package deployers

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"sync"
	"time"

	"gitea.thegux.fr/hmdeploy/connection"
	"gitea.thegux.fr/hmdeploy/docker"
	"gitea.thegux.fr/hmdeploy/models"
	"gitea.thegux.fr/hmdeploy/utils"
	"github.com/rs/zerolog/log"
)

const stateTickDuration = 4 * time.Second

var ErrSwarmDeployerNoArchive = errors.New("no archive found to be deployed")

// SwarmDeployer handles the deployment of a Docker service on the swarm instance.
type SwarmDeployer struct {
	*deployer
	conn        connection.IConnection
	dloc        docker.IClient
	drem        *docker.RemoteClient
	archivePath string
}

var _ IDeployer = (*SwarmDeployer)(nil)

func NewSwarmDeployer(
	ctx context.Context,
	project *models.Project,
	netInfo *models.HMNetInfo,
	dloc docker.IClient,
	drem *docker.RemoteClient,
) (SwarmDeployer, error) {
	var sd SwarmDeployer

	conn, err := connection.NewSSHConn(
		netInfo.IP.String(),
		netInfo.SSH.User,
		netInfo.SSH.Port,
		netInfo.SSH.PrivKey,
	)
	if err != nil {
		return sd, err
	}

	sd.conn = &conn
	sd.dloc = dloc
	sd.drem = drem
	sd.deployer = newDeployer(ctx, Swarm, project)

	return sd, nil
}

func (sd *SwarmDeployer) close() error {
	return sd.conn.Close()
}

func (sd *SwarmDeployer) clean() (err error) {
	if err = os.Remove(sd.archivePath); err != nil {
		log.Err(err).Str("archive", sd.archivePath).Msg("unable to clean local swarm archive file")
	}
	_, err = sd.conn.Execute(
		fmt.Sprintf("rm -f %s %s *.tar.gz *.tar", models.ComposeFile, models.EnvFile),
	)
	return
}

func (sd *SwarmDeployer) Clear() error {
	log.Debug().Msg("clearing swarm deployment...")

	if err := sd.clean(); err != nil {
		log.Err(err).Msg("unable to clean swarm conf remotly")
	}

	if err := sd.close(); err != nil {
		log.Err(err).Msg("unable to close swarm conn")
	}

	log.Debug().Msg("clear swarm deployment done")

	return nil
}

// Build builds the archive with mandatory files to deploy a swarm service.
//
// After the build, the path of the local archive built is set in
// the `archivePath` field.
func (sd *SwarmDeployer) Build() error {
	sd.processing.Store(true)
	defer sd.processing.Store(false)

	select {
	case <-sd.ctx.Done():
		sd.setDone(nil)
		return fmt.Errorf("%w, swarm project build skipped", ErrContextDone)
	default:
	}

	log.Info().Msg("building swarm archive for deployment...")

	filesToArchive := []string{}
	for idx := range sd.project.ImageNames {
		tarFile, err := sd.dloc.Save(sd.project.ImageNames[idx], sd.project.Dir)
		if err != nil {
			sd.setDone(err)
			return err
		}

		defer os.Remove(tarFile) //nolint: errcheck // defered

		// copy the file directly instead of adding it in the tar archive
		log.Info().Str("image", tarFile).Msg("Transferring image...")
		if err := sd.conn.CopyFile(tarFile, filepath.Base(tarFile)); err != nil {
			return err
		}
		log.Info().Str("image", tarFile).Msg("image transferred with success")
	}

	if envFilePath := sd.project.Deps.EnvFile; envFilePath != "" {
		filesToArchive = append(
			filesToArchive,
			envFilePath,
		)
		log.Info().Msg(".env file added to the archive for deployment")
	}

	filesToArchive = append(
		filesToArchive,
		sd.project.Deps.ComposeFile,
	)

	archivePath, err := utils.CreateArchive(
		sd.project.Dir,
		fmt.Sprintf("%s-%s", sd.project.Name, "swarm"),
		filesToArchive...)
	if err != nil {
		sd.setDone(err)
		return err
	}

	sd.archivePath = archivePath

	log.Info().Str("archive", archivePath).Msg("swarm archive built")
	return nil
}

func (sd *SwarmDeployer) Deploy() error {
	sd.processing.Store(true)
	defer sd.processing.Store(false)

	select {
	case <-sd.ctx.Done():
		sd.setDone(nil)
		return fmt.Errorf("%w, swarm deployment skipped", ErrContextDone)
	default:
	}

	if sd.archivePath == "" {
		sd.setDone(ErrSwarmDeployerNoArchive)
		return ErrSwarmDeployerNoArchive
	}

	log.Info().Str("archive", sd.archivePath).Msg("deploying archive to swarm...")

	for idx := range sd.project.ImageNames {
		if _, err := sd.conn.Execute("docker image load -i " + sd.project.ImageNames[idx] + ".tar"); err != nil {
			return err
		}
	}

	archiveDestPath := filepath.Base(sd.archivePath)
	log.Info().
		Str("archive", sd.archivePath).
		Msg("archive built with success, tranferring to swarm for deployment...")
	if err := sd.conn.CopyFile(sd.archivePath, archiveDestPath); err != nil {
		sd.setDone(err)
		return err
	}

	if _, err := sd.conn.Execute(fmt.Sprintf("tar xzvf %s", archiveDestPath)); err != nil {
		sd.setDone(err)
		return err
	}

	log.Info().Str("project", sd.project.Name).Msg("deploying swarm project...")
	composeFileBase := filepath.Base(sd.project.Deps.ComposeFile)
	if _, err := sd.conn.Execute(fmt.Sprintf("docker stack deploy -c %s %s --with-registry-auth", composeFileBase, sd.project.Name)); err != nil {
		sd.setDone(err)
		return err
	}

	if err := sd.checkState(docker.Running); err != nil {
		sd.setDone(err)
		return err
	}

	log.Info().Msg("swarm deployment done with success")

	sd.setDone(nil)
	return nil
}

// checkState checks the state of the deployment.
// It loops over all the services deployed for the project (replicas included) and
// checks if the `target` state match the services states.
//
// There's a timeout (default: 30s) that you can set with the options: `WithTimeout`.
func (sd *SwarmDeployer) checkState(target docker.ServiceStatus, options ...fnStateOption) error {
	var opts checkStateOption
	for _, opt := range options {
		opt(&opts)
	}

	var checkErr error
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()

		timeoutDuration := DefaultStateTimeout
		if opts.timeout != nil {
			timeoutDuration = *opts.timeout
		}

		ticker := time.NewTicker(stateTickDuration)
		ctx, fnCancel := context.WithDeadline(sd.ctx, time.Now().UTC().Add(timeoutDuration))
		defer fnCancel()

		for {
			select {
			case <-ticker.C:
				log.Info().
					Str("project", sd.project.Name).
					Str("state", string(target)).
					Msg("checking project state...")
				srvs, err := sd.drem.ExtractServicesDetails(docker.WithName(sd.project.Name))
				if err != nil {
					checkErr = err
					return
				}

				ready := true
			mainloop:
				for idx := range srvs {
					for idy := range srvs[idx].Replicas {
						if srvs[idx].Replicas[idy].State != docker.ServiceStatus(target) {
							log.Info().Dur("retry (ms)", stateTickDuration).Msg("project not in good state yet, retrying...")
							ready = false
							break mainloop
						}
					}
				}
				if ready {
					return
				}
			case <-ctx.Done():
				msg := "swarm deployment skipped"
				if errors.Is(ctx.Err(), context.DeadlineExceeded) {
					msg = "swarm check state timeout"
				}
				checkErr = fmt.Errorf("%w, %s", ErrContextDone, msg)
				return
			}
		}
	}()

	wg.Wait()
	return checkErr
}

func (sd *SwarmDeployer) Destroy() error {
	sd.processing.Store(true)
	defer sd.processing.Store(false)

	log.Info().Str("project", sd.project.Name).Msg("destroying swarm project...")
	if _, err := sd.conn.Execute(fmt.Sprintf("docker stack rm %s", sd.project.Name)); err != nil {
		sd.setDone(err)
		return err
	}

	if err := sd.checkState(docker.Shutdown); err != nil {
		sd.setDone(err)
		return err
	}

	log.Info().Msg("swarm undeployment done with success")

	sd.setDone(nil)
	return nil
}