package handles

import (
	"bytes"
	"encoding/base64"
	"image/png"
	"time"

	"github.com/Xhofe/go-cache"
	"github.com/alist-org/alist/v3/internal/model"
	"github.com/alist-org/alist/v3/internal/op"
	"github.com/alist-org/alist/v3/server/common"
	"github.com/gin-gonic/gin"
	"github.com/pquerna/otp/totp"
)

var loginCache = cache.NewMemCache[int]()
var (
	defaultDuration = time.Minute * 5
	defaultTimes    = 5
)

type LoginReq struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password"`
	OtpCode  string `json:"otp_code"`
}

// Login Deprecated
func Login(c *gin.Context) {
	var req LoginReq
	if err := c.ShouldBind(&req); err != nil {
		common.ErrorResp(c, err, 400)
		return
	}
	req.Password = model.StaticHash(req.Password)
	loginHash(c, &req)
}

// LoginHash login with password hashed by sha256
func LoginHash(c *gin.Context) {
	var req LoginReq
	if err := c.ShouldBind(&req); err != nil {
		common.ErrorResp(c, err, 400)
		return
	}
	loginHash(c, &req)
}

func loginHash(c *gin.Context, req *LoginReq) {
	// check count of login
	ip := c.ClientIP()
	count, ok := loginCache.Get(ip)
	if ok && count >= defaultTimes {
		common.ErrorStrResp(c, "Too many unsuccessful sign-in attempts have been made using an incorrect username or password, Try again later.", 429)
		loginCache.Expire(ip, defaultDuration)
		return
	}
	// check username
	user, err := op.GetUserByName(req.Username)
	if err != nil {
		common.ErrorResp(c, err, 400)
		loginCache.Set(ip, count+1)
		return
	}
	// validate password hash
	if err := user.ValidatePwdStaticHash(req.Password); err != nil {
		common.ErrorResp(c, err, 400)
		loginCache.Set(ip, count+1)
		return
	}
	// check 2FA
	if user.OtpSecret != "" {
		if !totp.Validate(req.OtpCode, user.OtpSecret) {
			common.ErrorStrResp(c, "Invalid 2FA code", 402)
			loginCache.Set(ip, count+1)
			return
		}
	}
	// generate token
	token, err := common.GenerateToken(user)
	if err != nil {
		common.ErrorResp(c, err, 400, true)
		return
	}
	common.SuccessResp(c, gin.H{"token": token})
	loginCache.Del(ip)
}

type UserResp struct {
	model.User
	Otp bool `json:"otp"`
}

// CurrentUser get current user by token
// if token is empty, return guest user
func CurrentUser(c *gin.Context) {
	user := c.MustGet("user").(*model.User)
	userResp := UserResp{
		User: *user,
	}
	userResp.Password = ""
	if userResp.OtpSecret != "" {
		userResp.Otp = true
	}
	common.SuccessResp(c, userResp)
}

func UpdateCurrent(c *gin.Context) {
	var req model.User
	if err := c.ShouldBind(&req); err != nil {
		common.ErrorResp(c, err, 400)
		return
	}
	user := c.MustGet("user").(*model.User)
	user.Username = req.Username
	if req.Password != "" {
		user.SetPassword(req.Password)
	}
	user.SsoID = req.SsoID
	if err := op.UpdateUser(user); err != nil {
		common.ErrorResp(c, err, 500)
	} else {
		common.SuccessResp(c)
	}
}

func Generate2FA(c *gin.Context) {
	user := c.MustGet("user").(*model.User)
	if user.IsGuest() {
		common.ErrorStrResp(c, "Guest user can not generate 2FA code", 403)
		return
	}
	key, err := totp.Generate(totp.GenerateOpts{
		Issuer:      "Alist",
		AccountName: user.Username,
	})
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	img, err := key.Image(400, 400)
	if err != nil {
		common.ErrorResp(c, err, 500)
		return
	}
	// to base64
	var buf bytes.Buffer
	png.Encode(&buf, img)
	b64 := base64.StdEncoding.EncodeToString(buf.Bytes())
	common.SuccessResp(c, gin.H{
		"qr":     "data:image/png;base64," + b64,
		"secret": key.Secret(),
	})
}

type Verify2FAReq struct {
	Code   string `json:"code" binding:"required"`
	Secret string `json:"secret" binding:"required"`
}

func Verify2FA(c *gin.Context) {
	var req Verify2FAReq
	if err := c.ShouldBind(&req); err != nil {
		common.ErrorResp(c, err, 400)
		return
	}
	user := c.MustGet("user").(*model.User)
	if user.IsGuest() {
		common.ErrorStrResp(c, "Guest user can not generate 2FA code", 403)
		return
	}
	if !totp.Validate(req.Code, req.Secret) {
		common.ErrorStrResp(c, "Invalid 2FA code", 400)
		return
	}
	user.OtpSecret = req.Secret
	if err := op.UpdateUser(user); err != nil {
		common.ErrorResp(c, err, 500)
	} else {
		common.SuccessResp(c)
	}
}

func LogOut(c *gin.Context) {
	err := common.InvalidateToken(c.GetHeader("Authorization"))
	if err != nil {
		common.ErrorResp(c, err, 500)
	} else {
		common.SuccessResp(c)
	}
}