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"
	"strings"
	"time"
)

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

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

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

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

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

	resp, err := s.client.Do(httpReq)
	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)
	}

	receiptID, err := s.repo.Create(ctx, &receipt)
	if err != nil {
		return nil, err
	}
	receipt.ID = int(receiptID)

	if s.shouldCreateTransaction(req) {
		transaction, err := s.createTransactionForReceipt(ctx, &receipt, req, receiptID)
		if err != nil {
			if rollbackErr := s.repo.Delete(ctx, receiptID); rollbackErr != nil {
				log.Printf("failed to rollback receipt %d after transaction error: %v", receiptID, rollbackErr)
			}
			return nil, err
		}
		receipt.TransactionID = &transaction.ID
	}

	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
}

func (s *ReceiptService) shouldCreateTransaction(req domain.AddReceiptRequest) bool {
	return s.transactionRepo != nil && req.FamilyID != nil && req.CreatedBy != nil
}

func (s *ReceiptService) createTransactionForReceipt(
	ctx context.Context,
	receipt *domain.Receipt,
	req domain.AddReceiptRequest,
	receiptID int64,
) (*domain.Transaction, error) {
	transactionType := "expense"
	if req.Type != nil && strings.TrimSpace(*req.Type) != "" {
		transactionType = strings.TrimSpace(*req.Type)
	}

	category := "receipt"
	if req.Category != nil && strings.TrimSpace(*req.Category) != "" {
		category = strings.TrimSpace(*req.Category)
	}

	description := buildReceiptTransactionDescription(receipt, req.Description)

	transaction := &domain.Transaction{
		FamilyID:    *req.FamilyID,
		Description: description,
		Type:        transactionType,
		DateTime:    receipt.IssuedAt,
		Category:    category,
		Amount:      receipt.TotalAmount,
		CreatedBy:   *req.CreatedBy,
		ReceiptID:   &receiptID,
	}

	if err := s.transactionRepo.Create(ctx, transaction); err != nil {
		return nil, err
	}

	return transaction, nil
}

func buildReceiptTransactionDescription(receipt *domain.Receipt, explicit *string) *string {
	if explicit != nil && strings.TrimSpace(*explicit) != "" {
		value := strings.TrimSpace(*explicit)
		return &value
	}

	if name := strings.TrimSpace(receipt.NameSPD); name != "" {
		return &name
	}

	if number := strings.TrimSpace(receipt.ReceiptNumber); number != "" {
		value := fmt.Sprintf("Receipt %s", number)
		return &value
	}

	return nil
}