package models

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"errors"
	"github.com/veypi/utils"
	"github.com/veypi/utils/log"
	"strings"
	"time"
)

// User db user model
type User struct {
	BaseModel
	Username  string `json:"username" gorm:"type:varchar(100);unique;not null"`
	Nickname  string `json:"nickname" gorm:"type:varchar(100)" json:",omitempty"`
	Phone     string `json:"phone" gorm:"type:varchar(20);unique;default:null" json:",omitempty"`
	Email     string `json:"email" gorm:"type:varchar(50);unique;default:null" json:",omitempty"`
	CheckCode string `gorm:"type:varchar(64);not null" json:"-"`
	RealCode  string `gorm:"type:varchar(32);not null" json:"-"`
	Position  string `json:"position"`
	// disabled 禁用
	Status string `json:"status"`

	Icon  string  `json:"icon"`
	Roles []*Role `json:"roles" gorm:"many2many:user_role;"`
}

// TODO:: roles 是否会造成token过大 ?
type PayLoad struct {
	ID       uint   `json:"id"`
	Username string `json:"username"`
	Nickname string `json:"nickname"`
	Icon     string `json:"icon"`
	Iat      int64  `json:"iat"` //token time
	Exp      int64  `json:"exp"`
	Roles    []uint `json:"roles"`
}

func (p *PayLoad) CheckAuth(name string, tags ...string) AuthLevel {
	res := AuthNone
	if p == nil || p.Roles == nil {
		return res
	}
	for _, id := range p.Roles {
		r := GlobalRoles[id]
		if r == nil {
			log.Warn().Msgf("not found role id: %d", id)
			continue
		}
		t := r.CheckAuth(name, tags...)
		if t > res {
			res = t
		}
	}
	return res
}

func (u *User) String() string {
	return u.Username + ":" + u.Nickname
}

func (u *User) CheckAuth(name string, tags ...string) AuthLevel {
	res := AuthNone
	if u == nil || u.Roles == nil {
		return res
	}
	for _, t := range u.Roles {
		r := GlobalRoles[t.ID]
		if r == nil {
			log.Warn().Msgf("not found role id: %d", t.ID)
			continue
		}
		t := r.CheckAuth(name, tags...)
		if t > res {
			res = t
		}
	}
	return res
}

func (u *User) GetToken(key string) (string, error) {
	header := map[string]string{
		"typ": "JWT",
		"alg": "HS256",
	}
	//header := "{\"typ\": \"JWT\", \"alg\": \"HS256\"}"
	now := time.Now().Unix()
	payload := PayLoad{
		ID:       u.ID,
		Username: u.Username,
		Nickname: u.Nickname,
		Icon:     u.Icon,
		Iat:      now,
		Exp:      now + 60*60*24,
	}
	for _, r := range u.Roles {
		payload.Roles = append(payload.Roles, r.ID)
	}
	a, err := json.Marshal(header)
	if err != nil {
		return "", err
	}
	b, err := json.Marshal(payload)
	if err != nil {
		return "", err
	}
	A := base64.StdEncoding.EncodeToString(a)
	B := base64.StdEncoding.EncodeToString(b)
	hmacCipher := hmac.New(sha256.New, []byte(key))
	hmacCipher.Write([]byte(A + "." + B))
	C := hmacCipher.Sum(nil)
	return A + "." + B + "." + base64.StdEncoding.EncodeToString(C), nil
}

var (
	InvalidToken = errors.New("invalid token")
	ExpiredToken = errors.New("expired token")
)

func ParseToken(token string, key string, payload *PayLoad) (bool, error) {
	var A, B, C string
	if seqs := strings.Split(token, "."); len(seqs) == 3 {
		A, B, C = seqs[0], seqs[1], seqs[2]
	} else {
		return false, InvalidToken
	}
	hmacCipher := hmac.New(sha256.New, []byte(key))
	hmacCipher.Write([]byte(A + "." + B))
	tempC := hmacCipher.Sum(nil)
	if !hmac.Equal([]byte(C), []byte(base64.StdEncoding.EncodeToString(tempC))) {
		return false, nil
	}
	tempPayload, err := base64.StdEncoding.DecodeString(B)
	if err != nil {
		return false, err
	}
	if err := json.Unmarshal(tempPayload, payload); err != nil {
		return false, err
	}
	if time.Now().Unix() > payload.Exp {
		return false, ExpiredToken
	}
	return true, nil
}

func (u *User) UpdateAuth(ps string) (err error) {
	u.RealCode = utils.RandSeq(32)
	u.CheckCode, err = utils.AesEncrypt(u.RealCode, []byte(ps))
	return err
}

func (u *User) CheckLogin(ps string) (bool, error) {
	temp, err := utils.AesDecrypt(u.CheckCode, []byte(ps))
	return temp == u.RealCode, err
}