/*-
 * ============LICENSE_START======================================================================
 * Copyright (C) 2023 Nordix Foundation. All rights reserved.
 * Copyright (C) 2020 Nokia. All rights reserved.
 * ===============================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 * ============LICENSE_END========================================================================
 */

package org.oran.datafile.ftp;

import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
import static org.mockito.Mockito.when;

import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
import com.jcraft.jsch.SftpException;

import java.nio.file.Paths;

import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.oran.datafile.configuration.SftpConfig;
import org.oran.datafile.exceptions.DatafileTaskException;
import org.oran.datafile.exceptions.NonRetryableDatafileTaskException;
import org.oran.datafile.model.FileServerData;

@ExtendWith(MockitoExtension.class)
class SftpClientTest {

    private static final String HOST = "127.0.0.1";
    private static final int SFTP_PORT = 1021;
    private static final String USERNAME = "bob";
    private static final String PASSWORD = "123";

    @Mock
    private JSch jschMock;

    @Mock
    private Session sessionMock;

    @Mock
    private ChannelSftp channelMock;

    @Test
    void openWithPort_success() throws Exception {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();

        SftpClient sftpClientSpy = spy(new SftpClient(expectedFileServerData, createSampleSftpClientSettings()));

        doReturn(jschMock).when(sftpClientSpy).createJsch();
        when(jschMock.getSession(anyString(), anyString(), anyInt())).thenReturn(sessionMock);
        when(sessionMock.openChannel(anyString())).thenReturn(channelMock);

        sftpClientSpy.open();

        verify(jschMock).getSession(USERNAME, HOST, SFTP_PORT);
        verify(sessionMock).setConfig("StrictHostKeyChecking", "no");
        verify(sessionMock).setPassword(PASSWORD);
        verify(sessionMock).connect();
        verify(sessionMock).openChannel("sftp");
        verifyNoMoreInteractions(sessionMock);

        verify(channelMock).connect();
        verifyNoMoreInteractions(channelMock);
    }

    @Test
    void openWithoutPort_success() throws Exception {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(null) //
            .build();

        SftpClient sftpClientSpy = spy(new SftpClient(expectedFileServerData, createSampleSftpClientSettings()));

        doReturn(jschMock).when(sftpClientSpy).createJsch();
        when(jschMock.getSession(anyString(), anyString(), anyInt())).thenReturn(sessionMock);
        when(sessionMock.openChannel(anyString())).thenReturn(channelMock);

        sftpClientSpy.open();

        verify(jschMock).getSession(USERNAME, HOST, 22);
    }

    @Test
    void open_throwsExceptionWithRetry() throws Exception {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();

        SftpClient sftpClientSpy = spy(new SftpClient(expectedFileServerData, createSampleSftpClientSettings()));

        doReturn(jschMock).when(sftpClientSpy).createJsch();
        when(jschMock.getSession(anyString(), anyString(), anyInt())).thenThrow(new JSchException("Failed"));

        DatafileTaskException exception = assertThrows(DatafileTaskException.class, () -> sftpClientSpy.open());
        assertEquals("Could not open Sftp client. com.jcraft.jsch.JSchException: Failed", exception.getMessage());
    }

    @Test
    void openAuthFail_throwsExceptionWithoutRetry() throws Exception {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();

        SftpClient sftpClientSpy = spy(new SftpClient(expectedFileServerData, createSampleSftpClientSettings()));

        doReturn(jschMock).when(sftpClientSpy).createJsch();
        when(jschMock.getSession(anyString(), anyString(), anyInt())).thenThrow(new JSchException("Auth fail"));

        NonRetryableDatafileTaskException exception =
            assertThrows(NonRetryableDatafileTaskException.class, () -> sftpClientSpy.open());
        assertEquals(
            "Could not open Sftp client, no retry attempts will be done. com.jcraft.jsch.JSchException: Auth fail",
            exception.getMessage());
    }

    @SuppressWarnings("resource")
    @Test
    void collectFile_success() throws DatafileTaskException, SftpException {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();
        SftpClient sftpClient = new SftpClient(expectedFileServerData, createSampleSftpClientSettings());

        sftpClient.sftpChannel = channelMock;

        sftpClient.collectFile("remote.xml", Paths.get("local.xml"));

        verify(channelMock).get("remote.xml", "local.xml");
        verifyNoMoreInteractions(channelMock);
    }

    @Test
    void collectFile_throwsExceptionWithRetry() throws SftpException {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();

        try (SftpClient sftpClient = new SftpClient(expectedFileServerData, createSampleSftpClientSettings())) {
            sftpClient.sftpChannel = channelMock;
            doThrow(new SftpException(ChannelSftp.SSH_FX_BAD_MESSAGE, "Failed")).when(channelMock).get(anyString(),
                anyString());

            assertThatThrownBy(() -> sftpClient.collectFile("remoteFile", Paths.get("localFile")))
                .isInstanceOf(DatafileTaskException.class).hasMessageStartingWith("Unable to get file from xNF. ")
                .hasMessageContaining(HOST);
        }
    }

    @Test
    void collectFileFileMissing_throwsExceptionWithoutRetry() throws SftpException {
        FileServerData expectedFileServerData = FileServerData.builder() //
            .serverAddress(HOST) //
            .userId(USERNAME) //
            .password(PASSWORD) //
            .port(SFTP_PORT) //
            .build();

        try (SftpClient sftpClient = new SftpClient(expectedFileServerData, createSampleSftpClientSettings())) {
            sftpClient.sftpChannel = channelMock;
            doThrow(new SftpException(ChannelSftp.SSH_FX_NO_SUCH_FILE, "Failed")).when(channelMock).get(anyString(),
                anyString());

            assertThatThrownBy(() -> sftpClient.collectFile("remoteFile", Paths.get("localFile")))
                .isInstanceOf(NonRetryableDatafileTaskException.class)
                .hasMessageStartingWith("Unable to get file from xNF. No retry attempts will be done")
                .hasMessageContaining("" + SFTP_PORT);
        }
    }

    @Test
    void close_success() {
        SftpClient sftpClient = new SftpClient(null, createSampleSftpClientSettings());

        sftpClient.session = sessionMock;
        sftpClient.sftpChannel = channelMock;

        sftpClient.close();

        verify(sessionMock).disconnect();
        verifyNoMoreInteractions(sessionMock);

        verify(channelMock).exit();;
        verifyNoMoreInteractions(channelMock);
    }

    private SftpClientSettings createSampleSftpClientSettings() {
        return new SftpClientSettings(createSampleSftpConfigNoStrictHostChecking());
    }

    private SftpConfig createSampleSftpConfigNoStrictHostChecking() {
        return SftpConfig.builder() //
            .strictHostKeyChecking(false).knownHostsFilePath("N/A").build();
    }

}