package wireguard

import (
	"io"

	"github.com/vishvananda/netlink"

	"github.com/pkg/errors"

	"github.com/h44z/wg-portal/internal/lowlevel"

	"github.com/h44z/wg-portal/internal/persistence"
)

type KeyGenerator interface {
	GetFreshKeypair() (persistence.KeyPair, error)
	GetPreSharedKey() (persistence.PreSharedKey, error)
}

// InterfaceManager provides methods to create/update/delete physical WireGuard devices.
type InterfaceManager interface {
	GetInterfaces() ([]*persistence.InterfaceConfig, error)
	GetInterface(id persistence.InterfaceIdentifier) (*persistence.InterfaceConfig, error)
	CreateInterface(id persistence.InterfaceIdentifier) error
	DeleteInterface(id persistence.InterfaceIdentifier) error
	UpdateInterface(cfg *persistence.InterfaceConfig) error
	ApplyDefaultConfigs(id persistence.InterfaceIdentifier) error
}

type ImportableInterface struct {
	persistence.InterfaceConfig
	ImportLocation string
	ImportType     string
}

type ImportManager interface {
	GetImportableInterfaces() (map[*ImportableInterface][]*persistence.PeerConfig, error)
	ImportInterface(cfg *ImportableInterface, peers []*persistence.PeerConfig) error
}

type ConfigFileGenerator interface {
	GetInterfaceConfig(cfg *persistence.InterfaceConfig, peers []*persistence.PeerConfig) (io.Reader, error)
	GetPeerConfig(peer *persistence.PeerConfig) (io.Reader, error)
}

type PeerManager interface {
	GetPeers(device persistence.InterfaceIdentifier) ([]*persistence.PeerConfig, error)
	SavePeers(peers ...*persistence.PeerConfig) error
	RemovePeer(peer persistence.PeerIdentifier) error
}

type IpManager interface {
	GetAllUsedIPs(device persistence.InterfaceIdentifier) ([]*netlink.Addr, error)
	GetUsedIPs(device persistence.InterfaceIdentifier, subnetCidr string) ([]*netlink.Addr, error)
	GetFreshIp(device persistence.InterfaceIdentifier, subnetCidr string, increment ...bool) (*netlink.Addr, error)
}

type Manager interface {
	KeyGenerator
	InterfaceManager
	PeerManager
	IpManager
	ImportManager
	ConfigFileGenerator
}

//
// -- Implementations
//

type PersistentManager struct {
	*wgCtrlKeyGenerator
	*templateHandler
	*wgCtrlManager
}

func NewPersistentManager(wg lowlevel.WireGuardClient, nl lowlevel.NetlinkClient, store store) (*PersistentManager, error) {
	wgManager, err := newWgCtrlManager(wg, nl, store)
	if err != nil {
		return nil, errors.WithMessage(err, "failed to initialize WireGuard manager")
	}

	tplManager, err := newTemplateHandler()
	if err != nil {
		return nil, errors.WithMessage(err, "failed to initialize template manager")
	}

	m := &PersistentManager{
		wgCtrlKeyGenerator: &wgCtrlKeyGenerator{},
		wgCtrlManager:      wgManager,
		templateHandler:    tplManager,
	}

	return m, nil
}