/*
    * 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.maven.plugins.changes.schema;
  
  import javax.inject.Named;
  import javax.inject.Singleton;
  import javax.xml.transform.stream.StreamSource;
  import javax.xml.validation.Schema;
  import javax.xml.validation.SchemaFactory;
  import javax.xml.validation.Validator;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.commons.io.input.XmlStreamReader;
  import org.xml.sax.SAXException;
  
  /**
   * @author Olivier Lamy
   * @since 28 juil. 2008
   * @version $Id$
   */
  @Named
  @Singleton
  public class DefaultChangesSchemaValidator implements ChangesSchemaValidator {
  
      /** property schema */
      public static final String W3C_XML_SCHEMA = "http://www.w3.org/2001/XMLSchema";
  
      public static final String CHANGES_SCHEMA_PATH = "META-INF/changes/xsd/";
  
      private Map<String, Schema> compiledSchemas = new HashMap<>();
  
      public XmlValidationHandler validateXmlWithSchema(File file, String schemaVersion, boolean failOnValidationError)
              throws SchemaValidatorException {
          try {
              String schemaPath = CHANGES_SCHEMA_PATH + "changes-" + schemaVersion + ".xsd";
  
              Schema schema = getSchema(schemaPath);
  
              Validator validator = schema.newValidator();
  
              XmlValidationHandler baseHandler = new XmlValidationHandler(failOnValidationError);
  
              validator.setErrorHandler(baseHandler);
  
              try (Reader reader = XmlStreamReader.builder().setFile(file).get()) {
                  validator.validate(new StreamSource(reader));
              }
  
              return baseHandler;
          } catch (IOException e) {
              throw new SchemaValidatorException("IOException : " + e.getMessage(), e);
          } catch (SAXException e) {
              throw new SchemaValidatorException("SAXException : " + e.getMessage(), e);
          } catch (Exception e) {
              throw new SchemaValidatorException("Exception : " + e.getMessage(), e);
          }
      }
  
      public Schema getSchema(String schemaPath) throws SAXException, IOException {
          if (this.compiledSchemas.containsKey(schemaPath)) {
              return this.compiledSchemas.get(schemaPath);
          }
          Schema schema = this.compileJAXPSchema(schemaPath);
  
          this.compiledSchemas.put(schemaPath, schema);
  
          return schema;
      }
  
      private Schema compileJAXPSchema(String uriSchema) throws IOException, SAXException, NullPointerException {
          try (InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream(uriSchema)) {
              if (in == null) {
                  throw new NullPointerException(" impossible to load schema with path " + uriSchema);
              }
  
              // newInstance de SchemaFactory not ThreadSafe
              final Schema schema = SchemaFactory.newInstance(W3C_XML_SCHEMA).newSchema(new StreamSource(in));
             return schema;
         }
     }
 
     public void loadSchema(String uriSchema) throws SchemaValidatorException {
         try {
             this.getSchema(uriSchema);
         } catch (SAXException e) {
             throw new SchemaValidatorException("SAXException : " + e.getMessage(), e);
         } catch (IOException e) {
             throw new SchemaValidatorException("IOException : " + e.getMessage(), e);
         }
     }
 }