// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: BUSL-1.1

package worker

import (
	"context"
	"fmt"
	"math"
	"net"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"time"

	"github.com/hashicorp/boundary/internal/cmd/base"
	"github.com/hashicorp/boundary/internal/daemon/cluster"
	"github.com/hashicorp/boundary/internal/daemon/cluster/handlers"
	"github.com/hashicorp/boundary/internal/daemon/worker/internal/metric"
	"github.com/hashicorp/boundary/internal/errors"
	"github.com/hashicorp/boundary/internal/event"
	pbs "github.com/hashicorp/boundary/internal/gen/controller/servers/services"
	"github.com/hashicorp/boundary/internal/server"
	"github.com/hashicorp/boundary/internal/util"
	"github.com/hashicorp/boundary/version"
	"github.com/hashicorp/go-secure-stdlib/parseutil"
	"github.com/hashicorp/nodeenrollment"
	"github.com/hashicorp/nodeenrollment/multihop"
	"github.com/hashicorp/nodeenrollment/protocol"
	"github.com/hashicorp/nodeenrollment/util/toggledlogger"
	"google.golang.org/grpc"
	"google.golang.org/grpc/backoff"
	"google.golang.org/grpc/connectivity"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/resolver"
	"google.golang.org/protobuf/types/known/structpb"
)

var HandleHcpbClusterId func(s string) string

// StartControllerConnections starts up the resolver and initiates controller
// connection client creation
func (w *Worker) StartControllerConnections() error {
	w.confAddressReceiversLock.Lock()
	defer w.confAddressReceiversLock.Unlock()
	const op = "worker.(Worker).StartControllerConnections"
	initialAddrs := make([]string, 0, len(w.conf.RawConfig.Worker.InitialUpstreams))
	for _, addr := range w.conf.RawConfig.Worker.InitialUpstreams {
		switch {
		case strings.HasPrefix(addr, "/"):
			initialAddrs = append(initialAddrs, addr)
		default:
			host, port, err := util.SplitHostPort(addr)
			if err != nil {
				return fmt.Errorf("error parsing upstream address: %w", err)
			}
			if port == "" {
				port = "9201"
			}
			initialAddrs = append(initialAddrs, util.JoinHostPort(host, port))
		}
	}

	if len(initialAddrs) == 0 {
		if w.conf.RawConfig.HcpbClusterId != "" && HandleHcpbClusterId != nil {
			clusterId, err := parseutil.ParsePath(w.conf.RawConfig.HcpbClusterId)
			if err != nil && !errors.Is(err, parseutil.ErrNotAUrl) {
				return fmt.Errorf("failed to parse HCP Boundary cluster ID:  %q: %w", clusterId, err)
			}
			clusterAddress := HandleHcpbClusterId(clusterId)
			initialAddrs = append(initialAddrs, clusterAddress)
			event.WriteSysEvent(w.baseContext, op, fmt.Sprintf("Setting HCP Boundary cluster address %s as upstream address", clusterAddress))
		} else {
			return errors.New(w.baseContext, errors.InvalidParameter, op, "no initial upstream addresses found")
		}
	}

	for _, ar := range w.addressReceivers {
		ar.InitialAddresses(initialAddrs)
	}
	if err := w.createClientConn(initialAddrs[0]); err != nil {
		return fmt.Errorf("error making client connection to upstream address %s: %w", initialAddrs[0], err)
	}
	return nil
}

// upstreamDialerFunc dials an upstream server. extraAlpnProtos can be provided
// to kms and pki connections and are used for identifying, on the server side,
// the intended purpose of the connection. The state provided by the worker to
// the server can be retrieved from the resulting *protocol.Conn.
func (w *Worker) upstreamDialerFunc(extraAlpnProtos ...string) func(context.Context, string) (net.Conn, error) {
	const op = "worker.(Worker).upstreamDialerFunc"
	return func(ctx context.Context, addr string) (net.Conn, error) {
		var conn net.Conn
		eventLogger, err := event.NewHclogLogger(w.baseContext, w.conf.Eventer)
		if err != nil {
			event.WriteError(w.baseContext, op, err)
			return nil, errors.Wrap(w.baseContext, err, op)
		}
		// Give the log a prefix
		eventLogger = eventLogger.Named(fmt.Sprintf("workerauth_dialer"))
		// Wrap the log in a toggle so we can turn it on and off via config and
		// SIGHUP
		eventLogger = toggledlogger.NewToggledLogger(eventLogger, w.conf.WorkerAuthDebuggingEnabled)
		st, err := w.workerConnectionInfo(addr)
		if err != nil {
			event.WriteError(w.baseContext, op, err)
			return nil, errors.Wrap(w.baseContext, err, op)
		}
		conn, err = protocol.Dial(
			ctx,
			w.WorkerAuthStorage,
			addr,
			nodeenrollment.WithLogger(eventLogger),
			nodeenrollment.WithState(st),
			nodeenrollment.WithStorageWrapper(w.conf.WorkerAuthStorageKms),
			nodeenrollment.WithRegistrationWrapper(w.conf.WorkerAuthKms),
			nodeenrollment.WithWrappingRegistrationFlowApplicationSpecificParams(st),
			nodeenrollment.WithExtraAlpnProtos(extraAlpnProtos),
			// If the activation token hasn't been populated, this won't do
			// anything, and it won't do anything if it's already been used
			nodeenrollment.WithActivationToken(w.conf.RawConfig.Worker.ControllerGeneratedActivationToken),
		)
		// No error and a valid connection means the WorkerAuthRegistrationRequest was populated
		// We can remove the stored workerAuthRequest file
		if err == nil && conn != nil {
			if w.conf.RawConfig.Worker.AuthStoragePath != "" {
				workerAuthReqFilePath := filepath.Join(w.conf.RawConfig.Worker.AuthStoragePath, base.WorkerAuthReqFile)
				// Intentionally ignoring any error removing this file
				_ = os.Remove(workerAuthReqFilePath)
			}
		}
		switch {
		case err == nil:
			// Nothing

		case errors.Is(err, nodeenrollment.ErrNotAuthorized):
			switch w.conf.RawConfig.Worker.ControllerGeneratedActivationToken {
			case "":
				// We don't event in this case, because the function retries
				// often and will spam the logs while waiting on the user to
				// transfer the worker-generated request over
				return nil, errors.Wrap(w.baseContext, err, op)

			default:
				// In this case, event, so that the operator can understand that
				// it was rejected
				event.WriteError(w.baseContext, op, fmt.Errorf("controller rejected activation token as invalid"))
				return nil, errors.Wrap(w.baseContext, err, op)
			}

		default:
			event.WriteError(w.baseContext, op, err)
			return nil, errors.Wrap(w.baseContext, err, op)
		}

		if conn != nil {
			if w.everAuthenticated.Load() == authenticationStatusNeverAuthenticated {
				w.everAuthenticated.Store(authenticationStatusFirstAuthentication)
			}

			event.WriteSysEvent(w.baseContext, op, "worker has successfully authenticated")
		}

		return conn, err
	}
}

func (w *Worker) createClientConn(addr string) error {
	const op = "worker.(Worker).createClientConn"

	var res resolver.Builder
	for _, v := range w.addressReceivers {
		if rec, ok := v.(*grpcResolverReceiver); ok {
			res = rec.Resolver
		}
	}
	if res == nil {
		return errors.New(w.baseContext, errors.Internal, op, "unable to find a resolver.Builder amongst the address receivers")
	}

	dialOpts := createDefaultGRPCDialOptions(res, w.upstreamDialerFunc())

	cc, err := grpc.DialContext(w.baseContext,
		fmt.Sprintf("%s:///%s", res.Scheme(), addr),
		dialOpts...,
	)
	if err != nil {
		return fmt.Errorf("error dialing controller for worker auth: %w", err)
	}

	w.GrpcClientConn.Store(cc)
	w.controllerMultihopConn.Store(multihop.NewMultihopServiceClient(cc))

	var producer handlers.UpstreamMessageServiceClientProducer
	producer = func(context.Context) (pbs.UpstreamMessageServiceClient, error) {
		return pbs.NewUpstreamMessageServiceClient(cc), nil
	}

	w.controllerUpstreamMsgConn.Store(&producer)

	go monitorUpstreamConnectionState(w.baseContext, cc, w.upstreamConnectionState)

	return nil
}

// createDefaultGRPCDialOptions creates grpc.DialOption using default options
func createDefaultGRPCDialOptions(res resolver.Builder, upstreamDialerFn func(context.Context, string) (net.Conn, error)) []grpc.DialOption {
	defaultTimeout := (time.Second + time.Nanosecond).String()
	defServiceConfig := fmt.Sprintf(`
	  {
		"loadBalancingConfig": [ { "round_robin": {} } ],
		"methodConfig": [
		  {
			"name": [],
			"timeout": %q,
			"waitForReady": true
		  }
		]
	  }
	  `, defaultTimeout)

	// minConnectTimeout replaces the unexported gRPC default value of 20
	// seconds with the WithConnectParams option below; otherwise it sets the
	// value to zero instead of unset, which causes it to be very small.
	const minConnectTimeout = 20 * time.Second

	dialOpts := []grpc.DialOption{
		grpc.WithResolvers(res),
		grpc.WithUnaryInterceptor(metric.InstrumentClusterClient()),
		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(math.MaxInt32)),
		grpc.WithDefaultCallOptions(grpc.MaxCallSendMsgSize(math.MaxInt32)),
		grpc.WithContextDialer(upstreamDialerFn),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithDefaultServiceConfig(defServiceConfig),
		// Don't have the resolver reach out for a service config from the
		// resolver, use the one specified as default
		grpc.WithDisableServiceConfig(),
		grpc.WithConnectParams(grpc.ConnectParams{
			Backoff: backoff.Config{
				BaseDelay:  time.Second,
				Multiplier: 1.2,
				Jitter:     0.2,
				MaxDelay:   3 * time.Second,
			},
			MinConnectTimeout: minConnectTimeout,
		}),
	}

	return dialOpts
}

// workerConnectionInfo returns the worker's cluster.WorkerConnectionInfo as
// a struct suitable to be used as the state field in a *protocol.Conn
func (w *Worker) workerConnectionInfo(addr string) (*structpb.Struct, error) {
	const op = "worker.(Worker).workerConnectionInfo"
	wci := &cluster.WorkerConnectionInfo{
		UpstreamAddress:  addr,
		BoundaryVersion:  version.Get().VersionNumber(),
		Name:             w.conf.RawConfig.Worker.Name,
		Description:      w.conf.RawConfig.Worker.Description,
		PublicAddr:       w.conf.RawConfig.Worker.PublicAddr,
		OperationalState: w.operationalState.Load().(server.OperationalState).String(),
	}
	if w.LastRoutingInfoSuccess() != nil && len(w.LastRoutingInfoSuccess().GetWorkerId()) > 0 {
		// even though we wont have the worker the first time we dial, any
		// redial attempts should result in the worker id being populated
		wci.WorkerId = w.LastRoutingInfoSuccess().GetWorkerId()
	}
	st, err := wci.AsConnectionStateStruct()
	if err != nil {
		return nil, errors.Wrap(w.baseContext, err, op, errors.WithMsg("getting worker state"))
	}
	return st, nil
}

// monitorUpstreamConnectionState listens for new state changes from grpc client
// connection and updates the state
func monitorUpstreamConnectionState(ctx context.Context, cc *grpc.ClientConn, connectionState *atomic.Value) {
	var state connectivity.State
	if v := connectionState.Load(); !util.IsNil(v) {
		state = v.(connectivity.State)
	}

	for cc.WaitForStateChange(ctx, state) {
		state = cc.GetState()

		// if the client is shutdown, exit function
		if state == connectivity.Shutdown {
			return
		}

		connectionState.Store(state)
	}
}