FamilyHUB/backend/src/integrations/receiptService/receipt_service.go

package receiptService

import (
	"FamilyHub/src/domain"
	"FamilyHub/src/repositories"
	"FamilyHub/src/utils"
	"bytes"
	"context"
	"crypto/tls"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"mime/multipart"
	"net/http"
	"time"
)

type ReceiptService struct {
	client *http.Client
	repo   repositories.ReceiptsRepository
}

func NewReceiptService(repo repositories.ReceiptsRepository) *ReceiptService {
	return &ReceiptService{
		client: &http.Client{
			Timeout: 60 * time.Second,
			Transport: &http.Transport{
				TLSClientConfig: &tls.Config{
					InsecureSkipVerify: true,
				},
			},
		},
		repo: repo,
	}
}

func (s *ReceiptService) GetReceipt(
	ctx context.Context,
	date string,
	number string,
) (*domain.Receipt, error) {
	url := "https://ch.info-center.by/ajax/check1.php"
	var receipt domain.Receipt

	body, contentType := buildMultipartBody(date, number)
	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodPost,
		url,
		body,
	)
	if err != nil {
		log.Println(err.Error())
		return nil, err
	}

	req.Header.Set("Content-Type", contentType)

	resp, err := s.client.Do(req)
	if err != nil {
		log.Println(err.Error())
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		log.Printf("external service returned %d\n", resp.StatusCode)
		return nil, fmt.Errorf("external service returned %d", resp.StatusCode)
	}

	var raw struct {
		Message map[string]interface{} `json:"message"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&raw); err != nil {
		log.Printf("external service returned %s\n", err.Error())
		return nil, err
	}

	bytes_, _ := json.Marshal(raw.Message)

	if err := json.Unmarshal(bytes_, &receipt); err != nil {
		return nil, err
	}

	if receipt.IssuedAtRaw == "" {
		return nil, errors.New("receipt not found")
	}

	positions, err := parsePositions(receipt.PositionsRaw)
	if err != nil {
		log.Printf("failed to parse positions: %s", err.Error())
		return nil, err
	}
	receipt.IssuedAt, err = utils.ParseIssuedAt(receipt.IssuedAtRaw)
	if err != nil {
		log.Printf("failed to parse issued at: %s", err.Error())
		return nil, err
	}

	receipt.Positions = positions

	for i := range receipt.Positions {
		p := &receipt.Positions[i]

		p.ProductCount, err = utils.ParseFloat(p.ProductCountRaw)
		if err != nil {
			log.Printf("failed to parse product count: %s", err.Error())
			return nil, err
		}

		p.Amount, err = utils.ParseFloat(p.AmountRaw)
		if err != nil {
			log.Printf("failed to parse amount: %s", err.Error())
			return nil, err
		}

		p.Discount, _ = utils.ParseFloat(p.DiscountRaw)
		p.Surcharge, _ = utils.ParseFloat(p.SurchargeRaw)
	}

	if _, err := s.repo.Create(ctx, &receipt); err != nil {
		return nil, err
	}
	return &receipt, nil
}

func buildMultipartBody(date, number string) (*bytes.Buffer, string) {
	body := &bytes.Buffer{}
	writer := multipart.NewWriter(body)

	_ = writer.WriteField("orig_date", date)
	_ = writer.WriteField("orig_ui", number)

	_ = writer.Close()

	return body, writer.FormDataContentType()
}

func parsePositions(raw string) ([]domain.Position, error) {
	var positions []domain.Position

	if raw == "" {
		return positions, nil
	}

	if err := json.Unmarshal([]byte(raw), &positions); err != nil {
		return nil, err
	}

	return positions, nil
}