package cmd

import (
	"context"
	"errors"
	"fmt"
	"io/fs"
	"log"
	"net"

	"github.com/edgelesssys/constellation/debugd/bootstrapper"
	"github.com/edgelesssys/constellation/debugd/cdbg/config"
	"github.com/edgelesssys/constellation/debugd/cdbg/state"
	"github.com/edgelesssys/constellation/debugd/debugd"
	depl "github.com/edgelesssys/constellation/debugd/debugd/deploy"
	pb "github.com/edgelesssys/constellation/debugd/service"
	configc "github.com/edgelesssys/constellation/internal/config"
	"github.com/edgelesssys/constellation/internal/constants"
	"github.com/edgelesssys/constellation/internal/file"
	statec "github.com/edgelesssys/constellation/internal/state"
	"github.com/spf13/afero"
	"github.com/spf13/cobra"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

var deployCmd = &cobra.Command{
	Use:   "deploy",
	Short: "Deploys a self-compiled bootstrapper binary and SSH keys on the current constellation",
	Long: `Deploys a self-compiled bootstrapper binary and SSH keys on the current constellation.
Uses config provided by --config and reads constellation config from its default location.
If required, you can override the IP addresses that are used for a deployment by specifying "--ips" and a list of IP addresses.
Specifying --bootstrapper will upload the bootstrapper from the specified path.`,
	RunE:    runDeploy,
	Example: "cdbg deploy\ncdbg deploy --config /path/to/config\ncdbg deploy --bootstrapper /path/to/bootstrapper --ips 192.0.2.1,192.0.2.2,192.0.2.3 --config /path/to/config",
}

func runDeploy(cmd *cobra.Command, args []string) error {
	debugConfigName, err := cmd.Flags().GetString("cdbg-config")
	if err != nil {
		return err
	}
	configName, err := cmd.Flags().GetString("config")
	if err != nil {
		return fmt.Errorf("parsing config path argument: %w", err)
	}
	fileHandler := file.NewHandler(afero.NewOsFs())
	debugConfig, err := config.FromFile(fileHandler, debugConfigName)
	if err != nil {
		return err
	}
	constellationConfig, err := configc.FromFile(fileHandler, configName)
	if err != nil {
		return err
	}

	return deploy(cmd, fileHandler, constellationConfig, debugConfig, bootstrapper.NewFileStreamer(afero.NewOsFs()))
}

func deploy(cmd *cobra.Command, fileHandler file.Handler, constellationConfig *configc.Config, debugConfig *config.CDBGConfig, reader fileToStreamReader) error {
	overrideBootstrapperPath, err := cmd.Flags().GetString("bootstrapper")
	if err != nil {
		return err
	}
	if len(overrideBootstrapperPath) > 0 {
		debugConfig.ConstellationDebugConfig.BootstrapperPath = overrideBootstrapperPath
	}

	if !constellationConfig.IsImageDebug() {
		log.Println("WARN: constellation image does not look like a debug image. Are you using a debug image?")
	}

	overrideIPs, err := cmd.Flags().GetStringSlice("ips")
	if err != nil {
		return err
	}
	var ips []string
	if len(overrideIPs) > 0 {
		ips = overrideIPs
	} else {
		var stat statec.ConstellationState
		err := fileHandler.ReadJSON(constants.StateFilename, &stat)
		if errors.Is(err, fs.ErrNotExist) {
			log.Println("Unable to load statefile. Maybe you forgot to run \"constellation create ...\" first?")
			return fmt.Errorf("loading statefile: %w", err)
		} else if err != nil {
			return fmt.Errorf("loading statefile: %w", err)
		}
		ips, err = getIPsFromConfig(stat, *constellationConfig)
		if err != nil {
			return err
		}
	}

	for _, ip := range ips {
		input := deployOnEndpointInput{
			debugdEndpoint:   net.JoinHostPort(ip, debugd.DebugdPort),
			bootstrapperPath: debugConfig.ConstellationDebugConfig.BootstrapperPath,
			reader:           reader,
			authorizedKeys:   debugConfig.ConstellationDebugConfig.AuthorizedKeys,
			systemdUnits:     debugConfig.ConstellationDebugConfig.SystemdUnits,
		}
		if err := deployOnEndpoint(cmd.Context(), input); err != nil {
			return err
		}
	}

	return nil
}

type deployOnEndpointInput struct {
	debugdEndpoint   string
	bootstrapperPath string
	reader           fileToStreamReader
	authorizedKeys   []configc.UserKey
	systemdUnits     []depl.SystemdUnit
}

// deployOnEndpoint deploys SSH public keys, systemd units and a locally built bootstrapper binary to a debugd endpoint.
func deployOnEndpoint(ctx context.Context, in deployOnEndpointInput) error {
	log.Printf("Deploying on %v\n", in.debugdEndpoint)
	dialCTX, cancel := context.WithTimeout(ctx, debugd.GRPCTimeout)
	defer cancel()
	conn, err := grpc.DialContext(dialCTX, in.debugdEndpoint, grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		return fmt.Errorf("connecting to other instance via gRPC: %w", err)
	}
	defer conn.Close()
	client := pb.NewDebugdClient(conn)

	log.Println("Uploading authorized keys")
	pbKeys := []*pb.AuthorizedKey{}
	for _, key := range in.authorizedKeys {
		pbKeys = append(pbKeys, &pb.AuthorizedKey{
			Username: key.Username,
			KeyValue: key.PublicKey,
		})
	}
	authorizedKeysResponse, err := client.UploadAuthorizedKeys(ctx, &pb.UploadAuthorizedKeysRequest{Keys: pbKeys}, grpc.WaitForReady(true))
	if err != nil || authorizedKeysResponse.Status != pb.UploadAuthorizedKeysStatus_UPLOAD_AUTHORIZED_KEYS_SUCCESS {
		return fmt.Errorf("uploading bootstrapper to instance %v failed: %v / %w", in.debugdEndpoint, authorizedKeysResponse, err)
	}

	if len(in.systemdUnits) > 0 {
		log.Println("Uploading systemd unit files")

		pbUnits := []*pb.ServiceUnit{}
		for _, unit := range in.systemdUnits {
			pbUnits = append(pbUnits, &pb.ServiceUnit{
				Name:     unit.Name,
				Contents: unit.Contents,
			})
		}
		uploadSystemdServiceUnitsResponse, err := client.UploadSystemServiceUnits(ctx, &pb.UploadSystemdServiceUnitsRequest{Units: pbUnits})
		if err != nil || uploadSystemdServiceUnitsResponse.Status != pb.UploadSystemdServiceUnitsStatus_UPLOAD_SYSTEMD_SERVICE_UNITS_SUCCESS {
			return fmt.Errorf("uploading systemd service unit to instance %v failed: %v / %w", in.debugdEndpoint, uploadSystemdServiceUnitsResponse, err)
		}
	}

	stream, err := client.UploadBootstrapper(ctx)
	if err != nil {
		return fmt.Errorf("starting bootstrapper upload to instance %v: %w", in.debugdEndpoint, err)
	}
	streamErr := in.reader.ReadStream(in.bootstrapperPath, stream, debugd.Chunksize, true)

	uploadResponse, closeErr := stream.CloseAndRecv()
	if closeErr != nil {
		return fmt.Errorf("closing upload stream after uploading bootstrapper to %v: %w", in.debugdEndpoint, closeErr)
	}
	if uploadResponse.Status == pb.UploadBootstrapperStatus_UPLOAD_BOOTSTRAPPER_FILE_EXISTS {
		log.Println("Bootstrapper was already uploaded")
		return nil
	}
	if uploadResponse.Status != pb.UploadBootstrapperStatus_UPLOAD_BOOTSTRAPPER_SUCCESS || streamErr != nil {
		return fmt.Errorf("uploading bootstrapper to instance %v failed: %v / %w", in.debugdEndpoint, uploadResponse, streamErr)
	}
	log.Println("Uploaded bootstrapper")
	return nil
}

func getIPsFromConfig(stat statec.ConstellationState, config configc.Config) ([]string, error) {
	controlPlanes, workers, err := state.GetScalingGroupsFromConfig(stat, &config)
	if err != nil {
		return nil, err
	}

	var ips []string
	// only deploy to non empty public IPs
	for _, ip := range append(controlPlanes.PublicIPs(), workers.PublicIPs()...) {
		if ip != "" {
			ips = append(ips, ip)
		}
	}
	// add bootstrapper IP if it is not already in the list
	var foundBootstrapperIP bool
	for _, ip := range ips {
		if ip == stat.BootstrapperHost {
			foundBootstrapperIP = true
			break
		}
	}
	if !foundBootstrapperIP && stat.BootstrapperHost != "" {
		ips = append(ips, stat.BootstrapperHost)
	}
	if len(ips) == 0 {
		return nil, fmt.Errorf("no public IPs found in statefile")
	}

	return ips, nil
}

func init() {
	rootCmd.AddCommand(deployCmd)

	deployCmd.Flags().StringSlice("ips", nil, "override the ips that the bootstrapper will be uploaded to (defaults to ips from constellation config)")
	deployCmd.Flags().String("bootstrapper", "", "override the path to the bootstrapper binary uploaded to instances (defaults to path set in config)")
}

type fileToStreamReader interface {
	ReadStream(filename string, stream bootstrapper.WriteChunkStream, chunksize uint, showProgress bool) error
}