package config

import (
	"encoding/json"
	"os"
	"path/filepath"
	"sync"
)

// Config 全局配置结构
type Config struct {
	mu       sync.RWMutex
	FTP      FTPConfig   `json:"ftp"`
	Web      WebConfig   `json:"web"`
	Admin    AdminConfig `json:"admin"`
	Database DBConfig    `json:"database"`
}

type FTPConfig struct {
	Host            string `json:"host"`
	Port            int    `json:"port"`
	PassivePortMin  int    `json:"passive_port_min"`
	PassivePortMax  int    `json:"passive_port_max"`
	RootDir         string `json:"root_dir"`
	EnableAnonymous bool   `json:"enable_anonymous"`
	MaxConnections  int    `json:"max_connections"`
	IdleTimeout     int    `json:"idle_timeout"` // 秒
}

type WebConfig struct {
	Host string `json:"host"`
	Port int    `json:"port"`
}

type AdminConfig struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

type DBConfig struct {
	Path string `json:"path"`
}

// DefaultConfig 返回默认配置
func DefaultConfig() *Config {
	return &Config{
		FTP: FTPConfig{
			Host:            "0.0.0.0",
			Port:            2121,
			PassivePortMin:  50000,
			PassivePortMax:  50100,
			RootDir:         "./ftp_root",
			EnableAnonymous: false,
			MaxConnections:  50,
			IdleTimeout:     300,
		},
		Web: WebConfig{
			Host: "0.0.0.0",
			Port: 8080,
		},
		Admin: AdminConfig{
			Username: "admin",
			Password: "admin123",
		},
		Database: DBConfig{
			Path: "./data/ftp.db",
		},
	}
}

// Load 从文件加载配置
func Load(path string) (*Config, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			cfg := DefaultConfig()
			if err := cfg.Save(path); err != nil {
				return nil, err
			}
			return cfg, nil
		}
		return nil, err
	}

	var cfg Config
	if err := json.Unmarshal(data, &cfg); err != nil {
		return nil, err
	}
	return &cfg, nil
}

// Save 保存配置到文件
func (c *Config) Save(path string) error {
	c.mu.RLock()
	defer c.mu.RUnlock()

	dir := filepath.Dir(path)
	if err := os.MkdirAll(dir, 0755); err != nil {
		return err
	}

	data, err := json.MarshalIndent(c, "", "  ")
	if err != nil {
		return err
	}

	return os.WriteFile(path, data, 0644)
}

// Get 安全获取配置副本
func (c *Config) Get() Config {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return *c
}

// Update 安全更新配置
func (c *Config) Update(fn func(cfg *Config)) {
	c.mu.Lock()
	defer c.mu.Unlock()
	fn(c)
}