package config

import (
	"errors"

	"go.wit.com/lib/protobuf/filepb"
	"google.golang.org/protobuf/proto"
)

// verify 'version' for .pb files
// application should die if they don't match
// returns (newVersion, oldVersion, error)
func VersionCheck(pb proto.Message) (string, string, error) {
	fullname, err := GetFilename(pb)
	if err != nil {
		return "", "", err
	}
	return VersionCheckFile(pb, fullname)
}

// verify 'version' for .pb files
// application should die if they don't match
// returns (newVersion, oldVersion, error)
func VersionCheckFile(pb proto.Message, filename string) (string, string, error) {
	var newVersion string
	var newUuid string
	var err error

	newVersion, err = GetString(pb, "version")
	if err != nil {
		return newVersion, "", err
	}

	newUuid, err = GetString(pb, "uuid")
	if err != nil {
		return newVersion, newUuid, err
	}

	oldVersion, oldUuid, err := filepb.IdentifyPB(filename)
	if err != nil {
		return newVersion, newUuid, err
	}

	if newVersion != oldVersion {
		return newVersion, oldVersion, errors.New("version mismatch")
	}

	if newUuid != oldUuid {
		return newVersion, oldVersion, errors.New("UUID mismatch")
	}

	return newVersion, oldVersion, nil
}