/*
    * 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.settings.building;
  
  import javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.io.File;
  import java.io.IOException;
  import java.io.StringReader;
  import java.io.StringWriter;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.building.FileSource;
  import org.apache.maven.building.Source;
  import org.apache.maven.settings.Settings;
  import org.apache.maven.settings.TrackableBase;
  import org.apache.maven.settings.io.SettingsParseException;
  import org.apache.maven.settings.io.SettingsReader;
  import org.apache.maven.settings.io.SettingsWriter;
  import org.apache.maven.settings.merge.MavenSettingsMerger;
  import org.apache.maven.settings.validation.SettingsValidator;
  import org.codehaus.plexus.interpolation.EnvarBasedValueSource;
  import org.codehaus.plexus.interpolation.InterpolationException;
  import org.codehaus.plexus.interpolation.PropertiesBasedValueSource;
  import org.codehaus.plexus.interpolation.RegexBasedInterpolator;
  
  /**
   * Builds the effective settings from a user settings file and/or a global settings file.
   *
   * @author Benjamin Bentmann
   */
  @Named
  @Singleton
  public class DefaultSettingsBuilder implements SettingsBuilder {
  
      private SettingsReader settingsReader;
  
      private SettingsWriter settingsWriter;
  
      private SettingsValidator settingsValidator;
  
      private final MavenSettingsMerger settingsMerger = new MavenSettingsMerger();
  
      @Inject
      public DefaultSettingsBuilder(
              SettingsReader settingsReader, SettingsWriter settingsWriter, SettingsValidator settingsValidator) {
          this.settingsReader = settingsReader;
          this.settingsWriter = settingsWriter;
          this.settingsValidator = settingsValidator;
      }
  
      public DefaultSettingsBuilder setSettingsReader(SettingsReader settingsReader) {
          this.settingsReader = settingsReader;
          return this;
      }
  
      public DefaultSettingsBuilder setSettingsWriter(SettingsWriter settingsWriter) {
          this.settingsWriter = settingsWriter;
          return this;
      }
  
      public DefaultSettingsBuilder setSettingsValidator(SettingsValidator settingsValidator) {
          this.settingsValidator = settingsValidator;
          return this;
      }
  
      @Override
      public SettingsBuildingResult build(SettingsBuildingRequest request) throws SettingsBuildingException {
          DefaultSettingsProblemCollector problems = new DefaultSettingsProblemCollector(null);
  
          Source globalSettingsSource =
                  getSettingsSource(request.getGlobalSettingsFile(), request.getGlobalSettingsSource());
          Settings globalSettings = readSettings(globalSettingsSource, request, problems);
  
          Source userSettingsSource = getSettingsSource(request.getUserSettingsFile(), request.getUserSettingsSource());
          Settings userSettings = readSettings(userSettingsSource, request, problems);
  
          settingsMerger.merge(userSettings, globalSettings, TrackableBase.GLOBAL_LEVEL);
  
         problems.setSource("");
 
         userSettings = interpolate(userSettings, request, problems);
 
         // for the special case of a drive-relative Windows path, make sure it's absolute to save plugins from trouble
         String localRepository = userSettings.getLocalRepository();
         if (localRepository != null && localRepository.length() > 0) {
             File file = new File(localRepository);
             if (!file.isAbsolute() && file.getPath().startsWith(File.separator)) {
                 userSettings.setLocalRepository(file.getAbsolutePath());
             }
         }
 
         if (hasErrors(problems.getProblems())) {
             throw new SettingsBuildingException(problems.getProblems());
         }
 
         return new DefaultSettingsBuildingResult(userSettings, problems.getProblems());
     }
 
     private boolean hasErrors(List<SettingsProblem> problems) {
         if (problems != null) {
             for (SettingsProblem problem : problems) {
                 if (SettingsProblem.Severity.ERROR.compareTo(problem.getSeverity()) >= 0) {
                     return true;
                 }
             }
         }
 
         return false;
     }
 
     private Source getSettingsSource(File settingsFile, Source settingsSource) {
         if (settingsSource != null) {
             return settingsSource;
         } else if (settingsFile != null && settingsFile.exists()) {
             return new FileSource(settingsFile);
         }
         return null;
     }
 
     private Settings readSettings(
             Source settingsSource, SettingsBuildingRequest request, DefaultSettingsProblemCollector problems) {
         if (settingsSource == null) {
             return new Settings();
         }
 
         problems.setSource(settingsSource.getLocation());
 
         Settings settings;
 
         try {
             Map<String, ?> options = Collections.singletonMap(SettingsReader.IS_STRICT, Boolean.TRUE);
 
             try {
                 settings = settingsReader.read(settingsSource.getInputStream(), options);
             } catch (SettingsParseException e) {
                 options = Collections.singletonMap(SettingsReader.IS_STRICT, Boolean.FALSE);
 
                 settings = settingsReader.read(settingsSource.getInputStream(), options);
 
                 problems.add(
                         SettingsProblem.Severity.WARNING, e.getMessage(), e.getLineNumber(), e.getColumnNumber(), e);
             }
         } catch (SettingsParseException e) {
             problems.add(
                     SettingsProblem.Severity.FATAL,
                     "Non-parseable settings " + settingsSource.getLocation() + ": " + e.getMessage(),
                     e.getLineNumber(),
                     e.getColumnNumber(),
                     e);
             return new Settings();
         } catch (IOException e) {
             problems.add(
                     SettingsProblem.Severity.FATAL,
                     "Non-readable settings " + settingsSource.getLocation() + ": " + e.getMessage(),
                     -1,
                     -1,
                     e);
             return new Settings();
         }
 
         settingsValidator.validate(settings, problems);
 
         return settings;
     }
 
     private Settings interpolate(
             Settings settings, SettingsBuildingRequest request, SettingsProblemCollector problems) {
         StringWriter writer = new StringWriter(1024 * 4);
 
         try {
             settingsWriter.write(writer, null, settings);
         } catch (IOException e) {
             throw new IllegalStateException("Failed to serialize settings to memory", e);
         }
 
         String serializedSettings = writer.toString();
 
         RegexBasedInterpolator interpolator = new RegexBasedInterpolator();
 
         interpolator.addValueSource(new PropertiesBasedValueSource(request.getUserProperties()));
 
         interpolator.addValueSource(new PropertiesBasedValueSource(request.getSystemProperties()));
 
         try {
             interpolator.addValueSource(new EnvarBasedValueSource());
         } catch (IOException e) {
             problems.add(
                     SettingsProblem.Severity.WARNING,
                     "Failed to use environment variables for interpolation: " + e.getMessage(),
                     -1,
                     -1,
                     e);
         }
 
         interpolator.addPostProcessor((expression, value) -> {
             if (value != null) {
                 // we're going to parse this back in as XML so we need to escape XML markup
                 value = value.toString()
                         .replace("&", "&amp;")
                         .replace("<", "&lt;")
                         .replace(">", "&gt;");
                 return value;
             }
             return null;
         });
 
         try {
             serializedSettings = interpolator.interpolate(serializedSettings, "settings");
         } catch (InterpolationException e) {
             problems.add(
                     SettingsProblem.Severity.ERROR, "Failed to interpolate settings: " + e.getMessage(), -1, -1, e);
 
             return settings;
         }
 
         Settings result;
         try {
             Map<String, ?> options = Collections.singletonMap(SettingsReader.IS_STRICT, Boolean.FALSE);
             result = settingsReader.read(new StringReader(serializedSettings), options);
         } catch (IOException e) {
             problems.add(
                     SettingsProblem.Severity.ERROR, "Failed to interpolate settings: " + e.getMessage(), -1, -1, e);
             return settings;
         }
 
         return result;
     }
 }