package streams

import (
	"errors"
	"fmt"
	"math"
	"strings"
)

func quote(text string) string {
	text = strings.Replace(text, "\\", "\\\\", -1)
	text = strings.Replace(text, "'", "\\'", -1)
	text = "'" + text + "'"
	return text
}

func unquote(text string) string {
	if strings.HasPrefix(text, "'") && strings.HasSuffix(text, "'") {
		text = text[1 : len(text)-2]
		text = strings.Replace(text, "\\'", "'", -1)
		text = strings.Replace(text, "\\\\", "\\", -1)
	}
	return text
}

type Metadata map[string]string

func DecodeMetadataFromBytes(b []byte) {
	// TODO
}

func decodeMetadataItem(text string, metadata *map[string]string) (err error) {
	parts := strings.SplitN(text, "=", 2)
	if len(parts) < 2 {
		err = errors.New("expected key=value but only got key")
		return
	}

	parts[1] = unquote(parts[1])
	(*metadata)[parts[0]] = parts[1]

	return
}

func DecodeMetadata(source string) (meta Metadata, err error) {
	// name='value'; name='value';name='value';
	meta = make(Metadata)
	// TODO

	return
}

func (meta Metadata) String() string {
	return string(meta.Bytes())
}

func (meta Metadata) Bytes() (buf []byte) {
	mstr := ""

	if meta != nil {
		for key, value := range meta {
			mstr += fmt.Sprintf("%s=%s;", key, quote(value))
		}
	}

	if len(mstr) > 16*256-1 {
		mstr = mstr[0 : 16*256]
	}

	lengthDiv := int(math.Ceil(float64(len(mstr)) / 16))
	lengthByte := byte(lengthDiv)

	buf = make([]byte, lengthDiv*16+1)
	buf[0] = lengthByte
	copy(buf[1:], []byte(mstr))

	return
}