// +build windows

/*
Copyright 2017 The Kubernetes Authors.

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 mount

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/golang/glog"
)

// Mounter provides the default implementation of mount.Interface
// for the windows platform.  This implementation assumes that the
// kubelet is running in the host's root mount namespace.
type Mounter struct {
	mounterPath string
}

// New returns a mount.Interface for the current system.
// It provides options to override the default mounter behavior.
// mounterPath allows using an alternative to `/bin/mount` for mounting.
func New(mounterPath string) Interface {
	return &Mounter{
		mounterPath: mounterPath,
	}
}

// Mount : mounts source to target as NTFS with given options.
func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error {
	target = normalizeWindowsPath(target)

	if source == "tmpfs" {
		glog.V(3).Infof("azureMount: mounting source (%q), target (%q), with options (%q)", source, target, options)
		return os.MkdirAll(target, 0755)
	}

	parentDir := filepath.Dir(target)
	if err := os.MkdirAll(parentDir, 0755); err != nil {
		return err
	}

	glog.V(4).Infof("azureMount: mount options(%q) source:%q, target:%q, fstype:%q, begin to mount",
		options, source, target, fstype)
	bindSource := ""

	// tell it's going to mount azure disk or azure file according to options
	if bind, _ := isBind(options); bind {
		// mount azure disk
		bindSource = normalizeWindowsPath(source)
	} else {
		if len(options) < 2 {
			glog.Warningf("azureMount: mount options(%q) command number(%d) less than 2, source:%q, target:%q, skip mounting",
				options, len(options), source, target)
			return nil
		}

		// empty implementation for mounting azure file
		return os.MkdirAll(target, 0755)
	}

	if output, err := exec.Command("cmd", "/c", "mklink", "/D", target, bindSource).CombinedOutput(); err != nil {
		glog.Errorf("mklink failed: %v, source(%q) target(%q) output: %q", err, bindSource, target, string(output))
		return err
	}

	return nil
}

// Unmount unmounts the target.
func (mounter *Mounter) Unmount(target string) error {
	glog.V(4).Infof("azureMount: Unmount target (%q)", target)
	target = normalizeWindowsPath(target)
	if output, err := exec.Command("cmd", "/c", "rmdir", target).CombinedOutput(); err != nil {
		glog.Errorf("rmdir failed: %v, output: %q", err, string(output))
		return err
	}
	return nil
}

// List returns a list of all mounted filesystems. todo
func (mounter *Mounter) List() ([]MountPoint, error) {
	return []MountPoint{}, nil
}

// IsMountPointMatch determines if the mountpoint matches the dir
func (mounter *Mounter) IsMountPointMatch(mp MountPoint, dir string) bool {
	return mp.Path == dir
}

// IsNotMountPoint determines if a directory is a mountpoint.
func (mounter *Mounter) IsNotMountPoint(dir string) (bool, error) {
	return IsNotMountPoint(mounter, dir)
}

// IsLikelyNotMountPoint determines if a directory is not a mountpoint.
func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error) {
	stat, err := os.Lstat(file)
	if err != nil {
		return true, err
	}
	// If current file is a symlink, then it is a mountpoint.
	if stat.Mode()&os.ModeSymlink != 0 {
		return false, nil
	}

	return true, nil
}

// GetDeviceNameFromMount given a mnt point, find the device
func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
	return getDeviceNameFromMount(mounter, mountPath, pluginDir)
}

// DeviceOpened determines if the device is in use elsewhere
func (mounter *Mounter) DeviceOpened(pathname string) (bool, error) {
	return false, nil
}

// PathIsDevice determines if a path is a device.
func (mounter *Mounter) PathIsDevice(pathname string) (bool, error) {
	return false, nil
}

// MakeRShared checks that given path is on a mount with 'rshared' mount
// propagation. Empty implementation here.
func (mounter *Mounter) MakeRShared(path string) error {
	return nil
}

func (mounter *SafeFormatAndMount) formatAndMount(source string, target string, fstype string, options []string) error {
	// Try to mount the disk
	glog.V(4).Infof("Attempting to formatAndMount disk: %s %s %s", fstype, source, target)

	if err := ValidateDiskNumber(source); err != nil {
		glog.Errorf("azureMount: formatAndMount failed, err: %v\n", err)
		return err
	}

	driveLetter, err := getDriveLetterByDiskNumber(source, mounter.Exec)
	if err != nil {
		return err
	}
	driverPath := driveLetter + ":"
	target = normalizeWindowsPath(target)
	glog.V(4).Infof("Attempting to formatAndMount disk: %s %s %s", fstype, driverPath, target)
	if output, err := mounter.Exec.Run("cmd", "/c", "mklink", "/D", target, driverPath); err != nil {
		glog.Errorf("mklink failed: %v, output: %q", err, string(output))
		return err
	}
	return nil
}

func normalizeWindowsPath(path string) string {
	normalizedPath := strings.Replace(path, "/", "\\", -1)
	if strings.HasPrefix(normalizedPath, "\\") {
		normalizedPath = "c:" + normalizedPath
	}
	return normalizedPath
}

// ValidateDiskNumber : disk number should be a number in [0, 99]
func ValidateDiskNumber(disk string) error {
	diskNum, err := strconv.Atoi(disk)
	if err != nil {
		return fmt.Errorf("wrong disk number format: %q, err:%v", disk, err)
	}

	if diskNum < 0 || diskNum > 99 {
		return fmt.Errorf("disk number out of range: %q", disk)
	}

	return nil
}

// Get drive letter according to windows disk number
func getDriveLetterByDiskNumber(diskNum string, exec Exec) (string, error) {
	cmd := fmt.Sprintf("(Get-Partition -DiskNumber %s).DriveLetter", diskNum)
	output, err := exec.Run("powershell", "/c", cmd)
	if err != nil {
		return "", fmt.Errorf("azureMount: Get Drive Letter failed: %v, output: %q", err, string(output))
	}
	if len(string(output)) < 1 {
		return "", fmt.Errorf("azureMount: Get Drive Letter failed, output is empty")
	}
	return string(output)[:1], nil
}
