package config

import (
	"fmt"
	"strings"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/config"
	"github.com/spf13/viper"
)

const (
	Separator = "."

	// EnvSeparator is a section separator in ENV variables.
	EnvSeparator = "_"
)

func CreateViper(opts ...Option) (*viper.Viper, *Opts) {
	v := viper.New()

	o := DefaultOpts()
	for i := range opts {
		opts[i](o)
	}

	if o.EnvPrefix != "" {
		v.SetEnvPrefix(o.EnvPrefix)
		v.AutomaticEnv()
		v.SetEnvKeyReplacer(strings.NewReplacer(Separator, EnvSeparator))
	}

	if o.Path != "" {
		v.SetConfigFile(o.Path)

		err := v.ReadInConfig()
		if err != nil {
			panic(fmt.Errorf("failed to read config: %w", err))
		}
	}

	if o.ConfigDir != "" {
		if err := config.ReadConfigDir(v, o.ConfigDir); err != nil {
			panic(fmt.Errorf("failed to read config dir: %w", err))
		}
	}

	return v, o
}

func ReloadViper(v *viper.Viper, o Opts) error {
	if o.Path != "" {
		err := v.ReadInConfig()
		if err != nil {
			return fmt.Errorf("rereading configuration file: %w", err)
		}
	}

	if o.ConfigDir != "" {
		if err := config.ReadConfigDir(v, o.ConfigDir); err != nil {
			return fmt.Errorf("rereading configuration dir: %w", err)
		}
	}

	return nil
}