/*
 * 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 java.io.File
import kotlin.system.exitProcess
import net.schmizz.sshj.SSHClient
import net.schmizz.sshj.sftp.FileAttributes
import net.schmizz.sshj.sftp.FileMode
import net.schmizz.sshj.sftp.OpenMode
import net.schmizz.sshj.sftp.RemoteFile
import net.schmizz.sshj.sftp.SFTPClient
import net.schmizz.sshj.userauth.UserAuthException
import org.apache.logging.log4j.LogManager

class SftpClient(sftpSettings: Map<String, String>) {
    private val log = LogManager.getLogger("SftpClient")
    private val ssh = SSHClient()
    private val instance: SFTPClient
    init {
        ssh.loadKnownHosts()
        ssh.addHostKeyVerifier(sftpSettings["fingerprint"])
        ssh.connect(sftpSettings["host"])
        try {
            ssh.authPassword(sftpSettings["user"], sftpSettings["password"])
            instance = ssh.newSFTPClient()
        } catch (ex: UserAuthException) {
            log.error("Invalid user authentication supplied.")
            exitProcess(1)
        } catch (ex: Exception) {
            ex.printStackTrace()
            log.error(ex.localizedMessage)
            exitProcess(1)
        }
    }

    fun listFiles(path: String): List<String> {
        return ls(path).filter { fileAttributes(it).mode.type == FileMode.Type.REGULAR }
    }

    fun open(file: File): RemoteFile {
        return instance.open(file.path, setOf(OpenMode.READ))
    }

    private fun fileAttributes(path: String): FileAttributes {
        return instance.lstat(path)
    }

    private fun ls(path: String): List<String> {
        return instance.ls(path).map { it.path }
    }

    fun close() {
        instance.close()
        ssh.disconnect()
    }
}