package qz.printer.action.pdf;

import org.apache.pdfbox.contentstream.operator.MissingOperandException;
import org.apache.pdfbox.contentstream.operator.Operator;
import org.apache.pdfbox.contentstream.operator.graphics.GraphicsOperatorProcessor;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.MissingResourceException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.graphics.PDXObject;
import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.apache.pdfbox.rendering.PageDrawer;
import org.apache.pdfbox.rendering.PageDrawerParameters;

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

public class OpaquePDFRenderer extends PDFRenderer {

    public OpaquePDFRenderer(PDDocument document) {
        super(document);
    }

    @Override
    protected PageDrawer createPageDrawer(PageDrawerParameters parameters) throws IOException {
        return new OpaquePageDrawer(parameters);
    }

    // override drawer to make use of customized draw object
    private class OpaquePageDrawer extends PageDrawer {
        public OpaquePageDrawer(PageDrawerParameters parameters) throws IOException {
            super(parameters);

            addOperator(new OpaqueDrawObject());
        }
    }

    // override draw object to remove any calls to show transparency
    private class OpaqueDrawObject extends GraphicsOperatorProcessor {

        public OpaqueDrawObject() { }

        public void process(Operator operator, List<COSBase> operands) throws IOException {
            if (operands.isEmpty()) {
                throw new MissingOperandException(operator, operands);
            } else {
                COSBase base0 = operands.get(0);
                if (base0 instanceof COSName) {
                    COSName objectName = (COSName)base0;
                    PDXObject xobject = context.getResources().getXObject(objectName);

                    if (xobject == null) {
                        throw new MissingResourceException("Missing XObject: " + objectName.getName());
                    } else {
                        if (xobject instanceof PDImageXObject) {
                            PDImageXObject image = (PDImageXObject)xobject;
                            context.drawImage(image);
                        } else if (xobject instanceof PDFormXObject) {
                            try {
                                context.increaseLevel();
                                if (context.getLevel() <= 25) {
                                    PDFormXObject form = (PDFormXObject)xobject;
                                    context.showForm(form);
                                }

                                //LOG.error("recursion is too deep, skipping form XObject");
                            }
                            finally {
                                context.decreaseLevel();
                            }
                        }

                    }
                }
            }
        }

        public String getName() {
            return "Do";
        }

    }
}