package controller

import (
	"fmt"
	"io"
	"net"
	"time"

	"github.com/openziti/ziti/v2/common/pb/cmd_pb"
	"github.com/openziti/ziti/v2/common/pb/ctrl_pb"
	"google.golang.org/protobuf/proto"

	"github.com/michaelquigley/pfxlog"
	"github.com/openziti/channel/v4"
	"github.com/openziti/channel/v4/protobufs"
	"github.com/openziti/ziti/v2/common/agentid"
	"github.com/openziti/ziti/v2/common/handler_common"
	"github.com/openziti/ziti/v2/common/pb/mgmt_pb"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

const (
	AgentAppId byte = 1

	AgentIdHeader         = 10
	AgentAddrHeader       = 11
	AgentIsVoterHeader    = 12
	AgentSnapshotFileName = 13
)

func (self *Controller) RegisterAgentBindHandler(bindHandler channel.BindHandler) {
	self.agentBindHandlers = append(self.agentBindHandlers, bindHandler)
}

func (self *Controller) bindAgentChannel(binding channel.Binding) error {
	binding.AddReceiveHandlerF(int32(ctrl_pb.ContentType_InspectRequestType), self.agentOpInspect)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_SnapshotDbRequestType), self.agentOpSnapshotDb)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftListMembersRequestType), self.agentOpRaftList)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftAddPeerRequestType), self.agentOpRaftAddPeer)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftRemovePeerRequestType), self.agentOpRaftRemovePeer)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftTransferLeadershipRequestType), self.agentOpRaftTransferLeadership)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftInitFromDb), self.agentOpInitFromDb)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftInit), self.agentOpInit)
	binding.AddReceiveHandlerF(int32(mgmt_pb.ContentType_RaftRestoreFromDb), self.agentOpRestoreFromDb)

	for _, bh := range self.agentBindHandlers {
		if err := binding.Bind(bh); err != nil {
			return err
		}
	}
	return nil
}

func (self *Controller) HandleCustomAgentAsyncOp(conn net.Conn) error {
	logrus.Debug("received agent operation request")

	appIdBuf := []byte{0}
	_, err := io.ReadFull(conn, appIdBuf)
	if err != nil {
		return err
	}
	appId := appIdBuf[0]

	if appId != agentid.AppIdAny && appId != AgentAppId {
		logrus.WithField("appId", appId).Debug("invalid app id on agent request")
		return errors.New("invalid operation for controller")
	}

	options := channel.DefaultOptions()
	options.ConnectTimeout = time.Second
	listener := channel.NewExistingConnListener(self.config.Id, conn, nil)
	_, err = channel.NewChannel("agent", listener, channel.BindHandlerF(self.bindAgentChannel), options)
	return err
}

func (self *Controller) agentOpInspect(m *channel.Message, ch channel.Channel) {
	request := &ctrl_pb.InspectRequest{}
	if err := proto.Unmarshal(m.Body, request); err != nil {
		self.sendInspectError(m, ch, err.Error())
		return
	}

	result := self.network.Inspections.InspectLocal(request.RequestedValues)

	response := &ctrl_pb.InspectResponse{
		Success: result.Success,
		Errors:  result.Errors,
	}

	for _, val := range result.Results {
		response.Values = append(response.Values, &ctrl_pb.InspectResponse_InspectValue{
			Name:  val.Name,
			Value: val.Value,
		})
	}

	body, err := proto.Marshal(response)
	if err != nil {
		self.sendInspectError(m, ch, err.Error())
		return
	}

	responseMsg := channel.NewMessage(int32(ctrl_pb.ContentType_InspectResponseType), body)
	responseMsg.ReplyTo(m)
	if err := ch.Send(responseMsg); err != nil {
		pfxlog.Logger().WithError(err).Error("failed to send inspect response")
	}
}

func (self *Controller) sendInspectError(m *channel.Message, ch channel.Channel, errMsg string) {
	response := &ctrl_pb.InspectResponse{
		Success: false,
		Errors:  []string{errMsg},
	}
	body, err := proto.Marshal(response)
	if err != nil {
		pfxlog.Logger().WithError(err).Error("failed to marshal inspect error response")
		return
	}
	responseMsg := channel.NewMessage(int32(ctrl_pb.ContentType_InspectResponseType), body)
	responseMsg.ReplyTo(m)
	if err := ch.Send(responseMsg); err != nil {
		pfxlog.Logger().WithError(err).Error("failed to send inspect error response")
	}
}

func (self *Controller) agentOpSnapshotDb(m *channel.Message, ch channel.Channel) {
	fileName, _ := m.GetStringHeader(AgentSnapshotFileName)

	log := pfxlog.Logger()
	if path, err := self.network.SnapshotDatabaseToFile(fileName); err != nil {
		log.WithError(err).Error("failed to snapshot db")
		handler_common.SendOpResult(m, ch, "db.snapshot", err.Error(), false)
	} else {
		handler_common.SendOpResult(m, ch, "db.snapshot", path, true)
	}
}

func (self *Controller) agentOpRaftList(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.list", "controller not running in clustered mode", false)
		return
	}

	members, err := self.raftController.ListMembers()
	if err != nil {
		handler_common.SendOpResult(m, ch, "cluster.list", err.Error(), false)
		return
	}

	result := &mgmt_pb.RaftMemberListResponse{}
	for _, member := range members {
		result.Members = append(result.Members, &mgmt_pb.RaftMember{
			Id:                member.Id,
			Addr:              member.Addr,
			IsVoter:           member.Voter,
			IsLeader:          member.Leader,
			Version:           member.Version,
			IsConnected:       member.Connected,
			IsPreferredLeader: member.PreferredLeader,
		})
	}

	if err = protobufs.MarshalTyped(result).ReplyTo(m).WithTimeout(time.Second).Send(ch); err != nil {
		pfxlog.Logger().WithError(err).Error("failure sending raft member list response")
	}
}

func (self *Controller) agentOpRaftAddPeer(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.add-peer", "controller not running in clustered mode", false)
		return
	}

	if !self.raftController.IsBootstrapped() {
		self.agentOpRaftJoinCluster(m, ch)
		return
	}

	addr, found := m.GetStringHeader(AgentAddrHeader)
	if !found {
		handler_common.SendOpResult(m, ch, "cluster.add-peer", "address not supplied", false)
		return
	}

	isVoter, found := m.GetBoolHeader(AgentIsVoterHeader)
	if !found {
		isVoter = true
	}

	req := &cmd_pb.AddPeerRequest{
		Addr:    addr,
		IsVoter: isVoter,
	}

	if err := self.raftController.Join(req); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.add-peer", err.Error(), false)
		return
	}

	handler_common.SendOpResult(m, ch, "cluster.add-peer", fmt.Sprintf("success, added peer at %v to cluster", addr), true)
}

func (self *Controller) agentOpRaftJoinCluster(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.join", "controller not running in clustered mode", false)
		return
	}

	if self.raftController.IsBootstrapped() {
		handler_common.SendOpResult(m, ch, "cluster.join",
			"Local instance is already initialized. Only uninitialized nodes may be joined to a cluster. ",
			false)
		return
	}

	addr, found := m.GetStringHeader(AgentAddrHeader)
	if !found {
		handler_common.SendOpResult(m, ch, "cluster.join", "address not supplied", false)
		return
	}

	_, peerAddr, err := self.raftController.Mesh.GetPeerInfo(addr, 5*time.Second)
	if err != nil {
		handler_common.SendOpResult(m, ch, "cluster.join", "unable to retrieve peer advertise address", false)
		return
	}

	if addr != string(peerAddr) {
		pfxlog.Logger().Infof("using peer advertise address '%s' instead of given address '%s'", peerAddr, addr)
		addr = string(peerAddr)
	}

	isVoter, found := m.GetBoolHeader(AgentIsVoterHeader)
	if !found {
		isVoter = true
	}

	req := &cmd_pb.AddPeerRequest{
		Addr:    self.raftController.Config.AdvertiseAddress.String(),
		Id:      self.config.Id.Token,
		IsVoter: isVoter,
	}

	if err = self.raftController.ForwardToAddr(addr, req); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.join", err.Error(), false)
		return
	}

	handler_common.SendOpResult(m, ch, "cluster.join", "success, added self to cluster", true)
}

func (self *Controller) agentOpRaftRemovePeer(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.remove-peer", "controller not running in clustered mode", false)
		return
	}

	id, found := m.GetStringHeader(AgentIdHeader)
	if !found {
		handler_common.SendOpResult(m, ch, "cluster.remove-peer", "id not supplied", false)
		return
	}

	req := &cmd_pb.RemovePeerRequest{
		Id: id,
	}

	if err := self.raftController.HandleRemovePeer(req); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.remove-peer", err.Error(), false)
		return
	}
	handler_common.SendOpResult(m, ch, "cluster.remove-peer", fmt.Sprintf("success, removed %v from cluster", id), true)
}

func (self *Controller) agentOpRaftTransferLeadership(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.transfer-leadership", "controller not running in clustered mode", false)
		return
	}

	id, _ := m.GetStringHeader(AgentIdHeader)
	req := &cmd_pb.TransferLeadershipRequest{
		Id: id,
	}

	if err := self.raftController.HandleTransferLeadership(req); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.transfer-leadership", err.Error(), false)
		return
	}
	handler_common.SendOpResult(m, ch, "cluster.transfer-leadership", "success", true)
}

func (self *Controller) agentOpInitFromDb(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.init-from-db", "controller not running in clustered mode", false)
		return
	}

	sourceDbPath := string(m.Body)
	if len(sourceDbPath) == 0 {
		handler_common.SendOpResult(m, ch, "cluster.init-from-db", "source db not supplied", false)
		return
	}

	if err := self.InitializeRaftFromBoltDb(sourceDbPath); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.init-from-db", err.Error(), false)
		return
	}
	handler_common.SendOpResult(m, ch, "cluster.init-from-db", fmt.Sprintf("success, initialized from [%v]", sourceDbPath), true)
}

func (self *Controller) agentOpRestoreFromDb(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "cluster.restore-from-db", "controller not running in clustered mode", false)
		return
	}

	sourceDbPath := string(m.Body)
	if len(sourceDbPath) == 0 {
		handler_common.SendOpResult(m, ch, "cluster.restore-from-db", "source db not supplied", false)
		return
	}

	if err := self.RaftRestoreFromBoltDb(sourceDbPath); err != nil {
		handler_common.SendOpResult(m, ch, "cluster.restore-from-db", err.Error(), false)
		return
	}
	handler_common.SendOpResult(m, ch, "cluster.restore-from-db", fmt.Sprintf("success, initialized from [%v]", sourceDbPath), true)
}

func (self *Controller) agentOpInit(m *channel.Message, ch channel.Channel) {
	if self.raftController == nil {
		handler_common.SendOpResult(m, ch, "init.edge", "controller not running in clustered mode", false)
		return
	}

	log := pfxlog.Logger().WithField("channel", ch.LogicalName())

	request := &mgmt_pb.InitRequest{}
	if err := proto.Unmarshal(m.Body, request); err != nil {
		log.WithError(err).Error("unable to parse InitRequest, closing channel")
		if err = ch.Close(); err != nil {
			log.WithError(err).Error("error closing mgmt channel")
		}
		return
	}

	if err := self.env.Managers.Identity.InitializeDefaultAdmin(request.Username, request.Password, request.Name); err != nil {
		handler_common.SendOpResult(m, ch, "init.edge", err.Error(), false)
	} else {
		handler_common.SendOpResult(m, ch, "init.edge", "success", true)
	}
}