package core

import (
	"context"
	"encoding/gob"
	"encoding/json"
	"errors"
	"fmt"
	"net/url"
	"time"

	"github.com/go-redis/redis/v8"
	"repositories.action2quare.com/ayo/gocommon"
	"repositories.action2quare.com/ayo/gocommon/logger"
	"repositories.action2quare.com/ayo/gocommon/wshandler"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
)

type accountID = primitive.ObjectID
type ticketID = primitive.ObjectID
type groupID = primitive.ObjectID
type Body = bson.M

func init() {
	gob.Register(memberDoc{})
}

func makeTid(gid groupID, in accountID) string {
	var out primitive.ObjectID
	for i := range in {
		out[12-i-1] = gid[i] ^ in[12-i-1]
	}
	return out.Hex()
}

type Invitation struct {
	GroupID     groupID `json:"_gid"`
	TicketID    string  `json:"_tid"`
	Inviter     bson.M  `json:"_inviter"` // memberDoc.Body
	ExpireAtUTC int64   `json:"_expire_at_utc"`
}

// 플레이어한테 공유하는 멤버 정보
type memberDoc struct {
	Body         `json:",inline"`
	Invite       bool  `json:"_invite"`
	InviteExpire int64 `json:"_invite_exp"`
}

type InvitationFail bson.M

type groupDoc struct {
	Body     `json:",inline"`
	Members  map[string]*memberDoc `json:"_members"`
	InCharge string                `json:"_incharge"`

	rh    *RedisonHandler
	id    groupID
	idhex string
}

type groupDocWithId struct {
	*groupDoc `json:",inline"`
	Gid       string `json:"_gid"`
}

func (gd *groupDoc) strid() string {
	if len(gd.idhex) == 0 {
		gd.idhex = gd.id.Hex()
	}
	return gd.idhex
}

func (gd *groupDoc) tid(in accountID) string {
	return makeTid(gd.id, in)
}

func (gd *groupDoc) mid(tid string) accountID {
	tidobj, _ := primitive.ObjectIDFromHex(tid)
	var out primitive.ObjectID
	for i := range tidobj {
		out[12-i-1] = gd.id[i] ^ tidobj[12-i-1]
	}
	return out
}

func (gd *groupDoc) addInvite(inviteeDoc bson.M, ttl time.Duration, max int) (*memberDoc, error) {
	targetmid := inviteeDoc["_mid"].(accountID)
	targetbody := inviteeDoc["body"].(bson.M)

	// 초대 가능한 빈 자리가 있나
	tids, err := gd.rh.JSONObjKeys(gd.strid(), "$._members")
	if err != nil {
		return nil, err
	}

	now := time.Now().UTC()
	createNewDoc := func() *memberDoc {
		return &memberDoc{
			Body:         targetbody,
			Invite:       true,
			InviteExpire: now.Add(ttl).Unix(),
		}
	}

	newtid := gd.tid(targetmid)
	if len(tids) < max {
		// 빈자리를 찾았다.
		newdoc := createNewDoc()
		_, err := gd.rh.JSONSet(gd.strid(), "$._members."+newtid, newdoc)
		return newdoc, err
	}

	expires, err := gd.rh.JSONGetInt64(gd.strid(), "$._members.._invite_exp")
	if err != nil {
		return nil, err
	}

	var delpaths []string
	for i, expire := range expires {
		if expire < now.Unix() {
			// 만료된 초대가 있네? 지우자
			delpaths = append(delpaths, "$._members."+tids[i])
		}
	}

	if len(delpaths) == 0 {
		// 빈자리가 없다
		return nil, nil
	}

	if err := gd.rh.JSONMDel(gd.strid(), delpaths); err != nil {
		return nil, err
	}

	newdoc := createNewDoc()
	_, err = gd.rh.JSONSet(gd.strid(), "$._members."+newtid, newdoc)
	return newdoc, err
}

func (gd *groupDoc) addMember(mid accountID, doc bson.M) (*memberDoc, error) {
	memdoc := &memberDoc{
		Body:         doc,
		Invite:       false,
		InviteExpire: 0,
	}

	if _, err := gd.rh.JSONSet(gd.strid(), "$._members."+gd.tid(mid), memdoc, SetOptionXX); err != nil {
		return nil, err
	}

	return memdoc, nil
}

func (gd *groupDoc) removeMember(mid accountID) error {
	_, err := gd.rh.JSONDel(gd.strid(), "$._members."+gd.tid(mid))
	return err
}

type groupInMemory struct {
	*groupConfig
	sendUpstreamMessage  func(*wshandler.UpstreamMessage)
	sendEnterRoomMessage func(groupID, accountID)
	sendLeaveRoomMessage func(groupID, accountID)
	rh                   *RedisonHandler
}

func (gm *groupInMemory) createGroup(newid groupID, charge accountID, chargeDoc bson.M) (*groupDoc, error) {
	tid := makeTid(newid, charge)

	gd := &groupDoc{
		Body: bson.M{},
		Members: map[string]*memberDoc{
			tid: {
				Body:         chargeDoc,
				Invite:       false,
				InviteExpire: 0,
			},
		},
		InCharge: tid,

		rh: gm.rh,
		id: newid,
	}

	_, err := gm.rh.JSONSet(gd.strid(), "$", gd, SetOptionNX)
	if err != nil {
		return nil, err
	}
	return gd, nil
}

func (gm *groupInMemory) find(id groupID) (*groupDoc, error) {
	if id.IsZero() {
		return nil, nil
	}

	_, err := gm.rh.JSONObjLen(id.Hex(), "$")
	if err == redis.Nil {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	return &groupDoc{
		rh: gm.rh,
		id: id,
	}, nil
}

func (gm *groupInMemory) Create(form url.Values, base bson.M) (groupID, error) {
	return primitive.NilObjectID, nil
}

func (gm *groupInMemory) Candidate(gid groupID, mid accountID, doc bson.M) error {
	logger.Error("not implemented func : Canidate")
	return nil
}

var errGroupNotExist = errors.New("group does not exist")

func (gm *groupInMemory) Join(gid groupID, mid accountID, doc bson.M) error {
	group, err := gm.find(gid)
	if err != nil {
		return err
	}

	if group == nil {
		// 그룹이 없다. 실패
		return errGroupNotExist
	}

	// 내 정보 업데이트할 때에도 사용됨
	_, err = group.addMember(mid, doc)

	return err
}

var errInviteeDocMidMissing = errors.New("inviteeDoc must have '_mid' field")
var errAlreadyInvited = errors.New("this target is already invited by someone or me")

func (gm *groupInMemory) Invite(gid groupID, mid accountID, inviterDoc bson.M, inviteeDoc bson.M) (string, error) {
	targetid, ok := inviteeDoc["_mid"].(accountID)
	if !ok {
		return "", errInviteeDocMidMissing
	}

	// targetid에 초대한 mid가 들어있다.
	already, err := gm.rh.Get(gm.rh.ctx, targetid.Hex()).Result()
	if err != nil && err != redis.Nil {
		return "", err
	}

	if len(already) > 0 {
		if already != mid.Hex() {
			// 이미 초대 중이다.
			// inviter한테 알려줘야 한다.
			gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
				Target: "@" + mid.Hex(),
				Body:   inviteeDoc,
				Tag:    []string{"InvitationFail"},
			})
		}
		return "", errAlreadyInvited
	}

	gd, err := gm.find(gid)
	if err != nil {
		return "", err
	}

	if gd == nil {
		gd, err = gm.createGroup(gid, mid, inviterDoc)
		if err != nil {
			return "", err
		}
		// 내가 wshandler room에 입장
		gm.sendEnterRoomMessage(gid, mid)

		gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
			Target: "@" + mid.Hex(),
			Body: groupDocWithId{
				groupDoc: gd,
				Gid:      gd.strid(),
			},
			Tag: []string{"GroupDocFull"},
		})
	}

	newdoc, err := gd.addInvite(inviteeDoc, time.Duration(gm.InviteExpire+1)*time.Second, gm.MaxMember)
	if err != nil {
		return "", err
	}

	// 초대 중 표시
	success, err := gm.rh.SetNX(gm.rh.ctx, targetid.Hex(), mid.Hex(), time.Duration(gm.InviteExpire)*time.Second).Result()
	if err != nil {
		return "", err
	}
	logger.Println("invitation key :", targetid.Hex(), success)

	// invitee에게 알림
	gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
		Target: "@" + targetid.Hex(),
		Body: Invitation{
			GroupID:     gid,
			TicketID:    gd.tid(targetid),
			Inviter:     inviterDoc,
			ExpireAtUTC: newdoc.InviteExpire,
		},
		Tag: []string{"Invitation"},
	})

	return gd.strid(), nil
}

func (gm *groupInMemory) CancelInvitation(gid groupID, tid ticketID) error {
	return nil
}

var errInvitationExpired = errors.New("invitation is already expired")

func (gm *groupInMemory) AcceptInvitation(gid groupID, mid accountID, member bson.M) error {
	logger.Println("accept invitation key :", mid.Hex())

	cnt, err := gm.rh.Del(gm.rh.ctx, mid.Hex()).Result()
	if err != nil {
		return err
	}
	if cnt == 0 {
		// 만료됨
		return errInvitationExpired
	}

	gd := groupDoc{
		id: gid,
		rh: gm.rh,
	}

	memberDoc, err := gd.addMember(mid, member)
	if err == nil {
		// 기존 멤버에게 새 멤버를 알림
		gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
			Target: "#" + gid.Hex(),
			Body: map[string]any{
				gd.tid(mid): memberDoc,
			},
			Tag: []string{"MemberDocFull"},
		})
		gm.sendEnterRoomMessage(gid, mid)

		// 새 멤버에 그룹 전체를 알림
		full, err := gm.rh.JSONGet(gd.strid(), "$")
		if err != nil {
			return err
		}

		logger.Println(full)
		var temp []groupDoc
		err = json.Unmarshal([]byte(full.(string)), &temp)
		if err != nil {
			return err
		}

		gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
			Target: "@" + mid.Hex(),
			Body: groupDocWithId{
				groupDoc: &temp[0],
				Gid:      gd.strid(),
			},
			Tag: []string{"GroupDocFull"},
		})
	}

	// 실패
	return err
}

func (gm *groupInMemory) DenyInvitation(gid groupID, mid accountID, tid ticketID) error {
	gm.rh.Del(gm.rh.ctx, mid.Hex()).Result()
	gd := groupDoc{
		id: gid,
		rh: gm.rh,
	}
	return gd.removeMember(mid)
}

func (gm *groupInMemory) QueryInvitations(mid accountID, after primitive.Timestamp) ([]bson.M, error) {
	return nil, nil
}
func (gm *groupInMemory) Exist(gid groupID, filter bson.M) (bool, error) {
	return false, nil
}
func (gm *groupInMemory) FindAll(filter bson.M, projection string, after primitive.Timestamp) ([]bson.M, error) {
	return nil, nil
}
func (gm *groupInMemory) FindOne(gid groupID, projection string) (bson.M, error) {
	return nil, nil
}
func (gm *groupInMemory) Leave(gid groupID, mid accountID) error {
	gd := groupDoc{
		id: gid,
		rh: gm.rh,
	}
	if err := gd.removeMember(mid); err != nil {
		return err
	}

	// 나한테는 빈 GroupDocFull을 보낸다. 그러면 지워짐
	gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
		Target: "@" + mid.Hex(),
		Body:   bson.M{"gid": gid},
		Tag:    []string{"GroupDocFull", gid.Hex()},
	})
	gm.sendLeaveRoomMessage(gid, mid)

	return nil
}

func (gm *groupInMemory) UpdateMemberDocument(gid groupID, mid accountID, doc bson.M) error {
	gd := groupDoc{
		id: gid,
		rh: gm.rh,
	}
	prefixPath := fmt.Sprintf("$._members.%s.", gd.tid(mid))
	err := gm.rh.JSONMSetRel(gd.strid(), prefixPath, doc)
	if err != nil {
		return err
	}

	gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
		Target: "#" + gid.Hex(),
		Body: map[string]any{
			gd.tid(mid): doc,
		},
		Tag: []string{"MemberDocFragment"},
	})

	return nil
}

func (gm *groupInMemory) Dismiss(gid groupID) error {
	return nil
}

func (gm *groupInMemory) UpdateGroupDocument(gid groupID, frag bson.M) error {
	gd := groupDoc{
		id: gid,
		rh: gm.rh,
	}

	if err := gm.rh.JSONMSetRel(gd.strid(), "$.", frag); err != nil {
		return err
	}

	// 업데이트 알림
	gm.sendUpstreamMessage(&wshandler.UpstreamMessage{
		Target: "#" + gid.Hex(),
		Body:   frag,
		Tag:    []string{"GroupDocFragment"},
	})

	return nil
}

func (cfg *groupConfig) prepareInMemory(ctx context.Context, typename string, sub *subTavern) (group, error) {
	// group document
	// member document
	region := sub.region
	wsh := sub.wsh
	storage := config.RegionStorage[sub.region]
	redisClient, err := gocommon.NewRedisClient(storage.Redis["tavern"])
	if err != nil {
		return nil, err
	}
	// 여기서는 subscribe channel
	// 각 함수에서는 publish
	gm := &groupInMemory{
		groupConfig: cfg,
		rh:          NewRedisonHandler(ctx, redisClient),
		sendUpstreamMessage: func(msg *wshandler.UpstreamMessage) {
			wsh.SendUpstreamMessage(region, msg)
		},
		sendEnterRoomMessage: func(gid groupID, accid accountID) {
			wsh.EnterRoom(region, gid.Hex(), accid)
		},
		sendLeaveRoomMessage: func(gid groupID, accid accountID) {
			wsh.LeaveRoom(region, gid.Hex(), accid)
		},
	}

	return gm, nil
}