package repository

import (
	"backend/pkg/fileStorage/config"
	s3Storage "backend/pkg/fileStorage/domain/aws"
	"backend/pkg/fileStorage/domain/repository"
	"backend/pkg/fileStorage/utils"
	errs "backend/pkg/library/errors"
	"bytes"
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
	"path"
	"strings"
	"time"

	"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"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
)

type AwsS3FileStorageRepositoryParam struct {
	Conf   *config.Config
	Logger errs.Logger
}

type AwsS3FileStorageRepository struct {
	AwsS3FileStorageRepositoryParam
}

func MustAwsS3FileStorageRepo(param AwsS3FileStorageRepositoryParam) repository.FileStorageRepository {
	return &AwsS3FileStorageRepository{
		param,
	}
}

// 每次上傳都用一個新的 Session
func (repo *AwsS3FileStorageRepository) getAwsSession() (*session.Session, error) {
	conf := &aws.Config{
		Region: aws.String(repo.Conf.AmazonS3Settings.Region),
		Credentials: credentials.NewStaticCredentials(
			repo.Conf.AmazonS3Settings.AccessKey,
			repo.Conf.AmazonS3Settings.SecretKey,
			"",
		),
	}

	awsSession, err := session.NewSession(conf)
	if err != nil {
		return nil, err
	}

	return awsSession, nil
}

func (repo *AwsS3FileStorageRepository) Move(_ context.Context, objectPath string, destinationPath string) error {
	awsSession, _ := repo.getAwsSession()
	svc := s3.New(awsSession)

	copyObjectInput := &s3.CopyObjectInput{
		Key:        aws.String(destinationPath),
		Bucket:     aws.String(repo.Conf.AmazonS3Settings.Bucket),
		CopySource: aws.String(path.Join(repo.Conf.AmazonS3Settings.Bucket, objectPath)),
	}
	deleteObjectInput := &s3.DeleteObjectInput{
		Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:    aws.String(objectPath),
	}
	if _, err := svc.CopyObject(copyObjectInput); err != nil {
		return err
	}
	if _, err := svc.DeleteObject(deleteObjectInput); err != nil {
		return err
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) Delete(_ context.Context, objectPath string) error {
	awsSession, _ := repo.getAwsSession()
	svc := s3.New(awsSession)

	deleteObjectInput := &s3.DeleteObjectInput{
		Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:    aws.String(objectPath),
	}
	deleteObjOutput, err := svc.DeleteObject(deleteObjectInput)
	if err != nil {
		return err
	}

	if deleteObjOutput.DeleteMarker != nil && deleteObjOutput.VersionId != nil {
		repo.Logger.Info(fmt.Sprintf("s3 - delete object, delete marker: %t, VersionId: %s", *deleteObjOutput.DeleteMarker, *deleteObjOutput.VersionId))
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) Exists(_ context.Context, objectPath string) (bool, error) {
	awsSession, _ := repo.getAwsSession()
	downloader := s3.New(awsSession)

	_, err := downloader.HeadObject(&s3.HeadObjectInput{
		Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:    aws.String(objectPath),
	})

	if err != nil {
		return false, err
	}

	return true, nil
}

func (repo *AwsS3FileStorageRepository) DeleteDirectory(_ context.Context, directoryPath string) error {
	if strings.HasPrefix(directoryPath, "/") {
		directoryPath = directoryPath[1:]
	}

	awsSession, _ := repo.getAwsSession()
	svc := s3.New(awsSession)

	listObjectsInput := &s3.ListObjectsV2Input{
		Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Prefix: aws.String(directoryPath),
	}
	listObjectsOutput, err := svc.ListObjectsV2(listObjectsInput)
	if err != nil {
		return err
	}

	for _, object := range listObjectsOutput.Contents {
		deleteObjectInput := &s3.DeleteObjectInput{
			Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
			Key:    object.Key,
		}
		go func(inp *s3.DeleteObjectInput) {
			_, _ = svc.DeleteObject(inp)
		}(deleteObjectInput)
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) UploadWithTTL(_ context.Context, content io.Reader, objectPath string, expires *time.Time) error {
	awsSession, _ := repo.getAwsSession()
	uploader := s3manager.NewUploader(awsSession)

	_, err := uploader.Upload(&s3manager.UploadInput{
		Bucket:             aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:                aws.String(objectPath),
		Body:               content,
		ACL:                aws.String(s3Storage.S3AclSetting),
		ContentDisposition: aws.String("attachment"),
		Expires:            expires,
	})

	if err != nil {
		return err
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) UploadFromData(_ context.Context, data []byte, objectPath string, contentType string) error {
	reader := bytes.NewReader(data)
	awsSession, _ := repo.getAwsSession()
	uploader := s3manager.NewUploader(awsSession)

	_, err := uploader.Upload(&s3manager.UploadInput{
		Bucket:      aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:         aws.String(objectPath),
		Body:        reader,
		ACL:         aws.String(s3Storage.S3AclSetting),
		ContentType: aws.String(contentType),
	})

	if err != nil {
		return err
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) UploadFromPath(_ context.Context, localFilePath string, objectPath string) error {
	file, err := os.Open(localFilePath)
	if err != nil {
		return err
	}
	defer file.Close()

	fileInfo, _ := file.Stat()
	buffer := make([]byte, fileInfo.Size())
	_, _ = file.Read(buffer)

	awsSession, err := repo.getAwsSession()
	if err != nil {
		return err
	}

	uploader := s3manager.NewUploader(awsSession)

	_, err = uploader.Upload(&s3manager.UploadInput{
		Bucket:             aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:                aws.String(objectPath),
		Body:               bytes.NewReader(buffer),
		ContentType:        aws.String(http.DetectContentType(buffer)),
		ACL:                aws.String(s3Storage.S3AclSetting),
		ContentDisposition: aws.String("attachment"),
	})

	if err != nil {
		return err
	}

	return nil
}

func (repo *AwsS3FileStorageRepository) GetPublicURL(_ context.Context, objectPath string) string {
	dirPart := strings.Split(objectPath, string(os.PathSeparator))

	return utils.URLJoin(repo.Conf.AmazonS3Settings.CloudFrontURI, dirPart...)
}

func (repo *AwsS3FileStorageRepository) Download(_ context.Context, objectPath string) ([]byte, error) {
	awsSession, _ := repo.getAwsSession()
	downloader := s3manager.NewDownloader(awsSession, func(d *s3manager.Downloader) {
		d.PartSize = 64 * 1024 * 1024 // 每部分 64MB
		d.Concurrency = 4
		d.BufferProvider = s3manager.NewPooledBufferedWriterReadFromProvider(1024 * 1024 * 8)
	})

	buff := &aws.WriteAtBuffer{}
	_, err := downloader.Download(buff, &s3.GetObjectInput{
		Bucket: aws.String(repo.Conf.AmazonS3Settings.Bucket),
		Key:    aws.String(objectPath),
	})
	data := buff.Bytes()
	if err != nil {
		return nil, err
	}

	return data, nil
}