package paymentsvc

import (
	"context"
	"errors"
	"sync"
)

var (
	ErrPaymentInProgress     = errors.New("payment is already in progress")
	ErrProviderNotConfigured = errors.New("payment provider is not configured")
)

type StatusUpdate struct {
	Code string `json:"code"`
}

type StatusHandler func(StatusUpdate)

type Provider interface {
	Sale(
		ctx context.Context,
		req SaleRequest,
		onStatus StatusHandler,
	) (*Result, error)
}

type Service struct {
	provider Provider

	mu   sync.Mutex
	busy bool
}

func NewService(provider Provider) *Service {
	return &Service{
		provider: provider,
	}
}

func (s *Service) Sale(
	ctx context.Context,
	req SaleRequest,
	onStatus StatusHandler,
) (*Result, error) {
	if s == nil || s.provider == nil {
		return nil, ErrProviderNotConfigured
	}

	s.mu.Lock()
	if s.busy {
		s.mu.Unlock()
		return nil, ErrPaymentInProgress
	}
	s.busy = true
	s.mu.Unlock()

	defer func() {
		s.mu.Lock()
		s.busy = false
		s.mu.Unlock()
	}()

	return s.provider.Sale(ctx, req, onStatus)
}