/*
    * 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.pmd.exec;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FilterReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.apache.maven.plugins.pmd.model.PmdErrorDetail;
  import org.apache.maven.plugins.pmd.model.PmdFile;
  import org.apache.maven.plugins.pmd.model.ProcessingError;
  import org.apache.maven.plugins.pmd.model.SuppressedViolation;
  import org.apache.maven.plugins.pmd.model.Violation;
  import org.apache.maven.plugins.pmd.model.io.xpp3.PmdXpp3Reader;
  import org.apache.maven.reporting.MavenReportException;
  
  /**
   * Provides access to the result of the pmd analysis.
   */
  public class PmdResult {
      private final List<ProcessingError> processingErrors = new ArrayList<>();
      private final List<Violation> violations = new ArrayList<>();
      private final List<SuppressedViolation> suppressedViolations = new ArrayList<>();
  
      public static final PmdResult EMPTY = new PmdResult();
  
      private PmdResult() {}
  
      public PmdResult(File pmdFile, String encoding) throws MavenReportException {
          loadResult(pmdFile, encoding);
      }
  
      public boolean hasViolations() {
          return !violations.isEmpty();
      }
  
      private void loadResult(File pmdFile, String encoding) throws MavenReportException {
          try (Reader reader1 = new BomFilter(encoding, new InputStreamReader(new FileInputStream(pmdFile), encoding))) {
              PmdXpp3Reader reader = new PmdXpp3Reader();
              PmdErrorDetail details = reader.read(reader1, false);
              processingErrors.addAll(details.getErrors());
              suppressedViolations.addAll(details.getSuppressedViolations());
  
              for (PmdFile file : details.getFiles()) {
                  String filename = file.getName();
                  for (Violation violation : file.getViolations()) {
                      violation.setFileName(filename);
                      violations.add(violation);
                  }
              }
          } catch (Exception e) {
              throw new MavenReportException(e.getMessage(), e);
          }
      }
  
      // Note: This seems to be a bug in PMD's XMLRenderer. The BOM is rendered multiple times.
      // once at the beginning of the file, which is Ok, but also in the middle of the file.
      // This filter just skips all BOMs if the encoding is not UTF-8
      private static class BomFilter extends FilterReader {
          private static final char BOM = '\uFEFF';
          private final boolean filter;
  
          BomFilter(String encoding, Reader in) {
              super(in);
              filter = !"UTF-8".equalsIgnoreCase(encoding);
          }
  
          @Override
          public int read() throws IOException {
              int c = super.read();
  
              if (!filter) {
                  return c;
              }
  
              while (c != -1 && c == BOM) {
                  c = super.read();
             }
             return c;
         }
 
         @Override
         public int read(char[] cbuf, int off, int len) throws IOException {
             int count = super.read(cbuf, off, len);
 
             if (!filter) {
                 return count;
             }
 
             if (count != -1) {
                 for (int i = off; i < off + count; i++) {
                     if (cbuf[i] == BOM) {
                         // shift the content one char to the left
                         System.arraycopy(cbuf, i + 1, cbuf, i, off + count - 1 - i);
                         count--;
                     }
                 }
             }
             return count;
         }
     }
 
     public Collection<Violation> getViolations() {
         return violations;
     }
 
     public Collection<SuppressedViolation> getSuppressedViolations() {
         return suppressedViolations;
     }
 
     public Collection<ProcessingError> getErrors() {
         return processingErrors;
     }
 }