package cluster

import (
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"strings"

	"github.com/Sirupsen/logrus"
	"github.com/docker/distribution/reference"
	apierrors "github.com/docker/docker/api/errors"
	apitypes "github.com/docker/docker/api/types"
	"github.com/docker/docker/api/types/backend"
	types "github.com/docker/docker/api/types/swarm"
	"github.com/docker/docker/daemon/cluster/convert"
	"github.com/docker/docker/daemon/logger"
	"github.com/docker/docker/pkg/ioutils"
	"github.com/docker/docker/pkg/stdcopy"
	swarmapi "github.com/docker/swarmkit/api"
	gogotypes "github.com/gogo/protobuf/types"
	"github.com/pkg/errors"
	"golang.org/x/net/context"
)

// GetServices returns all services of a managed swarm cluster.
func (c *Cluster) GetServices(options apitypes.ServiceListOptions) ([]types.Service, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	state := c.currentNodeState()
	if !state.IsActiveManager() {
		return nil, c.errNoManager(state)
	}

	filters, err := newListServicesFilters(options.Filters)
	if err != nil {
		return nil, err
	}
	ctx, cancel := c.getRequestContext()
	defer cancel()

	r, err := state.controlClient.ListServices(
		ctx,
		&swarmapi.ListServicesRequest{Filters: filters})
	if err != nil {
		return nil, err
	}

	services := []types.Service{}

	for _, service := range r.Services {
		services = append(services, convert.ServiceFromGRPC(*service))
	}

	return services, nil
}

// GetService returns a service based on an ID or name.
func (c *Cluster) GetService(input string) (types.Service, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	state := c.currentNodeState()
	if !state.IsActiveManager() {
		return types.Service{}, c.errNoManager(state)
	}

	ctx, cancel := c.getRequestContext()
	defer cancel()

	service, err := getService(ctx, state.controlClient, input)
	if err != nil {
		return types.Service{}, err
	}
	return convert.ServiceFromGRPC(*service), nil
}

// CreateService creates a new service in a managed swarm cluster.
func (c *Cluster) CreateService(s types.ServiceSpec, encodedAuth string) (*apitypes.ServiceCreateResponse, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	state := c.currentNodeState()
	if !state.IsActiveManager() {
		return nil, c.errNoManager(state)
	}

	ctx, cancel := c.getRequestContext()
	defer cancel()

	err := c.populateNetworkID(ctx, state.controlClient, &s)
	if err != nil {
		return nil, err
	}

	serviceSpec, err := convert.ServiceSpecToGRPC(s)
	if err != nil {
		return nil, apierrors.NewBadRequestError(err)
	}

	ctnr := serviceSpec.Task.GetContainer()
	if ctnr == nil {
		return nil, errors.New("service does not use container tasks")
	}

	if encodedAuth != "" {
		ctnr.PullOptions = &swarmapi.ContainerSpec_PullOptions{RegistryAuth: encodedAuth}
	}

	// retrieve auth config from encoded auth
	authConfig := &apitypes.AuthConfig{}
	if encodedAuth != "" {
		if err := json.NewDecoder(base64.NewDecoder(base64.URLEncoding, strings.NewReader(encodedAuth))).Decode(authConfig); err != nil {
			logrus.Warnf("invalid authconfig: %v", err)
		}
	}

	resp := &apitypes.ServiceCreateResponse{}

	// pin image by digest
	if os.Getenv("DOCKER_SERVICE_PREFER_OFFLINE_IMAGE") != "1" {
		digestImage, err := c.imageWithDigestString(ctx, ctnr.Image, authConfig)
		if err != nil {
			logrus.Warnf("unable to pin image %s to digest: %s", ctnr.Image, err.Error())
			resp.Warnings = append(resp.Warnings, fmt.Sprintf("unable to pin image %s to digest: %s", ctnr.Image, err.Error()))
		} else if ctnr.Image != digestImage {
			logrus.Debugf("pinning image %s by digest: %s", ctnr.Image, digestImage)
			ctnr.Image = digestImage
		} else {
			logrus.Debugf("creating service using supplied digest reference %s", ctnr.Image)
		}
	}

	r, err := state.controlClient.CreateService(ctx, &swarmapi.CreateServiceRequest{Spec: &serviceSpec})
	if err != nil {
		return nil, err
	}

	resp.ID = r.Service.ID
	return resp, nil
}

// UpdateService updates existing service to match new properties.
func (c *Cluster) UpdateService(serviceIDOrName string, version uint64, spec types.ServiceSpec, encodedAuth string, registryAuthFrom string) (*apitypes.ServiceUpdateResponse, error) {
	c.mu.RLock()
	defer c.mu.RUnlock()

	state := c.currentNodeState()
	if !state.IsActiveManager() {
		return nil, c.errNoManager(state)
	}

	ctx, cancel := c.getRequestContext()
	defer cancel()

	err := c.populateNetworkID(ctx, state.controlClient, &spec)
	if err != nil {
		return nil, err
	}

	serviceSpec, err := convert.ServiceSpecToGRPC(spec)
	if err != nil {
		return nil, apierrors.NewBadRequestError(err)
	}

	currentService, err := getService(ctx, state.controlClient, serviceIDOrName)
	if err != nil {
		return nil, err
	}

	newCtnr := serviceSpec.Task.GetContainer()
	if newCtnr == nil {
		return nil, errors.New("service does not use container tasks")
	}

	if encodedAuth != "" {
		newCtnr.PullOptions = &swarmapi.ContainerSpec_PullOptions{RegistryAuth: encodedAuth}
	} else {
		// this is needed because if the encodedAuth isn't being updated then we
		// shouldn't lose it, and continue to use the one that was already present
		var ctnr *swarmapi.ContainerSpec
		switch registryAuthFrom {
		case apitypes.RegistryAuthFromSpec, "":
			ctnr = currentService.Spec.Task.GetContainer()
		case apitypes.RegistryAuthFromPreviousSpec:
			if currentService.PreviousSpec == nil {
				return nil, errors.New("service does not have a previous spec")
			}
			ctnr = currentService.PreviousSpec.Task.GetContainer()
		default:
			return nil, errors.New("unsupported registryAuthFrom value")
		}
		if ctnr == nil {
			return nil, errors.New("service does not use container tasks")
		}
		newCtnr.PullOptions = ctnr.PullOptions
		// update encodedAuth so it can be used to pin image by digest
		if ctnr.PullOptions != nil {
			encodedAuth = ctnr.PullOptions.RegistryAuth
		}
	}

	// retrieve auth config from encoded auth
	authConfig := &apitypes.AuthConfig{}
	if encodedAuth != "" {
		if err := json.NewDecoder(base64.NewDecoder(base64.URLEncoding, strings.NewReader(encodedAuth))).Decode(authConfig); err != nil {
			logrus.Warnf("invalid authconfig: %v", err)
		}
	}

	resp := &apitypes.ServiceUpdateResponse{}

	// pin image by digest
	if os.Getenv("DOCKER_SERVICE_PREFER_OFFLINE_IMAGE") != "1" {
		digestImage, err := c.imageWithDigestString(ctx, newCtnr.Image, authConfig)
		if err != nil {
			logrus.Warnf("unable to pin image %s to digest: %s", newCtnr.Image, err.Error())
			resp.Warnings = append(resp.Warnings, fmt.Sprintf("unable to pin image %s to digest: %s", newCtnr.Image, err.Error()))
		} else if newCtnr.Image != digestImage {
			logrus.Debugf("pinning image %s by digest: %s", newCtnr.Image, digestImage)
			newCtnr.Image = digestImage
		} else {
			logrus.Debugf("updating service using supplied digest reference %s", newCtnr.Image)
		}
	}

	_, err = state.controlClient.UpdateService(
		ctx,
		&swarmapi.UpdateServiceRequest{
			ServiceID: currentService.ID,
			Spec:      &serviceSpec,
			ServiceVersion: &swarmapi.Version{
				Index: version,
			},
		},
	)

	return resp, err
}

// RemoveService removes a service from a managed swarm cluster.
func (c *Cluster) RemoveService(input string) error {
	c.mu.RLock()
	defer c.mu.RUnlock()

	state := c.currentNodeState()
	if !state.IsActiveManager() {
		return c.errNoManager(state)
	}

	ctx, cancel := c.getRequestContext()
	defer cancel()

	service, err := getService(ctx, state.controlClient, input)
	if err != nil {
		return err
	}

	_, err = state.controlClient.RemoveService(ctx, &swarmapi.RemoveServiceRequest{ServiceID: service.ID})
	return err
}

// ServiceLogs collects service logs and writes them back to `config.OutStream`
func (c *Cluster) ServiceLogs(ctx context.Context, input string, config *backend.ContainerLogsConfig, started chan struct{}) error {
	c.mu.RLock()
	state := c.currentNodeState()
	if !state.IsActiveManager() {
		c.mu.RUnlock()
		return c.errNoManager(state)
	}

	service, err := getService(ctx, state.controlClient, input)
	if err != nil {
		c.mu.RUnlock()
		return err
	}

	stream, err := state.logsClient.SubscribeLogs(ctx, &swarmapi.SubscribeLogsRequest{
		Selector: &swarmapi.LogSelector{
			ServiceIDs: []string{service.ID},
		},
		Options: &swarmapi.LogSubscriptionOptions{
			Follow: config.Follow,
		},
	})
	if err != nil {
		c.mu.RUnlock()
		return err
	}

	wf := ioutils.NewWriteFlusher(config.OutStream)
	defer wf.Close()
	close(started)
	wf.Flush()

	outStream := stdcopy.NewStdWriter(wf, stdcopy.Stdout)
	errStream := stdcopy.NewStdWriter(wf, stdcopy.Stderr)

	// Release the lock before starting the stream.
	c.mu.RUnlock()
	for {
		// Check the context before doing anything.
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}

		subscribeMsg, err := stream.Recv()
		if err == io.EOF {
			return nil
		}
		if err != nil {
			return err
		}

		for _, msg := range subscribeMsg.Messages {
			data := []byte{}

			if config.Timestamps {
				ts, err := gogotypes.TimestampFromProto(msg.Timestamp)
				if err != nil {
					return err
				}
				data = append(data, []byte(ts.Format(logger.TimeFormat)+" ")...)
			}

			data = append(data, []byte(fmt.Sprintf("%s.node.id=%s,%s.service.id=%s,%s.task.id=%s ",
				contextPrefix, msg.Context.NodeID,
				contextPrefix, msg.Context.ServiceID,
				contextPrefix, msg.Context.TaskID,
			))...)

			data = append(data, msg.Data...)

			switch msg.Stream {
			case swarmapi.LogStreamStdout:
				outStream.Write(data)
			case swarmapi.LogStreamStderr:
				errStream.Write(data)
			}
		}
	}
}

// imageWithDigestString takes an image such as name or name:tag
// and returns the image pinned to a digest, such as name@sha256:34234
func (c *Cluster) imageWithDigestString(ctx context.Context, image string, authConfig *apitypes.AuthConfig) (string, error) {
	ref, err := reference.ParseAnyReference(image)
	if err != nil {
		return "", err
	}
	namedRef, ok := ref.(reference.Named)
	if !ok {
		if _, ok := ref.(reference.Digested); ok {
			return "", errors.New("image reference is an image ID")
		}
		return "", errors.Errorf("unknown image reference format: %s", image)
	}
	// only query registry if not a canonical reference (i.e. with digest)
	if _, ok := namedRef.(reference.Canonical); !ok {
		namedRef = reference.TagNameOnly(namedRef)

		taggedRef, ok := namedRef.(reference.NamedTagged)
		if !ok {
			return "", errors.Errorf("image reference not tagged: %s", image)
		}

		repo, _, err := c.config.Backend.GetRepository(ctx, taggedRef, authConfig)
		if err != nil {
			return "", err
		}
		dscrptr, err := repo.Tags(ctx).Get(ctx, taggedRef.Tag())
		if err != nil {
			return "", err
		}

		namedDigestedRef, err := reference.WithDigest(taggedRef, dscrptr.Digest)
		if err != nil {
			return "", err
		}
		// return familiar form until interface updated to return type
		return reference.FamiliarString(namedDigestedRef), nil
	}
	// reference already contains a digest, so just return it
	return reference.FamiliarString(ref), nil
}