package storage

import (
	"context"
	"fmt"
	"io"
	"path"
	"strings"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
	"kra/internal/biz"
	"kra/internal/conf"
)

type aliyunStorage struct {
	bucket          *oss.Bucket
	baseURL, prefix string
}

func newAliyunStorage(config *conf.AdminBackend_ObjectStore) (biz.FileStorage, error) {
	if config == nil || config.Endpoint == "" || config.Bucket == "" || config.AccessKey == "" || config.SecretKey == "" {
		return nil, fmt.Errorf("aliyun-oss storage configuration is incomplete")
	}
	client, err := oss.New(config.Endpoint, config.AccessKey, config.SecretKey)
	if err != nil {
		return nil, err
	}
	bucket, err := client.Bucket(config.Bucket)
	if err != nil {
		return nil, err
	}
	return &aliyunStorage{bucket: bucket, baseURL: strings.TrimSuffix(config.BaseUrl, "/"), prefix: strings.Trim(config.PathPrefix, "/")}, nil
}
func (s *aliyunStorage) key(name string) string {
	if s.prefix == "" {
		return strings.TrimPrefix(name, "/")
	}
	return path.Join(s.prefix, strings.TrimPrefix(name, "/"))
}
func (s *aliyunStorage) unkey(key string) string {
	return strings.TrimPrefix(strings.TrimPrefix(key, s.prefix), "/")
}
func (s *aliyunStorage) file(key string, size int64) *biz.StoredFile {
	name := s.unkey(key)
	url := s.baseURL + "/" + key
	return &biz.StoredFile{Name: path.Base(name), Path: name, URL: url, Size: size}
}
func (s *aliyunStorage) Put(_ context.Context, name string, reader io.Reader) (*biz.StoredFile, error) {
	key := s.key(name)
	if err := s.bucket.PutObject(key, reader); err != nil {
		return nil, err
	}
	meta, err := s.bucket.GetObjectDetailedMeta(key)
	if err != nil {
		return nil, err
	}
	size := int64(0)
	_, _ = fmt.Sscan(meta.Get("Content-Length"), &size)
	return s.file(key, size), nil
}
func (s *aliyunStorage) Open(_ context.Context, name string) (io.ReadCloser, error) {
	return s.bucket.GetObject(s.key(name))
}
func (s *aliyunStorage) Delete(_ context.Context, name string) error {
	return s.bucket.DeleteObject(s.key(name))
}
func (s *aliyunStorage) Compose(ctx context.Context, names []string, destination string) (*biz.StoredFile, string, error) {
	return composeFiles(ctx, s, names, destination)
}
func (s *aliyunStorage) DeletePrefix(ctx context.Context, prefix string) error {
	cursor := ""
	for {
		items, next, more, err := s.List(ctx, prefix, cursor, 1000)
		if err != nil {
			return err
		}
		for _, item := range items {
			if err = s.Delete(ctx, item.Path); err != nil {
				return err
			}
		}
		if !more {
			return nil
		}
		cursor = next
	}
}
func (s *aliyunStorage) List(_ context.Context, prefix, cursor string, limit int) ([]*biz.StoredFile, string, bool, error) {
	if limit < 1 || limit > 1000 {
		limit = 100
	}
	result, err := s.bucket.ListObjects(oss.Prefix(s.key(prefix)), oss.Marker(cursor), oss.MaxKeys(limit))
	if err != nil {
		return nil, "", false, err
	}
	items := make([]*biz.StoredFile, 0, len(result.Objects))
	for _, object := range result.Objects {
		item := s.file(object.Key, object.Size)
		item.LastModified = object.LastModified
		items = append(items, item)
	}
	next := ""
	if result.IsTruncated {
		next = result.NextMarker
	}
	return items, next, result.IsTruncated, nil
}