package main

import (
	"errors"
	"regexp"
	"sync"

	"github.com/silenceper/pool"
	log "github.com/sirupsen/logrus"
	"golang.org/x/crypto/ssh"
)

type Box struct {
	name    string
	addr    string
	user    string
	key     string
	zfs     *BoxZfs
	sshPool pool.Pool
	created bool
	online  bool
	mx      sync.Mutex
}

type BoxSshPool struct {
	signer ssh.Signer
	config *ssh.ClientConfig
	client *ssh.Client
	logged bool
	mx     sync.Mutex
}

func (c *Config) NewBox(name, addr, user, key string) (b *Box, err error) {
	log.WithFields(log.Fields{"name": name, "addr": addr, "user": user, "key": key}).Debugf("starting")
	defer log.WithFields(log.Fields{"name": name, "addr": addr, "user": user, "key": key}).Debugf("done")

	re := regexp.MustCompile(boxNamePattern)
	if !re.MatchString(name) {
		err := errors.New("invalid name")
		log.WithFields(log.Fields{"name": b.name, "error": err}).Errorf("")
		return nil, err
	}

	p, err := NewSshPool(name, addr, user, key)
	if err != nil {
		log.WithFields(log.Fields{"name": b.name, "call": "NewSshPool", "error": err}).Errorf("")
		return nil, err
	}

	b = &Box{
		name: name,
		addr: addr,
		user: user,
		key:  key,
		zfs: &BoxZfs{
			online: false,
		},
		sshPool: p,
		online:  false,
		created: true,
	}

	b.zfs.box = b

	return b, nil
}

func (b *Box) Open() error {
	log.WithFields(log.Fields{"name": b.name}).Debugf("starting")
	defer log.WithFields(log.Fields{"name": b.name}).Debugf("done")

	b.mx.Lock()
	defer b.mx.Unlock()

	if b.online {
		return nil
	}

	hostname, err := b.Exec("hostname")
	if err != nil {
		log.WithFields(log.Fields{"name": b.name, "call": "Exec", "attr": "hostname", "error": err}).Errorf("")
		return err
	}

	log.WithFields(log.Fields{"name": b.name}).Debugf("hostname : %s", hostname)

	b.online = true

	if err := b.zfs.Open(); err != nil {
		log.WithFields(log.Fields{"name": b.name, "call": "zfs.Open", "error": err}).Errorf("")
		return err
	}

	return nil
}

func (b *Box) Close() error {
	log.WithFields(log.Fields{"name": b.name}).Debugf("starting")
	defer log.WithFields(log.Fields{"name": b.name}).Debugf("done")

	b.mx.Lock()
	defer b.mx.Unlock()

	if !b.online {
		return nil
	}

	if err := b.zfs.Close(); err != nil {
		log.WithFields(log.Fields{"name": b.name, "call": "zfs.Close", "error": err}).Errorf("")
		return err
	}

	b.online = false

	return nil
}

func (b *Box) Exec(cmd string) (r string, err error) {
	log.WithFields(log.Fields{"name": b.name, "cmd": cmd}).Debugf("starting")
	defer log.WithFields(log.Fields{"name": b.name, "cmd": cmd}).Debugf("done")

	if !b.created {
		err := errors.New("box not initialized")
		log.WithFields(log.Fields{"name": b.name, "error": err}).Errorf("")
		return "", err
	}

	v, err := b.sshPool.Get()
	if err != nil {
		log.WithFields(log.Fields{"name": b.name, "error": err, "call": "SshPool.Get"}).Errorf("")
		return "", err
	}

	defer b.sshPool.Put(v)
	s := v.(*Ssh)

	return s.Exec(cmd)
}

func TransferZfs(from, to Addr) error {
	log.WithFields(log.Fields{"from": from, "to": to}).Debugf("starting")
	defer log.WithFields(log.Fields{"from": from, "to": to}).Debugf("done")

	var (
		err                        error
		fromSnapshots, toSnapshots []*ZfsSnapshot
	)

	if fromSnapshots, err = from.ValidSnapshots(); err != nil {
		log.WithFields(log.Fields{"from": from, "to": to, "call": "ValidSnapshots", "attr": from, "error": err}).Errorf("")
		return err
	}

	if len(fromSnapshots) == 0 {
		return nil
	}

	if toSnapshots, err = to.ValidSnapshots(); err != nil {
		log.WithFields(log.Fields{"from": from, "to": to, "call": "ValidSnapshots", "attr": to, "error": err}).Errorf("")
		return err
	}

	if len(toSnapshots) == 0 {
		log.WithFields(log.Fields{"from": from, "to": to}).Debugf("initiating destination")
		if _, err := to.BoxExec("ssh " + from.Box() + " zfs send " + fromSnapshots[0].String() + " | zfs recv -F " + to.Path()); err != nil {
			log.WithFields(log.Fields{"from": from, "to": to, "call": "BoxExec", "error": err}).Errorf("")
			return err
		}
		newToSnapshot := &ZfsSnapshot{name: fromSnapshots[0].name, fs: cfg.box[to.Box()].zfs.filesystems[to.Path()]}
		toSnapshots = append(toSnapshots, newToSnapshot)
		cfg.box[to.Box()].zfs.filesystems[to.Path()].AddSnapshot(newToSnapshot)
	}

	fromFromSnapshotId := -1
	lastToSnapshot := toSnapshots[len(toSnapshots)-1]
	log.WithFields(log.Fields{"from": from, "to": to}).Debugf("searching last snapshot %s", lastToSnapshot.String())
	for id, v := range fromSnapshots {
		if v.name == lastToSnapshot.name {
			fromFromSnapshotId = id
			log.WithFields(log.Fields{"from": from, "to": to}).Debugf("found %s", v.String())
			break
		}
	}

	if fromFromSnapshotId == -1 {
		err := errors.New("zfs snapshot unsync")
		log.WithFields(log.Fields{"from": from, "to": to, "error": err}).Errorf("")
		return err
	}

	if fromFromSnapshotId < len(fromSnapshots)-1 {
		log.WithFields(log.Fields{"from": from, "to": to}).Debugf("transfering from %s to %s", fromSnapshots[fromFromSnapshotId].name, fromSnapshots[len(fromSnapshots)-1].name)

		if _, err := to.BoxExec("ssh " + from.Box() + " zfs send -I " + fromSnapshots[fromFromSnapshotId].String() + " " + fromSnapshots[len(fromSnapshots)-1].String() + " | zfs recv -F " + to.Path()); err != nil {
			log.WithFields(log.Fields{"from": from, "to": to, "call": "BoxExec", "error": err}).Errorf("")
			return err
		}

		for _, v := range fromSnapshots[fromFromSnapshotId:] {
			cfg.box[to.Box()].zfs.filesystems[to.Path()].AddSnapshot(&ZfsSnapshot{name: v.name, fs: cfg.box[to.Box()].zfs.filesystems[to.Path()]})
		}
	}

	return nil
}