package usecase

import (
	"context"

	"github.com/gofrs/uuid/v5"

	"github.com/saveinmed/backend-go/internal/domain"
)

// Repository defines DB contract for the core entities.
type Repository interface {
	CreateCompany(ctx context.Context, company *domain.Company) error
	ListCompanies(ctx context.Context) ([]domain.Company, error)

	CreateProduct(ctx context.Context, product *domain.Product) error
	ListProducts(ctx context.Context) ([]domain.Product, error)

	CreateOrder(ctx context.Context, order *domain.Order) error
	GetOrder(ctx context.Context, id uuid.UUID) (*domain.Order, error)
	UpdateOrderStatus(ctx context.Context, id uuid.UUID, status domain.OrderStatus) error
}

// PaymentGateway abstracts Mercado Pago integration.
type PaymentGateway interface {
	CreatePreference(ctx context.Context, order *domain.Order) (*domain.PaymentPreference, error)
}

type Service struct {
	repo Repository
	pay  PaymentGateway
}

// NewService wires use cases together.
func NewService(repo Repository, pay PaymentGateway) *Service {
	return &Service{repo: repo, pay: pay}
}

func (s *Service) RegisterCompany(ctx context.Context, company *domain.Company) error {
	company.ID = uuid.Must(uuid.NewV7())
	return s.repo.CreateCompany(ctx, company)
}

func (s *Service) ListCompanies(ctx context.Context) ([]domain.Company, error) {
	return s.repo.ListCompanies(ctx)
}

func (s *Service) RegisterProduct(ctx context.Context, product *domain.Product) error {
	product.ID = uuid.Must(uuid.NewV7())
	return s.repo.CreateProduct(ctx, product)
}

func (s *Service) ListProducts(ctx context.Context) ([]domain.Product, error) {
	return s.repo.ListProducts(ctx)
}

func (s *Service) CreateOrder(ctx context.Context, order *domain.Order) error {
	order.ID = uuid.Must(uuid.NewV7())
	order.Status = domain.OrderStatusPending
	return s.repo.CreateOrder(ctx, order)
}

func (s *Service) GetOrder(ctx context.Context, id uuid.UUID) (*domain.Order, error) {
	return s.repo.GetOrder(ctx, id)
}

func (s *Service) UpdateOrderStatus(ctx context.Context, id uuid.UUID, status domain.OrderStatus) error {
	return s.repo.UpdateOrderStatus(ctx, id, status)
}

func (s *Service) CreatePaymentPreference(ctx context.Context, id uuid.UUID) (*domain.PaymentPreference, error) {
	order, err := s.repo.GetOrder(ctx, id)
	if err != nil {
		return nil, err
	}
	return s.pay.CreatePreference(ctx, order)
}