/*
Copyright 2015 The Kubernetes Authors All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package cinder

import (
	"errors"
	"io/ioutil"
	"os"
	"path"
	"strings"
	"time"

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

type CinderDiskUtil struct{}

// Attaches a disk specified by a volume.CinderPersistenDisk to the current kubelet.
// Mounts the disk to it's global path.
func (util *CinderDiskUtil) AttachDisk(b *cinderVolumeBuilder, globalPDPath string) error {
	options := []string{}
	if b.readOnly {
		options = append(options, "ro")
	}
	cloud, err := b.plugin.getCloudProvider()
	if err != nil {
		return err
	}
	diskid, err := cloud.AttachDisk(b.pdName)
	if err != nil {
		return err
	}

	var devicePath string
	numTries := 0
	for {
		devicePath = makeDevicePath(diskid)
		// probe the attached vol so that symlink in /dev/disk/by-id is created
		probeAttachedVolume()

		_, err := os.Stat(devicePath)
		if err == nil {
			break
		}
		if err != nil && !os.IsNotExist(err) {
			return err
		}
		numTries++
		if numTries == 10 {
			return errors.New("Could not attach disk: Timeout after 60s")
		}
		time.Sleep(time.Second * 6)
	}
	notmnt, err := b.mounter.IsLikelyNotMountPoint(globalPDPath)
	if err != nil {
		if os.IsNotExist(err) {
			if err := os.MkdirAll(globalPDPath, 0750); err != nil {
				return err
			}
			notmnt = true
		} else {
			return err
		}
	}
	if notmnt {
		err = b.blockDeviceMounter.FormatAndMount(devicePath, globalPDPath, b.fsType, options)
		if err != nil {
			os.Remove(globalPDPath)
			return err
		}
		glog.V(2).Infof("Safe mount successful: %q\n", devicePath)
	}
	return nil
}

func makeDevicePath(diskid string) string {
	files, _ := ioutil.ReadDir("/dev/disk/by-id/")
	for _, f := range files {
		if strings.Contains(f.Name(), "virtio-") {
			devid_prefix := f.Name()[len("virtio-"):len(f.Name())]
			if strings.Contains(diskid, devid_prefix) {
				glog.V(4).Infof("Found disk attached as %q; full devicepath: %s\n", f.Name(), path.Join("/dev/disk/by-id/", f.Name()))
				return path.Join("/dev/disk/by-id/", f.Name())
			}
		}
	}
	glog.Warningf("Failed to find device for the diskid: %q\n", diskid)
	return ""
}

// Unmounts the device and detaches the disk from the kubelet's host machine.
func (util *CinderDiskUtil) DetachDisk(cd *cinderVolumeCleaner) error {
	globalPDPath := makeGlobalPDName(cd.plugin.host, cd.pdName)
	if err := cd.mounter.Unmount(globalPDPath); err != nil {
		return err
	}
	if err := os.Remove(globalPDPath); err != nil {
		return err
	}
	glog.V(2).Infof("Successfully unmounted main device: %s\n", globalPDPath)

	cloud, err := cd.plugin.getCloudProvider()
	if err != nil {
		return err
	}

	if err = cloud.DetachDisk(cd.pdName); err != nil {
		return err
	}
	glog.V(2).Infof("Successfully detached cinder volume %s", cd.pdName)
	return nil
}

func (util *CinderDiskUtil) DeleteVolume(cd *cinderVolumeDeleter) error {
	cloud, err := cd.plugin.getCloudProvider()
	if err != nil {
		return err
	}

	if err = cloud.DeleteVolume(cd.pdName); err != nil {
		glog.V(2).Infof("Error deleting cinder volume %s: %v", cd.pdName, err)
		return err
	}
	glog.V(2).Infof("Successfully deleted cinder volume %s", cd.pdName)
	return nil
}

func (util *CinderDiskUtil) CreateVolume(c *cinderVolumeProvisioner) (volumeID string, volumeSizeGB int, err error) {
	cloud, err := c.plugin.getCloudProvider()
	if err != nil {
		return "", 0, err
	}

	volSizeBytes := c.options.Capacity.Value()
	// Cinder works with gigabytes, convert to GiB with rounding up
	volSizeGB := int(volume.RoundUpSize(volSizeBytes, 1024*1024*1024))
	name := volume.GenerateVolumeName(c.options.ClusterName, c.options.PVName, 255) // Cinder volume name can have up to 255 characters
	name, err = cloud.CreateVolume(name, volSizeGB, c.options.CloudTags)
	if err != nil {
		glog.V(2).Infof("Error creating cinder volume: %v", err)
		return "", 0, err
	}
	glog.V(2).Infof("Successfully created cinder volume %s", name)
	return name, volSizeGB, nil
}

func probeAttachedVolume() error {
	executor := exec.New()
	args := []string{"trigger"}
	cmd := executor.Command("/usr/bin/udevadm", args...)
	_, err := cmd.CombinedOutput()
	if err != nil {
		glog.Errorf("error running udevadm trigger %v\n", err)
		return err
	}
	glog.V(4).Infof("Successfully probed all attachments")
	return nil
}
