package main

import (
	"crypto/ecdsa"
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"os"
)

func LoadMasterKey(path string) (*ecdsa.PrivateKey, error) {
	masterKeyFile, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	// The second argument is not an error.
	derEncoded, _ := pem.Decode(masterKeyFile)
	if derEncoded == nil {
		return nil, fmt.Errorf("failed to decode master key file")
	}

	masterKey, err := x509.ParseECPrivateKey(derEncoded.Bytes)
	if err != nil {
		return nil, err
	}

	return masterKey, nil
}