package net.curisit.securis;

import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.Date;

import net.curisit.securis.ConnectionManager.Command;
import net.curisit.securis.beans.LicenseBean;
import net.curisit.securis.beans.RequestBean;
import net.curisit.securis.beans.SignedLicenseBean;
import net.curisit.securis.beans.StatusBean;
import net.curisit.securis.utils.JsonUtils;
import net.curisit.securis.utils.Params;
import net.curisit.securis.utils.SignatureHelper;

import org.apache.commons.io.FileUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * Manage all licenses tasks, just like validation, renew, requesting, ...
 * 
 * @author roberto <roberto.sanchez@curisit.net>
 */
public class LicenseManager {

    private static final Logger LOG = LogManager.getLogger(License.class);

    private static LicenseManager singleton = new LicenseManager();

    public static final String PING_MESSAGE = "SeCuris API OK";

    private LicenseManager() {
    }

    public static LicenseManager getInstance() {
        return singleton;
    }

    /**
     * Loads a license from file
     * 
     * @param licFile
     * @return The license bean
     * @throws SeCurisException
     */
    public LicenseBean load(File licFile) throws SeCurisException {
        LicenseBean licBean;
        try {
            licBean = JsonUtils.json2object(FileUtils.readFileToString(licFile), LicenseBean.class);
        } catch (IOException e) {
            throw new SeCurisException("Error getting license data from file: " + licFile, e);
        }
        return licBean;
    }

    /**
     * Validates the license stored in {@code licFile} and get the corresponding
     * LicenseBean
     * <p>
     * The validation includes:
     * <ul>
     * <li>Signature</li>
     * <li>HW data</li>
     * <li>Logo CRC</li>
     * </ul>
     * </p>
     * 
     * @param licFile
     * @return The license bean stored in file
     * @throws SeCurisException
     */
    public LicenseBean validateLicense(File licFile) throws SeCurisException {

        return validateLicense(licFile, false);
    }

    /**
     * Validates the license stored in {@code licFile} and get the corresponding
     * LicenseBean. The License date is not validated
     * <p>
     * The validation includes:
     * <ul>
     * <li>Signature</li>
     * <li>HW data</li>
     * <li>Logo CRC</li>
     * </ul>
     * </p>
     * 
     * @param licFile
     * @return The license bean stored in file
     * @throws SeCurisException
     */
    public LicenseBean validateLicense(File licFile, boolean excludeDateValidation) throws SeCurisException {
        LicenseBean licBean = load(licFile);
        SignatureHelper.getInstance().validateSignature(licBean);
        LicenseValidator.getInstance().validateHW(licBean, Params.get(Params.KEYS.APPLICATION_CODE), Params.get(Params.KEYS.CUSTOMER_CODE),
                Params.get(Params.KEYS.PACK_CODE));
        LicenseValidator.getInstance().validateLogo(licBean);

        if (!excludeDateValidation) {
            if (new Date().after(licBean.getExpirationDate())) {
                throw new SeCurisException("License has expired");
            }
        }

        return licBean;
    }

    /**
     * Request to server for a valid license
     * 
     * @return The license bean returned by the server
     * @throws SeCurisException
     */
    public SignedLicenseBean requestLicense() throws SeCurisException {
        RequestBean req = ReqGenerator.getInstance().createRequest(Params.get(Params.KEYS.APPLICATION_CODE), Params.get(Params.KEYS.CUSTOMER_CODE),
                Params.get(Params.KEYS.PACK_CODE));

        SignedLicenseBean lic = requestLicenseToServer(req);
        return lic;
    }

    /**
     * Generate a license file using a {@link LicenseBean}
     * 
     * @param license
     * @param file
     * @throws SeCurisException
     */
    public void save(LicenseBean license, File file) throws SeCurisException {
        SignedLicenseBean signedLic = new SignedLicenseBean(license);
        save(signedLic, file);
    }

    /**
     * Generate a license file using a {@link LicenseBean}
     * 
     * @param license
     * @param file
     * @throws SeCurisException
     */
    public void save(SignedLicenseBean signedLic, File file) throws SeCurisException {
        byte[] json;
        try {
            json = JsonUtils.toPrettyJSON(signedLic).getBytes("utf-8");
            Files.write(Paths.get(file.toURI()), json, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING);
        } catch (UnsupportedEncodingException e) {
            LOG.error("Error creating json doc from license: " + signedLic, e);
            throw new SeCurisException("Error creating json doc from license: " + signedLic, e);
        } catch (IOException e) {
            LOG.error("Error creating license file: " + file, e);
            throw new SeCurisException("Error creating json doc from license: " + signedLic, e);
        }

        LOG.debug("License saved in {}", file);

    }

    private SignedLicenseBean requestLicenseToServer(RequestBean req) throws SeCurisException {
        SignedLicenseBean lic = ConnectionManager.getInstance().executePost(Command.CREATE_LIC, SignedLicenseBean.class, req);

        return lic;
    }

    /**
     * Creates a new request file with current hardware in the File passed as
     * parameter
     * 
     * @param outputRequestFile
     *            File where the request data will be saved
     * @return The generated request bean
     * @throws SeCurisException
     */
    public RequestBean createRequestFile(File outputRequestFile) throws SeCurisException {
        RequestBean req = ReqGenerator.getInstance().createRequest(Params.get(Params.KEYS.APPLICATION_CODE), Params.get(Params.KEYS.CUSTOMER_CODE),
                Params.get(Params.KEYS.PACK_CODE));

        ReqGenerator.getInstance().save(req, outputRequestFile);

        return req;
    }

    /**
     * Send the current license file to server, which is previously validated,
     * to get a renewed one if it is prepared in server side.
     * 
     * @param licenseFile
     *            Current and valid License file
     * @return New license bean if server creates a new one, otherwise the same
     *         current License bean will be returned
     * @throws SeCurisException
     */
    public SignedLicenseBean renew(File licenseFile) throws SeCurisException {
        LicenseBean lic = validateLicense(licenseFile);

        SignedLicenseBean newLic = ConnectionManager.getInstance().executePost(Command.RENEW_LIC, SignedLicenseBean.class, lic);

        return newLic;
    }

    public void testServer() throws SeCurisException {
        StatusBean status = ConnectionManager.getInstance().executeGet(Command.TEST, StatusBean.class);
        if (!PING_MESSAGE.equals(status.getMessage())) {
            throw new SeCurisException("SeCuris Server is not running in given URL");
        }
    }

}