package ipp

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"io"
)

type resolution struct {
	name                string
	crossFeedResolution int32
	feedResolution      int32
	units               int8
}

func NewResolution(name string, xfres int32, fres int32) *resolution {
	r := new(resolution)
	r.name = name
	r.crossFeedResolution = xfres
	r.feedResolution = fres
	r.units = 3 // 3 seems to mean dpi (rfc3805)
	return r
}

func (r *resolution) unmarshal(byteStream io.Reader) {
	var length uint16
	binary.Read(byteStream, binary.BigEndian, &length)
	attributeName := make([]byte, length)
	if length > 0 {
		binary.Read(byteStream, binary.BigEndian, attributeName)
	}
	r.name = string(attributeName)
	binary.Read(byteStream, binary.BigEndian, &length)
	if length != 9 {
		panic("Wrong length in resolution")
	}
	binary.Read(byteStream, binary.BigEndian, &r.crossFeedResolution)
	binary.Read(byteStream, binary.BigEndian, &r.feedResolution)
	binary.Read(byteStream, binary.BigEndian, &r.units)
}

func (r resolution) Name() string {
	return r.name
}

func (r resolution) String() string {
	return fmt.Sprintf("%v:%v,%v,%v", r.name, r.crossFeedResolution, r.feedResolution, r.units)
}

func (r *resolution) marshal() []byte {

	b := make([]byte, 0, 14+len(r.name))
	buf := bytes.NewBuffer(b)
	buf.WriteByte(byte(resolutionValueTag))
	binary.Write(buf, binary.BigEndian, uint16(len(r.name)))
	buf.WriteString(r.name)
	binary.Write(buf, binary.BigEndian, uint16(9))
	binary.Write(buf, binary.BigEndian, int32(r.crossFeedResolution))
	binary.Write(buf, binary.BigEndian, int32(r.feedResolution))
	buf.WriteByte(byte(r.units))
	return buf.Bytes()
}

func (r *resolution) valueTag() tag {
	return resolutionValueTag
}