package storage

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
	"github.com/drama-generator/backend/pkg/config"
)

// OssStorage 阿里云 OSS 存储实现
type OssStorage struct {
	client       *oss.Client
	bucket       *oss.Bucket
	bucketName   string
	customDomain string
	endpoint     string
}

// NewOssStorage 创建 OSS 存储实例
func NewOssStorage(cfg *config.OssConfig) (*OssStorage, error) {
	if cfg.Endpoint == "" || cfg.AccessKeyID == "" || cfg.AccessKeySecret == "" || cfg.BucketName == "" {
		return nil, fmt.Errorf("OSS configuration is incomplete")
	}

	client, err := oss.New(cfg.Endpoint, cfg.AccessKeyID, cfg.AccessKeySecret)
	if err != nil {
		return nil, fmt.Errorf("failed to create OSS client: %w", err)
	}

	bucket, err := client.Bucket(cfg.BucketName)
	if err != nil {
		return nil, fmt.Errorf("failed to get OSS bucket: %w", err)
	}

	return &OssStorage{
		client:       client,
		bucket:       bucket,
		bucketName:   cfg.BucketName,
		customDomain: cfg.CustomDomain,
		endpoint:     cfg.Endpoint,
	}, nil
}

// Upload 上传文件到 OSS
func (s *OssStorage) Upload(localPath, category string) (string, error) {
	// 读取本地文件
	file, err := os.Open(localPath)
	if err != nil {
		return "", fmt.Errorf("failed to open file: %w", err)
	}
	defer file.Close()

	// 生成 OSS 对象键
	ext := filepath.Ext(localPath)
	timestamp := time.Now().Format("20060102_150405_000")
	objectKey := fmt.Sprintf("%s/%s%s", category, timestamp, ext)

	// 上传到 OSS
	err = s.bucket.PutObject(objectKey, file)
	if err != nil {
		return "", fmt.Errorf("failed to upload to OSS: %w", err)
	}

	// 构建访问 URL
	url := s.GetURL(objectKey)
	return url, nil
}

// UploadWithFilename 使用指定文件名上传文件到 OSS
func (s *OssStorage) UploadWithFilename(localPath, category, filename string) (string, error) {
	file, err := os.Open(localPath)
	if err != nil {
		return "", fmt.Errorf("failed to open file: %w", err)
	}
	defer file.Close()

	objectKey := fmt.Sprintf("%s/%s", category, filename)

	err = s.bucket.PutObject(objectKey, file)
	if err != nil {
		return "", fmt.Errorf("failed to upload to OSS: %w", err)
	}

	return s.GetURL(objectKey), nil
}

// GetURL 获取 OSS 对象的访问 URL
func (s *OssStorage) GetURL(objectKey string) string {
	if s.customDomain != "" {
		// 使用自定义域名（CDN）
		domain := strings.TrimSuffix(s.customDomain, "/")
		if !strings.HasPrefix(domain, "http") {
			domain = "https://" + domain
		}
		return fmt.Sprintf("%s/%s", domain, objectKey)
	}

	// 使用默认 OSS 域名
	return fmt.Sprintf("https://%s.%s/%s", s.bucketName, s.endpoint, objectKey)
}

// Delete 删除 OSS 对象
func (s *OssStorage) Delete(objectKey string) error {
	err := s.bucket.DeleteObject(objectKey)
	if err != nil {
		return fmt.Errorf("failed to delete OSS object: %w", err)
	}
	return nil
}

// IsConfigured 检查 OSS 是否已配置
func IsOssConfigured(cfg *config.OssConfig) bool {
	return cfg != nil &&
		cfg.Endpoint != "" &&
		cfg.AccessKeyID != "" &&
		cfg.AccessKeySecret != "" &&
		cfg.BucketName != ""
}