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

import (
	"bufio"
	"encoding/binary"
)

// SetOfStrings is the strings attribute
type SetOfStrings struct {
	name   string
	values []string
	vTag   tag
}

// NewSetOfStrings creates a new strings attribute
func NewSetOfStrings(name string, t tag, values []string) *SetOfStrings {
	s := new(SetOfStrings)
	s.name = name
	s.vTag = t
	s.values = values //make([]string, 0)
	return s
}

func (s SetOfStrings) String() string {
	r := s.name + " :"
	for _, v := range s.values {
		r = r + " " + v
	}
	return r
}

func (s *SetOfStrings) valueTag() tag {
	return s.vTag
}

func (s *SetOfStrings) unmarshal(byteStream *bufio.Reader, valueTag tag) error {
	var length uint16
	s.vTag = valueTag
	s.values = make([]string, 0, 1)
	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)
	for length > 0 {
		valueBytes := make([]byte, length)
		err := binary.Read(byteStream, binary.BigEndian, valueBytes)
		if err != nil {
			return err
		}
		s.values = append(s.values, string(valueBytes))
		next, err := byteStream.Peek(3)
		if err != nil {
			break
		}
		if next[0] != byte(valueTag) || next[1] != 0x00 || next[2] != 0x00 {
			break
		}
		// Remove the value tag with the zero length from the stream
		byteStream.Discard(3)
		binary.Read(byteStream, binary.BigEndian, &length)
	}
	return nil
}

func (s *SetOfStrings) marshal() []byte {
	l := 5 + len(s.name) + len(s.values[0])
	for i := range s.values[1:] {
		l += 5 + len(s.values[i+1])
	}
	res := make([]byte, l)
	p := 0
	res[p] = byte(s.vTag)
	p++
	binary.BigEndian.PutUint16(res[p:p+2], uint16(len(s.name)))
	p += 2
	copy(res[p:], []byte(s.name))
	p += len(s.name)
	binary.BigEndian.PutUint16(res[p:p+2], uint16(len(s.values[0])))
	p += 2
	copy(res[p:], []byte(s.values[0]))
	p += len(s.values[0])
	for i := range s.values[1:] {
		res[p] = byte(s.vTag)
		p++
		binary.BigEndian.PutUint16(res[p:p+2], uint16(0))
		p = p + 2
		binary.BigEndian.PutUint16(res[p:p+2], uint16(len(s.values[i+1])))
		p = p + 2
		copy(res[p:], []byte(s.values[i+1]))
		p += len(s.values[i+1])
	}

	return res
}

// AddValue adds a new sring to the set
func (s *SetOfStrings) AddValue(v string) {
	s.values = append(s.values, v)
}