/*
 * Copyright 2007 Sascha Weinreuter
 *
 * 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.intellij.plugins.relaxNG.validation;

import com.intellij.javaee.UriUtil;
import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.progress.ProgressManager;
import com.intellij.openapi.util.AtomicNotNullLazyValue;
import com.intellij.openapi.util.Key;
import com.intellij.openapi.util.NotNullLazyValue;
import com.intellij.openapi.vfs.VfsUtilCore;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.PsiFile;
import com.intellij.psi.search.PsiElementProcessor;
import com.intellij.psi.util.CachedValue;
import com.intellij.psi.util.CachedValueProvider;
import com.intellij.psi.util.CachedValuesManager;
import com.intellij.psi.xml.XmlFile;
import com.intellij.util.containers.ContainerUtil;
import com.thaiopensource.datatype.xsd.DatatypeLibraryFactoryImpl;
import com.thaiopensource.relaxng.impl.SchemaReaderImpl;
import com.thaiopensource.util.PropertyMap;
import com.thaiopensource.util.PropertyMapBuilder;
import com.thaiopensource.validate.Schema;
import com.thaiopensource.xml.sax.Sax2XMLReaderCreator;
import com.thaiopensource.xml.sax.XMLReaderCreator;
import org.intellij.plugins.relaxNG.compact.RncFileType;
import org.intellij.plugins.relaxNG.model.resolve.RelaxIncludeIndex;
import org.jetbrains.annotations.NotNull;
import org.kohsuke.rngom.ast.builder.BuildException;
import org.kohsuke.rngom.ast.builder.IncludedGrammar;
import org.kohsuke.rngom.ast.builder.SchemaBuilder;
import org.kohsuke.rngom.ast.om.ParsedPattern;
import org.kohsuke.rngom.binary.SchemaBuilderImpl;
import org.kohsuke.rngom.binary.SchemaPatternBuilder;
import org.kohsuke.rngom.digested.DPattern;
import org.kohsuke.rngom.digested.DSchemaBuilderImpl;
import org.kohsuke.rngom.dt.CachedDatatypeLibraryFactory;
import org.kohsuke.rngom.dt.CascadingDatatypeLibraryFactory;
import org.kohsuke.rngom.dt.DoNothingDatatypeLibraryFactoryImpl;
import org.kohsuke.rngom.dt.builtin.BuiltinDatatypeLibraryFactory;
import org.kohsuke.rngom.parse.IllegalSchemaException;
import org.kohsuke.rngom.parse.Parseable;
import org.kohsuke.rngom.parse.compact.CompactParseable;
import org.kohsuke.rngom.parse.xml.SAXParseable;
import org.relaxng.datatype.DatatypeLibrary;
import org.relaxng.datatype.DatatypeLibraryFactory;
import org.relaxng.datatype.helpers.DatatypeLibraryLoader;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import java.io.StringReader;
import java.util.concurrent.ConcurrentMap;

public class RngParser {
  private static final Logger LOG = Logger.getInstance("#org.intellij.plugins.relaxNG.validation.RngParser");

  private static final NotNullLazyValue<DatatypeLibraryFactory> DT_LIBRARY_FACTORY = new AtomicNotNullLazyValue<DatatypeLibraryFactory>() {
    @NotNull
    @Override
    protected DatatypeLibraryFactory compute() {
      return new BuiltinDatatypeLibraryFactory(new CachedDatatypeLibraryFactory(
        new CascadingDatatypeLibraryFactory(createXsdDatatypeFactory(), new DatatypeLibraryLoader())) {
          @Override
          public synchronized DatatypeLibrary createDatatypeLibrary(String namespaceURI) {
            return super.createDatatypeLibrary(namespaceURI);
          }
        });
    }
  };

  private static final ConcurrentMap<String, DPattern> ourCache = ContainerUtil.createConcurrentSoftMap();

  private static DatatypeLibraryFactory createXsdDatatypeFactory() {
    try {
      return new DatatypeLibraryFactoryImpl();
    } catch (Throwable e) {
      LOG.error("Could not create DT library implementation 'com.thaiopensource.datatype.xsd.DatatypeLibraryFactoryImpl'. Plugin's classpath seems to be broken.", e);
      return new DoNothingDatatypeLibraryFactoryImpl();
    }
  }

  static final Key<CachedValue<Schema>> SCHEMA_KEY = Key.create("SCHEMA");

  public static final DefaultHandler DEFAULT_HANDLER = new DefaultHandler() {
    @Override
    public void error(SAXParseException e) throws SAXException {
      LOG.info("e.getMessage() = " + e.getMessage() + " [" + e.getSystemId() + "]");
      LOG.info(e);
    }
  };

  static final PropertyMap EMPTY_PROPS = new PropertyMapBuilder().toPropertyMap();

  public static DPattern getCachedPattern(final PsiFile descriptorFile, final ErrorHandler eh) {
    final VirtualFile file = descriptorFile.getVirtualFile();

    if (file == null) {
      return parsePattern(descriptorFile, eh, false);
    }
    String url = file.getUrl();
    DPattern pattern = ourCache.get(url);
    if (pattern == null) {
      pattern = parsePattern(descriptorFile, eh, false);
    }
    if (pattern != null) {
      DPattern oldPattern = ourCache.putIfAbsent(url, pattern);
      if (oldPattern != null) {
        return oldPattern;
      }
    }
    return pattern;
  }

  public static DPattern parsePattern(final PsiFile file, final ErrorHandler eh, boolean checking) {
    try {
      final Parseable p = createParsable(file, eh);
      if (checking) {
        p.parse(new SchemaBuilderImpl(eh, DT_LIBRARY_FACTORY.getValue(), new SchemaPatternBuilder()));
      } else {
        return p.parse(new DSchemaBuilderImpl());
      }
    } catch (BuildException e) {
      LOG.info(e);
    } catch (IllegalSchemaException e) {
      final VirtualFile virtualFile = file.getVirtualFile();
      if (virtualFile != null) {
        if (LOG.isDebugEnabled()) {
          LOG.debug("invalid schema: " + virtualFile.getPresentableUrl(), e);
        } else {
          LOG.info("invalid schema: " + virtualFile.getPresentableUrl() + ". [" + e.getMessage() + "]");
        }
      }
    }
    return null;
  }

  private static Parseable createParsable(final PsiFile file, final ErrorHandler eh) {
    final InputSource source = makeInputSource(file);
    final VirtualFile virtualFile = file.getVirtualFile();

    if (file.getFileType() == RncFileType.getInstance()) {
      return new CompactParseable(source, eh) {
        @Override
        public ParsedPattern parseInclude(String uri, SchemaBuilder schemaBuilder, IncludedGrammar g, String inheritedNs)
                throws BuildException, IllegalSchemaException
        {
          ProgressManager.checkCanceled();
          return super.parseInclude(resolveURI(virtualFile, uri), schemaBuilder, g, inheritedNs);
        }
      };
    } else {
      return new SAXParseable(source, eh) {
        @Override
        public ParsedPattern parseInclude(String uri, SchemaBuilder schemaBuilder, IncludedGrammar g, String inheritedNs)
                throws BuildException, IllegalSchemaException
        {
          ProgressManager.checkCanceled();
          return super.parseInclude(resolveURI(virtualFile, uri), schemaBuilder, g, inheritedNs);
        }
      };
    }
  }

  private static String resolveURI(VirtualFile descriptorFile, String s) {
    final VirtualFile file = UriUtil.findRelativeFile(s, descriptorFile);
    if (file != null) {
      s = VfsUtilCore.fixIDEAUrl(file.getUrl());
    }
    return s;
  }

  public static Schema getCachedSchema(final XmlFile descriptorFile) {
    CachedValue<Schema> value = descriptorFile.getUserData(SCHEMA_KEY);
    if (value == null) {
      final CachedValueProvider<Schema> provider = () -> {
        final InputSource inputSource = makeInputSource(descriptorFile);

        try {
          final Schema schema = new MySchemaReader(descriptorFile).createSchema(inputSource, EMPTY_PROPS);
          final PsiElementProcessor.CollectElements<XmlFile> processor = new PsiElementProcessor.CollectElements<>();
          RelaxIncludeIndex.processForwardDependencies(descriptorFile, processor);
          if (processor.getCollection().size() > 0) {
            return CachedValueProvider.Result.create(schema, processor.toArray(), descriptorFile);
          } else {
            return CachedValueProvider.Result.createSingleDependency(schema, descriptorFile);
          }
        } catch (Exception e) {
          LOG.info(e);
          return CachedValueProvider.Result.createSingleDependency(null, descriptorFile);
        }
      };

      final CachedValuesManager mgr = CachedValuesManager.getManager(descriptorFile.getProject());
      value = mgr.createCachedValue(provider,  false);
      descriptorFile.putUserData(SCHEMA_KEY, value);
    }
    return value.getValue();
  }

  private static InputSource makeInputSource(PsiFile descriptorFile) {
    final InputSource inputSource = new InputSource(new StringReader(descriptorFile.getText()));
    final VirtualFile file = descriptorFile.getVirtualFile();
    if (file != null) {
      inputSource.setSystemId(VfsUtilCore.fixIDEAUrl(file.getUrl()));
    }
    return inputSource;
  }

  static class MySchemaReader extends SchemaReaderImpl {
    private final PsiFile myDescriptorFile;

    public MySchemaReader(PsiFile descriptorFile) {
      myDescriptorFile = descriptorFile;
    }

    @Override
    protected com.thaiopensource.relaxng.parse.Parseable createParseable(XMLReaderCreator xmlReaderCreator, InputSource inputSource, ErrorHandler errorHandler) {
      if (myDescriptorFile.getFileType() == RncFileType.getInstance()) {
        return new com.thaiopensource.relaxng.parse.compact.CompactParseable(inputSource, errorHandler);
      } else {
        return new com.thaiopensource.relaxng.parse.sax.SAXParseable(new Sax2XMLReaderCreator(), inputSource, errorHandler);
      }
    }
  }
}