package aliyun

import (
	"context"
	"errors"
	"fmt"
	"io"
	"strings"

	"git.apinb.com/ops/files/internal/storage"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
)

// Open 返回对象存储中的只读内容流。
func (c *Client) Open(ctx context.Context, objectKey string, byteRange *storage.ByteRange) (io.ReadCloser, error) {
	if strings.TrimSpace(objectKey) == "" {
		return nil, fmt.Errorf("对象键不能为空")
	}
	request := &oss.GetObjectRequest{
		Bucket: oss.Ptr(c.bucket),
		Key:    oss.Ptr(objectKey),
	}
	if byteRange != nil {
		rangeHeader := fmt.Sprintf("bytes=%d-%d", byteRange.Start, byteRange.End)
		request.Range = &rangeHeader
	}
	result, err := c.client.GetObject(ctx, request)
	if err != nil {
		return nil, fmt.Errorf("读取对象: %w", err)
	}
	if result == nil || result.Body == nil {
		return nil, fmt.Errorf("对象内容为空")
	}
	return result.Body, nil
}

func (c *Client) Stat(ctx context.Context, objectKey string) (storage.ObjectInfo, error) {
	if strings.TrimSpace(objectKey) == "" {
		return storage.ObjectInfo{}, fmt.Errorf("对象键不能为空")
	}

	result, err := c.client.GetObjectMeta(ctx, &oss.GetObjectMetaRequest{
		Bucket: oss.Ptr(c.bucket),
		Key:    oss.Ptr(objectKey),
	})
	if err != nil {
		var serviceError *oss.ServiceError
		if errors.As(err, &serviceError) && serviceError.Code == "NoSuchKey" {
			return storage.ObjectInfo{}, storage.ErrObjectNotFound
		}
		return storage.ObjectInfo{}, fmt.Errorf("查询对象元数据: %w", err)
	}
	if result == nil {
		return storage.ObjectInfo{}, fmt.Errorf("对象元数据为空")
	}
	if result.ContentLength < 0 {
		return storage.ObjectInfo{}, fmt.Errorf("对象大小无效: %d", result.ContentLength)
	}
	if result.ETag == nil {
		return storage.ObjectInfo{}, fmt.Errorf("对象 ETag 缺失")
	}
	etag := strings.TrimSpace(strings.Trim(strings.TrimSpace(*result.ETag), "\""))
	if etag == "" {
		return storage.ObjectInfo{}, fmt.Errorf("对象 ETag 无效")
	}
	if result.LastModified == nil || result.LastModified.IsZero() {
		return storage.ObjectInfo{}, fmt.Errorf("对象最后修改时间缺失")
	}

	return storage.ObjectInfo{
		Size:         result.ContentLength,
		StorageETag:  etag,
		LastModified: *result.LastModified,
	}, nil
}

func (c *Client) Delete(ctx context.Context, objectKey string) error {
	if strings.TrimSpace(objectKey) == "" {
		return fmt.Errorf("对象键不能为空")
	}

	_, err := c.client.DeleteObject(ctx, &oss.DeleteObjectRequest{
		Bucket: oss.Ptr(c.bucket),
		Key:    oss.Ptr(objectKey),
	})
	if err != nil {
		return fmt.Errorf("删除对象: %w", err)
	}

	return nil
}

func (c *Client) Status(ctx context.Context) (storage.RuntimeStatus, error) {
	_, err := c.client.ListObjectsV2(ctx, &oss.ListObjectsV2Request{Bucket: oss.Ptr(c.bucket), MaxKeys: 1})
	if err != nil {
		return storage.RuntimeStatus{Provider: c.Provider(), Container: c.Container()}, fmt.Errorf("检查 OSS 存储状态: %w", err)
	}
	return storage.RuntimeStatus{Provider: c.Provider(), Container: c.Container(), Writable: true}, nil
}