/*
 * Copyright (c) 1997, 2022 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package com.sun.tools.xjc.api.impl.s2j;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import javax.xml.XMLConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.validation.SchemaFactory;

import com.sun.codemodel.JCodeModel;
import com.sun.istack.NotNull;
import com.sun.istack.SAXParseException2;
import com.sun.tools.xjc.ErrorReceiver;
import com.sun.tools.xjc.ModelLoader;
import com.sun.tools.xjc.Options;
import com.sun.tools.xjc.api.ClassNameAllocator;
import com.sun.tools.xjc.api.ErrorListener;
import com.sun.tools.xjc.api.SchemaCompiler;
import com.sun.tools.xjc.api.SpecVersion;
import com.sun.tools.xjc.model.Model;
import com.sun.tools.xjc.outline.Outline;
import com.sun.tools.xjc.reader.internalizer.DOMForest;
import com.sun.tools.xjc.reader.internalizer.SCDBasedBindingSet;
import com.sun.tools.xjc.reader.xmlschema.parser.LSInputSAXWrapper;
import com.sun.tools.xjc.reader.xmlschema.parser.XMLSchemaInternalizationLogic;
import org.glassfish.jaxb.core.unmarshaller.DOMScanner;
import org.glassfish.jaxb.core.v2.util.XmlFactory;
import com.sun.xml.xsom.XSSchemaSet;
import java.nio.file.Files;
import java.nio.file.Paths;

import org.w3c.dom.Element;
import org.w3c.dom.ls.LSInput;
import org.w3c.dom.ls.LSResourceResolver;
import org.xml.sax.ContentHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.LocatorImpl;

/**
 * {@link SchemaCompiler} implementation.
 *
 * This class builds a {@link DOMForest} until the {@link #bind()} method,
 * then this method does the rest of the hard work.
 *
 * @see ModelLoader
 *
 * @author
 *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
 */
public final class SchemaCompilerImpl extends ErrorReceiver implements SchemaCompiler {

    /**
     * User-specified error receiver.
     * This field can be null, in which case errors need to be discarded.
     */
    private ErrorListener errorListener;

    protected final Options opts = new Options();

    protected @NotNull DOMForest forest;

    /**
     * Set to true once an error is found.
     */
    private boolean hadError;

    public SchemaCompilerImpl() {
        opts.compatibilityMode = Options.EXTENSION;
        resetSchema();

        if(System.getProperty("xjc-api.test")!=null) {
            opts.debugMode = true;
            opts.verbose = true;
        }
    }

    @NotNull
    @Override
    public Options getOptions() {
        return opts;
    }

    @Override
    public ContentHandler getParserHandler( String systemId ) {
        return forest.getParserHandler(systemId,true);
    }

    @Override
    public void parseSchema( String systemId, Element element ) {
        checkAbsoluteness(systemId);
        try {
            DOMScanner scanner = new DOMScanner();

            // use a locator that sets the system ID correctly
            // so that we can resolve relative URLs in most of the case.
            // it still doesn't handle xml:base and XInclude and all those things
            // correctly. There's just no way to make all those things work with DOM!
            LocatorImpl loc = new LocatorImpl();
            loc.setSystemId(systemId);
            scanner.setLocator(loc);

            scanner.setContentHandler(getParserHandler(systemId));
            scanner.scan(element);
        } catch (SAXException e) {
            // since parsing DOM shouldn't cause a SAX exception
            // and our handler will never throw it, it's not clear
            // if this will ever happen.
            fatalError(new SAXParseException2(
                e.getMessage(), null, systemId,-1,-1, e));
        }
    }

    @Override
    public void parseSchema(InputSource source) {
        checkAbsoluteness(source.getSystemId());
        try {
            forest.parse(source,true);
        } catch (SAXException e) {
            // parsers are required to report an error to ErrorHandler,
            // so we should never see this error.
            e.printStackTrace();
        }
    }

    @Override
    public void setTargetVersion(SpecVersion version) {
        if(version==null)
            version = SpecVersion.LATEST;
        opts.target = version;
    }

    @Override
    public void parseSchema(String systemId, XMLStreamReader reader) throws XMLStreamException {
        checkAbsoluteness(systemId);
        forest.parse(systemId,reader,true);
    }

    /**
     * Checks if the system ID is absolute.
     */
    @SuppressWarnings("ResultOfObjectAllocationIgnored")
    private void checkAbsoluteness(String systemId) {
        // we need to be able to handle system IDs like "urn:foo", which java.net.URL can't process,
        // but OTOH we also need to be able to process system IDs like "file://a b c/def.xsd",
        // which java.net.URI can't process. So for now, let's fail only if both of them fail.
        // eventually we need a proper URI class that works for us.
        try {
            new URL(systemId);
        } catch( MalformedURLException mue) {
            try {
                new URI(systemId);
            } catch (URISyntaxException e ) {
                throw new IllegalArgumentException("system ID '"+systemId+"' isn't absolute",e);
            }
        }
    }

    @Override
    public void setEntityResolver(EntityResolver entityResolver) {
        forest.setEntityResolver(entityResolver);
        opts.entityResolver = entityResolver;
    }

    @Override
    public void setDefaultPackageName(String packageName) {
        opts.defaultPackage2 = packageName;
    }

    @Override
    public void forcePackageName(String packageName) {
        opts.defaultPackage = packageName;
    }

    @Override
    public void setClassNameAllocator(ClassNameAllocator allocator) {
        opts.classNameAllocator = allocator;
    }

    @Override
    public void resetSchema() {
        forest = new DOMForest(new XMLSchemaInternalizationLogic(), opts);
        forest.setErrorHandler(this);
        forest.setEntityResolver(opts.entityResolver);
    }

    @Override
    public JAXBModelImpl bind() {
        // this has been problematic. turn it off.
//        if(!forest.checkSchemaCorrectness(this))
//            return null;

        // parse all the binding files given via XJC -b options.
        // this also takes care of the binding files given in the -episode option.
        for (InputSource is : opts.getBindFiles())
            parseSchema(is);

        // internalization
        SCDBasedBindingSet scdBasedBindingSet = forest.transform(opts.isExtensionMode());

        if (!NO_CORRECTNESS_CHECK) {
            // correctness check
            SchemaFactory sf = XmlFactory.createSchemaFactory(XMLConstants.W3C_XML_SCHEMA_NS_URI, opts.disableXmlSecurity);

            // fix for https://jaxb.dev.java.net/issues/show_bug.cgi?id=795
            // taken from SchemaConstraintChecker, TODO XXX FIXME UGLY
            if (opts.entityResolver != null) {
                sf.setResourceResolver(new LSResourceResolver() {
                    @Override
                    public LSInput resolveResource(String type, String namespaceURI, String publicId, String systemId, String baseURI) {
                        try {
                            // XSOM passes the namespace URI to the publicID parameter.
                            // we do the same here .
                            InputSource is = opts.entityResolver.resolveEntity(namespaceURI, systemId == null ? "" : systemId);
                            return isExists(is) ? new LSInputSAXWrapper(is) : null;
                        } catch (SAXException | IOException e) {
                            // TODO: is this sufficient?
                            return null;
                        }
                    }
                });
            }

            sf.setErrorHandler(new DowngradingErrorHandler(this));
            forest.weakSchemaCorrectnessCheck(sf);
            if (hadError)
                return null;    // error in the correctness check. abort now
        }

        JCodeModel codeModel = new JCodeModel();

        ModelLoader gl = new ModelLoader(opts,codeModel,this);
        try {
            XSSchemaSet result = gl.createXSOM(forest, scdBasedBindingSet);
            if(result==null)
                return null;

            // we need info about each field, so we go ahead and generate the
            // skeleton at this point.
            // REVISIT: we should separate FieldRenderer and FieldAccessor
            // so that accessors can be used before we build the code.
            Model model = gl.annotateXMLSchema(result);
            if(model==null)   return null;

            if(hadError)        return null;    // if we have any error by now, abort

            model.setPackageLevelAnnotations(opts.packageLevelAnnotations);

            Outline context = model.generateCode(opts,this);
            if(context==null)   return null;

            if(hadError)        return null;

            return new JAXBModelImpl(context);
        } catch( SAXException e ) {
            // since XSOM uses our parser that scans DOM,
            // no parser error is possible.
            // all the other errors will be directed to ErrorReceiver
            // before it's thrown, so when the exception is thrown
            // the error should have already been reported.

            // thus ignore.
            return null;
        }
    }

    @Override
    public void setErrorListener(ErrorListener errorListener) {
        this.errorListener = errorListener;
    }

    @Override
    public void info(SAXParseException exception) {
        if(errorListener!=null)
            errorListener.info(exception);
    }
    @Override
    public void warning(SAXParseException exception) {
        if(errorListener!=null)
            errorListener.warning(exception);
    }
    @Override
    public void error(SAXParseException exception) {
        hadError = true;
        if(errorListener!=null)
            errorListener.error(exception);
    }
    @Override
    public void fatalError(SAXParseException exception) {
        hadError = true;
        if(errorListener!=null)
            errorListener.fatalError(exception);
    }

    private static boolean isExists(InputSource is) {
        if (is == null) {
            return false;
        }
        try {
            URI uri = new URI(is.getSystemId());
            if ("file".equals(uri.getScheme())) {
                return Files.exists(Paths.get(uri));
            }
        } catch (URISyntaxException ex) {
            //ignore, let it be handled by parser as is
        }
        return true;
    }

    /**
     * We use JAXP 1.3 to do a schema correctness check, but we know
     * it doesn't always work. So in case some people hit the problem,
     * this switch is here so that they can turn it off as a workaround.
     */
    private static boolean NO_CORRECTNESS_CHECK = false;

    static {
        try {
            NO_CORRECTNESS_CHECK = Boolean.getBoolean(SchemaCompilerImpl.class.getName()+".noCorrectnessCheck");
        } catch( Throwable t) {
            // ignore
        }
    }
}