package main

import (
	"fmt"
	"io/ioutil"
	"time"

	"github.com/goburrow/serial"
	"github.com/sirupsen/logrus"
	"gopkg.in/yaml.v2"
)

type SerialConfig struct {
	Address  string `yaml:"address"`
	BaudRate int    `yaml:"baudrate"`
	DataBits int    `yaml:"databits"`
	StopBits int    `yaml:"stopbits"`
	Parity   string `yaml:"parity"`
}

type ClientConfig struct {
	Serial        SerialConfig `yaml:"serial_config"`
	Paranoid      bool         `yaml:"paranoid"`
	Debug         bool         `yaml:"debug"`
	GNUPGBinary   string       `yaml:"gnupg_bin"`
	OpenSSLBinary string       `yaml:"openssl_bin"`
	MySQLDSN      string       `yaml:"mysql_dsn"`
}

var defaultConfig = ClientConfig{
	Serial: SerialConfig{
		Address:  "/dev/ttyUSB0",
		BaudRate: 115200,
		DataBits: 8,
		StopBits: 1,
		Parity:   "N",
	},
	Paranoid:      false,
	Debug:         false,
	OpenSSLBinary: "/usr/bin/openssl",
	GNUPGBinary:   "/usr/bin/gpg",
	MySQLDSN:      "<username>:<password>@/database?parseTime=true",
}

func generateExampleConfig(configFile string) (config *ClientConfig, err error) {
	config = &defaultConfig
	configBytes, err := yaml.Marshal(config)
	if err != nil {
		logrus.Errorf("could not generate configuration data")
		return
	}

	logrus.Infof("example data for %s:\n\n---\n%s\n", configFile, configBytes)
	return
}

func readConfig(configFile string) (config *ClientConfig, err error) {
	source, err := ioutil.ReadFile(configFile)
	if err != nil {
		logrus.Errorf("opening configuration file failed: %v", err)
		if exampleConfig, err := generateExampleConfig(configFile); err != nil {
			return nil, err
		} else {
			logrus.Info("starting with default config")
			return exampleConfig, nil
		}
	}
	if err := yaml.Unmarshal(source, &config); err != nil {
		return nil, fmt.Errorf("loading configuration file failed: %v", err)
	}

	return config, nil
}

func fillSerialConfig(clientConfig *ClientConfig) *serial.Config {
	return &serial.Config{
		Address:  clientConfig.Serial.Address,
		BaudRate: clientConfig.Serial.BaudRate,
		DataBits: clientConfig.Serial.DataBits,
		StopBits: clientConfig.Serial.StopBits,
		Parity:   clientConfig.Serial.Parity,
		Timeout:  30 * time.Second,
	}
}