package storage

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"

	"github.com/tencentyun/cos-go-sdk-v5"
	"gotest/internal/config"
)

// COSStorage 腾讯云 COS 对象存储实现
type COSStorage struct {
	client  *cos.Client
	baseURL string
}

// NewCOSStorage 创建 COS 存储实例
func NewCOSStorage(cfg *config.COSConfig) (*COSStorage, error) {
	// 拼接 bucket 访问地址: https://<bucket>.cos.<region>.myqcloud.com
	bucketURL := fmt.Sprintf("https://%s.cos.%s.myqcloud.com", cfg.Bucket, cfg.Region)
	u, err := url.Parse(bucketURL)
	if err != nil {
		return nil, fmt.Errorf("解析 COS bucket 地址失败: %w", err)
	}
	baseURL := &cos.BaseURL{BucketURL: u}
	client := cos.NewClient(baseURL, &http.Client{
		Transport: &cos.AuthorizationTransport{
			SecretID:  cfg.SecretID,
			SecretKey: cfg.SecretKey,
		},
	})
	return &COSStorage{
		client:  client,
		baseURL: cfg.BaseURL,
	}, nil
}

// Upload 上传文件到 COS
func (s *COSStorage) Upload(key string, reader io.Reader, contentType string) (string, error) {
	ctx := context.Background()
	opt := &cos.ObjectPutOptions{
		ObjectPutHeaderOptions: &cos.ObjectPutHeaderOptions{
			ContentType: contentType,
		},
	}
	_, err := s.client.Object.Put(ctx, key, reader, opt)
	if err != nil {
		return "", fmt.Errorf("上传文件到 COS 失败: %w", err)
	}
	return s.GetURL(key), nil
}

// Delete 删除 COS 中的文件
func (s *COSStorage) Delete(key string) error {
	ctx := context.Background()
	_, err := s.client.Object.Delete(ctx, key, nil)
	return err
}

// GetURL 获取 COS 文件访问 URL
// 优先使用 BaseURL 拼接，为空时回退到 bucket 地址
func (s *COSStorage) GetURL(key string) string {
	base := strings.TrimRight(s.baseURL, "/")
	if base == "" {
		base = strings.TrimRight(s.client.BaseURL.BucketURL.String(), "/")
	}
	return base + "/" + key
}