/*
 * 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 java.io.File;
import java.io.IOException;
import java.io.InputStream;
import junit.framework.TestCase;
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.text.PDFTextStripper;

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

    @Override
    protected void setUp() throws Exception
    {
        OUT_DIR.mkdirs();
    }

    /**
     * Embed a TTF as CIDFontType2.
     */
    public void testCIDFontType2() throws Exception
    {
        validateCIDFontType2(false);
    }

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

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

        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);

        PDPageContentStream contentStream = new PDPageContentStream(document, page);
        contentStream.beginText();
        contentStream.setFont(vfont, 20);
        contentStream.newLineAtOffset(50, 700);
        contentStream.showText(text);
        contentStream.endText();
        contentStream.close();

        // 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

        document.close();

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

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

        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);
        PDPageContentStream contentStream = new PDPageContentStream(document, page);

        contentStream.beginText();
        contentStream.setFont(vfont, 20);
        contentStream.newLineAtOffset(50, 700);
        contentStream.showText(text);
        contentStream.endText();
        contentStream.close();

        // 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++));
        }
        document.close();

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

    private void validateCIDFontType2(boolean useSubset) throws Exception
    {
        PDDocument document = new PDDocument();
        PDPage page = new PDPage(PDRectangle.A4);
        document.addPage(page);

        InputStream input = TestFontEmbedding.class.getClassLoader().getResourceAsStream(
                "org/apache/pdfbox/ttf/LiberationSans-Regular.ttf");
        PDType0Font font = PDType0Font.load(document, input, useSubset);

        PDPageContentStream stream = new PDPageContentStream(document, page);

        stream.beginText();
        stream.setFont(font, 12);

        String text = "Unicode русский язык Tiếng Việt";
        stream.newLineAtOffset(50, 600);
        stream.showText(text);

        stream.endText();
        stream.close();
        
        File file = new File(OUT_DIR, "CIDFontType2.pdf");
        document.save(file);
        document.close();

        // 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 = PDDocument.load(file);
        PDFTextStripper stripper = new PDFTextStripper();
        return stripper.getText(document);
    }
}
