package service

import (
	"errors"
	"time"

	"gotest/internal/config"
	"gotest/internal/middleware"
	"gotest/internal/model"
	"gotest/internal/repository"

	"github.com/golang-jwt/jwt/v5"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

// AuthService 认证服务
type AuthService struct {
	userRepo *repository.UserRepository
	cfg      *config.Config
}

// NewAuthService 创建认证服务实例
func NewAuthService(userRepo *repository.UserRepository, cfg *config.Config) *AuthService {
	return &AuthService{userRepo: userRepo, cfg: cfg}
}

// Login 用户登录，校验账号密码并返回 JWT token
func (s *AuthService) Login(username, password string) (string, *model.User, error) {
	user, err := s.userRepo.FindByUsername(username)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return "", nil, errors.New("用户名或密码错误")
		}
		return "", nil, err
	}

	// 校验密码
	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
		return "", nil, errors.New("用户名或密码错误")
	}

	// 校验账号状态
	if user.Status != 1 {
		return "", nil, errors.New("账号已被禁用")
	}

	// 生成 token
	token, err := s.GenerateToken(user)
	if err != nil {
		return "", nil, err
	}

	return token, user, nil
}

// GenerateToken 根据用户信息生成 JWT token
func (s *AuthService) GenerateToken(user *model.User) (string, error) {
	claims := middleware.Claims{
		UserID: user.ID,
		Role:   user.Role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(s.cfg.JWT.ExpireHours) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(s.cfg.JWT.Secret))
}