package main

import (
	"bytes"
	"io/ioutil"
	"os"

	"github.com/yggdrasil-network/yggdrasil-go/src/config"
)

func readConfig(useconf *bool, useconffile *string, normaliseconf *bool) *config.NodeConfig {
	// Use a configuration file. If -useconf, the configuration will be read
	// from stdin. If -useconffile, the configuration will be read from the
	// filesystem.
	var conf []byte
	var err error
	if *useconffile != "" {
		// Read the file from the filesystem
		conf, err = ioutil.ReadFile(*useconffile)
	} else {
		// Read the file from stdin.
		conf, err = ioutil.ReadAll(os.Stdin)
	}
	if err != nil {
		panic(err)
	}
	// If there's a byte order mark - which Windows 10 is now incredibly fond of
	// throwing everywhere when it's converting things into UTF-16 for the hell
	// of it - remove it and decode back down into UTF-8. This is necessary
	// because hjson doesn't know what to do with UTF-16 and will panic
	if bytes.Compare(conf[0:2], []byte{0xFF, 0xFE}) == 0 ||
		bytes.Compare(conf[0:2], []byte{0xFE, 0xFF}) == 0 {
		utf := unicode.UTF16(unicode.BigEndian, unicode.UseBOM)
		decoder := utf.NewDecoder()
		conf, err = decoder.Bytes(conf)
		if err != nil {
			panic(err)
		}
	}
	// Generate blank configuration
	cfg := config.GenerateConfig()
	// ... and then update it with the supplied HJSON input
	if err := cfg.UnmarshalHJSON(conf); err != nil {
		panic(err)
	}
	return cfg
}