package adminauth

import (
	"errors"
	"time"

	"hfb_sys/backend/internal/model"
	"hfb_sys/backend/internal/modules/auth"

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

const (
	defaultAdminUsername = "admin"
	defaultAdminPassword = "admin123456"
)

type Repository struct {
	db  *gorm.DB
	jwt *auth.JWTManager
}

func NewRepository(db *gorm.DB, jwt *auth.JWTManager) *Repository {
	return &Repository{db: db, jwt: jwt}
}

func (r *Repository) Login(username string, password string) (LoginResult, error) {
	if err := r.ensureDefaultAdmin(); err != nil {
		return LoginResult{}, err
	}
	var admin model.AdminUser
	if err := r.db.Where("username = ?", username).First(&admin).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return LoginResult{}, ErrInvalidCredential
		}
		return LoginResult{}, err
	}
	if admin.Status != "active" {
		return LoginResult{}, ErrAdminDisabled
	}
	if err := bcrypt.CompareHashAndPassword([]byte(admin.PasswordHash), []byte(password)); err != nil {
		return LoginResult{}, ErrInvalidCredential
	}
	now := time.Now()
	admin.LastLoginAt = &now
	if err := r.db.Save(&admin).Error; err != nil {
		return LoginResult{}, err
	}
	tokens, err := r.jwt.GenerateSubjectPair(admin.ID, admin.Username, "admin")
	if err != nil {
		return LoginResult{}, err
	}
	return LoginResult{Admin: toDTO(admin), Tokens: tokens}, nil
}

func (r *Repository) FindByID(id uint64) (*AdminDTO, error) {
	var admin model.AdminUser
	if err := r.db.First(&admin, id).Error; err != nil {
		return nil, err
	}
	if admin.Status != "active" {
		return nil, ErrAdminDisabled
	}
	dto := toDTO(admin)
	return &dto, nil
}

func (r *Repository) ensureDefaultAdmin() error {
	var count int64
	if err := r.db.Model(&model.AdminUser{}).Count(&count).Error; err != nil {
		return err
	}
	if count > 0 {
		return nil
	}
	hash, err := bcrypt.GenerateFromPassword([]byte(defaultAdminPassword), bcrypt.DefaultCost)
	if err != nil {
		return err
	}
	admin := model.AdminUser{
		Username:     defaultAdminUsername,
		PasswordHash: string(hash),
		Nickname:     "超级管理员",
		Status:       "active",
	}
	return r.db.Create(&admin).Error
}

func toDTO(admin model.AdminUser) AdminDTO {
	return AdminDTO{
		ID:          admin.ID,
		Username:    admin.Username,
		Nickname:    admin.Nickname,
		Status:      admin.Status,
		LastLoginAt: admin.LastLoginAt,
	}
}