package image

import (
	"context"
	"errors"
	"fmt"
	"io"

	"github.com/containerd/platforms"
	"github.com/docker/cli/cli"
	"github.com/docker/cli/cli/command"
	"github.com/docker/cli/cli/command/completion"
	"github.com/docker/cli/internal/jsonstream"
	"github.com/moby/moby/client"
	"github.com/moby/sys/sequential"
	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
	"github.com/spf13/cobra"
)

type loadOptions struct {
	input    string
	quiet    bool
	platform []string
}

// newLoadCommand creates a new "docker image load" command.
func newLoadCommand(dockerCLI command.Cli) *cobra.Command {
	var opts loadOptions

	cmd := &cobra.Command{
		Use:   "load [OPTIONS]",
		Short: "Load an image from a tar archive or STDIN",
		Args:  cli.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runLoad(cmd.Context(), dockerCLI, opts)
		},
		Annotations: map[string]string{
			"aliases": "docker image load, docker load",
		},
		ValidArgsFunction:     cobra.NoFileCompletions,
		DisableFlagsInUseLine: true,
	}

	flags := cmd.Flags()

	flags.StringVarP(&opts.input, "input", "i", "", "Read from tar archive file, instead of STDIN")
	flags.BoolVarP(&opts.quiet, "quiet", "q", false, "Suppress the load output")
	flags.StringSliceVar(&opts.platform, "platform", []string{}, `Load only the given platform(s). Formatted as a comma-separated list of "os[/arch[/variant]]" (e.g., "linux/amd64,linux/arm64/v8").`)
	_ = flags.SetAnnotation("platform", "version", []string{"1.48"})

	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
	return cmd
}

func runLoad(ctx context.Context, dockerCli command.Cli, opts loadOptions) error {
	var input io.Reader = dockerCli.In()

	// TODO(thaJeztah): add support for "-" as STDIN to match other commands, possibly making it a required positional argument.
	switch opts.input {
	case "":
		// To avoid getting stuck, verify that a tar file is given either in
		// the input flag or through stdin and if not display an error message and exit.
		if dockerCli.In().IsTerminal() {
			return errors.New("requested load from stdin, but stdin is empty")
		}
	default:
		// We use sequential.Open to use sequential file access on Windows, avoiding
		// depleting the standby list un-necessarily. On Linux, this equates to a regular os.Open.
		file, err := sequential.Open(opts.input)
		if err != nil {
			return err
		}
		defer file.Close()
		input = file
	}

	var options []client.ImageLoadOption
	if opts.quiet || !dockerCli.Out().IsTerminal() {
		options = append(options, client.ImageLoadWithQuiet(true))
	}

	platformList := []ocispec.Platform{}
	for _, p := range opts.platform {
		pp, err := platforms.Parse(p)
		if err != nil {
			return fmt.Errorf("invalid platform: %w", err)
		}
		platformList = append(platformList, pp)
	}
	if len(platformList) > 0 {
		options = append(options, client.ImageLoadWithPlatforms(platformList...))
	}

	response, err := dockerCli.Client().ImageLoad(ctx, input, options...)
	if err != nil {
		return err
	}
	defer response.Body.Close()

	if response.Body != nil && response.JSON {
		return jsonstream.Display(ctx, response.Body, dockerCli.Out())
	}

	_, err = io.Copy(dockerCli.Out(), response.Body)
	return err
}