/*

Copyright (c) 2017-2018 VMware, Inc. 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 object

import (

	"bufio"

	"bytes"

	"context"

	"fmt"

	"io"

	"log"

	"path"

	"strings"

	"github.com/vmware/govmomi/vim25/progress"

	"github.com/vmware/govmomi/vim25/soap"

)

// DatastoreFileManager combines FileManager and VirtualDiskManager to manage files on a Datastore

type DatastoreFileManager struct {

	Datacenter         *Datacenter

	Datastore          *Datastore

	FileManager        *FileManager

	VirtualDiskManager *VirtualDiskManager

	Force            bool

	DatacenterTarget *Datacenter

}

// NewFileManager creates a new instance of DatastoreFileManager

func (d Datastore) NewFileManager(dc *Datacenter, force bool) *DatastoreFileManager {

	c := d.Client()

	m := &DatastoreFileManager{

		Datacenter:         dc,

		Datastore:          &d,

		FileManager:        NewFileManager(c),

		VirtualDiskManager: NewVirtualDiskManager(c),

		Force:              force,

		DatacenterTarget:   dc,

	}

	return m

}

func (m *DatastoreFileManager) WithProgress(ctx context.Context, s progress.Sinker) context.Context {

	return context.WithValue(ctx, m, s)

}

func (m *DatastoreFileManager) wait(ctx context.Context, task *Task) error {

	var logger progress.Sinker

	if s, ok := ctx.Value(m).(progress.Sinker); ok {

		logger = s

	}

	_, err := task.WaitForResult(ctx, logger)

	return err

}

// Delete dispatches to the appropriate Delete method based on file name extension

func (m *DatastoreFileManager) Delete(ctx context.Context, name string) error {

	switch path.Ext(name) {

	case ".vmdk":

		return m.DeleteVirtualDisk(ctx, name)

	default:

		return m.DeleteFile(ctx, name)

	}

}

// DeleteFile calls FileManager.DeleteDatastoreFile

func (m *DatastoreFileManager) DeleteFile(ctx context.Context, name string) error {

	p := m.Path(name)

	task, err := m.FileManager.DeleteDatastoreFile(ctx, p.String(), m.Datacenter)

	if err != nil {

		return err

	}

	return m.wait(ctx, task)

}

// DeleteVirtualDisk calls VirtualDiskManager.DeleteVirtualDisk

// Regardless of the Datastore type, DeleteVirtualDisk will fail if 'ddb.deletable=false',

// so if Force=true this method attempts to set 'ddb.deletable=true' before starting the delete task.

func (m *DatastoreFileManager) DeleteVirtualDisk(ctx context.Context, name string) error {

	p := m.Path(name)

	var merr error

	if m.Force {

		merr = m.markDiskAsDeletable(ctx, p)

	}

	task, err := m.VirtualDiskManager.DeleteVirtualDisk(ctx, p.String(), m.Datacenter)

	if err != nil {

		log.Printf("markDiskAsDeletable(%s): %s", p, merr)

		return err

	}

	return m.wait(ctx, task)

}

// CopyFile calls FileManager.CopyDatastoreFile

func (m *DatastoreFileManager) CopyFile(ctx context.Context, src string, dst string) error {

	srcp := m.Path(src)

	dstp := m.Path(dst)

	task, err := m.FileManager.CopyDatastoreFile(ctx, srcp.String(), m.Datacenter, dstp.String(), m.DatacenterTarget, m.Force)

	if err != nil {

		return err

	}

	return m.wait(ctx, task)

}

// Copy dispatches to the appropriate FileManager or VirtualDiskManager Copy method based on file name extension

func (m *DatastoreFileManager) Copy(ctx context.Context, src string, dst string) error {

	srcp := m.Path(src)

	dstp := m.Path(dst)

	f := m.FileManager.CopyDatastoreFile

	if srcp.IsVMDK() {

		// types.VirtualDiskSpec=nil as it is not implemented by vCenter

		f = func(ctx context.Context, src string, srcDC *Datacenter, dst string, dstDC *Datacenter, force bool) (*Task, error) {

			return m.VirtualDiskManager.CopyVirtualDisk(ctx, src, srcDC, dst, dstDC, nil, force)

		}

	}

	task, err := f(ctx, srcp.String(), m.Datacenter, dstp.String(), m.DatacenterTarget, m.Force)

	if err != nil {

		return err

	}

	return m.wait(ctx, task)

}

// MoveFile calls FileManager.MoveDatastoreFile

func (m *DatastoreFileManager) MoveFile(ctx context.Context, src string, dst string) error {

	srcp := m.Path(src)

	dstp := m.Path(dst)

	task, err := m.FileManager.MoveDatastoreFile(ctx, srcp.String(), m.Datacenter, dstp.String(), m.DatacenterTarget, m.Force)

	if err != nil {

		return err

	}

	return m.wait(ctx, task)

}

// Move dispatches to the appropriate FileManager or VirtualDiskManager Move method based on file name extension

func (m *DatastoreFileManager) Move(ctx context.Context, src string, dst string) error {

	srcp := m.Path(src)

	dstp := m.Path(dst)

	f := m.FileManager.MoveDatastoreFile

	if srcp.IsVMDK() {

		f = m.VirtualDiskManager.MoveVirtualDisk

	}

	task, err := f(ctx, srcp.String(), m.Datacenter, dstp.String(), m.DatacenterTarget, m.Force)

	if err != nil {

		return err

	}

	return m.wait(ctx, task)

}

// Path converts path name to a DatastorePath

func (m *DatastoreFileManager) Path(name string) *DatastorePath {

	var p DatastorePath

	if !p.FromString(name) {

		p.Path = name

		p.Datastore = m.Datastore.Name()

	}

	return &p

}

func (m *DatastoreFileManager) markDiskAsDeletable(ctx context.Context, path *DatastorePath) error {

	r, _, err := m.Datastore.Download(ctx, path.Path, &soap.DefaultDownload)

	if err != nil {

		return err

	}

	defer r.Close()

	hasFlag := false

	buf := new(bytes.Buffer)

	s := bufio.NewScanner(&io.LimitedReader{R: r, N: 2048}) // should be only a few hundred bytes, limit to be sure

	for s.Scan() {

		line := s.Text()

		if strings.HasPrefix(line, "ddb.deletable") {

			hasFlag = true

			continue

		}

		fmt.Fprintln(buf, line)

	}

	if err := s.Err(); err != nil {

		return err // any error other than EOF

	}

	if !hasFlag {

		return nil // already deletable, so leave as-is

	}

	// rewrite the .vmdk with ddb.deletable flag removed (the default is true)

	return m.Datastore.Upload(ctx, buf, path.Path, &soap.DefaultUpload)

}