package link

import (
	apperrors "cgnolink/errors"
	"github.com/patrickmn/go-cache"
	"net/url"
)

var linkNotFoundError = apperrors.NotFoundError{Message: "Link with given ID was not found."}

type Service interface {
	Create(link *Link) error
	GetById(id string) (*Link, error)
	AccessLink(id string, password string) (*url.URL, error)
	GetAll(limit int, offset int) (Links, error)
	Update(data *Link) error
	DeleteById(id string) error
}

type PgService struct {
	rep   Repository
	cache *cache.Cache
}

func (service *PgService) AccessLink(id string, password string) (*url.URL, error) {
	link, err := service.GetById(id)
	if err != nil {
		return nil, err
	}

	if link.Password != "" {
		if password == "" || link.Password != password {
			return nil, linkNotFoundError
		}
	}

	return &link.RedirectURL, nil
}

func NewService(rep Repository) Service {
	return &PgService{
		rep:   rep,
		cache: cache.New(cache.NoExpiration, 0),
	}
}

func (service *PgService) Create(link *Link) error {
	existingLink, err := service.rep.FindById(link.Id)
	if err != nil {
		return apperrors.UnknownError{Err: err}
	}

	if existingLink != nil {
		return apperrors.AlreadyExistsError{Message: "Link with given ID already exists."}
	}

	if err = service.rep.Save(link); err != nil {
		return apperrors.UnknownError{Err: err}
	}

	return nil
}

func (service *PgService) GetById(id string) (*Link, error) {
	if v, found := service.cache.Get(id); found {
		if link, ok := v.(*Link); ok {
			return link, nil
		}
	}

	link, err := service.rep.FindById(id)
	if err != nil {
		return nil, apperrors.UnknownError{Err: err}
	}

	if link == nil {
		return nil, linkNotFoundError
	}

	service.cache.Set(id, link, cache.DefaultExpiration)

	return link, nil
}

func (service *PgService) GetAll(limit int, offset int) (Links, error) {
	links, err := service.rep.GetAll(limit, offset)
	if err != nil {
		return nil, apperrors.UnknownError{Err: err}
	}

	return links, nil
}

func (service *PgService) Update(data *Link) error {
	if err := service.rep.Update(data); err != nil {
		return apperrors.UnknownError{Err: err}
	}
	service.cache.Delete(data.Id)

	return nil
}

func (service *PgService) DeleteById(id string) error {
	if err := service.rep.DeleteById(id); err != nil {
		return apperrors.UnknownError{Err: err}
	}
	service.cache.Delete(id)

	return nil
}