package docker

import (
	"context"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"

	"github.com/docker/docker/api/types"
	"github.com/docker/docker/client"
)

func SaveImageTar(ctx context.Context, image, path, name string, doPull, rm bool) error {

	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
	if err != nil {
		return fmt.Errorf("docker client error: %v", err)
	}
	defer cli.Close()

	if doPull {
		if err := pullImage(ctx, cli, image); err != nil {
			return fmt.Errorf("pull image %s failed: %v", image, err)
		}
	}

	if err := saveToTar(ctx, cli, image, path, name); err != nil {
		return fmt.Errorf("save image %s failed: %v", image, err)
	}

	if rm {
		if err := rmImage(ctx, cli, image); err != nil {
			return fmt.Errorf("remove image %s failed: %v", image, err)
		}
	}

	return nil
}

func pullImage(ctx context.Context, cli *client.Client, image string) error {
	// try pull image
	r, err := cli.ImagePull(ctx, image, types.ImagePullOptions{})
	if err != nil {
		return fmt.Errorf("pull image %s failed: %v", image, err)
	}
	defer r.Close()

	io.Copy(os.Stdout, r)

	return nil
}

func rmImage(ctx context.Context, cli *client.Client, image string) error {
	_, err := cli.ImageRemove(ctx, image, types.ImageRemoveOptions{})
	if err != nil {
		return err
	}

	return nil
}

func saveToTar(ctx context.Context, cli *client.Client, image, path, name string) error {
	out, err := cli.ImageSave(ctx, []string{image})
	if err != nil {
		return fmt.Errorf("save image %s failed: %v", image, err)
	}
	defer out.Close()

	filename := name
	if filename == "" {
		strs := strings.Split(image, "/")
		filename = fmt.Sprintf("%s.tar", strings.ReplaceAll(strs[len(strs)-1], ":", "_"))
	}

	filep := filepath.Join(path, filename)

	target, err := os.Create(filep)
	if err != nil {
		return fmt.Errorf("create file %s failed: %v", filep, err)
	}
	defer target.Close()

	if _, err := io.Copy(target, out); err != nil {
		return fmt.Errorf("copy file %s failed: %v", filep, err)
	}

	return nil
}