package org.snmp4j.agent.tutorial.impl;

import org.snmp4j.agent.mo.snmp.DateAndTime;
import org.snmp4j.agent.mo.snmp.tc.DateAndTimeTC;
import org.snmp4j.agent.tutorial.Snmp4jAgentTutorialMib;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.*;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.nio.file.attribute.PosixFilePermission;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Set;

/**
 * Created by fock on 20.06.2016.
 */
public class Snmp4JAgentTutorialFileTreeRowHelper {

    private static final byte[] PERMS = { 'r', 'w', 'x' };

    public static Variable[] createRowFromFile(File file) throws IOException {
        return createRowFromPath(file.toPath());
    }



    public static Variable[] createRowFromPath(Path path) throws IOException {
        Variable[] row = new Variable[10];
        String pathString = path.toString();
        row[0] = new OctetString(pathString.substring(0, Math.min(pathString.length(), 255)));

        BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);

        if (Files.isDirectory(path, LinkOption.NOFOLLOW_LINKS)) {
            row[1] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileType.directory);
        }
        else if (Files.isRegularFile(path, LinkOption.NOFOLLOW_LINKS)) {
            row[1] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileType.regularFile);
        }
        else if (Files.isSymbolicLink(path)) {
            row[1] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileType.symbolicLink);
        }
        else {
            row[1] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileType.other);
        }

        GregorianCalendar creationDateAndTime = new GregorianCalendar();
        creationDateAndTime.setTimeInMillis(attrs.creationTime().toMillis());
        row[2] = DateAndTime.makeDateAndTime(creationDateAndTime);

        GregorianCalendar lastModifiedDateAndTime = new GregorianCalendar();
        creationDateAndTime.setTimeInMillis(attrs.lastModifiedTime().toMillis());
        row[3] = DateAndTime.makeDateAndTime(lastModifiedDateAndTime);

        GregorianCalendar lastAccessDateAndTime = new GregorianCalendar();
        creationDateAndTime.setTimeInMillis(attrs.lastAccessTime().toMillis());
        row[4] = DateAndTime.makeDateAndTime(lastAccessDateAndTime);

        long fileSize = Files.size(path);
        row[5] = new UnsignedInteger32(Math.min(fileSize, 4294967295L));

        if (fileSize < 1024) {
            row[6] = new UnsignedInteger32(fileSize);
            row[7] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileSizeUnit.bytes);
        }
        else if (fileSize < (1L << 20)) {
            row[6] = new UnsignedInteger32(fileSize / 1024);
            row[7] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileSizeUnit.kiloBytes);
        }
        else if (fileSize < (1L << 30)) {
            row[6] = new UnsignedInteger32(fileSize / (1L << 20));
            row[7] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileSizeUnit.megaBytes);
        }
        else if (fileSize < (1L << 40)) {
            row[6] = new UnsignedInteger32(fileSize / (1L << 30));
            row[7] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileSizeUnit.gigaBytes);
        }
        else {
            row[6] = new UnsignedInteger32(fileSize / (1L << 50));
            row[7] = new Integer32(Snmp4jAgentTutorialMib.Snmp4jAgentTutorialFileSizeUnit.petaBytes);
        }

        row[8] = new Integer32(path.hashCode());

        OctetString permissions = new OctetString("         ");
        try {
            Set<PosixFilePermission> permissionSet = Files.getPosixFilePermissions(path, LinkOption.NOFOLLOW_LINKS);
            for (int i = 0; i < PosixFilePermission.values().length; i++) {
                if (permissionSet.contains(PosixFilePermission.values()[i])) {
                    permissions.set(i, PERMS[i % 3]);
                }
            }
        }
        catch (UnsupportedOperationException uoex) {
            // ignore
        }
        row[9] = permissions;

        return row;
    }
}