package ipp

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

type ippMessageHeader struct {
	versionNumber versionNumber
	operationID   OperationID
	requestID     uint32
}

func (h *ippMessageHeader) unmarshal(byteStream io.Reader) {
	binary.Read(byteStream, binary.BigEndian, &h.versionNumber)
	binary.Read(byteStream, binary.BigEndian, &h.operationID)
	binary.Read(byteStream, binary.BigEndian, &h.requestID)
}

func (h *ippMessageHeader) marshal() []byte {
	b := make([]byte, 0, 8)
	buf := bytes.NewBuffer(b)
	binary.Write(buf, binary.BigEndian, h.versionNumber)
	binary.Write(buf, binary.BigEndian, h.operationID)
	binary.Write(buf, binary.BigEndian, h.requestID)
	return buf.Bytes()
}

func (h ippMessageHeader) String() string {
	return fmt.Sprintf("Version number: %v Operation Id: %v Request Id: %v", h.versionNumber, h.operationID, h.requestID)
}

type AddValuer interface {
	addValue(interface{})
}

type Request struct {
	a      *Attributes
	header ippMessageHeader
}

func NewRequest(op OperationID, requestID uint32) *Request {
	r := new(Request)
	r.header.operationID = op
	r.header.requestID = requestID
	r.header.versionNumber = 0x0200
	r.a = new(Attributes)
	return r
}

func (r Request) String() string {
	return r.header.String() + "\n" + r.a.String()
}

func (r *Request) UnMarshal(body io.Reader) {
	buffbody := bufio.NewReader(body)
	r.header.unmarshal(buffbody)
	r.a = UnMarshalAttributes(buffbody)
}

func (r *Request) RequestID() uint32 {
	return r.header.requestID
}

// Operation returns the operation is of the request.
func (r *Request) Operation() OperationID {
	return r.header.operationID
}

func (r *Request) GetAttribute(name string) Attribute {
	for _, a := range r.a.operation {
		if a.Name() == name {
			return a
		}
	}
	for _, a := range r.a.job {
		if a.Name() == name {
			return a
		}
	}
	for _, a := range r.a.printer {
		if a.Name() == name {
			return a
		}
	}
	for _, a := range r.a.unsupported {
		if a.Name() == name {
			return a
		}
	}
	return nil
}

// Marshal converts the request object to a ipp request
func (r *Request) Marshal() []byte {

	var buf bytes.Buffer
	buf.Write(r.header.marshal())
	if len(r.a.operation) > 0 {
		buf.WriteByte(byte(operationAttributes))
		for _, e := range r.a.operation {
			buf.Write(e.marshal())
		}
	}
	if len(r.a.job) > 0 {
		buf.WriteByte(byte(jobAttributes))
		for _, e := range r.a.job {
			buf.Write(e.marshal())
		}
	}
	if len(r.a.printer) > 0 {
		buf.WriteByte(byte(printerAttributes))
		for _, e := range r.a.printer {
			buf.Write(e.marshal())
		}
	}
	buf.WriteByte(byte(endOfAttributes))
	return buf.Bytes()
}

// AddPrinterAttribute adds a printer attribute to the request object
func (r *Request) AddPrinterAttribute(a Attribute) error {
	if a != nil {
		r.a.addAttribute(printerAttributes, a)
		return nil
	}
	return ErrNilAttribute
}

// AddOperatonAttribute adds a operation attribute to the request object
func (r *Request) AddOperatonAttribute(a Attribute) error {
	if a != nil {
		r.a.addAttribute(operationAttributes, a)
		return nil
	}
	return ErrNilAttribute
}

// AddJobAttribute adds a job attribute to the request object
func (r *Request) AddJobAttribute(a Attribute) error {
	if a != nil {
		r.a.addAttribute(jobAttributes, a)
		return nil
	}
	return ErrNilAttribute
}