package peer

import (
	"cwtch.im/cwtch/event"
	"cwtch.im/cwtch/model"
	"cwtch.im/cwtch/protocol"
	"cwtch.im/cwtch/protocol/connections"
	"encoding/base64"
	"encoding/json"
	"errors"
	"git.openprivacy.ca/openprivacy/libricochet-go/connectivity"
	"git.openprivacy.ca/openprivacy/libricochet-go/identity"
	"git.openprivacy.ca/openprivacy/libricochet-go/log"
	"github.com/golang/protobuf/proto"
	"strings"
	"sync"
	"time"
)

// cwtchPeer manages incoming and outgoing connections and all processing for a Cwtch cwtchPeer
type cwtchPeer struct {
	Profile  *model.Profile
	mutex    sync.Mutex
	shutdown bool
	started  bool

	engine   connections.Engine
	queue    *event.Queue
	eventBus *event.Manager
}

// CwtchPeer provides us with a way of testing systems built on top of cwtch without having to
// directly implement a cwtchPeer.
type CwtchPeer interface {
	Init(connectivity.ACN, *event.Manager)
	PeerWithOnion(string) *connections.PeerPeerConnection
	InviteOnionToGroup(string, string) error
	SendMessageToPeer(string, string) string

	TrustPeer(string) error
	BlockPeer(string) error
	AcceptInvite(string) error
	RejectInvite(string)

	JoinServer(string)
	SendMessageToGroup(string, string) error
	SendMessageToGroupTracked(string, string) (string, error)

	GetProfile() *model.Profile

	GetPeers() map[string]connections.ConnectionState
	GetServers() map[string]connections.ConnectionState

	StartGroup(string) (string, []byte, error)

	ImportGroup(string) (string, error)
	ExportGroup(string) (string, error)

	GetGroup(string) *model.Group
	GetGroups() []string
	AddContact(nick, onion string, publickey []byte, trusted bool)
	GetContacts() []string
	GetContact(string) *model.PublicProfile

	IsStarted() bool
	Listen()
	Shutdown()
}

// NewCwtchPeer creates and returns a new cwtchPeer with the given name.
func NewCwtchPeer(name string) CwtchPeer {
	cp := new(cwtchPeer)
	cp.Profile = model.GenerateNewProfile(name)
	cp.shutdown = false
	return cp
}

// FromProfile generates a new peer from a profile.
func FromProfile(profile *model.Profile) CwtchPeer {
	cp := new(cwtchPeer)
	cp.Profile = profile
	return cp
}

// Init instantiates a cwtchPeer
func (cp *cwtchPeer) Init(acn connectivity.ACN, eventBus *event.Manager) {
	cp.queue = event.NewEventQueue(100)
	go cp.eventHandler()

	cp.eventBus = eventBus
	cp.eventBus.Subscribe(event.EncryptedGroupMessage, cp.queue.EventChannel)
	cp.eventBus.Subscribe(event.NewGroupInvite, cp.queue.EventChannel)

	// Calculate a list of Peers who have been Blocked.
	blockedPeers := []string{}
	for _, contact := range cp.Profile.GetContacts() {
		c, _ := cp.Profile.GetContact(contact)
		if c.Blocked {
			blockedPeers = append(blockedPeers, c.Onion)
		}
	}

	// TODO: Would be nice if ProtocolEngine did not need to explicitly be given the Private Key.
	identity := identity.InitializeV3(cp.Profile.Name, &cp.Profile.Ed25519PrivateKey, &cp.Profile.Ed25519PublicKey)
	cp.engine = connections.NewProtocolEngine(identity, cp.Profile.Ed25519PrivateKey, acn, eventBus, blockedPeers)
}

// ImportGroup intializes a group from an imported source rather than a peer invite
func (cp *cwtchPeer) ImportGroup(exportedInvite string) (groupID string, err error) {
	if strings.HasPrefix(exportedInvite, "torv3") {
		data, err := base64.StdEncoding.DecodeString(exportedInvite[5+44:])
		if err == nil {
			cpp := &protocol.CwtchPeerPacket{}
			err = proto.Unmarshal(data, cpp)
			if err == nil {
				jsobj, err := proto.Marshal(cpp.GetGroupChatInvite())
				if err == nil {
					cp.eventBus.Publish(event.NewEvent(event.NewGroupInvite, map[event.Field]string{
						event.GroupInvite: string(jsobj),
					}))
				} else {
					log.Errorf("error serializing group: %v", err)
				}
				return cpp.GroupChatInvite.GetGroupName(), nil
			}
		}
	} else {
		err = errors.New("unsupported exported group type")
	}
	return
}

// ExportGroup serializes a group invite so it can be given offline
func (cp *cwtchPeer) ExportGroup(groupID string) (string, error) {
	group := cp.Profile.GetGroupByGroupID(groupID)
	if group != nil {
		invite, err := group.Invite(group.GetInitialMessage())
		if err == nil {
			exportedInvite := "torv3" + base64.StdEncoding.EncodeToString(cp.Profile.Ed25519PublicKey) + base64.StdEncoding.EncodeToString(invite)
			return exportedInvite, err
		}
	}
	return "", errors.New("group id could not be found")
}

// StartGroup create a new group linked to the given server and returns the group ID, an invite or an error.
func (cp *cwtchPeer) StartGroup(server string) (string, []byte, error) {
	return cp.StartGroupWithMessage(server, []byte{})
}

// StartGroupWithMessage create a new group linked to the given server and returns the group ID, an invite or an error.
func (cp *cwtchPeer) StartGroupWithMessage(server string, initialMessage []byte) (groupID string, invite []byte, err error) {
	groupID, invite, err = cp.Profile.StartGroupWithMessage(server, initialMessage)
	if err == nil {
		group := cp.GetGroup(groupID)
		jsobj, err := json.Marshal(group)
		if err == nil {
			cp.eventBus.Publish(event.NewEvent(event.GroupCreated, map[event.Field]string{
				event.Data: string(jsobj),
			}))
		}
	} else {
		log.Errorf("error creating group: %v", err)
	}
	return
}

// GetGroups returns an unordered list of all group IDs.
func (cp *cwtchPeer) GetGroups() []string {
	return cp.Profile.GetGroups()
}

// GetGroup returns a pointer to a specific group, nil if no group exists.
func (cp *cwtchPeer) GetGroup(groupID string) *model.Group {
	return cp.Profile.GetGroupByGroupID(groupID)
}

func (cp *cwtchPeer) AddContact(nick, onion string, publickey []byte, trusted bool) {
	pp := &model.PublicProfile{Name: nick, Ed25519PublicKey: publickey, Trusted: trusted, Blocked: false, Onion: onion, Attributes: map[string]string{"nick": nick}}
	cp.Profile.AddContact(onion, pp)
	pd, _ := json.Marshal(pp)
	cp.eventBus.Publish(event.NewEvent(event.PeerCreated, map[event.Field]string{
		event.Data:       string(pd),
		event.RemotePeer: onion,
	}))
}

// GetContacts returns an unordered list of onions
func (cp *cwtchPeer) GetContacts() []string {
	return cp.Profile.GetContacts()
}

// GetContact returns a given contact, nil is no such contact exists
func (cp *cwtchPeer) GetContact(onion string) *model.PublicProfile {
	contact, _ := cp.Profile.GetContact(onion)
	return contact
}

// GetProfile returns the profile associated with this cwtchPeer.
func (cp *cwtchPeer) GetProfile() *model.Profile {
	return cp.Profile
}

// PeerWithOnion is the entry point for cwtchPeer relationships
func (cp *cwtchPeer) PeerWithOnion(onion string) *connections.PeerPeerConnection {
	cp.eventBus.Publish(event.NewEvent(event.PeerRequest, map[event.Field]string{event.RemotePeer: onion}))
	return nil
}

// InviteOnionToGroup kicks off the invite process
func (cp *cwtchPeer) InviteOnionToGroup(onion string, groupid string) error {
	group := cp.Profile.GetGroupByGroupID(groupid)
	if group == nil {
		return errors.New("invalid group id")
	}

	invite, err := group.Invite(group.InitialMessage)
	if err == nil {
		cp.eventBus.Publish(event.NewEvent(event.InvitePeerToGroup, map[event.Field]string{event.RemotePeer: onion, event.GroupInvite: string(invite)}))
	}
	return err
}

// JoinServer manages a new server connection with the given onion address
func (cp *cwtchPeer) JoinServer(onion string) {
	cp.eventBus.Publish(event.NewEvent(event.JoinServer, map[event.Field]string{event.GroupServer: onion}))
}

// SendMessageToGroup attempts to sent the given message to the given group id.
// TODO: Deprecate in favour of SendMessageToGroupTracked
func (cp *cwtchPeer) SendMessageToGroup(groupid string, message string) error {
	_, err := cp.SendMessageToGroupTracked(groupid, message)
	return err
}

// SendMessageToGroup attempts to sent the given message to the given group id.
// It returns the signature of the message which can be used to identify it in any UX layer.
func (cp *cwtchPeer) SendMessageToGroupTracked(groupid string, message string) (string, error) {
	group := cp.Profile.GetGroupByGroupID(groupid)
	if group == nil {
		return "", errors.New("invalid group id")
	}
	ct, sig, err := cp.Profile.EncryptMessageToGroup(message, groupid)

	if err == nil {
		cp.eventBus.Publish(event.NewEvent(event.SendMessageToGroup, map[event.Field]string{event.GroupServer: group.GroupServer, event.Ciphertext: string(ct), event.Signature: string(sig)}))
	}

	return string(sig), err
}

func (cp *cwtchPeer) SendMessageToPeer(onion string, message string) string {
	event := event.NewEvent(event.SendMessageToPeer, map[event.Field]string{event.RemotePeer: onion, event.Data: message})
	cp.eventBus.Publish(event)
	return event.EventID
}

// GetPeers returns a list of peer connections.
func (cp *cwtchPeer) GetPeers() map[string]connections.ConnectionState {
	return cp.engine.GetPeers()
}

// GetServers returns a list of server connections
func (cp *cwtchPeer) GetServers() map[string]connections.ConnectionState {
	return cp.engine.GetServers()
}

// TrustPeer sets an existing peer relationship to trusted
func (cp *cwtchPeer) TrustPeer(peer string) error {
	err := cp.Profile.TrustPeer(peer)
	if err == nil {
		cp.PeerWithOnion(peer)
	}
	return err
}

// BlockPeer blocks an existing peer relationship.
func (cp *cwtchPeer) BlockPeer(peer string) error {
	err := cp.Profile.BlockPeer(peer)
	cp.eventBus.Publish(event.NewEvent(event.BlockPeer, map[event.Field]string{event.RemotePeer: peer}))
	return err
}

// AcceptInvite accepts a given existing group invite
func (cp *cwtchPeer) AcceptInvite(groupID string) error {
	err := cp.Profile.AcceptInvite(groupID)
	if err != nil {
		return err
	}
	cp.eventBus.Publish(event.NewEvent(event.AcceptGroupInvite, map[event.Field]string{event.GroupID: groupID}))
	cp.JoinServer(cp.Profile.Groups[groupID].GroupServer)

	return nil
}

// RejectInvite rejects a given group invite.
func (cp *cwtchPeer) RejectInvite(groupID string) {
	cp.Profile.RejectInvite(groupID)
}

func (cp *cwtchPeer) Listen() {
	cp.eventBus.Publish(event.NewEvent(event.ProtocolEngineStartListen, map[event.Field]string{}))
}

// Shutdown kills all connections and cleans up all goroutines for the peer
func (cp *cwtchPeer) Shutdown() {
	cp.shutdown = true
	cp.engine.Shutdown()
	cp.queue.Shutdown()
}

// IsStarted returns true if Listen() has successfully been run before on this connection (ever). TODO: we will need to properly unset this flag on error if we want to support resumption in the future
func (cp *cwtchPeer) IsStarted() bool {
	return cp.started
}

// eventHandler process events from other subsystems
func (cp *cwtchPeer) eventHandler() {
	for {
		ev := cp.queue.Next()
		switch ev.EventType {
		case event.EncryptedGroupMessage:
			ok, groupID, message, seen := cp.Profile.AttemptDecryption([]byte(ev.Data[event.Ciphertext]), []byte(ev.Data[event.Signature]))
			if ok && !seen {
				cp.eventBus.Publish(event.NewEvent(event.NewMessageFromGroup, map[event.Field]string{event.TimestampReceived: message.Received.Format(time.RFC3339Nano), event.TimestampSent: message.Timestamp.Format(time.RFC3339Nano), event.Data: message.Message, event.GroupID: groupID, event.Signature: string(message.Signature), event.PreviousSignature: string(message.PreviousMessageSig), event.RemotePeer: message.PeerID}))
			}
		case event.NewGroupInvite:
			var groupInvite protocol.GroupChatInvite
			proto.Unmarshal([]byte(ev.Data[event.GroupInvite]), &groupInvite)
			cp.Profile.ProcessInvite(&groupInvite, ev.Data[event.RemotePeer])
		default:
			if ev.EventType != "" {
				log.Errorf("peer event handler received an event it was not subscribed for: %v", ev.EventType)
			}
			return
		}
	}
}