// Copyright (c) 2024-2026 Tencent Zhuque Lab. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Requirement: Any integration or derivative work must explicitly attribute
// Tencent Zhuque Lab (https://github.com/Tencent/AI-Infra-Guard) in its
// documentation or user interface, as detailed in the NOTICE file.

package websocket

import (
	"fmt"
	"os"
	"path/filepath"
)

// FileUploadConfig 文件上传配置
type FileUploadConfig struct {
	UploadDir string `json:"upload_dir"` // 文件上传目录
}

// DefaultFileUploadConfig 默认文件上传配置
func DefaultFileUploadConfig() *FileUploadConfig {
	return &FileUploadConfig{
		UploadDir: "./uploads",
	}
}

// LoadFileUploadConfigFromEnv 从环境变量加载文件上传配置
func LoadFileUploadConfigFromEnv() *FileUploadConfig {
	config := DefaultFileUploadConfig()

	// 从环境变量读取配置
	if uploadDir := os.Getenv("FILE_UPLOAD_DIR"); uploadDir != "" {
		config.UploadDir = uploadDir
	}

	return config
}

// ValidateConfig 验证配置的有效性
func (c *FileUploadConfig) ValidateConfig() error {
	// 检查存储目录是否存在或可以创建
	if err := c.ensureUploadDir(); err != nil {
		return fmt.Errorf("存储目录配置错误: %v", err)
	}
	return nil
}

// ensureUploadDir 确保上传目录存在并且可写
func (c *FileUploadConfig) ensureUploadDir() error {
	// 获取绝对路径
	absPath, err := filepath.Abs(c.UploadDir)
	if err != nil {
		return fmt.Errorf("无法解析存储路径: %v", err)
	}

	// 检查目录是否存在
	if _, err := os.Stat(absPath); os.IsNotExist(err) {
		// 目录不存在，尝试创建
		if err := os.MkdirAll(absPath, 0755); err != nil {
			return fmt.Errorf("无法创建存储目录 %s: %v", absPath, err)
		}
	}

	// 检查目录是否可写
	if err := c.checkDirWritable(absPath); err != nil {
		return fmt.Errorf("存储目录不可写: %v", err)
	}

	// 更新为绝对路径
	c.UploadDir = absPath
	return nil
}

// checkDirWritable 检查目录是否可写
func (c *FileUploadConfig) checkDirWritable(dir string) error {
	// 尝试创建一个临时文件来测试写权限
	testFile := filepath.Join(dir, ".test_write")
	file, err := os.Create(testFile)
	if err != nil {
		return err
	}
	defer func() {
		file.Close()
		os.Remove(testFile) // 清理测试文件
	}()
	return nil
}

// GetFileURL 根据文件名生成完整的文件访问URL
func (c *FileUploadConfig) GetFileURL(fileName string) string {
	return fileName
}