package services

import (
	"bytes"
	"context"
	"encoding/base64"
	"encoding/binary"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"math/big"
	"net"
	"net/http"
	"strconv"
	"time"

	"github.com/divyam234/teldrive-go/models"
	"github.com/divyam234/teldrive-go/schemas"
	"github.com/divyam234/teldrive-go/types"
	"github.com/divyam234/teldrive-go/utils"
	"github.com/divyam234/teldrive-go/utils/auth"
	"github.com/gin-gonic/gin"
	"github.com/go-jose/go-jose/v3/jwt"
	"github.com/gorilla/websocket"
	"github.com/gotd/td/session"
	tgauth "github.com/gotd/td/telegram/auth"
	"github.com/gotd/td/telegram/auth/qrlogin"
	"github.com/gotd/td/tg"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type AuthService struct {
	Db            *gorm.DB
	SessionMaxAge int
}

type SessionData struct {
	Version int
	Data    session.Data
}
type SocketMessage struct {
	AuthType      string `json:"authType"`
	Message       string `json:"message"`
	PhoneNo       string `json:"phoneNo,omitempty"`
	PhoneCodeHash string `json:"phoneCodeHash,omitempty"`
	PhoneCode     string `json:"phoneCode,omitempty"`
}

func IP4toInt(IPv4Address net.IP) int64 {
	IPv4Int := big.NewInt(0)
	IPv4Int.SetBytes(IPv4Address.To4())
	return IPv4Int.Int64()
}

func Pack32BinaryIP4(ip4Address string) []byte {
	ipv4Decimal := IP4toInt(net.ParseIP(ip4Address))

	buf := new(bytes.Buffer)
	binary.Write(buf, binary.BigEndian, uint32(ipv4Decimal))
	return buf.Bytes()
}

func generateTgSession(dcID int, authKey []byte, port int) string {

	dcMaps := map[int]string{
		1: "149.154.175.53",
		2: "149.154.167.51",
		3: "149.154.175.100",
		4: "149.154.167.91",
		5: "91.108.56.130",
	}

	dcIDByte := byte(dcID)
	serverAddressBytes := Pack32BinaryIP4(dcMaps[dcID])
	portByte := make([]byte, 2)
	binary.BigEndian.PutUint16(portByte, uint16(port))

	packet := make([]byte, 0)
	packet = append(packet, dcIDByte)
	packet = append(packet, serverAddressBytes...)
	packet = append(packet, portByte...)
	packet = append(packet, authKey...)

	base64Encoded := base64.URLEncoding.EncodeToString(packet)
	return "1" + base64Encoded
}

func GetUserSessionCookieName(c *gin.Context) string {

	isHttps := c.Request.URL.Scheme == "https"
	var cookieName string
	if isHttps {
		cookieName = "__Secure-user-session"
	} else {
		cookieName = "user-session"
	}

	return cookieName
}

func (as *AuthService) LogIn(c *gin.Context) (*schemas.Message, *types.AppError) {
	var session types.TgSession
	if err := c.ShouldBindJSON(&session); err != nil {
		return nil, &types.AppError{Error: errors.New("invalid request payload"), Code: http.StatusBadRequest}
	}

	now := time.Now().UTC()

	jwtClaims := &types.JWTClaims{Claims: jwt.Claims{
		Subject:  strconv.Itoa(session.UserID),
		IssuedAt: jwt.NewNumericDate(now),
		Expiry:   jwt.NewNumericDate(now.Add(time.Duration(as.SessionMaxAge) * time.Second)),
	}, TgSession: session.Sesssion,
		Name:      session.Name,
		UserName:  session.UserName,
		Bot:       session.Bot,
		IsPremium: session.IsPremium,
	}

	jweToken, err := auth.Encode(jwtClaims)

	if err != nil {
		return nil, &types.AppError{Error: err, Code: http.StatusBadRequest}
	}

	user := models.User{
		UserId:    session.UserID,
		Name:      session.Name,
		UserName:  session.UserName,
		IsPremium: session.IsPremium,
		TgSession: session.Sesssion,
	}
	if err := as.Db.Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "user_id"}},
		DoUpdates: clause.Assignments(map[string]interface{}{"tg_session": session.Sesssion}),
	}).Create(&user).Error; err != nil {
		return nil, &types.AppError{Error: errors.New("failed to create or update user"), Code: http.StatusInternalServerError}
	}

	c.SetCookie(GetUserSessionCookieName(c), jweToken, as.SessionMaxAge, "/", c.Request.Host, false, false)
	return &schemas.Message{Status: true, Message: "login success"}, nil
}

func (as *AuthService) GetSession(c *gin.Context) *types.Session {

	cookie, err := c.Request.Cookie(GetUserSessionCookieName(c))

	if err != nil {
		return nil
	}

	jwePayload, err := auth.Decode(cookie.Value)

	if err != nil {
		return nil
	}

	now := time.Now().UTC()

	newExpires := now.Add(time.Duration(as.SessionMaxAge) * time.Second)

	session := &types.Session{Name: jwePayload.Name, UserName: jwePayload.UserName, Expires: newExpires.Format(time.RFC3339)}

	jwePayload.IssuedAt = jwt.NewNumericDate(now)

	jwePayload.Expiry = jwt.NewNumericDate(newExpires)

	jweToken, err := auth.Encode(jwePayload)

	if err != nil {
		return nil
	}
	c.SetCookie(GetUserSessionCookieName(c), jweToken, as.SessionMaxAge, "/", c.Request.Host, false, false)
	return session
}

func (as *AuthService) Logout(c *gin.Context) (*schemas.Message, *types.AppError) {
	val, _ := c.Get("jwtUser")
	jwtUser := val.(*types.JWTClaims)
	userId, _ := strconv.Atoi(jwtUser.Subject)
	tgClient, err, stop := utils.GetAuthClient(jwtUser.TgSession, userId)

	if err != nil {
		return nil, &types.AppError{Error: err, Code: http.StatusInternalServerError}
	}

	tgClient.Tg.API().AuthLogOut(c)
	utils.StopClient(stop, userId)
	c.SetCookie(GetUserSessionCookieName(c), "", -1, "/", c.Request.Host, false, false)
	return &schemas.Message{Status: true, Message: "logout success"}, nil
}

func prepareSession(user *tg.User, data *session.Data) *types.TgSession {
	sessionString := generateTgSession(data.DC, data.AuthKey, 443)
	session := &types.TgSession{
		Sesssion:  sessionString,
		UserID:    int(user.ID),
		Bot:       user.Bot,
		UserName:  user.Username,
		Name:      fmt.Sprintf("%s %s", user.FirstName, user.LastName),
		IsPremium: user.Premium,
	}
	return session
}

func (as *AuthService) HandleQrCodeLogin(c *gin.Context) {
	upgrader := websocket.Upgrader{
		CheckOrigin: func(r *http.Request) bool {
			return true
		},
	}
	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		log.Println(err)
		return
	}
	defer conn.Close()

	dispatcher := tg.NewUpdateDispatcher()
	loggedIn := qrlogin.OnLoginToken(dispatcher)
	sessionStorage := &session.StorageMemory{}
	tgClient, stop, _ := utils.GetNonAuthClient(dispatcher, sessionStorage)
	defer stop()
	for {
		message := &SocketMessage{}
		err := conn.ReadJSON(message)
		if message.AuthType == "qr" {
			authorization, err := tgClient.QR().Auth(c, loggedIn, func(ctx context.Context, token qrlogin.Token) error {
				conn.WriteJSON(map[string]interface{}{"type": "auth", "payload": map[string]string{"token": token.URL()}})
				return nil
			})
			if err != nil {
				break
			}
			user, ok := authorization.User.AsNotEmpty()
			if !ok {
				break
			}
			res, _ := sessionStorage.LoadSession(c)
			sessionData := &SessionData{}
			json.Unmarshal(res, sessionData)
			session := prepareSession(user, &sessionData.Data)
			conn.WriteJSON(map[string]interface{}{"type": "auth", "payload": session, "message": "success"})
		}
		if message.AuthType == "phone" && message.Message == "sendcode" {
			res, err := tgClient.Auth().SendCode(c, message.PhoneNo, tgauth.SendCodeOptions{})
			if err != nil {
				break
			}
			code := res.(*tg.AuthSentCode)
			conn.WriteJSON(map[string]interface{}{"type": "auth", "payload": map[string]string{"phoneCodeHash": code.PhoneCodeHash}})
		}
		if message.AuthType == "phone" && message.Message == "signin" {
			auth, err := tgClient.Auth().SignIn(c, message.PhoneNo, message.PhoneCode, message.PhoneCodeHash)
			if err != nil {
				break
			}
			user, ok := auth.User.AsNotEmpty()
			if !ok {
				break
			}
			res, _ := sessionStorage.LoadSession(c)
			sessionData := &SessionData{}
			json.Unmarshal(res, sessionData)
			session := prepareSession(user, &sessionData.Data)
			conn.WriteJSON(map[string]interface{}{"type": "auth", "payload": session, "message": "success"})
		}
		if err != nil {
			log.Println(err)
			return
		}
	}
}