package main

import (
	"context"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strings"

	"github.com/containers/image/types"
	"github.com/containers/libpod/cmd/podman/cliconfig"
	"github.com/containers/libpod/cmd/podman/libpodruntime"
	"github.com/containers/libpod/cmd/podman/shared"
	"github.com/containers/libpod/libpod"
	"github.com/containers/libpod/libpod/image"
	ns "github.com/containers/libpod/pkg/namespaces"
	"github.com/containers/libpod/pkg/spec"
	"github.com/containers/storage"
	"github.com/cri-o/ocicni/pkg/ocicni"
	"github.com/ghodss/yaml"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
	"k8s.io/api/core/v1"
)

const (
	// https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
	createDirectoryPermission = 0755
	// https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
	createFilePermission = 0644
)

var (
	playKubeCommand     cliconfig.KubePlayValues
	playKubeDescription = `Command reads in a structured file of Kubernetes YAML.

  It creates the pod and containers described in the YAML.  The containers within the pod are then started and the ID of the new Pod is output.`
	_playKubeCommand = &cobra.Command{
		Use:   "kube [flags] KUBEFILE",
		Short: "Play a pod based on Kubernetes YAML",
		Long:  playKubeDescription,
		RunE: func(cmd *cobra.Command, args []string) error {
			playKubeCommand.InputArgs = args
			playKubeCommand.GlobalFlags = MainGlobalOpts
			playKubeCommand.Remote = remoteclient
			return playKubeCmd(&playKubeCommand)
		},
		Example: `podman play kube demo.yml
  podman play kube --cert-dir /mycertsdir --tls-verify=true --quiet myWebPod`,
	}
)

func init() {
	playKubeCommand.Command = _playKubeCommand
	playKubeCommand.SetHelpTemplate(HelpTemplate())
	playKubeCommand.SetUsageTemplate(UsageTemplate())
	flags := playKubeCommand.Flags()
	flags.StringVar(&playKubeCommand.Authfile, "authfile", "", "Path of the authentication file. Default is ${XDG_RUNTIME_DIR}/containers/auth.json. Use REGISTRY_AUTH_FILE environment variable to override")
	flags.StringVar(&playKubeCommand.CertDir, "cert-dir", "", "`Pathname` of a directory containing TLS certificates and keys")
	flags.StringVar(&playKubeCommand.Creds, "creds", "", "`Credentials` (USERNAME:PASSWORD) to use for authenticating to a registry")
	flags.BoolVarP(&playKubeCommand.Quiet, "quiet", "q", false, "Suppress output information when pulling images")
	flags.StringVar(&playKubeCommand.SignaturePolicy, "signature-policy", "", "`Pathname` of signature policy file (not usually used)")
	flags.BoolVar(&playKubeCommand.TlsVerify, "tls-verify", true, "Require HTTPS and verify certificates when contacting registries")
}

func playKubeCmd(c *cliconfig.KubePlayValues) error {
	args := c.InputArgs
	if len(args) > 1 {
		return errors.New("you can only play one kubernetes file at a time")
	}
	if len(args) < 1 {
		return errors.New("you must supply at least one file")
	}

	ctx := getContext()
	runtime, err := libpodruntime.GetRuntime(ctx, &c.PodmanCommand)
	if err != nil {
		return errors.Wrapf(err, "could not get runtime")
	}
	defer runtime.Shutdown(false)

	pod, err := playKubeYAMLCmd(c, ctx, runtime, args[0])
	if err != nil && pod != nil {
		if err2 := runtime.RemovePod(ctx, pod, true, true); err2 != nil {
			logrus.Errorf("unable to remove pod %s after failing to play kube", pod.ID())
		}
	}
	return err
}

func playKubeYAMLCmd(c *cliconfig.KubePlayValues, ctx context.Context, runtime *libpod.Runtime, yamlFile string) (*libpod.Pod, error) {
	var (
		containers    []*libpod.Container
		pod           *libpod.Pod
		podOptions    []libpod.PodCreateOption
		podYAML       v1.Pod
		registryCreds *types.DockerAuthConfig
		writer        io.Writer
	)

	content, err := ioutil.ReadFile(yamlFile)
	if err != nil {
		return nil, err
	}

	if err := yaml.Unmarshal(content, &podYAML); err != nil {
		return nil, errors.Wrapf(err, "unable to read %s as YAML", yamlFile)
	}

	// check for name collision between pod and container
	podName := podYAML.ObjectMeta.Name
	for _, n := range podYAML.Spec.Containers {
		if n.Name == podName {
			fmt.Printf("a container exists with the same name (%s) as the pod in your YAML file; changing pod name to %s_pod\n", podName, podName)
			podName = fmt.Sprintf("%s_pod", podName)
		}
	}

	podOptions = append(podOptions, libpod.WithInfraContainer())
	podOptions = append(podOptions, libpod.WithPodName(podName))
	// TODO for now we just used the default kernel namespaces; we need to add/subtract this from yaml

	nsOptions, err := shared.GetNamespaceOptions(strings.Split(shared.DefaultKernelNamespaces, ","))
	if err != nil {
		return nil, err
	}
	podOptions = append(podOptions, nsOptions...)
	podPorts := getPodPorts(podYAML.Spec.Containers)
	podOptions = append(podOptions, libpod.WithInfraContainerPorts(podPorts))

	// Create the Pod
	pod, err = runtime.NewPod(ctx, podOptions...)
	if err != nil {
		return pod, err
	}

	podInfraID, err := pod.InfraContainerID()
	if err != nil {
		return pod, err
	}

	namespaces := map[string]string{
		// Disabled during code review per mheon
		//"pid":  fmt.Sprintf("container:%s", podInfraID),
		"net":  fmt.Sprintf("container:%s", podInfraID),
		"user": fmt.Sprintf("container:%s", podInfraID),
		"ipc":  fmt.Sprintf("container:%s", podInfraID),
		"uts":  fmt.Sprintf("container:%s", podInfraID),
	}
	if !c.Quiet {
		writer = os.Stderr
	}

	dockerRegistryOptions := image.DockerRegistryOptions{
		DockerRegistryCreds: registryCreds,
		DockerCertPath:      c.CertDir,
	}
	if c.Flag("tls-verify").Changed {
		dockerRegistryOptions.DockerInsecureSkipTLSVerify = types.NewOptionalBool(!c.TlsVerify)
	}

	// map from name to mount point
	volumes := make(map[string]string)
	for _, volume := range podYAML.Spec.Volumes {
		hostPath := volume.VolumeSource.HostPath
		if hostPath == nil {
			return pod, errors.Errorf("HostPath is currently the only supported VolumeSource")
		}
		if hostPath.Type != nil {
			switch *hostPath.Type {
			case v1.HostPathDirectoryOrCreate:
				if _, err := os.Stat(hostPath.Path); os.IsNotExist(err) {
					if err := os.Mkdir(hostPath.Path, createDirectoryPermission); err != nil {
						return pod, errors.Errorf("Error creating HostPath %s at %s", volume.Name, hostPath.Path)
					}
				}
				// unconditionally label a newly created volume as private
				if err := libpod.LabelVolumePath(hostPath.Path, false); err != nil {
					return pod, errors.Wrapf(err, "Error giving %s a label", hostPath.Path)
				}
				break
			case v1.HostPathFileOrCreate:
				if _, err := os.Stat(hostPath.Path); os.IsNotExist(err) {
					f, err := os.OpenFile(hostPath.Path, os.O_RDONLY|os.O_CREATE, createFilePermission)
					if err != nil {
						return pod, errors.Errorf("Error creating HostPath %s at %s", volume.Name, hostPath.Path)
					}
					if err := f.Close(); err != nil {
						logrus.Warnf("Error in closing newly created HostPath file: %v", err)
					}
				}
				// unconditionally label a newly created volume as private
				if err := libpod.LabelVolumePath(hostPath.Path, false); err != nil {
					return pod, errors.Wrapf(err, "Error giving %s a label", hostPath.Path)
				}
				break
			case v1.HostPathDirectory:
			case v1.HostPathFile:
			case v1.HostPathUnset:
				// do nothing here because we will verify the path exists in validateVolumeHostDir
				break
			default:
				return pod, errors.Errorf("Directories are the only supported HostPath type")
			}
		}

		if err := createconfig.ValidateVolumeHostDir(hostPath.Path); err != nil {
			return pod, errors.Wrapf(err, "Error in parsing HostPath in YAML")
		}
		volumes[volume.Name] = hostPath.Path
	}

	for _, container := range podYAML.Spec.Containers {
		newImage, err := runtime.ImageRuntime().New(ctx, container.Image, c.SignaturePolicy, c.Authfile, writer, &dockerRegistryOptions, image.SigningOptions{}, false, nil)
		if err != nil {
			return pod, err
		}
		createConfig, err := kubeContainerToCreateConfig(ctx, container, runtime, newImage, namespaces, volumes)
		if err != nil {
			return pod, err
		}
		ctr, err := shared.CreateContainerFromCreateConfig(runtime, createConfig, ctx, pod)
		if err != nil {
			return pod, err
		}
		containers = append(containers, ctr)
	}

	// start the containers
	for _, ctr := range containers {
		if err := ctr.Start(ctx, true); err != nil {
			// Making this a hard failure here to avoid a mess
			// the other containers are in created status
			return pod, err
		}
	}

	// We've now successfully converted this YAML into a pod
	// print our pod and containers, signifying we succeeded
	fmt.Printf("Pod:\n%s\n", pod.ID())
	if len(containers) == 1 {
		fmt.Printf("Container:\n")
	}
	if len(containers) > 1 {
		fmt.Printf("Containers:\n")
	}
	for _, ctr := range containers {
		fmt.Println(ctr.ID())
	}

	return pod, nil
}

// getPodPorts converts a slice of kube container descriptions to an
// array of ocicni portmapping descriptions usable in libpod
func getPodPorts(containers []v1.Container) []ocicni.PortMapping {
	var infraPorts []ocicni.PortMapping
	for _, container := range containers {
		for _, p := range container.Ports {
			portBinding := ocicni.PortMapping{
				HostPort:      p.HostPort,
				ContainerPort: p.ContainerPort,
				Protocol:      strings.ToLower(string(p.Protocol)),
			}
			if p.HostIP != "" {
				logrus.Debug("HostIP on port bindings is not supported")
			}
			infraPorts = append(infraPorts, portBinding)
		}
	}
	return infraPorts
}

// kubeContainerToCreateConfig takes a v1.Container and returns a createconfig describing a container
func kubeContainerToCreateConfig(ctx context.Context, containerYAML v1.Container, runtime *libpod.Runtime, newImage *image.Image, namespaces map[string]string, volumes map[string]string) (*createconfig.CreateConfig, error) {
	var (
		containerConfig createconfig.CreateConfig
	)

	// The default for MemorySwappiness is -1, not 0
	containerConfig.Resources.MemorySwappiness = -1

	containerConfig.Image = containerYAML.Image
	containerConfig.ImageID = newImage.ID()
	containerConfig.Name = containerYAML.Name
	containerConfig.Tty = containerYAML.TTY
	containerConfig.WorkDir = containerYAML.WorkingDir

	imageData, _ := newImage.Inspect(ctx)

	containerConfig.User = "0"
	if imageData != nil {
		containerConfig.User = imageData.Config.User
	}

	if containerConfig.SecurityOpts != nil {
		if containerYAML.SecurityContext.ReadOnlyRootFilesystem != nil {
			containerConfig.ReadOnlyRootfs = *containerYAML.SecurityContext.ReadOnlyRootFilesystem
		}
		if containerYAML.SecurityContext.Privileged != nil {
			containerConfig.Privileged = *containerYAML.SecurityContext.Privileged
		}

		if containerYAML.SecurityContext.AllowPrivilegeEscalation != nil {
			containerConfig.NoNewPrivs = !*containerYAML.SecurityContext.AllowPrivilegeEscalation
		}
	}

	containerConfig.Command = []string{}
	if imageData != nil && imageData.Config != nil {
		containerConfig.Command = append(containerConfig.Command, imageData.Config.Entrypoint...)
	}
	if len(containerConfig.Command) != 0 {
		containerConfig.Command = append(containerConfig.Command, containerYAML.Command...)
	} else if imageData != nil && imageData.Config != nil {
		containerConfig.Command = append(containerConfig.Command, imageData.Config.Cmd...)
	}
	if imageData != nil && len(containerConfig.Command) == 0 {
		return nil, errors.Errorf("No command specified in container YAML or as CMD or ENTRYPOINT in this image for %s", containerConfig.Name)
	}

	containerConfig.StopSignal = 15

	// If the user does not pass in ID mappings, just set to basics
	if containerConfig.IDMappings == nil {
		containerConfig.IDMappings = &storage.IDMappingOptions{}
	}

	containerConfig.NetMode = ns.NetworkMode(namespaces["net"])
	containerConfig.IpcMode = ns.IpcMode(namespaces["ipc"])
	containerConfig.UtsMode = ns.UTSMode(namespaces["uts"])
	// disabled in code review per mheon
	//containerConfig.PidMode = ns.PidMode(namespaces["pid"])
	containerConfig.UsernsMode = ns.UsernsMode(namespaces["user"])
	if len(containerConfig.WorkDir) == 0 {
		containerConfig.WorkDir = "/"
	}

	// Set default environment variables and incorporate data from image, if necessary
	envs := shared.EnvVariablesFromData(imageData)

	// Environment Variables
	for _, e := range containerYAML.Env {
		envs[e.Name] = e.Value
	}
	containerConfig.Env = envs

	for _, volume := range containerYAML.VolumeMounts {
		host_path, exists := volumes[volume.Name]
		if !exists {
			return nil, errors.Errorf("Volume mount %s specified for container but not configured in volumes", volume.Name)
		}
		if err := createconfig.ValidateVolumeCtrDir(volume.MountPath); err != nil {
			return nil, errors.Wrapf(err, "error in parsing MountPath")
		}
		containerConfig.Volumes = append(containerConfig.Volumes, fmt.Sprintf("%s:%s", host_path, volume.MountPath))
	}
	return &containerConfig, nil
}