package volumes

import (
	"bufio"
	"context"
	"fmt"
	"os"
	"strings"

	"github.com/containers/libpod/cmd/podman/common"
	"github.com/containers/libpod/cmd/podman/registry"
	"github.com/containers/libpod/cmd/podman/utils"
	"github.com/containers/libpod/pkg/domain/entities"
	"github.com/pkg/errors"
	"github.com/spf13/cobra"
)

var (
	volumePruneDescription = `Volumes that are not currently owned by a container will be removed.

  The command prompts for confirmation which can be overridden with the --force flag.
  Note all data will be destroyed.`
	pruneCommand = &cobra.Command{
		Use:   "prune",
		Args:  common.NoArgs,
		Short: "Remove all unused volumes",
		Long:  volumePruneDescription,
		RunE:  prune,
	}
)

var (
	pruneOptions entities.VolumePruneOptions
)

func init() {
	registry.Commands = append(registry.Commands, registry.CliCommand{
		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
		Command: pruneCommand,
		Parent:  volumeCmd,
	})
	flags := pruneCommand.Flags()
	flags.BoolVarP(&pruneOptions.Force, "force", "f", false, "Do not prompt for confirmation")
}

func prune(cmd *cobra.Command, args []string) error {
	var (
		errs utils.OutputErrors
	)
	// Prompt for confirmation if --force is not set
	if !pruneOptions.Force {
		reader := bufio.NewReader(os.Stdin)
		fmt.Println("WARNING! This will remove all volumes not used by at least one container.")
		fmt.Print("Are you sure you want to continue? [y/N] ")
		answer, err := reader.ReadString('\n')
		if err != nil {
			return errors.Wrapf(err, "error reading input")
		}
		if strings.ToLower(answer)[0] != 'y' {
			return nil
		}
	}
	responses, err := registry.ContainerEngine().VolumePrune(context.Background(), pruneOptions)
	if err != nil {
		return err
	}
	for _, r := range responses {
		if r.Err == nil {
			fmt.Println(r.Id)
		} else {
			errs = append(errs, r.Err)
		}
	}
	return errs.PrintErrors()
}