package service

import (
	"bytes"
	"fmt"
	"io"

	"sync"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"tencent_ocr/pkg/errors"
)

type UploadService struct {
	s3Client     *s3.S3
	bucket       string
	customDomain string
	mu           sync.RWMutex
}

func NewUploadService(accessKey, secretKey, bucket, endpoint, customDomain string) (*UploadService, error) {
	sess, err := session.NewSession(&aws.Config{
		Endpoint:    aws.String(endpoint),
		Region:      aws.String("auto"),
		Credentials: credentials.NewStaticCredentials(accessKey, secretKey, ""),
	})
	if err != nil {
		return nil, errors.Wrap(err, "failed to create S3 session")
	}

	return &UploadService{
		s3Client:     s3.New(sess),
		bucket:       bucket,
		customDomain: customDomain,
	}, nil
}

func (s *UploadService) UploadFile(file io.Reader, fileName, contentType string) (string, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()

	// Read file content
	fileBytes, err := io.ReadAll(file)
	if err != nil {
		return "", errors.Wrap(err, "failed to read file")
	}

	// Upload file to R2
	_, err = s.s3Client.PutObject(&s3.PutObjectInput{
		Bucket:      aws.String(s.bucket),
		Key:         aws.String(fileName),
		Body:        bytes.NewReader(fileBytes),
		ContentType: aws.String(contentType),
		ACL:        aws.String("public-read"),
	})
	if err != nil {
		return "", errors.Wrap(err, "failed to upload file to R2")
	}

	// Generate file URL
	imageURL := fmt.Sprintf("https://%s/%s", s.customDomain, fileName)
	return imageURL, nil
}

func (s *UploadService) IsValidFileType(contentType string) bool {
	allowedTypes := []string{
		"image/jpeg",
		"image/png",
		"image/gif",
		"image/bmp",
		"image/tiff",
		"image/webp",
	}
	for _, t := range allowedTypes {
		if contentType == t {
			return true
		}
	}
	return false
}

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