package client

//
// Storage
//
import (
	"crypto/sha256"
	"encoding/json"
	"errors"
	"path/filepath"
	"sort"
	"sync"

	"forge.redroom.link/yves/meowlib"
	"github.com/dgraph-io/badger"
	"github.com/google/uuid"
)

type PeerStorage struct {
	DbFile string `json:"db_file,omitempty"`
	mu     sync.RWMutex
	db     *badger.DB
	cache  map[string]*Peer
}

// open opens the Badger database. Caller must hold mu (write).
func (ps *PeerStorage) open() error {
	if ps.DbFile == "" {
		ps.DbFile = uuid.New().String()
		GetConfig().GetIdentity().Save()
	}
	if ps.cache == nil {
		ps.cache = make(map[string]*Peer)
	}
	opts := badger.DefaultOptions(filepath.Join(GetConfig().StoragePath, GetConfig().GetIdentity().Uuid, ps.DbFile))
	opts.Logger = nil
	var err error
	ps.db, err = badger.Open(opts)
	return err
}

// close closes the Badger database. Caller must hold mu (write).
func (ps *PeerStorage) close() {
	ps.db.Close()
}

// StorePeer stores a peer in the Badger database with Peer.Uid as key.
func (ps *PeerStorage) StorePeer(peer *Peer) error {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	return ps.storePeerLocked(peer)
}

// storePeerLocked is StorePeer without acquiring the lock. Caller must hold mu (write).
func (ps *PeerStorage) storePeerLocked(peer *Peer) error {
	if err := ps.open(); err != nil {
		return err
	}
	defer ps.close()
	jsonsrv, err := json.Marshal(peer)
	if err != nil {
		return err
	}
	password, err := GetConfig().GetMemPass()
	if err != nil {
		return err
	}
	if peer.dbPassword != "" {
		password = peer.dbPassword
	}
	data, err := meowlib.SymEncrypt(password, jsonsrv)
	if err != nil {
		return err
	}
	shakey := sha256.Sum256([]byte(peer.Uid))
	key := shakey[:]
	ps.cache[peer.Uid] = peer
	return ps.db.Update(func(txn *badger.Txn) error {
		return txn.Set(key, data)
	})
}

// LoadPeer loads a Peer from the Badger database with Peer.GetUid() as key.
func (ps *PeerStorage) LoadPeer(uid string, password string) (*Peer, error) {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	var peer Peer
	if err := ps.open(); err != nil {
		return nil, err
	}
	defer ps.close()
	shakey := sha256.Sum256([]byte(uid))
	key := shakey[:]
	err := ps.db.View(func(txn *badger.Txn) error {
		item, err := txn.Get(key)
		if err != nil {
			return err
		}
		return item.Value(func(val []byte) error {
			jsonsrv, err := meowlib.SymDecrypt(password, val)
			if err != nil {
				return err
			}
			return json.Unmarshal(jsonsrv, &peer)
		})
	})
	return &peer, err
}

// DeletePeer deletes a Peer from the Badger database with Peer.GetUid() as key.
func (ps *PeerStorage) DeletePeer(uid string) error {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	if err := ps.open(); err != nil {
		return err
	}
	defer ps.close()
	shakey := sha256.Sum256([]byte(uid))
	key := shakey[:]
	err := ps.db.Update(func(txn *badger.Txn) error {
		return txn.Delete(key)
	})
	if err == nil {
		delete(ps.cache, uid)
	}
	return err
}

// LoadPeers loads all Peers from the Badger database and populates the cache.
func (ps *PeerStorage) LoadPeers(password string) ([]*Peer, error) {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	var peers []*Peer
	if err := ps.open(); err != nil {
		return nil, err
	}
	defer ps.close()
	err := ps.db.View(func(txn *badger.Txn) error {
		opts := badger.DefaultIteratorOptions
		opts.PrefetchSize = 10
		it := txn.NewIterator(opts)
		defer it.Close()
		for it.Rewind(); it.Valid(); it.Next() {
			item := it.Item()
			var sc Peer
			err := item.Value(func(val []byte) error {
				jsonsrv, err := meowlib.SymDecrypt(password, val)
				if err != nil {
					return err
				}
				return json.Unmarshal(jsonsrv, &sc)
			})
			if err == nil {
				peers = append(peers, &sc)
				ps.cache[sc.Uid] = &sc
			}
		}
		return nil
	})
	sort.Slice(peers, func(i, j int) bool {
		return peers[i].Name < peers[j].Name
	})
	return peers, err
}

// GetPeers returns all peers from the cache as a sorted slice.
func (ps *PeerStorage) GetPeers() ([]*Peer, error) {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	peers := make([]*Peer, 0, len(ps.cache))
	for _, peer := range ps.cache {
		peers = append(peers, peer)
	}
	sort.Slice(peers, func(i, j int) bool {
		return peers[i].Name < peers[j].Name
	})
	return peers, nil
}

func (ps *PeerStorage) GetFromPublicKey(publickey string) *Peer {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, peer := range ps.cache {
		if peer.ContactPublicKey == publickey {
			return peer
		}
	}
	return nil
}

func (ps *PeerStorage) GetFromInvitationId(invitationId string) *Peer {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, peer := range ps.cache {
		if peer.InvitationId == invitationId {
			return peer
		}
	}
	return nil
}

func (ps *PeerStorage) GetFromMyLookupKey(publickey string) *Peer {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, peer := range ps.cache {
		if peer.MyLookupKp.Public == publickey {
			return peer
		}
	}
	return nil
}

func (ps *PeerStorage) NameExists(name string) bool {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, peer := range ps.cache {
		if peer.Name == name {
			return true
		}
	}
	return false
}

func (ps *PeerStorage) GetFromName(name string) *Peer {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, peer := range ps.cache {
		if peer.Name == name {
			return peer
		}
	}
	return nil
}

func (ps *PeerStorage) GetFromUid(uid string) *Peer {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	return ps.cache[uid]
}

// CheckInvitation checks if the received contact card is an answer to an invitation.
func (ps *PeerStorage) CheckInvitation(ReceivedContact *meowlib.ContactCard) (isAnswer bool, proposedNick string, receivedNick string, invitationMessage string) {
	ps.mu.RLock()
	defer ps.mu.RUnlock()
	for _, p := range ps.cache {
		if p.InvitationId == ReceivedContact.InvitationId {
			return true, p.Name, ReceivedContact.Name, ReceivedContact.InvitationMessage
		}
	}
	return false, "", ReceivedContact.Name, ReceivedContact.InvitationMessage
}

// FinalizeInvitation completes an invitation handshake and persists the updated peer.
func (ps *PeerStorage) FinalizeInvitation(ReceivedContact *meowlib.ContactCard) error {
	ps.mu.Lock()
	defer ps.mu.Unlock()
	for i, p := range ps.cache {
		if p.InvitationId == ReceivedContact.InvitationId {
			ps.cache[i].ContactEncryption = ReceivedContact.EncryptionPublicKey
			ps.cache[i].ContactLookupKey = ReceivedContact.LookupPublicKey
			ps.cache[i].ContactPublicKey = ReceivedContact.ContactPublicKey
			if ps.cache[i].MySymKey == "" {
				ps.cache[i].MySymKey = ReceivedContact.SymetricKey
			}
			srvs := []string{}
			for srv := range ReceivedContact.PullServers {
				srvs = append(srvs, ReceivedContact.PullServers[srv].GetUid())
			}
			ps.cache[i].ContactPullServers = srvs
			return ps.storePeerLocked(ps.cache[i])
		}
	}
	return errors.New("no matching contact found for invitationId " + ReceivedContact.InvitationId)
}