package config

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

	"github.com/spf13/viper"
)

// Config 全局配置结构
type Config struct {
	Server   ServerConfig   `mapstructure:"server"`
	Database DatabaseConfig `mapstructure:"database"`
	Storage  StorageConfig  `mapstructure:"storage"`
	Admin    AdminConfig    `mapstructure:"admin"`
	JWT      JWTConfig      `mapstructure:"jwt"`
	Log      LogConfig      `mapstructure:"log"`
}

type ServerConfig struct {
	Port   string `mapstructure:"port"`
	Mode   string `mapstructure:"mode"` // debug / release / test
	Domain string `mapstructure:"domain"` // 生产环境域名
}

type DatabaseConfig struct {
	Driver string `mapstructure:"driver"`
	Source string `mapstructure:"source"`
}

type StorageConfig struct {
	Root    string `mapstructure:"root"`    // 文件存储根目录
	Backups string `mapstructure:"backups"` // 备份目录
}

type AdminConfig struct {
	Username string `mapstructure:"username"`
	Password string `mapstructure:"password"`
	Email    string `mapstructure:"email"`
	Role     string `mapstructure:"role"`
}

type JWTConfig struct {
	Secret string `mapstructure:"secret"`
	Expire string `mapstructure:"expire"` // 如 24h
}

type LogConfig struct {
	Level   string `mapstructure:"level"`    // debug/info/warn/error
	Dir     string `mapstructure:"dir"`      // 日志文件目录，为空则仅输出到控制台
	MaxDays int    `mapstructure:"max_days"` // 日志保留天数
}

var cfg *Config

// Load 加载配置文件，不存在时使用默认值并生成示例配置
func Load(path string) (*Config, error) {
	v := viper.New()
	setDefaults(v)

	// 设置环境变量前缀
	v.SetEnvPrefix("FSS")
	v.AutomaticEnv()

	if path == "" {
		path = "config.yaml"
	}

	// 尝试加载配置文件
	if _, err := os.Stat(path); err == nil {
		v.SetConfigFile(path)
		if err := v.ReadInConfig(); err != nil {
			return nil, fmt.Errorf("读取配置文件失败: %w", err)
		}
	} else {
		// 配置文件不存在时生成一份默认配置
		_ = v.SafeWriteConfigAs(path)
	}

	c := &Config{}
	if err := v.Unmarshal(c); err != nil {
		return nil, fmt.Errorf("解析配置失败: %w", err)
	}
	cfg = c
	return c, nil
}

func setDefaults(v *viper.Viper) {
	v.SetDefault("server.port", "8100")
	v.SetDefault("server.mode", "debug")
	v.SetDefault("server.domain", "https://file.yunzer.cn")

	v.SetDefault("database.driver", "sqlite")
	v.SetDefault("database.source", "./storage/data.db")

	v.SetDefault("storage.root", "./storage/files")
	v.SetDefault("storage.backups", "./storage/backups")

	v.SetDefault("admin.username", "admin")
	v.SetDefault("admin.password", "admin123")
	v.SetDefault("admin.email", "admin@example.com")
	v.SetDefault("admin.role", "super_admin")

	v.SetDefault("jwt.secret", "please-change-this-secret-key")
	v.SetDefault("jwt.expire", "24h")

	v.SetDefault("log.level", "info")
	v.SetDefault("log.dir", "./storage/logs")
	v.SetDefault("log.max_days", 7)
}

// Get 获取全局配置
func Get() *Config {
	if cfg == nil {
		c, _ := Load("")
		cfg = c
	}
	return cfg
}

// EnsureDirs 确保所有存储相关目录存在
func (c *Config) EnsureDirs() error {
	dirs := []string{
		filepath.Dir(c.Database.Source),
		c.Storage.Root,
		c.Storage.Backups,
		c.Log.Dir,
	}
	for _, d := range dirs {
		if d == "" {
			continue
		}
		if err := os.MkdirAll(d, 0o755); err != nil {
			return fmt.Errorf("创建目录 %s 失败: %w", d, err)
		}
	}
	return nil
}