int) error
}

// SyncWireguardConfig updates all wgN.conf files for the specified
// ring
func (z *Zone) SyncWireguardConfig(ring int) error {
	switch ring {
	case 0:
		return syncWireguardConfig(z.zones, z.zones, ring)
	case 1:
		return syncWireguardConfig(z.zones, z, ring)
	default:
		return fs.ErrInvalid
	}
}

// PruneWireguardConfig removes wgN.conf files of machines with
// the corresponding ring disabled.
func (z *Zone) PruneWireguardConfig(ring int) error {
	return pruneWireguardConfig(z, ring)
}

// WriteWireguardKeys rewrites all wgN.{key,pub} files on this zone
func (z *Zone) WriteWireguardKeys(ring int) error {
	return writeWireguardKeys(z, ring)
}

// SyncWireguardConfig updates all wgN.conf files for the specified
// ring
func (m *Zones) SyncWireguardConfig(ring int) error {
	switch ring {
	case 0:
		return syncWireguardConfig(m, m, ring)
	case 1:
		var err error
		m.ForEachZone(func(z *Zone) bool {
			err = syncWireguardConfig(m, z, ring)
			return err != nil
		})
		return err
	default:
		return fs.ErrInvalid
	}
}

// PruneWireguardConfig removes wgN.conf files of machines with
// the corresponding ring disabled on all zones
func (m *Zones) PruneWireguardConfig(ring int) error {
	return pruneWireguardConfig(m, ring)
}

// WriteWireguardKeys rewrites all wgN.{key,pub} files
func (m *Zones) WriteWireguardKeys(ring int) error {
	return writeWireguardKeys(m, ring)
}

func syncWireguardConfig(z ZoneIterator, m machineRinger, ring int) error {
	r, err := NewRing(z, m, ring)
	if err != nil {
		return err
	}

	m.ForEachMachine(func(p *Machine) bool {
		if _, ok := p.getRingInfo(ring); ok {
			err = p.writeWireguardRingConfig(r)
		} else {
			err = p.RemoveWireguardConfig(ring)
		}
		return err != nil
	})

	return err
}

func pruneWireguardConfig(m MachineIterator, ring int) error {
	var err error

	m.ForEachMachine(func(p *Machine) bool {
		_, ok := p.getRingInfo(ring)
		if !ok {
			err = p.RemoveWireguardConfig(ring)
		}
		return err != nil
	})

	return err
}

func writeWireguardKeys(m MachineIterator, ring int) error {
	var err error

	m.ForEachMachine(func(p *Machine) bool {
		err = p.WriteWireguardKeys(ring)
		if os.IsNotExist(err) {
			// ignore
			err = nil
		}

		return err != nil
	})

	return err
}