package service

import (
	"errors"
	"fmt"
	"math/rand"
	"time"

	"affiliate_dash/internal/model"
	"affiliate_dash/internal/pkg/jwt"

	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

type AuthService struct {
	db  *gorm.DB
	jwt *jwt.Manager
}

func NewAuthService(db *gorm.DB, jm *jwt.Manager) *AuthService {
	return &AuthService{db: db, jwt: jm}
}

type LoginResult struct {
	Token string      `json:"token"`
	User  *model.User `json:"user"`
}

func (s *AuthService) Login(username, password string) (*LoginResult, error) {
	var user model.User
	if err := s.db.Where("username = ?", username).First(&user).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, errors.New("用户名或密码错误")
		}
		return nil, err
	}
	if user.Status != 1 {
		return nil, errors.New("账号已禁用")
	}
	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(password)); err != nil {
		return nil, errors.New("用户名或密码错误")
	}
	token, err := s.jwt.Generate(user.ID, user.Username, user.Role)
	if err != nil {
		return nil, err
	}
	return &LoginResult{Token: token, User: &user}, nil
}

func (s *AuthService) Register(username, password, nickname string) (*model.User, error) {
	var count int64
	s.db.Model(&model.User{}).Where("username = ?", username).Count(&count)
	if count > 0 {
		return nil, errors.New("用户名已存在")
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return nil, err
	}
	user := &model.User{
		Username:     username,
		PasswordHash: string(hash),
		Nickname:     nickname,
		Role:         model.RoleDistributor,
		Status:       1,
		InviteCode:   generateInviteCode(),
	}
	if user.Nickname == "" {
		user.Nickname = username
	}
	if err := s.db.Create(user).Error; err != nil {
		return nil, err
	}
	return user, nil
}

func (s *AuthService) GetProfile(userID uint) (*model.User, error) {
	var user model.User
	if err := s.db.First(&user, userID).Error; err != nil {
		return nil, err
	}
	return &user, nil
}

func (s *AuthService) EnsureAdmin() error {
	var count int64
	s.db.Model(&model.User{}).Where("role = ?", model.RoleAdmin).Count(&count)
	if count > 0 {
		return nil
	}
	hash, err := bcrypt.GenerateFromPassword([]byte("admin123"), bcrypt.DefaultCost)
	if err != nil {
		return err
	}
	admin := &model.User{
		Username:     "admin",
		PasswordHash: string(hash),
		Nickname:     "管理员",
		Role:         model.RoleAdmin,
		Status:       1,
		InviteCode:   "ADMIN001",
	}
	return s.db.Create(admin).Error
}

func generateInviteCode() string {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	return fmt.Sprintf("D%06d", r.Intn(1000000))
}