package example

import (
	"fmt"
	"github.com/pkg/errors"
	"gorm.io/gorm"
)

type Repository interface {
	Create(*User) error
	Update(*User) error
	Delete(uint64) error
	FindByID(uint64) (*User, error)
	FindAll() ([]*User, error)
	UpdatePassword(username string, password string) error
}

func NewUserRepository(db *gorm.DB) Repository {
	return &userRepo{db: db}
}

type userRepo struct {
	db *gorm.DB
}

func (r *userRepo) Create(user *User) error {
	return r.db.Create(user).Error
}
func (r *userRepo) Update(user *User) error {
	if db := r.db.Updates(&User{
		ID:       user.ID,
		Username: user.Username,
		Password: user.Password,
		Version:  user.Version,
	}); db.Error != nil {
		return db.Error
	} else {
		if db.RowsAffected == 0 {
			return errors.New(fmt.Sprintf("user record version mismatch, id=%d, update version=%d", user.ID, user.Version.Int64))
		}
	}
	return nil
}

func (r *userRepo) Delete(id uint64) error {
	return r.db.Delete(&User{}, "id=?", id).Error
}

func (r *userRepo) FindByID(id uint64) (*User, error) {
	u := &User{}
	if err := r.db.Where("id=?", id).First(u).Error; err != nil {
		return nil, err
	}
	return u, nil
}

func (r *userRepo) FindAll() ([]*User, error) {
	us := make([]*User, 0)
	if err := r.db.Find(&us).Error; err != nil {
		return nil, err
	}
	return us, nil
}

func (r *userRepo) UpdatePassword(username, password string) error {
	return r.db.Where("username=?", username).Updates(&User{Password: password}).Error
}