package config

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
)

var validUUID = regexp.MustCompile("^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$")

// Read the configuration file
func Read(configFile string) (*Configuration, error) {

	fc := &Configuration{}

	f, err := os.Open(configFile)
	if err != nil {
		return nil, fmt.Errorf("Can not open file %v: %v", configFile, err)
	}
	defer f.Close()

	jsonDecoder := json.NewDecoder(f)
	if err := jsonDecoder.Decode(&fc); err != nil {
		return nil, fmt.Errorf("Can not unmarshal JSON: %v", err)
	}

	return fc, nil

}

// Write the configuration into a file, specified by the configuration filepath
func Write(cfg *Configuration, configFile string) error {

	if _, err := os.Stat(configFile); os.IsNotExist(err) {
		configDir := filepath.Dir(configFile)
		err := os.MkdirAll(configDir, os.ModeDir)
		if err != nil {
			return fmt.Errorf("Can not create config directory %v: %v", configDir, err)
		}
	}

	f, err := os.Create(configFile)
	if err != nil {
		return fmt.Errorf("Can not write config file: %v", err)
	}
	defer f.Close()

	encoder := json.NewEncoder(f)
	encoder.SetIndent("", "  ")
	err = encoder.Encode(cfg)
	if err != nil {
		return fmt.Errorf("Error in encoding struct to json: %v", err)
	}

	return nil

}