package util

import (
	"context"
	"epic/internal/consts"
	"fmt"
	"io"
	"net/http"
	"os"
	"sync"
	"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"
)

var (
	s3Client *s3.Client
	s3Once   sync.Once
)

// getS3Client 获取S3客户端（单例模式）
func getS3Client() (*s3.Client, error) {
	var err error
	s3Once.Do(func() {
		accessKey := consts.S3AccessKey
		secretKey := consts.S3SecretKey
		region := consts.S3Region
		endpoint := consts.S3Endpoint

		if accessKey == "" || secretKey == "" || endpoint == "" {
			err = fmt.Errorf("missing S3 credentials or endpoint info in consts")
			return
		}

		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, cfgErr := config.LoadDefaultConfig(context.TODO(),
			config.WithCredentialsProvider(customProvider),
			config.WithEndpointResolverWithOptions(customResolver),
		)
		if cfgErr != nil {
			err = fmt.Errorf("failed to load S3 config: %w", cfgErr)
			return
		}
		cfg.Region = region
		s3Client = s3.NewFromConfig(cfg)
	})

	return s3Client, err
}

// 下载网络图片并上传到OSS，返回OSS路径
// imageUrl: 网络图片完整URL
// fileName: 上传到OSS的完整objectKey（如 epic/image/hero/herocode.jpg）
// 返回: OSS上的图片URL，或错误
func DownloadAndUploadToOSS(ctx context.Context, imageUrl string, fileName string) (string, error) {
	fmt.Printf("开始下载图片: %s\n", imageUrl)
	resp, err := http.Get(imageUrl)
	if err != nil {
		Error(ctx, "下载图片失败", imageUrl, err)
		return "", fmt.Errorf("failed to download image: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		Error(ctx, "下载图片状态码异常", imageUrl, resp.StatusCode)
		return "", fmt.Errorf("failed to download image: status %d", resp.StatusCode)
	}

	tmpFile, err := os.CreateTemp("", "ossimg-*.tmp")
	if err != nil {
		Error(ctx, "创建临时文件失败", err)
		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 {
		Error(ctx, "保存图片到临时文件失败", tmpFilePath, err)
		return "", fmt.Errorf("failed to save image to temp file: %w", err)
	}

	s3Client, err := getS3Client()
	if err != nil {
		Error(ctx, "获取S3客户端失败", err)
		return "", fmt.Errorf("failed to get S3 client: %w", err)
	}

	bucket := consts.S3Bucket
	if bucket == "" {
		Error(ctx, "S3 bucket未配置")
		return "", fmt.Errorf("missing S3 bucket info in consts")
	}

	tmpFile.Seek(0, io.SeekStart)

	fmt.Printf("开始上传到OSS: bucket=%s, key=%s\n", bucket, fileName)
	_, err = s3Client.PutObject(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucket),
		Key:    aws.String(fileName),
		Body:   tmpFile,
	})
	if err != nil {
		Error(ctx, "上传到S3失败", fileName, err)
		return "", fmt.Errorf("failed to upload to S3: %w", err)
	}

	ossUrl := fmt.Sprintf("%s/%s", consts.S3Endpoint, fileName)
	fmt.Printf("上传成功，OSS图片URL: %s\n", ossUrl)
	return ossUrl, nil
}

// RefreshOssPresignedUrlCache 批量刷新OSS图片的预签名URL到Redis缓存
// keys: OSS对象key（如 epic/hero/xxx.png）
// expire: 预签名URL有效期（建议30分钟-2小时）
func RefreshOssPresignedUrlCache(ctx context.Context, keys []string, expire time.Duration) error {
	s3Client, err := getS3Client()
	if err != nil {
		return err
	}
	bucket := consts.S3Bucket
	presignClient := s3.NewPresignClient(s3Client)

	for _, key := range keys {
		presignResult, err := presignClient.PresignGetObject(ctx, &s3.GetObjectInput{
			Bucket: &bucket,
			Key:    &key,
		}, func(opts *s3.PresignOptions) {
			opts.Expires = expire
		})
		if err != nil {
			Error(ctx, "生成预签名URL失败", key, err)
			continue
		}
		// 缓存到Redis，key可加前缀区分
		cacheKey := "oss:presignurl:" + key
		if err := RedisCache.Set(ctx, cacheKey, presignResult.URL, expire); err != nil {
			Error(ctx, "写入Redis失败", cacheKey, err)
		} else {
			// 打印预签名可访问地址
			fmt.Printf("预签名可访问地址: %s\n", presignResult.URL)
		}
	}
	return nil
}