package handleSsh;

import com.jcraft.jsch.*;
import java.util.ArrayList;
import java.io.File;


public class DownloadFiles {

    private static final String LOCAL_BASIC_PATH = "/home/rasta5man/dev/oms/downloads/";

    //ADD FILES TO DOWNLOAD IN MAIN METHOD
    private static ArrayList<String> filesToDownload = new ArrayList<>();



    public static void main(String[] args) throws JSchException {

        ArrayList<Server> allServers = new BuildServerArray().getAllServers();

        for (Server server : allServers) {

            String remoteBasicPath = "";
            if(server.getUsername().equals("root")) { // je to LM
                remoteBasicPath = "/root/flowserver/";
            }
            else {
                remoteBasicPath = "/home/unipi/flowserver/";
            }


            filesToDownload.clear();
            filesToDownload.add(remoteBasicPath + "databases/nodes.table");
//            filesToDownload.add(remoteBasicPath + "databases/settings.table");


            System.out.println("Connecting to server: " + server);
            downloadFiles(server);
        }
    }


    /**
     * Establishes SFTP connection and downloads files.
     */
    public static void downloadFiles(Server server) throws JSchException {

        JSch jsch = new JSch();
        jsch.setKnownHosts("/home/rasta5man/.ssh/known_hosts");
        jsch.addIdentity( "/home/rasta5man/.ssh/oms_key" );
        Session session = null;
        ChannelSftp sftpChannel = null;

        try {

            session = jsch.getSession(server.getUsername(), server.getHost(), server.getPort());
            session.setPassword(server.getPassword());
            //session.setConfig("StrictHostKeyChecking", "no"); // Avoids checking for new host keys (not recommended for production)
            session.connect();

            sftpChannel = (ChannelSftp) session.openChannel("sftp");
            sftpChannel.connect();

            for (String fileToDownload : filesToDownload) {
                System.out.println("Downloading " + fileToDownload + " to " + server);

                // 3. Perform the file download
                System.out.println("Attempting to download remote file: " + fileToDownload);

                String localFileName = getFileName(fileToDownload);
                File localFile = new File(LOCAL_BASIC_PATH + localFileName + server.getHost());

                // JSch's get() method downloads the remote file to the local path
                sftpChannel.get(fileToDownload, localFile.getAbsolutePath());
                System.out.println("\n✅ Success! File downloaded to: " + localFile.getAbsolutePath());
            }

        } catch (JSchException e) {
            // Handle connection, authentication, or channel opening errors
            System.err.println("\n❌ SFTP Connection Error: " + e.getMessage());
            e.printStackTrace();
        } catch (SftpException e) {
            // Handle file-specific errors (e.g., file not found, permission denied)
            System.err.println("\n❌ SFTP File Transfer Error: " + e.getMessage() + " (Error code: " + e.id + ")");
            System.err.println("Please check if the remote file path exists and permissions are correct.");
            e.printStackTrace();
        } finally {
            // 4. Clean up resources
            if (sftpChannel != null && sftpChannel.isConnected()) {
                sftpChannel.disconnect();
                System.out.println("SFTP Channel disconnected.");
            }
            if (session != null && session.isConnected()) {
                session.disconnect();
                System.out.println("Session disconnected.");
            }
        }
    }

    /**
     * Extracts the filename from a given file path string.
     * It assumes a Unix-style path separator ('/'), which is standard for SFTP.
     *
     * @param path The full file path (e.g., "/home/george/pictures/downtown.jpg").
     * @return The filename (e.g., "downtown.jpg"). Returns an empty string if the input is null or empty.
     */
    public static String getFileName(String path) {
        if (path == null || path.isEmpty()) {
            return "";
        }
        int lastSeparatorIndex = path.lastIndexOf('/');

        // If the path contains a separator, return the substring after it.
        // Otherwise, the entire path is considered the filename.
        return (lastSeparatorIndex == -1)
                ? path
                : path.substring(lastSeparatorIndex + 1);
    }

}