package at.gv.egiz.pdfas.web.servlets;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egiz.pdfas.common.exceptions.PdfAsException;
import at.gv.egiz.pdfas.lib.api.sign.IPlainSigner;
import at.gv.egiz.pdfas.sigs.pades.PAdESSigner;
import at.gv.egiz.pdfas.web.exception.PdfAsWebException;
import at.gv.egiz.pdfas.web.helper.PdfAsHelper;
import at.gv.egiz.pdfas.web.helper.PdfAsParameterExtractor;
import at.gv.egiz.pdfas.web.helper.RemotePDFFetcher;
import at.gv.egiz.sl.util.BKUSLConnector;
import at.gv.egiz.sl.util.MOAConnector;

/**
 * Servlet implementation class Sign
 */
public class ExternSignServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	private static final String UPLOAD_PDF_DATA = "pdfFile";
	private static final String UPLOAD_DIRECTORY = "upload";
	private static final int THRESHOLD_SIZE = 1024 * 1024 * 3; // 3MB
	private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
	private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB

	private static final Logger logger = LoggerFactory
			.getLogger(ExternSignServlet.class);
	
	/**
	 * Default constructor.
	 */
	public ExternSignServlet() {
	}

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		
		System.out.println("Get signing request");
		logger.info("Get signing request");
		
		String errorUrl = PdfAsParameterExtractor.getInvokeErrorURL(request);
		PdfAsHelper.setErrorURL(request, response, errorUrl);
		try {
			// Mandatory Parameters on Get Request:
			String invokeUrl = PdfAsParameterExtractor.getInvokeURL(request);
			PdfAsHelper.setInvokeURL(request, response, invokeUrl);

			String pdfUrl = PdfAsParameterExtractor.getPdfUrl(request);

			if (pdfUrl == null) {
				throw new PdfAsWebException(
						"No PDF URL given! Use POST request to sign without PDF URL.");
			}

			byte[] pdfData = RemotePDFFetcher.fetchPdfFile(pdfUrl);
			doSignature(request, response, pdfData);
		} catch (Exception e) {
			PdfAsHelper.setSessionException(request, response, e.getMessage(),
					e);
			PdfAsHelper.gotoError(getServletContext(), request, response);
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		
		System.out.println("Post signing request");
		logger.info("Post signing request");
		
		String errorUrl = PdfAsParameterExtractor.getInvokeErrorURL(request);
		PdfAsHelper.setErrorURL(request, response, errorUrl);
		
		try {
			byte[] filecontent = null;

			// checks if the request actually contains upload file
			if (!ServletFileUpload.isMultipartContent(request)) {
				// No Uploaded data!
				if (PdfAsParameterExtractor.getPdfUrl(request) != null) {
					doGet(request, response);
					return;
				} else {
					throw new PdfAsWebException("No Signature data defined!");
				}
			} else {
				// configures upload settings
				DiskFileItemFactory factory = new DiskFileItemFactory();
				factory.setSizeThreshold(THRESHOLD_SIZE);
				factory.setRepository(new File(System
						.getProperty("java.io.tmpdir")));

				ServletFileUpload upload = new ServletFileUpload(factory);
				upload.setFileSizeMax(MAX_FILE_SIZE);
				upload.setSizeMax(MAX_REQUEST_SIZE);

				// constructs the directory path to store upload file
				String uploadPath = getServletContext().getRealPath("")
						+ File.separator + UPLOAD_DIRECTORY;
				// creates the directory if it does not exist
				File uploadDir = new File(uploadPath);
				if (!uploadDir.exists()) {
					uploadDir.mkdir();
				}

				List formItems = upload.parseRequest(request);
				logger.debug(formItems.size() + " Items in form data");
				if (formItems.size() < 1) {
					// No Uploaded data!
					// Try do get
					// No Uploaded data!
					if (PdfAsParameterExtractor.getPdfUrl(request) != null) {
						doGet(request, response);
						return;
					} else {
						throw new PdfAsWebException(
								"No Signature data defined!");
					}
				} else {
					for(int i = 0; i < formItems.size(); i++) {
						Object obj = formItems.get(i);
						if(obj instanceof FileItem) {
							FileItem item = (FileItem) obj;
							if(item.getFieldName().equals(UPLOAD_PDF_DATA)) {
								filecontent = item.get();
								logger.debug("Found pdf Data!");
							} else {
								request.setAttribute(item.getFieldName(), item.getString());
								logger.debug("Setting " + item.getFieldName() + " = " + item.getString());
							}
						} else {
							logger.info(obj.getClass().getName() +  " - " + obj.toString());
						}
					}
				}
			}
			
			if(filecontent == null) {
				if (PdfAsParameterExtractor.getPdfUrl(request) != null) {
					filecontent = RemotePDFFetcher.fetchPdfFile(PdfAsParameterExtractor.getPdfUrl(request));
				}
			}

			if(filecontent == null) {
				throw new PdfAsException("No Signature data available");
			}
			
			doSignature(request, response, filecontent);
		} catch (Exception e) {
			PdfAsHelper.setSessionException(request, response, e.getMessage(),
					e);
			PdfAsHelper.gotoError(getServletContext(), request, response);
		}
	}

	protected void doSignature(HttpServletRequest request,
			HttpServletResponse response, byte[] pdfData) throws Exception {
		// Get Connector
		String connector = PdfAsParameterExtractor.getConnector(request);

		String invokeUrl = PdfAsParameterExtractor.getInvokeURL(request);
		PdfAsHelper.setInvokeURL(request, response, invokeUrl);
		
		String errorUrl = PdfAsParameterExtractor.getInvokeErrorURL(request);
		PdfAsHelper.setErrorURL(request, response, errorUrl);
		
		logger.debug("Starting signature creation with: " + connector);
		
		IPlainSigner signer;
		if (connector.equals("bku") || connector.equals("onlinebku") || connector.equals("mobilebku")) {
			// start asynchronous signature creation
			PdfAsHelper.startSignature(request, response, getServletContext(), pdfData);
		} else if (connector.equals("jks") || connector.equals("moa")) {
			// start synchronous siganture creation
			byte[] pdfSignedData = PdfAsHelper.synchornousSignature(request,
					response, pdfData);
			PdfAsHelper.setSignedPdf(request, response, pdfSignedData);
			PdfAsHelper.gotoProvidePdf(getServletContext(), request, response);
			return;
		} else {
			throw new PdfAsWebException("Invalid connector (bku | moa | jks)");
		}

	}

}