package config

import (
	"fmt"
	"strings"

	"git.hujye.com/infrastructure/go-web-gin/env"
	"github.com/spf13/viper"
)

var (
	globalConfig  *Config
	viperInstance *viper.Viper
)

// Config represents the application configuration
type Config struct {
	Server ServerConfig `mapstructure:"server"`
	App    AppConfig    `mapstructure:"app"`
	Log    LogConfig    `mapstructure:"log"`
}

// ServerConfig represents server configuration
type ServerConfig struct {
	Port int    `mapstructure:"port"`
	Host string `mapstructure:"host"`
	Mode string `mapstructure:"mode"` // debug, release, test
}

// AppConfig represents application configuration
type AppConfig struct {
	Name        string `mapstructure:"name"`
	Environment string `mapstructure:"environment"`
	LogLevel    string `mapstructure:"log_level"`
}

// LogConfig represents log configuration
type LogConfig struct {
	OutputToFile bool   `mapstructure:"output_to_file"`
	Filename     string `mapstructure:"filename"`
	MaxSize      int    `mapstructure:"max_size"`
	MaxBackups   int    `mapstructure:"max_backups"`
	MaxAge       int    `mapstructure:"max_age"`
	Compress     bool   `mapstructure:"compress"`
}

// Load loads configuration from environment variable CFG_PATH
// Default path is config/config.yml
func Load() (*Config, error) {
	v := viper.New()
	v.SetConfigFile(env.GetCfgPath())
	v.SetConfigType("yaml")

	// Read environment variables
	v.AutomaticEnv()
	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))

	// Read config file
	if err := v.ReadInConfig(); err != nil {
		return nil, fmt.Errorf("failed to read config file: %w", err)
	}

	var cfg Config
	if err := v.Unmarshal(&cfg); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	globalConfig = &cfg
	viperInstance = v
	return &cfg, nil
}

// Get returns the global configuration
// Must call Load first
func Get() *Config {
	if globalConfig == nil {
		// Return default config if not loaded
		return &Config{
			Server: ServerConfig{
				Port: 8080,
				Host: "0.0.0.0",
				Mode: "debug",
			},
			App: AppConfig{
				Name:        "go-web-gin",
				Environment: string(env.Local),
				LogLevel:    "info",
			},
			Log: LogConfig{
				OutputToFile: true,
				Filename:     "logs/app.log",
				MaxSize:      100,
				MaxBackups:   3,
				MaxAge:       28,
				Compress:     true,
			},
		}
	}
	return globalConfig
}

// GetAddr returns the server address (host:port)
func (c *Config) GetAddr() string {
	return fmt.Sprintf("%s:%d", c.Server.Host, c.Server.Port)
}

// IsDebug returns true if server mode is debug
func (c *Config) IsDebug() bool {
	return c.Server.Mode == "debug"
}

// IsRelease returns true if server mode is release
func (c *Config) IsRelease() bool {
	return c.Server.Mode == "release"
}

// GetString returns a custom string config value by key
// Supports dot notation for nested keys, e.g. "database.host"
func GetString(key string) string {
	if viperInstance != nil {
		return viperInstance.GetString(key)
	}
	return ""
}

// GetInt returns a custom int config value by key
func GetInt(key string) int {
	if viperInstance != nil {
		return viperInstance.GetInt(key)
	}
	return 0
}

// GetBool returns a custom bool config value by key
func GetBool(key string) bool {
	if viperInstance != nil {
		return viperInstance.GetBool(key)
	}
	return false
}

// GetStringSlice returns a custom string slice config value by key
func GetStringSlice(key string) []string {
	if viperInstance != nil {
		return viperInstance.GetStringSlice(key)
	}
	return nil
}

// GetValue returns a custom config value of any type by key
func GetValue(key string) any {
	if viperInstance != nil {
		return viperInstance.Get(key)
	}
	return nil
}

// Viper returns the underlying viper instance for advanced usage
func Viper() *viper.Viper {
	return viperInstance
}