/*
 * Copyright 2015 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.pdfbox.examples.pdfa;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.security.KeyStore;
import java.util.HashSet;
import java.util.Set;

import org.apache.pdfbox.Loader;
import org.apache.pdfbox.examples.pdmodel.CreatePDFA;
import org.apache.pdfbox.examples.signature.CreateSignature;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.pdmodel.common.PDMetadata;
import org.apache.pdfbox.preflight.ValidationResult;
import org.apache.pdfbox.preflight.ValidationResult.ValidationError;
import org.apache.pdfbox.preflight.parser.PreflightParser;
import org.apache.xmpbox.XMPMetadata;
import org.apache.xmpbox.schema.DublinCoreSchema;
import org.apache.xmpbox.xml.DomXmpParser;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.verapdf.gf.foundry.VeraGreenfieldFoundryProvider;
import org.verapdf.pdfa.Foundries;
import org.verapdf.pdfa.PDFAParser;
import org.verapdf.pdfa.PDFAValidator;
import org.verapdf.pdfa.flavours.PDFAFlavour;

/**
 *
 * @author Tilman Hausherr
 */
class CreatePDFATest
{
    private static final String OUTDIR = "target/test-output";

    @BeforeAll
    static void setUp()
    {
        new File(OUTDIR).mkdirs();
    }

    /**
     * Test of doIt method of class CreatePDFA.
     */
    @Test
    void testCreatePDFA() throws Exception
    {
        String pdfaFilename = OUTDIR + "/PDFA.pdf";
        String signedPdfaFilename = OUTDIR + "/PDFA_signed.pdf";
        String keystorePath = "src/test/resources/org/apache/pdfbox/examples/signature/keystore.p12";
        String message = "The quick brown fox jumps over the lazy dog äöüÄÖÜß @°^²³ {[]}";
        String dir = "../pdfbox/src/main/resources/org/apache/pdfbox/resources/ttf/";
        String fontfile = dir + "LiberationSans-Regular.ttf";
        CreatePDFA.main(new String[] { pdfaFilename, message, fontfile });

        // sign PDF - because we want to make sure that the signed PDF is also PDF/A-1b
        KeyStore keystore = KeyStore.getInstance("PKCS12");
        keystore.load(new FileInputStream(keystorePath), "123456".toCharArray());
        CreateSignature signing = new CreateSignature(keystore, "123456".toCharArray());
        signing.signDetached(new File(pdfaFilename), new File(signedPdfaFilename));

        // Verify that it is PDF/A-1b
        ValidationResult result = PreflightParser.validate(new File(signedPdfaFilename));
        for (ValidationError ve : result.getErrorsList())
        {
            System.err.println(ve.getErrorCode() + ": " + ve.getDetails());
        }
        assertTrue(result.isValid(), "PDF file created with CreatePDFA is not valid PDF/A-1b");

        // check the XMP metadata
        try (PDDocument document = Loader.loadPDF(new File(pdfaFilename)))
        {
            PDDocumentCatalog catalog = document.getDocumentCatalog();
            PDMetadata meta = catalog.getMetadata();
            DomXmpParser xmpParser = new DomXmpParser();
            XMPMetadata metadata = xmpParser.parse(meta.toByteArray());
            DublinCoreSchema dc = metadata.getDublinCoreSchema();
            assertEquals(pdfaFilename, dc.getTitle());
        }

        File signedFile = new File(signedPdfaFilename);
        try (BufferedReader br = new BufferedReader(
                new InputStreamReader(new FileInputStream(signedFile))))
        {
            String line;
            boolean isIncrementalArea = false;
            Set<String> set = new HashSet<>();
            int linePos = 0;
            while ((line = br.readLine()) != null)
            {
                ++linePos;
                if (line.equals("%%EOF"))
                {
                    isIncrementalArea = true;
                    set.clear(); // for cases with several revisions
                }
                if (!isIncrementalArea)
                {
                    continue;
                }
                if (line.matches("\\d+ 0 obj"))
                {
                    int pos = line.indexOf(" 0 obj");
                    line = line.substring(0, pos);
                    assertFalse(set.contains(line), "object '" + line
                            + " 0 obj' twice in incremental part of PDF at line " + linePos);
                    set.add(line);
                }
            }
        }

        // https://docs.verapdf.org/develop/
        VeraGreenfieldFoundryProvider.initialise();
        PDFAFlavour flavour = PDFAFlavour.fromString("1b");
        try (PDFAParser parser = Foundries.defaultInstance().createParser(new File(signedPdfaFilename), flavour))
        {
            PDFAValidator validator = Foundries.defaultInstance().createValidator(flavour, false);
            org.verapdf.pdfa.results.ValidationResult veraResult = validator.validate(parser);
            assertTrue(veraResult.isCompliant());
        }
    }
}
