// Package plugctl provides an API for Kasa smart home switches.
package plugctl

import (
	"io"
	"net"
)

// Plug provides an API for a single Kasa smart home switch.
type Plug struct {
	Addr net.TCPAddr
}

type msg struct {
	System *systemMsg `json:"system,omitempty"`
	EMeter *eMeterMsg `json:"emeter,omitempty"`
}

type eMeterMsg struct {
	GetRealtime *getRealtimeMsg `json:"get_realtime"`
}

type getRealtimeMsg struct{}

type systemMsg struct {
	GetSysInfo    *getSysInfoMsg    `json:"get_sysinfo"`
	SetRelayState *setRelayStateMsg `json:"set_relay_state,omitempty"`
}

type getSysInfoMsg struct{}

type setRelayStateMsg struct {
	State int `json:"state"`
}

type decryptReader struct {
	r io.Reader
	c byte
}

func newDecrypter(r io.Reader) *decryptReader {
	return &decryptReader{
		r: r,
		c: 0xab,
	}
}

func (d *decryptReader) Read(b []byte) (int, error) {
	n, err := d.r.Read(b)
	for i, x := range b {
		b[i] = d.c ^ x
		d.c = x
	}
	return n, err
}

type encryptWriter struct {
	w io.Writer
	c byte
}

func newEncrypter(w io.Writer) *encryptWriter {
	return &encryptWriter{
		w: w,
		c: 0xab,
	}
}

func (e *encryptWriter) Write(b []byte) (int, error) {
	eb := make([]byte, len(b))
	for i, x := range b {
		e.c ^= x
		eb[i] = e.c
	}
	return e.w.Write(eb)
}