package service

import (
	"context"
	"sync"

	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common"
	"github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/common/profile"
	ocr "github.com/tencentcloud/tencentcloud-sdk-go/tencentcloud/ocr/v20181119"
	"tencent_ocr/pkg/errors"
)

type OCRService struct {
	client          *ocr.Client
	tencentSecretID string
	tencentSecretKey string
	mu              sync.RWMutex
}

func NewOCRService(tencentSecretID, tencentSecretKey string) (*OCRService, error) {
	credential := common.NewCredential(tencentSecretID, tencentSecretKey)
	cpf := profile.NewClientProfile()
	cpf.HttpProfile.Endpoint = "ocr.tencentcloudapi.com"
	
	client, err := ocr.NewClient(credential, "", cpf)
	if err != nil {
		return nil, errors.Wrap(err, "failed to create Tencent Cloud OCR client")
	}

	return &OCRService{
		client:          client,
		tencentSecretID: tencentSecretID,
		tencentSecretKey: tencentSecretKey,
	}, nil
}

func (s *OCRService) ProcessImage(ctx context.Context, imageBase64 string) (string, error) {
	if imageBase64 == "" {
		return "", errors.NewClientError("image data is required")
	}

	s.mu.RLock()
	defer s.mu.RUnlock()

	// Create OCR request
	request := ocr.NewGeneralHandwritingOCRRequest()
	request.ImageBase64 = common.StringPtr(imageBase64)

	// Perform OCR
	response, err := s.client.GeneralHandwritingOCRWithContext(ctx, request)
	if err != nil {
		return "", errors.Wrap(err, "failed to perform OCR")
	}

	// Extract text from OCR response
	var ocrText string
	for _, textDetection := range response.Response.TextDetections {
		ocrText += *textDetection.DetectedText + "\n"
	}

	return ocrText, nil
}

// Close implements graceful shutdown
func (s *OCRService) Close() error {
	s.mu.Lock()
	defer s.mu.Unlock()
	
	// Add any cleanup logic here if needed
	return nil
}