// VulcanizeDB
// Copyright © 2019 Vulcanize

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package fetcher

import (
	"strings"

	log "github.com/sirupsen/logrus"

	"github.com/vulcanize/vulcanizedb/libraries/shared/storage/utils"
	"github.com/vulcanize/vulcanizedb/pkg/fs"
)

type IStorageFetcher interface {
	FetchStorageDiffs(chan<- utils.StorageDiffRow, chan<- error)
}

type CsvTailStorageFetcher struct {
	tailer fs.Tailer
}

func NewCsvTailStorageFetcher(tailer fs.Tailer) CsvTailStorageFetcher {
	return CsvTailStorageFetcher{tailer: tailer}
}

func (storageFetcher CsvTailStorageFetcher) FetchStorageDiffs(out chan<- utils.StorageDiffRow, errs chan<- error) {
	t, tailErr := storageFetcher.tailer.Tail()
	if tailErr != nil {
		errs <- tailErr
	}
	log.Debug("fetching storage diffs...")
	for line := range t.Lines {
		row, parseErr := utils.FromStrings(strings.Split(line.Text, ","))
		if parseErr != nil {
			errs <- parseErr
		} else {
			out <- row
		}
	}
}
