/*
	Copyright NetFoundry Inc.

	Licensed under the Apache License, Version 2.0 (the "License");
	you may not use this file except in compliance with the License.
	You may obtain a copy of the License at

	https://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
*/

package controller

import (
	"bytes"
	"compress/gzip"
	"crypto/x509"
	"encoding/json"
	"fmt"
	"github.com/openziti/transport/v2"
	"github.com/openziti/ziti/common/capabilities"
	"github.com/openziti/ziti/common/config"
	"github.com/openziti/ziti/controller/event"
	"github.com/openziti/ziti/controller/events"
	"github.com/openziti/ziti/controller/handler_peer_ctrl"
	"math/big"
	"os"
	"sync/atomic"
	"time"

	"github.com/openziti/ziti/controller/db"
	"github.com/pkg/errors"

	"github.com/michaelquigley/pfxlog"
	"github.com/openziti/channel/v2"
	"github.com/openziti/channel/v2/protobufs"
	"github.com/openziti/foundation/v2/versions"
	"github.com/openziti/identity"
	"github.com/openziti/metrics"
	"github.com/openziti/storage/boltz"
	"github.com/openziti/xweb/v2"
	"github.com/openziti/ziti/common/health"
	fabricMetrics "github.com/openziti/ziti/common/metrics"
	"github.com/openziti/ziti/common/pb/ctrl_pb"
	"github.com/openziti/ziti/common/profiler"
	"github.com/openziti/ziti/controller/api_impl"
	"github.com/openziti/ziti/controller/command"
	"github.com/openziti/ziti/controller/handler_ctrl"
	"github.com/openziti/ziti/controller/network"
	"github.com/openziti/ziti/controller/raft"
	"github.com/openziti/ziti/controller/raft/mesh"
	"github.com/openziti/ziti/controller/xctrl"
	"github.com/openziti/ziti/controller/xmgmt"
	"github.com/openziti/ziti/controller/xt"
	"github.com/openziti/ziti/controller/xt_random"
	"github.com/openziti/ziti/controller/xt_smartrouting"
	"github.com/openziti/ziti/controller/xt_weighted"
	"github.com/sirupsen/logrus"
)

type Controller struct {
	config             *Config
	network            *network.Network
	raftController     *raft.Controller
	localDispatcher    *command.LocalDispatcher
	ctrlConnectHandler *handler_ctrl.ConnectHandler
	xctrls             []xctrl.Xctrl
	xmgmts             []xmgmt.Xmgmt

	xwebFactoryRegistry xweb.Registry
	xweb                xweb.Instance

	ctrlListener channel.UnderlayListener
	mgmtListener channel.UnderlayListener

	shutdownC         chan struct{}
	isShutdown        atomic.Bool
	agentBindHandlers []channel.BindHandler
	metricsRegistry   metrics.Registry
	versionProvider   versions.VersionProvider
	eventDispatcher   *events.Dispatcher
}

func (c *Controller) GetPeerSigners() []*x509.Certificate {
	if c.raftController == nil || c.raftController.Mesh == nil {
		return nil
	}

	var certs []*x509.Certificate

	for _, peer := range c.raftController.Mesh.GetPeers() {
		certs = append(certs, peer.SigningCerts...)
	}

	return certs
}

func (c *Controller) GetId() *identity.TokenId {
	return c.config.Id
}

func (c *Controller) GetMetricsRegistry() metrics.Registry {
	return c.metricsRegistry
}

func (c *Controller) GetOptions() *network.Options {
	return c.config.Network
}

func (c *Controller) GetCommandDispatcher() command.Dispatcher {
	if c.raftController == nil {
		if c.localDispatcher != nil {
			return c.localDispatcher
		}
		devVersion := versions.MustParseSemVer("0.0.0")
		version := versions.MustParseSemVer(c.GetVersionProvider().Version())
		c.localDispatcher = &command.LocalDispatcher{
			EncodeDecodeCommands: devVersion.Equals(version),
			Limiter:              command.NewRateLimiter(c.config.CommandRateLimiter, c.metricsRegistry, c.shutdownC),
		}
		return c.localDispatcher
	}
	return c.raftController
}

func (c *Controller) IsRaftEnabled() bool {
	return c.raftController != nil
}

func (c *Controller) GetDb() boltz.Db {
	return c.config.Db
}

func (c *Controller) GetVersionProvider() versions.VersionProvider {
	return c.versionProvider
}

func (c *Controller) GetCloseNotify() <-chan struct{} {
	return c.shutdownC
}

func (c *Controller) GetRaftConfig() *raft.Config {
	return c.config.Raft
}

func (c *Controller) GetCommandRateLimiterConfig() command.RateLimiterConfig {
	return c.config.CommandRateLimiter
}

func (c *Controller) RenderJsonConfig() (string, error) {
	jsonMap, err := config.ToJsonCompatibleMap(c.config.src)
	if err != nil {
		return "", err
	}
	b, err := json.Marshal(jsonMap)
	return string(b), err
}

func NewController(cfg *Config, versionProvider versions.VersionProvider) (*Controller, error) {
	metricRegistry := metrics.NewRegistry(cfg.Id.Token, nil)

	shutdownC := make(chan struct{})

	log := pfxlog.Logger()

	c := &Controller{
		config:              cfg,
		shutdownC:           shutdownC,
		xwebFactoryRegistry: xweb.NewRegistryMap(),
		metricsRegistry:     metricRegistry,
		versionProvider:     versionProvider,
		eventDispatcher:     events.NewDispatcher(shutdownC),
	}

	if cfg.Raft != nil {
		c.raftController = raft.NewController(c, c)
		if err := c.raftController.Init(); err != nil {
			log.WithError(err).Panic("error starting raft")
		}

		cfg.Db = c.raftController.GetDb()
	}

	c.registerXts()

	if n, err := network.NewNetwork(c); err == nil {
		c.network = n
	} else {
		return nil, err
	}

	if c.raftController != nil {
		if err := c.raftController.Bootstrap(); err != nil {
			log.WithError(err).Panic("error bootstrapping raft")
		}
	}

	c.eventDispatcher.InitializeNetworkEvents(c.network)

	if cfg.Ctrl.Options.NewListener != nil {
		c.network.AddRouterPresenceHandler(&OnConnectSettingsHandler{
			config: cfg,
			settings: map[int32][]byte{
				int32(ctrl_pb.SettingTypes_NewCtrlAddress): []byte((*cfg.Ctrl.Options.NewListener).String()),
			},
		})
	}

	if c.raftController != nil {
		logrus.Info("Adding router presence handler to send out ctrl addresses")
		c.network.AddRouterPresenceHandler(
			NewOnConnectCtrlAddressesUpdateHandler(c.config.Ctrl.Listener.String(), c.raftController),
		)
	}

	if err := c.showOptions(); err != nil {
		return nil, err
	}

	c.initWeb()

	return c, nil
}

func (c *Controller) initWeb() {
	healthChecker, err := c.initializeHealthChecks()
	if err != nil {
		logrus.WithError(err).Fatalf("failed to create health checker")
	}

	c.xweb = xweb.NewDefaultInstance(c.xwebFactoryRegistry, c.config.Id)

	if err := c.xweb.GetRegistry().Add(health.NewHealthCheckApiFactory(healthChecker)); err != nil {
		logrus.WithError(err).Fatalf("failed to create health checks api factory")
	}

	if err := c.xweb.GetRegistry().Add(api_impl.NewManagementApiFactory(c.config.Id, c.network, c.xmgmts)); err != nil {
		logrus.WithError(err).Fatalf("failed to create management api factory")
	}

	if err := c.xweb.GetRegistry().Add(api_impl.NewMetricsApiFactory(c.config.Id, c.network, c.xmgmts)); err != nil {
		logrus.WithError(err).Fatalf("failed to create metrics api factory")
	}

}

func (c *Controller) Run() error {
	c.startProfiling()

	if err := c.registerComponents(); err != nil {
		return fmt.Errorf("error registering component: %s", err)
	}
	versionInfo := c.network.VersionProvider.AsVersionInfo()
	versionHeader, err := c.network.VersionProvider.EncoderDecoder().Encode(versionInfo)

	if err != nil {
		pfxlog.Logger().Panicf("could not prepare version headers: %v", err)
	}

	capabilityMask := &big.Int{}
	capabilityMask.SetBit(capabilityMask, capabilities.ControllerCreateTerminatorV2, 1)
	capabilityMask.SetBit(capabilityMask, capabilities.ControllerSingleRouterLinkSource, 1)
	capabilityMask.SetBit(capabilityMask, capabilities.ControllerCreateCircuitV2, 1)
	headers := map[int32][]byte{
		channel.HelloVersionHeader:                       versionHeader,
		int32(ctrl_pb.ControlHeaders_CapabilitiesHeader): capabilityMask.Bytes(),
	}

	if c.raftController != nil {
		headers[mesh.PeerAddrHeader] = []byte(c.config.Raft.AdvertiseAddress.String())
	}

	/**
	 * ctrl listener/accepter.
	 */
	ctrlChannelListenerConfig := channel.ListenerConfig{
		ConnectOptions:   c.config.Ctrl.Options.ConnectOptions,
		PoolConfigurator: fabricMetrics.GoroutinesPoolMetricsConfigF(c.network.GetMetricsRegistry(), "pool.listener.ctrl"),
		Headers:          headers,
		TransportConfig:  transport.Configuration{"protocol": "ziti-ctrl"},
	}
	ctrlListener := channel.NewClassicListener(c.config.Id, c.config.Ctrl.Listener, ctrlChannelListenerConfig)
	c.ctrlListener = ctrlListener
	if err := c.ctrlListener.Listen(c.ctrlConnectHandler); err != nil {
		panic(err)
	}

	ctrlAccepter := handler_ctrl.NewCtrlAccepter(c.network, c.xctrls, c.config.Ctrl.Options.Options, c.config.Ctrl.Options.RouterHeartbeatOptions, c.config.Trace.Handler)

	ctrlAcceptors := map[string]channel.UnderlayAcceptor{}
	if c.raftController != nil {
		c.raftController.ConfigureMeshHandlers(handler_peer_ctrl.NewBindHandler(c.network, c.raftController, c.config.Ctrl.Options.PeerHeartbeatOptions))
		ctrlAcceptors[mesh.ChannelTypeMesh] = c.raftController.GetMesh()
	}

	underlayDispatcher := channel.NewUnderlayDispatcher(channel.UnderlayDispatcherConfig{
		Listener:        ctrlListener,
		ConnectTimeout:  c.config.Ctrl.Options.ConnectTimeout,
		TransportConfig: nil,
		Acceptors:       ctrlAcceptors,
		DefaultAcceptor: ctrlAccepter,
	})

	go underlayDispatcher.Run()

	if err := c.config.Configure(c.xweb); err != nil {
		panic(err)
	}

	go c.xweb.Run()

	// event handlers
	if err := c.eventDispatcher.WireEventHandlers(c.getEventHandlerConfigs()); err != nil {
		panic(err)
	}

	c.network.Run()

	return nil
}

func (c *Controller) getEventHandlerConfigs() []*events.EventHandlerConfig {
	var result []*events.EventHandlerConfig

	if e, ok := c.config.src["events"]; ok {
		if em, ok := e.(map[interface{}]interface{}); ok {
			for id, v := range em {
				if config, ok := v.(map[interface{}]interface{}); ok {
					result = append(result, &events.EventHandlerConfig{
						Id:     id,
						Config: config,
					})
				}
			}
		}
	}
	return result
}

func (c *Controller) GetCloseNotifyChannel() <-chan struct{} {
	return c.shutdownC
}

func (c *Controller) Shutdown() {
	if c.isShutdown.CompareAndSwap(false, true) {
		close(c.shutdownC)

		if c.ctrlListener != nil {
			if err := c.ctrlListener.Close(); err != nil {
				pfxlog.Logger().WithError(err).Error("failed to close ctrl channel listener")
			}
		}

		if c.mgmtListener != nil {
			if err := c.mgmtListener.Close(); err != nil {
				pfxlog.Logger().WithError(err).Error("failed to close mgmt channel listener")
			}
		}

		if c.config.Db != nil {
			if err := c.config.Db.Close(); err != nil {
				pfxlog.Logger().WithError(err).Error("failed to close db")
			}
		}

		go c.xweb.Shutdown()
	}
}

func (c *Controller) showOptions() error {
	if ctrl, err := json.MarshalIndent(c.config.Ctrl.Options, "", "  "); err == nil {
		pfxlog.Logger().Infof("ctrl = %s", string(ctrl))
	} else {
		return err
	}
	return nil
}

func (c *Controller) startProfiling() {
	if c.config.Profile.Memory.Path != "" {
		go profiler.NewMemoryWithShutdown(c.config.Profile.Memory.Path, c.config.Profile.Memory.Interval, c.shutdownC).Run()
	}
	if c.config.Profile.CPU.Path != "" {
		if cpu, err := profiler.NewCPUWithShutdown(c.config.Profile.CPU.Path, c.shutdownC); err == nil {
			go cpu.Run()
		} else {
			logrus.Errorf("unexpected error launching cpu profiling (%v)", err)
		}
	}
}

func (c *Controller) registerXts() {
	xt.GlobalRegistry().RegisterFactory(xt_smartrouting.NewFactory())
	xt.GlobalRegistry().RegisterFactory(xt_random.NewFactory())
	xt.GlobalRegistry().RegisterFactory(xt_weighted.NewFactory())
}

func (c *Controller) registerComponents() error {
	c.ctrlConnectHandler = handler_ctrl.NewConnectHandler(c.config.Id, c.network)
	c.eventDispatcher.AddClusterEventHandler(event.ClusterEventHandlerF(c.routerDispatchCallback))
	return nil
}

func (c *Controller) RegisterXctrl(x xctrl.Xctrl) error {
	if err := c.config.Configure(x); err != nil {
		return err
	}
	if x.Enabled() {
		c.xctrls = append(c.xctrls, x)
		if c.config.Trace.Handler != nil {
			for _, decoder := range x.GetTraceDecoders() {
				c.config.Trace.Handler.AddDecoder(decoder)
			}
		}
	}
	return nil
}

func (c *Controller) RegisterXmgmt(x xmgmt.Xmgmt) error {
	if err := c.config.Configure(x); err != nil {
		return err
	}
	if x.Enabled() {
		c.xmgmts = append(c.xmgmts, x)
	}
	return nil
}

func (c *Controller) GetXWebInstance() xweb.Instance {
	return c.xweb
}

func (c *Controller) GetNetwork() *network.Network {
	return c.network
}

func (c *Controller) Identity() identity.Identity {
	return c.config.Id
}

func (c *Controller) GetEventDispatcher() event.Dispatcher {
	return c.eventDispatcher
}

func (c *Controller) routerDispatchCallback(evt *event.ClusterEvent) {
	if evt.EventType == event.ClusterMembersChanged {
		var endpoints []string
		for _, peer := range evt.Peers {
			endpoints = append(endpoints, peer.Addr)
		}
		updMsg := &ctrl_pb.UpdateCtrlAddresses{
			Addresses: endpoints,
			IsLeader:  c.raftController.IsLeader(),
			Index:     evt.Index,
		}

		for _, r := range c.network.AllConnectedRouters() {
			if err := protobufs.MarshalTyped(updMsg).Send(r.Control); err != nil {
				pfxlog.Logger().WithError(err).WithField("routerId", r.Id).Error("unable to update controller endpoints on router")
			}
		}
	}
}

func (c *Controller) TryInitializeRaftFromBoltDb() error {
	val, found := c.config.src["db"]
	if !found {
		return nil
	}

	path := fmt.Sprintf("%v", val)
	if _, err := os.Stat(path); err != nil {
		if os.IsNotExist(err) {
			return errors.Wrapf(err, "source db not found at [%v], either remove 'db' config setting or fix path ", path)
		}
		return errors.Wrapf(err, "invalid db path [%v]", path)
	}

	return c.InitializeRaftFromBoltDb(path)
}

func (c *Controller) InitializeRaftFromBoltDb(sourceDbPath string) error {
	log := pfxlog.Logger()

	log.Info("waiting for raft cluster to settle before syncing raft to database")
	start := time.Now()
	for c.raftController.GetLeaderAddr() == "" {
		if time.Since(start) > time.Second*30 {
			log.Panic("cannot sync raft to database as cluster has not settled within timeout")
		} else {
			log.Info("waiting for raft cluster to elect a leader, to allow syncing db to raft")
		}
		time.Sleep(time.Second)
	}

	if _, err := os.Stat(sourceDbPath); err != nil {
		if os.IsNotExist(err) {
			return errors.Wrapf(err, "source db not found at [%v]", sourceDbPath)
		}
		return errors.Wrapf(err, "invalid db path [%v]", sourceDbPath)
	}

	sourceDb, err := db.Open(sourceDbPath)
	if err != nil {
		return err
	}
	defer func() {
		if err = sourceDb.Close(); err != nil {
			log.WithError(err).Error("error closing migration source bolt db")
		}
	}()

	log.Infof("initializing from bolt db [%v]", sourceDbPath)

	buf := &bytes.Buffer{}
	gzWriter := gzip.NewWriter(buf)
	snapshotId, err := sourceDb.SnapshotToWriter(gzWriter)
	if err != nil {
		return err
	}

	if err = gzWriter.Close(); err != nil {
		return errors.Wrap(err, "error finishing gz compression of migration snapshot")
	}

	cmd := &command.SyncSnapshotCommand{
		SnapshotId:   snapshotId,
		Snapshot:     buf.Bytes(),
		SnapshotSink: c.network.RestoreSnapshot,
	}

	return c.raftController.Dispatch(cmd)
}