/*
 * sftp-reader
 * Copyright (C) 2020 Memoriav
 *
 * 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 <https://www.gnu.org/licenses/>.
 */

package org.memobase

import com.github.doyaaaaaken.kotlincsv.dsl.csvReader
import com.github.doyaaaaaken.kotlincsv.util.MalformedCSVException
import java.io.File
import org.apache.logging.log4j.LogManager

class FileValidation(val sftp: SftpClient) {
    private val log = LogManager.getLogger("FileValidation")

    private val supportedExtensions = mapOf(
        Pair("csv", "CSV"),
        Pair("tsv", "TSV")
    )

    fun validate(file: File): Report {
        when (val format = validateExtension(file)) {
            "CSV", "TSV" -> {
                val remoteFile = sftp.open(file)
                val stream = remoteFile.RemoteFileInputStream()
                try {
                    csvReader {
                        charset = "UTF-8"
                        delimiter = if (format == "CSV") ',' else '\t'
                        quoteChar = '"'
                        escapeChar = '\\'
                    }.readAll(stream)
                } catch (ex: MalformedCSVException) {
                    remoteFile.close()
                    return Report(id = file.name, status = "invalid", path = file.path, format = format, error = ex.localizedMessage)
                }
                remoteFile.close()
                return Report(id = file.name, status = "valid", path = file.path, format = format, error = "")
            }
            else -> return Report(id = file.name, status = "invalid", path = file.path, format = format, error = "Not a valid file extension: ${file.name}.")
        }
    }

    private fun validateExtension(file: File): String {
        return supportedExtensions.getOrDefault(file.extension, "INVALID")
    }
}