package station

import (
	"bytes"

	jsonv2 "encoding/json/v2"
	"golang.org/x/sys/unix"
)

// SoftwareName and SoftwareVersion are the identity sent to the reflector
// after login. Edit them here.
const (
	SoftwareName    = "funknetz"
	SoftwareVersion = "1.0.0"
)

type nodeSoftware struct {
	SW          string `json:"sw"`
	SWVer       string `json:"swVer"`
	ProjVer     string `json:"projVer"`
	MachineArch string `json:"machineArch,omitempty"`
}

func softwareIdentityBody() ([]byte, error) {
	raw, err := marshalNode(false)
	if err != nil {
		return nil, err
	}
	return appendString(nil, string(raw)), nil
}

func nodeInfoV3(iv, key []byte) ([]byte, error) {
	raw, err := marshalNode(true)
	if err != nil {
		return nil, err
	}
	body := appendBlob(nil, iv)
	body = appendBlob(body, key)
	return appendString(body, string(raw)), nil
}

func marshalNode(arch bool) ([]byte, error) {
	info := nodeSoftware{
		SW:      SoftwareName,
		SWVer:   SoftwareVersion,
		ProjVer: SoftwareVersion,
	}
	if arch {
		if name, ok := machineArch(); ok {
			info.MachineArch = name
		}
	}
	return jsonv2.Marshal(info)
}

func machineArch() (string, bool) {
	var u unix.Utsname
	if err := unix.Uname(&u); err != nil {
		return "", false
	}
	b := u.Machine[:]
	if i := bytes.IndexByte(b, 0); i >= 0 {
		b = b[:i]
	}
	if len(b) == 0 {
		return "", false
	}
	return string(b), true
}