package gateway

import (
	"bytes"
	"encoding/base64"
	"encoding/xml"
	"github.com/pkg/errors"
	"fmt"
	"io"
	"sort"
	"strings"
	"sync"

	"dev.narayana.im/narayana/telegabber/xmpp/extensions"

	log "github.com/sirupsen/logrus"
	"github.com/soheilhy/args"
	"gosrc.io/xmpp"
	"gosrc.io/xmpp/stanza"
)

type Reply struct {
	Author string
	Id     string
	Start  uint64
	End    uint64
}

const NSNick string = "http://jabber.org/protocol/nick"

// Queue stores presences to send later
var Queue = make(map[string]*stanza.Presence)
var QueueLock = sync.Mutex{}

// Jid stores the component's JID object
var Jid *stanza.Jid

// DirtySessions denotes that some Telegram session configurations
// were changed and need to be re-flushed to the YamlDB
var DirtySessions = false

// MessageOutgoingPermission allows to fake outgoing messages by foreign JIDs
var MessageOutgoingPermission = false

// CapsType is a capability category
type CapsType int
const (
	CapsAudio CapsType = iota
)

// ContactType is a disco JID category
type ContactType int
const (
	ContactTransport CapsType = iota
	ContactPM
)

// SendMessage creates and sends a message stanza
func SendMessage(to string, from string, body string, id string, component *xmpp.Component, reply *Reply, isOutgoing bool) {
	sendMessageWrapper(to, from, body, id, component, reply, "", isOutgoing)
}

// SendServiceMessage creates and sends a simple message stanza from transport
func SendServiceMessage(to string, body string, component *xmpp.Component) {
	sendMessageWrapper(to, "", body, "", component, nil, "", false)
}

// SendTextMessage creates and sends a simple message stanza
func SendTextMessage(to string, from string, body string, component *xmpp.Component) {
	sendMessageWrapper(to, from, body, "", component, nil, "", false)
}

// SendMessageWithOOB creates and sends a message stanza with OOB URL
func SendMessageWithOOB(to string, from string, body string, id string, component *xmpp.Component, reply *Reply, oob string, isOutgoing bool) {
	sendMessageWrapper(to, from, body, id, component, reply, oob, isOutgoing)
}

func sendMessageWrapper(to string, from string, body string, id string, component *xmpp.Component, reply *Reply, oob string, isOutgoing bool) {
	toJid, err := stanza.NewJid(to)
	if err != nil {
		log.WithFields(log.Fields{
			"to": to,
		}).Error(errors.Wrap(err, "Invalid to JID!"))
		return
	}
	bareTo := toJid.Bare()

	componentJid := Jid.Full()

	var logFrom string
	var messageFrom string
	var messageTo string
	if from == "" {
		logFrom = componentJid
		messageFrom = componentJid
	} else {
		logFrom = from
		messageFrom = from + "@" + componentJid
	}
	if isOutgoing {
		messageTo = messageFrom
		messageFrom = bareTo + "/" + Jid.Resource
	} else {
		messageTo = to
	}

	log.WithFields(log.Fields{
		"from": logFrom,
		"to":   to,
	}).Warn("Got message")

	message := stanza.Message{
		Attrs: stanza.Attrs{
			From: messageFrom,
			To:   messageTo,
			Type: "chat",
			Id:   id,
		},
		Body: body,
	}

	if oob != "" {
		message.Extensions = append(message.Extensions, stanza.OOB{
			URL: oob,
		})
	}
	if reply != nil {
		message.Extensions = append(message.Extensions, extensions.Reply{
			To: reply.Author,
			Id: reply.Id,
		})
		if reply.End > 0 {
			message.Extensions = append(message.Extensions, extensions.NewReplyFallback(reply.Start, reply.End))
		}
	}

	if isOutgoing {
		carbonMessage := extensions.ClientMessage{
			Attrs: stanza.Attrs{
				From: bareTo,
				To:   to,
				Type: "chat",
			},
		}
		carbonMessage.Extensions = append(carbonMessage.Extensions, extensions.CarbonSent{
			Forwarded: stanza.Forwarded{
				Stanza: extensions.ClientMessage(message),
			},
		})
		privilegeMessage := stanza.Message{
			Attrs: stanza.Attrs{
				From: Jid.Bare(),
				To:   toJid.Domain,
			},
		}
		privilegeMessage.Extensions = append(privilegeMessage.Extensions, extensions.ComponentPrivilege{
			Forwarded: stanza.Forwarded{
				Stanza: carbonMessage,
			},
		})
		sendMessage(&privilegeMessage, component)
	} else {
		sendMessage(&message, component)
	}
}

// SetNickname sets a new nickname for a contact
func SetNickname(to string, from string, nickname string, component *xmpp.Component) {
	componentJid := Jid.Bare()
	messageFrom := from + "@" + componentJid

	log.WithFields(log.Fields{
		"from": from,
		"to":   to,
	}).Warn("Set nickname")

	message := stanza.Message{
		Attrs: stanza.Attrs{
			From: messageFrom,
			To:   to,
			Type: "headline",
		},
		Extensions: []stanza.MsgExtension{
			stanza.PubSubEvent{
				EventElement: stanza.ItemsEvent{
					Node: NSNick,
					Items: []stanza.ItemEvent{
						stanza.ItemEvent{
							Any: &stanza.Node{
								XMLName: xml.Name{Space: NSNick, Local: "nick"},
								Content: nickname,
							},
						},
					},
				},
			},
		},
	}

	sendMessage(&message, component)
}

func sendMessage(message *stanza.Message, component *xmpp.Component) {
	// explicit check, as marshalling is expensive
	if log.GetLevel() == log.DebugLevel {
		xmlMessage, err := xml.Marshal(message)
		if err == nil {
			log.Debug(string(xmlMessage))
		} else {
			log.Debugf("%#v", message)
		}
	}

	_ = ResumableSend(component, message)
}

// LogBadPresence verbosely logs a presence
func LogBadPresence(presence *stanza.Presence) {
	log.Errorf("Couldn't send presence: %#v", presence)
}

// SPFrom is a Telegram user id
var SPFrom = args.NewString()

// SPType is a presence type
var SPType = args.NewString()

// SPShow is a availability status
var SPShow = args.NewString()

// SPStatus is a verbose status
var SPStatus = args.NewString()

// SPNickname is a XEP-0172 nickname
var SPNickname = args.NewString()

// SPPhoto is a XEP-0153 hash of avatar in vCard
var SPPhoto = args.NewString()

// SPResource is an optional resource
var SPResource = args.NewString()

// SPImmed skips queueing
var SPImmed = args.NewBool(args.Default(true))

// SPCaps is a XEP-0115 verification string
var SPCaps = args.NewString()

func newPresence(bareJid string, to string, args ...args.V) stanza.Presence {
	var presenceFrom string
	if SPFrom.IsSet(args) {
		presenceFrom = SPFrom.Get(args) + "@" + bareJid
		if SPResource.IsSet(args) {
			resource := SPResource.Get(args)
			if resource != "" {
				presenceFrom += "/" + resource
			}
		}
	} else {
		presenceFrom = bareJid
	}

	presence := stanza.Presence{Attrs: stanza.Attrs{
		From: presenceFrom,
		To:   to,
	}}

	if SPType.IsSet(args) {
		t := SPType.Get(args)
		if t != "" {
			presence.Attrs.Type = stanza.StanzaType(t)
		}
	}
	if SPShow.IsSet(args) {
		show := SPShow.Get(args)
		if show != "" {
			presence.Show = stanza.PresenceShow(show)
		}
	}
	if SPStatus.IsSet(args) {
		status := SPStatus.Get(args)
		if status != "" {
			presence.Status = status
		}
	}
	if SPNickname.IsSet(args) {
		nickname := SPNickname.Get(args)
		if nickname != "" {
			presence.Extensions = append(presence.Extensions, extensions.PresenceNickExtension{
				Text: nickname,
			})
		}
	}
	if SPPhoto.IsSet(args) {
		photo := SPPhoto.Get(args)
		if photo != "" {
			presence.Extensions = append(presence.Extensions, extensions.PresenceXVCardUpdateExtension{
				Photo: extensions.PresenceXVCardUpdatePhoto{
					Text: photo,
				},
			})
		}
	}
	if SPCaps.IsSet(args) {
		ver := SPCaps.Get(args)
		if ver != "" {
			presence.Extensions = append(presence.Extensions, extensions.CapsExtension{
				Hash: "sha-1",
				Node: "https://dev.narayana.im/narayana/telegabber/",
				Ver:  ver,
			})
		}
	}

	return presence
}

// SendPresence creates and sends a presence stanza
func SendPresence(component *xmpp.Component, to string, args ...args.V) error {
	var logFrom string
	bareJid := Jid.Bare()
	if SPFrom.IsSet(args) {
		logFrom = SPFrom.Get(args)
	} else {
		logFrom = bareJid
	}

	log.WithFields(log.Fields{
		"type": SPType.Get(args),
		"from": logFrom,
		"to":   to,
	}).Info("Got presence")

	presence := newPresence(bareJid, to, args...)

	// explicit check, as marshalling is expensive
	if log.GetLevel() == log.DebugLevel {
		xmlPresence, err := xml.Marshal(presence)
		if err == nil {
			log.Debug(string(xmlPresence))
		} else {
			log.Debugf("%#v", presence)
		}
	}

	immed := SPImmed.Get(args)
	if immed {
		err := ResumableSend(component, presence)
		if err != nil {
			LogBadPresence(&presence)
			return err
		}
	} else {
		QueueLock.Lock()
		Queue[presence.From+presence.To] = &presence
		QueueLock.Unlock()
	}

	return nil
}

// ResumableSend tries to resume the connection once and sends the packet again
func ResumableSend(component *xmpp.Component, packet stanza.Packet) error {
	err := component.Send(packet)
	if err != nil && strings.HasPrefix(err.Error(), "cannot send packet") {
		log.Warn("Packet send failed, trying to resume the connection...")
		err = component.Connect()
		if err == nil {
			err = component.Send(packet)
		}
	}

	if err != nil {
		log.Error(err.Error())
	}
	return err
}

// SplitJID tokenizes a JID string to bare JID and resource
func SplitJID(from string) (string, string, bool) {
	fromJid, err := stanza.NewJid(from)
	if err != nil {
		log.WithFields(log.Fields{
			"from": from,
		}).Error(errors.Wrap(err, "Invalid from JID!"))
		return "", "", false
	}
	return fromJid.Bare(), fromJid.Resource, true
}

func getDiscoFeatures(caps []CapsType) []string {
	features := []string{
		"http://jabber.org/protocol/caps",
		"http://jabber.org/protocol/disco#info",
	}
	for typ := range features {
		switch typ {
		case CapsAudio:
			features = append(
				features,
				"urn:xmpp:jingle-message:0",
				"urn:xmpp:jingle:1",
				"urn:xmpp:jingle:apps:dtls:0",
				"urn:xmpp:jingle:apps:rtp:1",
				"urn:xmpp:jingle:apps:rtp:audio",
				"urn:xmpp:jingle:transports:ice-udp:1",
			)
		}
	}
	return features
}

// GetDiscoInfo generates a disco info IQ query response
func GetDiscoInfo(typ ContactType, features []string) *stanza.DiscoInfo {
	disco := stanza.DiscoInfo{}
	if typ == ContactPM {
		disco.AddIdentity("", "account", "registered")
	} else {
		disco.AddIdentity("Telegram Gateway", "gateway", "telegram")
	}
	disco.AddFeatures(features...)
	return &disco
}


// GetCapsVer hashes a capabilities set into a verification string
func GetCapsVer(caps []CapsType) (string, error) {
	features := getDiscoFeatures(caps)
	disco := GetDiscoInfo(features)
	discoToCapsHash(disco)
	buf := new(bytes.Buffer)
	binval := base64.NewEncoder(base64.StdEncoding, buf)
	_, err = io.Copy(binval, file)
	binval.Close()
	if err != nil {
		return "", errors.Wrap(err, "Error calculating caps base64")
	}
	return buf.String(), nil
}

func iOctetComparator(a, b string) bool {
	return a < b
}

func discoToCaps(disco *stanza.DiscoInfo) string {
	var s strings.Builder
	var identities, vars, capsForms []string

	for _, identity := range disco.Identity {
		identities = append(identities, fmt.Sprintf(
			"%s/%s//%s",
			identity.Category,
			identity.Type,
			identity.Name,
		))
	}
	sort.Slice(identities, iOctetComparator)
	for _, identity := range identities {
		s.WriteString(identity)
		s.WriteString(">")
	}

	for _, feature := range disco.Features {
		vars = append(vars, feature.Var)
	}
	sort.Slice(vars, iOctetComparator)
	for _, var := range vars {
		s.WriteString(var)
		s.WriteString(">")
	}

	for disco
	s.WriteString(
}