package util

import (
	"context"
	"epic/internal/consts"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/credentials"
	"github.com/aws/aws-sdk-go-v2/service/s3"
)

// DownloadAndUploadToOSS 下载网络图片并上传到OSS，返回OSS路径
// imageUrl: 网络图片完整URL
// 返回: OSS上的图片URL，或错误
func DownloadAndUploadToOSS(ctx context.Context, imageUrl string) (string, error) {
	// 1. 下载 imageUrl 到本地临时文件
	resp, err := http.Get(imageUrl)
	if err != nil {
		return "", fmt.Errorf("failed to download image: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("failed to download image: status %d", resp.StatusCode)
	}

	tmpFile, err := os.CreateTemp("", "ossimg-*.tmp")
	if err != nil {
		return "", fmt.Errorf("failed to create temp file: %w", err)
	}
	tmpFilePath := tmpFile.Name()
	defer func() {
		tmpFile.Close()
		os.Remove(tmpFilePath)
	}()

	_, err = io.Copy(tmpFile, resp.Body)
	if err != nil {
		return "", fmt.Errorf("failed to save image to temp file: %w", err)
	}

	// 2. 上传临时文件到OSS，获取OSS路径
	accessKey := consts.S3AccessKey
	secretKey := consts.S3SecretKey
	bucket := consts.S3Bucket
	region := consts.S3Region
	endpoint := consts.S3Endpoint
	if accessKey == "" || secretKey == "" || bucket == "" || endpoint == "" {
		return "", fmt.Errorf("missing S3 credentials or bucket info in consts")
	}

	customResolver := aws.EndpointResolverWithOptionsFunc(func(service, region string, options ...interface{}) (aws.Endpoint, error) {
		if service == s3.ServiceID {
			return aws.Endpoint{URL: endpoint}, nil
		}
		return aws.Endpoint{}, fmt.Errorf("unknown service requested")
	})
	customProvider := credentials.NewStaticCredentialsProvider(accessKey, secretKey, "")
	cfg, err := config.LoadDefaultConfig(ctx,
		config.WithCredentialsProvider(customProvider),
		config.WithEndpointResolverWithOptions(customResolver),
	)
	if err != nil {
		return "", fmt.Errorf("failed to load S3 config: %w", err)
	}
	cfg.Region = region
	s3Client := s3.NewFromConfig(cfg)

	// 生成唯一的 object key
	fileName := filepath.Base(tmpFilePath)
	objectKey := fmt.Sprintf("images/%d_%s", time.Now().UnixNano(), fileName)

	tmpFile.Seek(0, io.SeekStart)
	_, err = tmpFile.Stat()
	if err != nil {
		return "", fmt.Errorf("failed to stat temp file: %w", err)
	}

	// 上传
	_, err = s3Client.PutObject(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(objectKey),
		Body:   tmpFile,
	})
	if err != nil {
		return "", fmt.Errorf("failed to upload to S3: %w", err)
	}

	// 4. 返回OSS路径（拼接URL）
	ossUrl := fmt.Sprintf("%s/%s/%s", endpoint, bucket, objectKey)
	return ossUrl, nil
}