/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.pdmodel.font;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashSet;
import java.util.Set;

import org.apache.pdfbox.Loader;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.PDPageContentStream.AppendMode;
import org.apache.pdfbox.rendering.TestPDFToImage;
import org.apache.pdfbox.text.PDFTextStripper;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.parallel.Execution;
import org.junit.jupiter.api.parallel.ExecutionMode;

/**
 * Tests font embedding.
 *
 * @author John Hewson
 * @author Tilman Hausherr
 */
@Execution(ExecutionMode.CONCURRENT)
class TestFontEmbedding
{
    private static final File OUT_DIR = new File("target/test-output");

    @BeforeAll
    static void setUp()
    {
        OUT_DIR.mkdirs();
    }

    /**
     * Embed a TTF as CIDFontType2.
     * 
     * @throws IOException
     */
    @Test
    void testCIDFontType2() throws IOException
    {
        validateCIDFontType2(false);
    }

    /**
     * Embed a TTF as CIDFontType2 with subsetting.
     * 
     * @throws IOException
     */
    @Test
    void testCIDFontType2Subset() throws IOException
    {
        validateCIDFontType2(true);
    }

    /**
     * Embed a monospace TTF as vertical CIDFontType2 with subsetting.
     *
     * @throws IOException
     */
    @Test
    void testCIDFontType2VerticalSubsetMonospace() throws IOException
    {
        String text = "「ABC」";
        String expectedExtractedtext = "「\nA\nB\nC\n」";
        File pdf = new File(OUT_DIR, "CIDFontType2VM.pdf");

        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage(PDRectangle.A4);
            document.addPage(page);
            File ipafont = new File("target/fonts/ipag00303", "ipag.ttf");
            PDType0Font vfont = PDType0Font.loadVertical(document, ipafont);
            try (PDPageContentStream contentStream = new PDPageContentStream(document, page))
            {
                contentStream.beginText();
                contentStream.setFont(vfont, 20);
                contentStream.newLineAtOffset(50, 700);
                contentStream.showText(text);
                contentStream.endText();
            }
            // Check the font substitution
            byte[] encode = vfont.encode(text);
            int cid = ((encode[0] & 0xFF) << 8) + (encode[1] & 0xFF);
            assertEquals(7392, cid); // it's 441 without substitution
            // Check the dictionaries
            COSDictionary fontDict = vfont.getCOSObject();
            assertEquals(COSName.IDENTITY_V, fontDict.getDictionaryObject(COSName.ENCODING));

            document.save(pdf);

            // Vertical metrics are fixed during subsetting, so do this after calling save()
            COSDictionary descFontDict = vfont.getDescendantFont().getCOSObject();
            COSArray dw2 = (COSArray) descFontDict.getDictionaryObject(COSName.DW2);
            assertNull(dw2); // This font uses default values for DW2
            COSArray w2 = (COSArray) descFontDict.getDictionaryObject(COSName.W2);
            assertEquals(0, w2.size()); // Monospaced font has no entries
        }

        // Check text extraction
        String extracted = getUnicodeText(pdf);        
        assertEquals(expectedExtractedtext, extracted.replaceAll("\r", "").trim());
    }

    /**
     * Embed a proportional TTF as vertical CIDFontType2 with subsetting.
     *
     * @throws IOException
     */
    @Test
    void testCIDFontType2VerticalSubsetProportional() throws IOException
    {
        String text = "「ABC」";
        String expectedExtractedtext = "「\nA\nB\nC\n」";
        File pdf = new File(OUT_DIR, "CIDFontType2VP.pdf");

        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage(PDRectangle.A4);
            document.addPage(page);
            File ipafont = new File("target/fonts/ipagp00303", "ipagp.ttf");
            PDType0Font vfont = PDType0Font.loadVertical(document, ipafont);
            try (PDPageContentStream contentStream = new PDPageContentStream(document, page))
            {
                contentStream.beginText();
                contentStream.setFont(vfont, 20);
                contentStream.newLineAtOffset(50, 700);
                contentStream.showText(text);
                contentStream.endText();
            }
            // Check the font substitution
            byte[] encode = vfont.encode(text);
            int cid = ((encode[0] & 0xFF) << 8) + (encode[1] & 0xFF);
            assertEquals(12607, cid); // it's 12461 without substitution
            // Check the dictionaries
            COSDictionary fontDict = vfont.getCOSObject();
            assertEquals(COSName.IDENTITY_V, fontDict.getDictionaryObject(COSName.ENCODING));

            document.save(pdf);

            // Vertical metrics are fixed during subsetting, so do this after calling save()
            COSDictionary descFontDict = vfont.getDescendantFont().getCOSObject();
            COSArray dw2 = (COSArray) descFontDict.getDictionaryObject(COSName.DW2);
            assertNull(dw2); // This font uses default values for DW2
            // c [ w1_1y v_1x v_1y ... w1_ny v_nx v_ny ]
            COSArray w2 = (COSArray) descFontDict.getDictionaryObject(COSName.W2);
            assertEquals(2, w2.size());
            assertEquals(12607, w2.getInt(0)); // Start CID
            COSArray metrics = (COSArray) w2.getObject(1);
            int i = 0;
            for (int n : new int[] {-570, 500, 450, -570, 500, 880})
            {
                assertEquals(n, metrics.getInt(i++));
            }
        }

        // Check text extraction
        String extracted = getUnicodeText(pdf);
        assertEquals(expectedExtractedtext, extracted.replaceAll("\r", "").trim());
    }

    @Test
    void testBengali() throws IOException
    {
        String BANGLA_TEXT_1 = "আমি কোন পথে ক্ষীরের লক্ষ্মী ষন্ড পুতুল রুপো গঙ্গা ঋষি";
        String BANGLA_TEXT_2 = "দ্রুত গাঢ় শেয়াল অলস কুকুর জুড়ে জাম্প ধুর্ত  হঠাৎ ভাঙেনি মৌলিক ঐশি দৈ";
        String BANGLA_TEXT_3 = "ঋষি কল্লোল ব্যাস নির্ভয় ";

        String expectedExtractedtext = BANGLA_TEXT_1 + "\n" + BANGLA_TEXT_2 + "\n" + BANGLA_TEXT_3;
        File pdf = new File(OUT_DIR, "Bengali.pdf");

        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage(PDRectangle.A4);
            document.addPage(page);
            PDFont font = PDType0Font.load(document, 
                    this.getClass().getResourceAsStream("/org/apache/pdfbox/ttf/Lohit-Bengali.ttf"));

            try (PDPageContentStream contentStream = new PDPageContentStream(document, page))
            {
                contentStream.beginText();
                contentStream.setFont(font, 18);
                contentStream.newLineAtOffset(10, 750);
                contentStream.showText(BANGLA_TEXT_1);
                contentStream.newLineAtOffset(0, -30);
                contentStream.showText(BANGLA_TEXT_2);
                contentStream.newLineAtOffset(0, -30);
                contentStream.showText(BANGLA_TEXT_3);
                contentStream.endText();
            }

            document.save(pdf);
        }

        File IN_DIR = new File("src/test/resources/org/apache/pdfbox/ttf");
 
        // compare rendering
        TestPDFToImage testPDFToImage = new TestPDFToImage(TestPDFToImage.class.getName());
        if (!testPDFToImage.doTestFile(pdf, IN_DIR.getAbsolutePath(), OUT_DIR.getAbsolutePath()))
        {
            // don't fail, rendering is different on different systems, result must be viewed manually
            System.err.println("Rendering of " + pdf + " failed or is not identical to expected rendering in " + IN_DIR + " directory");
        }

        // Check text extraction
        String extracted = getUnicodeText(pdf);
        //assertEquals(expectedExtractedtext, extracted.replaceAll("\r", "").trim());
    }

    /**
     * Test corner case of PDFBOX-4302.
     *
     * @throws java.io.IOException
     */
    @Test
    void testMaxEntries() throws IOException
    {
        File file;
        String text;
        text = "あいうえおかきくけこさしすせそたちつてとなにぬねのはひふへほまみむめもやゆよらりるれろわをん" +
                "アイウエオカキクケコサシスセソタチツテトナニヌネノハヒフヘホマミムメモヤユヨラリルレロワヲン" +
                "１２３４５６７８";

        // The test must have MAX_ENTRIES_PER_OPERATOR unique characters
        Set<Character> set = new HashSet<>(ToUnicodeWriter.MAX_ENTRIES_PER_OPERATOR);
        for (int i = 0; i < text.length(); ++i)
        {
            set.add(text.charAt(i));
        }
        assertEquals(ToUnicodeWriter.MAX_ENTRIES_PER_OPERATOR, set.size());

        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage(PDRectangle.A0);
            document.addPage(page);
            File ipafont = new File("target/fonts/ipag00303", "ipag.ttf");
            PDType0Font font = PDType0Font.load(document, ipafont);
            try (PDPageContentStream contentStream = new PDPageContentStream(document, page))
            {
                contentStream.beginText();
                contentStream.setFont(font, 20);
                contentStream.newLineAtOffset(50, 3000);
                contentStream.showText(text);
                contentStream.endText();
            }
            file = new File(OUT_DIR, "PDFBOX-4302-test.pdf");
            document.save(file);
        }

        // check that the extracted text matches what we wrote
        String extracted = getUnicodeText(file);
        assertEquals(text, extracted.trim());
    }

    private void validateCIDFontType2(boolean useSubset) throws IOException
    {
        String text;
        File file;
        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage(PDRectangle.A4);
            document.addPage(page);
            InputStream input = PDFont.class.getResourceAsStream(
                    "/org/apache/pdfbox/resources/ttf/LiberationSans-Regular.ttf");
            PDType0Font font = PDType0Font.load(document, input, useSubset);
            try (PDPageContentStream stream = new PDPageContentStream(document, page))
            {
                stream.beginText();
                stream.setFont(font, 12);
                text = "Unicode русский язык Tiếng Việt";
                stream.newLineAtOffset(50, 600);
                stream.showText(text);
                stream.endText();
            }
            file = new File(OUT_DIR, "CIDFontType2" + (useSubset ? "-useSubset" : "") + ".pdf");
            document.save(file);
        }

        // check that the extracted text matches what we wrote
        String extracted = getUnicodeText(file);
        assertEquals(text, extracted.trim());
    }

    private String getUnicodeText(File file) throws IOException
    {
        PDDocument document = Loader.loadPDF(file);
        PDFTextStripper stripper = new PDFTextStripper();
        return stripper.getText(document);
    }

    /**
     * Test that an embedded and subsetted font can be reused.
     * 
     * @throws IOException 
     */
    @Test
    void testReuseEmbeddedSubsettedFont() throws IOException
    {
        String text1 = "The quick brown fox";
        String text2 = "xof nworb kciuq ehT";
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try (PDDocument document = new PDDocument())
        {
            PDPage page = new PDPage();
            document.addPage(page);
            InputStream input = PDFont.class.getResourceAsStream(
                    "/org/apache/pdfbox/resources/ttf/LiberationSans-Regular.ttf");
            PDType0Font font = PDType0Font.load(document, input);
            try (PDPageContentStream stream = new PDPageContentStream(document, page))
            {
                stream.beginText();
                stream.setFont(font, 20);
                stream.newLineAtOffset(50, 600);
                stream.showText(text1);
                stream.endText();
            }
            document.save(baos);
        }
        // Append, while reusing the font subset
        try (PDDocument document = Loader.loadPDF(baos.toByteArray()))
        {
            PDPage page = document.getPage(0);
            PDFont font = page.getResources().getFont(COSName.getPDFName("F1"));
            try (PDPageContentStream stream = new PDPageContentStream(document, page, AppendMode.APPEND, true))
            {
                stream.beginText();
                stream.setFont(font, 20);
                stream.newLineAtOffset(250, 600);
                stream.showText(text2);
                stream.endText();
            }
            baos.reset();
            document.save(baos);
        }
        // Test that both texts are there
        try (PDDocument document = Loader.loadPDF(baos.toByteArray()))
        {
            PDFTextStripper stripper = new PDFTextStripper();
            String extractedText = stripper.getText(document);
            assertEquals(text1 + " " + text2, extractedText.trim());
        }
    }
}
