package service

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"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}
}

// allowedModules 允许的模块列表
var allowedModules = map[string]string{
	"enterprise": "enterprise",
	"shop":       "shop",
	"food":       "food",
	"game":       "game",
	"app":        "app",
	"music":      "music",
	"common":     "common",
}

// Upload 上传文件，返回访问 URL
// module 指定上传到的模块（enterprise/shop/food/game/app/music/common）
// filename 原始文件名，contentType MIME 类型，fileSize 文件大小，reader 文件内容流
func (s *UploadService) Upload(module string, 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)
	}

	// 校验并规范化模块名
	mod := allowedModules[module]
	if mod == "" {
		mod = "common"
	}

	// 生成存储 key：模块名/日期/时间戳文件名
	ext := filepath.Ext(filename)
	key := fmt.Sprintf("%s/%s%s", mod, 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
}

// FileInfo 文件信息
type FileInfo struct {
	Name    string `json:"name"`
	URL     string `json:"url"`
	Size    int64  `json:"size"`
	ModTime string `json:"mod_time"`
	IsDir   bool   `json:"is_dir"`
}

// ListFiles 列出指定模块下的所有文件（递归遍历子目录）
func (s *UploadService) ListFiles(module string) ([]FileInfo, error) {
	mod := allowedModules[module]
	if mod == "" {
		mod = "common"
	}

	dirPath := filepath.Join(s.cfg.Upload.Path, mod)
	var result []FileInfo

	// 递归遍历
	err := filepath.Walk(dirPath, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return nil // 跳过错误
		}
		if info.IsDir() {
			return nil // 跳过目录
		}
		// 计算相对路径作为 key
		relPath, err := filepath.Rel(s.cfg.Upload.Path, path)
		if err != nil {
			return nil
		}
		relPath = filepath.ToSlash(relPath) // 统一用 /
		url := s.storage.GetURL(relPath)
		result = append(result, FileInfo{
			Name:    info.Name(),
			URL:     url,
			Size:    info.Size(),
			ModTime: info.ModTime().Format("2006-01-02 15:04:05"),
			IsDir:   false,
		})
		return nil
	})
	if err != nil {
		if os.IsNotExist(err) {
			return []FileInfo{}, nil
		}
		return nil, fmt.Errorf("读取目录失败: %w", err)
	}

	// 按修改时间倒序
	sort.Slice(result, func(i, j int) bool {
		return result[i].ModTime > result[j].ModTime
	})

	return result, nil
}

// DeleteFile 删除指定模块下的文件
// filename 可以是文件名或完整相对路径（如 2026/07/10/xxx.png）
func (s *UploadService) DeleteFile(module, filename string) error {
	mod := allowedModules[module]
	if mod == "" {
		mod = "common"
	}

	// 防止路径穿越：去掉模块名前缀（如果有的话）和 ..
	cleanName := strings.ReplaceAll(filename, "..", "")
	cleanName = strings.TrimPrefix(cleanName, mod+"/")
	cleanName = strings.TrimPrefix(cleanName, mod)

	key := filepath.Join(mod, cleanName)
	key = filepath.ToSlash(key)

	return s.storage.Delete(key)
}

// GetModules 返回所有支持的模块
func (s *UploadService) GetModules() []map[string]string {
	return []map[string]string{
		{"key": "enterprise", "label": "企业官网"},
		{"key": "shop", "label": "跨境电商"},
		{"key": "food", "label": "外卖平台"},
		{"key": "game", "label": "游戏平台"},
		{"key": "app", "label": "应用商店"},
		{"key": "music", "label": "音乐平台"},
		{"key": "common", "label": "公共资源"},
	}
}

// EnsureUploadDir 确保上传目录和各模块子目录存在
func (s *UploadService) EnsureUploadDir() {
	basePath := s.cfg.Upload.Path
	for mod := range allowedModules {
		os.MkdirAll(filepath.Join(basePath, mod), 0755)
	}
}

// sanitizeFilename 清理文件名中的危险字符
func sanitizeFilename(name string) string {
	name = strings.ReplaceAll(name, "..", "")
	name = strings.ReplaceAll(name, "/", "_")
	name = strings.ReplaceAll(name, "\\", "_")
	return name
}