package containerd

import (
	"fmt"

	"github.com/containerd/containerd"
	"github.com/containerd/containerd/cio"
	"github.com/containerd/containerd/oci"
	specs "github.com/opencontainers/runtime-spec/specs-go"
)

func (d *Driver) isContainerdRunning() (bool, error) {
	return d.client.IsServing(d.ctxContainerd)
}

func (d *Driver) getContainerdVersion() (containerd.Version, error) {
	return d.client.Version(d.ctxContainerd)
}

func (d *Driver) pullImage(imageName string) (containerd.Image, error) {
	return d.client.Pull(d.ctxContainerd, imageName, containerd.WithPullUnpack)
}

func (d *Driver) createContainer(image containerd.Image, containerName, containerSnapshotName, containerdRuntime string, env []string, config *TaskConfig) (containerd.Container, error) {
	if config.Command == "" && len(config.Args) > 0 {
		return nil, fmt.Errorf("Command is empty. Cannot set --args without --command.")
	}

	// Command set by the user, to override entrypoint or cmd defined in the image.
	var args []string
	if config.Command != "" {
		args = append(args, config.Command)
	}

	// Arguments to the command set by the user.
	if len(config.Args) > 0 {
		args = append(args, config.Args...)
	}

	var opts []oci.SpecOpts

	opts = append(opts, oci.WithImageConfigArgs(image, args))

	// Enable privileged mode.
	if config.Privileged {
		opts = append(opts, oci.WithPrivileged)
	}

	// Launch container in read-only mode.
	if config.ReadOnlyRootfs {
		opts = append(opts, oci.WithRootFSReadonly())
	}

	// Add capabilities.
	if len(config.CapAdd) > 0 {
		opts = append(opts, oci.WithAddedCapabilities(config.CapAdd))
	}

	// Drop capabilities.
	if len(config.CapDrop) > 0 {
		opts = append(opts, oci.WithDroppedCapabilities(config.CapDrop))
	}

	// Set environment variables.
	opts = append(opts, oci.WithEnv(env))

	// Add linux devices into the container.
	for _, device := range config.Devices {
		opts = append(opts, oci.WithLinuxDevice(device, "rwm"))
	}

	// Set mounts. fstab style mount options are supported.
	// List of all supported mount options.
	// https://github.com/containerd/containerd/blob/master/mount/mount_linux.go#L187-L211
	mounts := make([]specs.Mount, 0)
	for _, mount := range config.Mounts {
		if (mount.Type == "bind" || mount.Type == "volume") && len(mount.Options) <= 0 {
			return nil, fmt.Errorf("Options cannot be empty for mount type: %s. You need to atleast pass rbind and ro.", mount.Type)
		}

		m := specs.Mount{}
		m.Type = mount.Type
		m.Destination = mount.Target
		m.Source = mount.Source
		m.Options = mount.Options
		mounts = append(mounts, m)
	}

	if len(mounts) > 0 {
		opts = append(opts, oci.WithMounts(mounts))
	}

	return d.client.NewContainer(
		d.ctxContainerd,
		containerName,
		containerd.WithRuntime(containerdRuntime, nil),
		containerd.WithNewSnapshot(containerSnapshotName, image),
		containerd.WithNewSpec(opts...),
	)
}

func (d *Driver) loadContainer(id string) (containerd.Container, error) {
	return d.client.LoadContainer(d.ctxContainerd, id)
}

func (d *Driver) createTask(container containerd.Container) (containerd.Task, error) {
	return container.NewTask(d.ctxContainerd, cio.NewCreator(cio.WithStdio))
}

func (d *Driver) getTask(container containerd.Container) (containerd.Task, error) {
	return container.Task(d.ctxContainerd, cio.Load)
}