// Copyright 2021, Henrik Sölver henrik.solver@gmail.com
// SPDX-License-Identifier: BSD-3-Clause
package ipp

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

// setOfIntegers is a helper type that is used to handle integer types
// which only differs in tag value.
type setOfIntegers struct {
	name   string
	values []int32
}

func unmarshalIntegers(byteStream *bufio.Reader, valueTag tag) (*setOfIntegers, error) {

	s := new(setOfIntegers)
	s.values = make([]int32, 0, 1)

	var length uint16
	binary.Read(byteStream, binary.BigEndian, &length)
	name := make([]byte, length)
	if length > 0 {
		binary.Read(byteStream, binary.BigEndian, name)
	}
	s.name = string(name)
	binary.Read(byteStream, binary.BigEndian, &length)
	if length != 4 {
		return nil, fmt.Errorf("wrong value-length of integer attribute %v", length)
	}
	var value int32 //valueBytes := make([]byte, length)
	for length > 0 {
		err := binary.Read(byteStream, binary.BigEndian, &value)
		if err != nil {
			return nil, err
		}
		s.values = append(s.values, value)
		next, err := byteStream.Peek(3)
		if err != nil {
			// end of byte stream
			break
		}
		if next[0] != byte(valueTag) || next[1] != 0x00 || next[2] != 0x00 {
			// End of attribute
			break
		}
		// Remove the value tag with the zero length from the stream
		byteStream.Discard(3)
		binary.Read(byteStream, binary.BigEndian, &length)
	}

	return s, nil
}