package s3

import (
	"fmt"
	"os/exec"

	"github.com/golang/glog"
	"k8s.io/kubernetes/pkg/util/mount"
)

// Mounter interface which can be implemented
// by the different mounter types
type Mounter interface {
	Stage(stagePath string) error
	Unstage(stagePath string) error
	Mount(source string, target string) error
	Unmount(target string) error
}

const (
	s3fsMounterType     = "s3fs"
	goofysMounterType   = "goofys"
	s3qlMounterType     = "s3ql"
	s3backerMounterType = "s3backer"
)

// newMounter returns a new mounter depending on the mounterType parameter
func newMounter(bucket *bucket, cfg *Config) (Mounter, error) {
	switch cfg.Mounter {
	case s3fsMounterType:
		return newS3fsMounter(bucket, cfg)

	case goofysMounterType:
		return newGoofysMounter(bucket, cfg)

	case s3qlMounterType:
		return newS3qlMounter(bucket, cfg)

	case s3backerMounterType:
		return newS3backerMounter(bucket, cfg)

	}
	return nil, fmt.Errorf("Error mounting bucket %s, invalid mounter specified: %s", bucket.Name, cfg.Mounter)
}

func fuseMount(path string, command string, args []string) error {
	cmd := exec.Command(command, args...)

	out, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("Error fuseMount command: %s\nargs: %s\noutput: %s", command, args, out)
	}

	return nil
}

func fuseUnmount(path string, command string) error {
	if err := mount.New("").Unmount(path); err != nil {
		return err
	}
	// as fuse quits immediately, we will try to wait until the process is done
	process, err := findFuseMountProcess(path, command)
	if err != nil {
		glog.Errorf("Error getting PID of fuse mount: %s", err)
		return nil
	}
	if process == nil {
		glog.Warningf("Unable to find PID of fuse mount %s, it must have finished already", path)
		return nil
	}
	glog.Infof("Found fuse pid %v of mount %s, checking if it still runs", process.Pid, path)
	return waitForProcess(process, 1)
}