package service

import (
	"fmt"
	"io"
	"path/filepath"
	"time"

	"gotest/internal/config"
	"gotest/internal/storage"
)

// UploadService 文件上传服务
type UploadService struct {
	storage storage.Storage
	cfg     *config.Config
}

// NewUploadService 创建上传服务实例
func NewUploadService(s storage.Storage, cfg *config.Config) *UploadService {
	return &UploadService{storage: s, cfg: cfg}
}

// Upload 上传文件，返回访问 URL
// filename 原始文件名（用于提取扩展名），contentType MIME 类型，fileSize 文件大小（字节），reader 文件内容流
func (s *UploadService) Upload(filename string, contentType string, fileSize int64, reader io.Reader) (string, error) {
	// 校验文件大小
	if fileSize > s.cfg.Upload.MaxSize {
		return "", fmt.Errorf("文件大小超过限制（最大 %d 字节）", s.cfg.Upload.MaxSize)
	}

	// 校验文件类型
	allowed := false
	for _, t := range s.cfg.Upload.AllowedTypes {
		if t == contentType {
			allowed = true
			break
		}
	}
	if !allowed {
		return "", fmt.Errorf("不支持的文件类型: %s", contentType)
	}

	// 生成存储 key：按日期分目录 + 时间戳文件名
	ext := filepath.Ext(filename)
	key := fmt.Sprintf("%s%s", time.Now().Format("2006/01/02/150405.000000"), ext)

	url, err := s.storage.Upload(key, reader, contentType)
	if err != nil {
		return "", fmt.Errorf("文件上传失败: %w", err)
	}

	return url, nil
}