package reader

import (
	"encoding/json"
	"io"
	"regexp"
)

type TXTBlockReader struct {
	*LineReader
	nextline string
}

func NewTXTBlockReader(filename string, reader io.Reader) *TXTBlockReader {
	return &TXTBlockReader{
		LineReader: NewLineReader(filename, reader),
	}
}

var regrecord = regexp.MustCompile(`^(?:[\.\/a-zA-Z0-9_]*:)?V:(\{.*)`)

func (br *TXTBlockReader) ReadBlock() (block map[string]any, linecount int, err error) {
	eof := false
	line := br.nextline
	for {
		for {
			br.nextline, linecount, eof, err = br.ReadLine()
			if err != nil {
				return
			}
			if br.nextline == "" && eof {
				if line == "" {
					return
				}
				break
			}
			if regrecord.MatchString(br.nextline) {
				break
			}
			line += br.nextline
		}
		linecount--
		if !regrecord.MatchString(line) {
			line = br.nextline
			continue
		}
		line = regrecord.ReplaceAllString(line, "$1")
		block = map[string]any{}
		err = json.Unmarshal([]byte(line), &block)
		if err != nil {
			return
		}
		return
	}
}