package client

import (
	"context"
	"errors"
	"fmt"
	"github.com/docker/compose/v2/pkg/progress"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/network"
	dockerclient "github.com/docker/docker/client"
	"github.com/docker/docker/pkg/jsonmessage"
	"github.com/docker/go-connections/nat"
	"strconv"
	"strings"
	"uncloud/internal/api"
	machinedocker "uncloud/internal/machine/docker"
	"uncloud/internal/secret"
)

// CreateContainer creates a new container for the given service on the specified machine.
func (cli *Client) CreateContainer(
	ctx context.Context, serviceID string, spec api.ServiceSpec, machineID string,
) (container.CreateResponse, error) {
	var resp container.CreateResponse

	machine, err := cli.InspectMachine(ctx, machineID)
	if err != nil {
		return resp, fmt.Errorf("inspect machine '%s': %w", machineID, err)
	}

	suffix, err := secret.RandomAlphaNumeric(4)
	if err != nil {
		return resp, fmt.Errorf("generate random suffix: %w", err)
	}
	containerName := fmt.Sprintf("%s-%s", spec.Name, suffix)

	config := &container.Config{
		Cmd:   spec.Container.Command,
		Image: spec.Container.Image,
		Labels: map[string]string{
			api.LabelServiceID:   serviceID,
			api.LabelServiceName: spec.Name,
			api.LabelManaged:     "",
		},
	}
	if spec.Mode == api.ServiceModeGlobal {
		config.Labels[api.LabelServiceMode] = api.ServiceModeGlobal
	}

	if len(spec.Ports) > 0 {
		encodedPorts := make([]string, len(spec.Ports))
		for i, p := range spec.Ports {
			encodedPorts[i], err = p.String()
			if err != nil {
				return resp, fmt.Errorf("encode service port spec: %w", err)
			}
		}

		config.Labels[api.LabelServicePorts] = strings.Join(encodedPorts, ",")
	}

	portBindings := make(nat.PortMap)
	for _, p := range spec.Ports {
		if p.Mode != api.PortModeHost {
			continue
		}
		port := nat.Port(fmt.Sprintf("%d/%s", p.ContainerPort, p.Protocol))
		portBindings[port] = []nat.PortBinding{
			{
				HostPort: strconv.Itoa(int(p.PublishedPort)),
			},
		}
		if p.HostIP.IsValid() {
			portBindings[port][0].HostIP = p.HostIP.String()
		}
	}
	hostConfig := &container.HostConfig{
		Binds:        spec.Container.Volumes,
		Init:         spec.Container.Init,
		PortBindings: portBindings,
	}
	netConfig := &network.NetworkingConfig{
		EndpointsConfig: map[string]*network.EndpointSettings{
			machinedocker.NetworkName: {},
		},
	}

	// Proxy Docker gRPC requests to the selected machine.
	ctx = proxyToMachine(ctx, machine.Machine)

	pw := progress.ContextWriter(ctx)
	eventID := fmt.Sprintf("Container %s on %s", containerName, machine.Machine.Name)

	pw.Event(progress.CreatingEvent(eventID))
	resp, err = cli.Docker.CreateContainer(ctx, config, hostConfig, netConfig, nil, containerName)
	if err != nil {
		if !dockerclient.IsErrNotFound(err) {
			return resp, err
		}

		// Pull the missing image and create the container again.
		if err = cli.pullImageWithProgress(ctx, config.Image, machine.Machine.Name, eventID); err != nil {
			return resp, err
		}
		if resp, err = cli.Docker.CreateContainer(ctx, config, hostConfig, netConfig, nil, containerName); err != nil {
			return resp, err
		}
	}
	pw.Event(progress.CreatedEvent(eventID))

	return resp, nil
}

func (cli *Client) pullImageWithProgress(ctx context.Context, image, machineName, parentEventID string) error {
	pw := progress.ContextWriter(ctx)
	eventID := fmt.Sprintf("Image %s on %s", image, machineName)
	pw.Event(progress.Event{
		ID:         eventID,
		ParentID:   parentEventID,
		Status:     progress.Working,
		StatusText: "Pulling",
	})

	pullCh, err := cli.Docker.PullImage(ctx, image)
	if err != nil {
		pw.Event(progress.Event{
			ID:         eventID,
			ParentID:   parentEventID,
			Text:       "Error",
			Status:     progress.Error,
			StatusText: errors.Unwrap(err).Error(),
		})
		return fmt.Errorf("pull image: %w", err)
	}

	// Wait for pull to complete by reading all progress messages and converting them to events.
	for msg := range pullCh {
		if msg.Err != nil {
			err = msg.Err
		} else {
			if msg.Message.Error != nil {
				err = errors.New(msg.Message.Error.Message)
			}
		}
		if err != nil {
			pw.Event(progress.Event{
				ID:         eventID,
				ParentID:   parentEventID,
				Text:       "Error",
				Status:     progress.Error,
				StatusText: errors.Unwrap(err).Error(),
			})
			return fmt.Errorf("pull image: %w", err)
		}

		// TODO: add like in compose: --quiet-pull Pull without printing progress information
		e := toPullProgressEvent(msg.Message)
		if e != nil {
			e.ID = fmt.Sprintf("%s on %s", e.ID, machineName)
			e.ParentID = eventID
			// Grand children events are not printed by the tty progress writer but they are still required
			// to calculate the progress line of their parent.
			pw.Event(*e)
		}
	}
	pw.Event(progress.Event{
		ID:         eventID,
		ParentID:   parentEventID,
		Status:     progress.Done,
		StatusText: "Pulled",
	})

	return nil
}

// toPullProgressEvent converts a JSON progress message from the Docker API to a progress event.
// It's based on toPullProgressEvent from Docker Compose.
func toPullProgressEvent(jm jsonmessage.JSONMessage) *progress.Event {
	if jm.ID == "" || jm.Progress == nil {
		return nil
	}

	var (
		total   int64
		percent int
		current int64
	)
	text := jm.Progress.String()
	stat := progress.Working

	switch jm.Status {
	case "Preparing", "Waiting", "Pulling fs layer":
		percent = 0
	case "Downloading", "Extracting", "Verifying Checksum":
		current = jm.Progress.Current
		total = jm.Progress.Total
		if jm.Progress.Total > 0 {
			percent = int(jm.Progress.Current * 100 / jm.Progress.Total)
		}
	case "Download complete", "Already exists", "Pull complete":
		stat = progress.Done
		percent = 100
	}

	if strings.Contains(jm.Status, "Image is up to date") ||
		strings.Contains(jm.Status, "Downloaded newer image") {
		stat = progress.Done
		percent = 100
	}

	return &progress.Event{
		ID:         jm.ID,
		Current:    current,
		Total:      total,
		Percent:    percent,
		Text:       jm.Status,
		Status:     stat,
		StatusText: text,
	}
}

// InspectContainer returns the information about the specified container within the service.
func (cli *Client) InspectContainer(ctx context.Context, serviceID, containerID string) (api.MachineContainer, error) {
	var ctr api.MachineContainer

	svc, err := cli.InspectService(ctx, serviceID)
	if err != nil {
		return ctr, fmt.Errorf("inspect service: %w", err)
	}

	for _, c := range svc.Containers {
		if c.Container.ID == containerID || c.Container.Name() == containerID {
			ctr = c
		}
	}
	if ctr.MachineID == "" {
		return ctr, ErrNotFound
	}

	return ctr, nil
}

// StartContainer starts the specified container within the service.
func (cli *Client) StartContainer(ctx context.Context, serviceID, containerID string) error {
	ctr, err := cli.InspectContainer(ctx, serviceID, containerID)
	if err != nil {
		return err
	}

	machine, err := cli.InspectMachine(ctx, ctr.MachineID)
	if err != nil {
		return fmt.Errorf("inspect machine '%s': %w", ctr.MachineID, err)
	}
	ctx = proxyToMachine(ctx, machine.Machine)

	pw := progress.ContextWriter(ctx)
	eventID := fmt.Sprintf("Container %s on %s", ctr.Container.Name(), machine.Machine.Name)

	pw.Event(progress.StartingEvent(eventID))
	if err = cli.Docker.StartContainer(ctx, ctr.Container.ID, container.StartOptions{}); err != nil {
		return err
	}
	pw.Event(progress.StartedEvent(eventID))

	return nil
}

// StopContainer stops the specified container within the service.
func (cli *Client) StopContainer(
	ctx context.Context, serviceID, containerID string, opts container.StopOptions,
) error {
	ctr, err := cli.InspectContainer(ctx, serviceID, containerID)
	if err != nil {
		return err
	}

	machine, err := cli.InspectMachine(ctx, ctr.MachineID)
	if err != nil {
		return fmt.Errorf("inspect machine '%s': %w", ctr.MachineID, err)
	}
	ctx = proxyToMachine(ctx, machine.Machine)

	pw := progress.ContextWriter(ctx)
	eventID := fmt.Sprintf("Container %s on %s", ctr.Container.Name(), machine.Machine.Name)

	pw.Event(progress.StoppingEvent(eventID))
	if err = cli.Docker.StopContainer(ctx, ctr.Container.ID, opts); err != nil {
		return err
	}
	pw.Event(progress.StoppedEvent(eventID))

	return nil
}

// RemoveContainer removes the specified container within the service.
func (cli *Client) RemoveContainer(
	ctx context.Context, serviceID, containerID string, opts container.RemoveOptions,
) error {
	ctr, err := cli.InspectContainer(ctx, serviceID, containerID)
	if err != nil {
		return err
	}

	machine, err := cli.InspectMachine(ctx, ctr.MachineID)
	if err != nil {
		return fmt.Errorf("inspect machine '%s': %w", ctr.MachineID, err)
	}
	ctx = proxyToMachine(ctx, machine.Machine)

	pw := progress.ContextWriter(ctx)
	eventID := fmt.Sprintf("Container %s on %s", ctr.Container.Name(), machine.Machine.Name)

	pw.Event(progress.RemovingEvent(eventID))
	if err = cli.Docker.RemoveContainer(ctx, ctr.Container.ID, opts); err != nil {
		return err
	}
	pw.Event(progress.RemovedEvent(eventID))

	return nil
}