/*
 * Created on 20 ott 2016
 * Copyright 2015 by Andrea Vacondio (andrea.vacondio@gmail.com).
 * This file is part of Sejda.
 *
 * Sejda is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Sejda is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Sejda.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.sejda.impl.sambox;

import static org.sejda.common.ComponentsUtility.nullSafeCloseQuietly;
import static org.sejda.core.notification.dsl.ApplicationEventsNotifier.notifyEvent;
import static org.sejda.core.support.io.IOUtils.createTemporaryBuffer;
import static org.sejda.core.support.io.model.FileOutput.file;
import static org.sejda.core.support.prefix.NameGenerator.nameGenerator;
import static org.sejda.core.support.prefix.model.NameGenerationRequest.nameRequest;

import java.io.File;

import org.sejda.core.support.io.MultipleOutputWriter;
import org.sejda.core.support.io.OutputWriters;
import org.sejda.impl.sambox.component.DefaultPdfSourceOpener;
import org.sejda.impl.sambox.component.PDDocumentHandler;
import org.sejda.impl.sambox.component.PdfWatermarker;
import org.sejda.model.exception.TaskException;
import org.sejda.model.input.PdfSource;
import org.sejda.model.input.PdfSourceOpener;
import org.sejda.model.parameter.WatermarkParameters;
import org.sejda.model.pdf.encryption.PdfAccessPermission;
import org.sejda.model.task.BaseTask;
import org.sejda.model.task.TaskExecutionContext;
import org.sejda.sambox.pdmodel.PageNotFoundException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * SAMBox implementation of a task applying a watermark to a list of {@link PdfSource}, to every page or a subset of them.
 * 
 * @author Andrea Vacondio
 *
 */
public class WatermarkTask extends BaseTask<WatermarkParameters> {

    private static final Logger LOG = LoggerFactory.getLogger(WatermarkTask.class);

    private int totalSteps;
    private PDDocumentHandler documentHandler = null;
    private MultipleOutputWriter outputWriter;
    private PdfSourceOpener<PDDocumentHandler> documentLoader;

    @Override
    public void before(WatermarkParameters parameters, TaskExecutionContext executionContext) throws TaskException {
        super.before(parameters, executionContext);
        totalSteps = parameters.getSourceList().size();
        documentLoader = new DefaultPdfSourceOpener();
        outputWriter = OutputWriters.newMultipleOutputWriter(parameters.getExistingOutputPolicy(), executionContext);
    }

    @Override
    public void execute(WatermarkParameters parameters) throws TaskException {
        int currentStep = 0;

        for (PdfSource<?> source : parameters.getSourceList()) {
            executionContext().assertTaskNotCancelled();
            currentStep++;
            LOG.debug("Opening {}", source);
            try {
                documentHandler = source.open(documentLoader);
                documentHandler.getPermissions().ensurePermission(PdfAccessPermission.MODIFY);
                documentHandler.setCreatorOnPDDocument();

                File tmpFile = createTemporaryBuffer(parameters.getOutput());
                LOG.debug("Created output on temporary buffer {}", tmpFile);

                PdfWatermarker watermarker = new PdfWatermarker(parameters, documentHandler.getUnderlyingPDDocument());
                for (Integer page : parameters.getPages(documentHandler.getNumberOfPages())) {
                    executionContext().assertTaskNotCancelled();
                    try {
                        watermarker.mark(documentHandler.getPage(page));
                    } catch (PageNotFoundException e) {
                        executionContext().assertTaskIsLenient(e);
                        notifyEvent(executionContext().notifiableTaskMetadata())
                                .taskWarning(String.format("Page %d was skipped, could not be watermarked", page), e);
                    }
                }

                documentHandler.setVersionOnPDDocument(parameters.getVersion());
                documentHandler.setCompress(parameters.isCompress());
                documentHandler.savePDDocument(tmpFile);

                String outName = nameGenerator(parameters.getOutputPrefix())
                        .generate(nameRequest().originalName(source.getName()).fileNumber(currentStep));
                outputWriter.addOutput(file(tmpFile).name(outName));
            } finally {
                nullSafeCloseQuietly(documentHandler);
            }

            notifyEvent(executionContext().notifiableTaskMetadata()).stepsCompleted(currentStep).outOf(totalSteps);
        }

        parameters.getOutput().accept(outputWriter);
        LOG.debug("Input documents watermarked and written to {}", parameters.getOutput());
    }

    @Override
    public void after() {
        nullSafeCloseQuietly(documentHandler);
    }

}