/*
    * 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.internal.impl;
  
  import javax.xml.stream.Location;
  import javax.xml.stream.XMLStreamException;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.function.Function;
  
  import org.apache.maven.api.di.Inject;
  import org.apache.maven.api.di.Named;
  import org.apache.maven.api.services.BuilderProblem;
  import org.apache.maven.api.services.Interpolator;
  import org.apache.maven.api.services.Source;
  import org.apache.maven.api.services.ToolchainsBuilder;
  import org.apache.maven.api.services.ToolchainsBuilderException;
  import org.apache.maven.api.services.ToolchainsBuilderRequest;
  import org.apache.maven.api.services.ToolchainsBuilderResult;
  import org.apache.maven.api.services.xml.ToolchainsXmlFactory;
  import org.apache.maven.api.services.xml.XmlReaderException;
  import org.apache.maven.api.services.xml.XmlReaderRequest;
  import org.apache.maven.api.toolchain.PersistedToolchains;
  import org.apache.maven.internal.impl.model.DefaultInterpolator;
  import org.apache.maven.toolchain.v4.MavenToolchainsMerger;
  import org.apache.maven.toolchain.v4.MavenToolchainsTransformer;
  
  /**
   * Builds the effective toolchains from a user toolchains file and/or a global toolchains file.
   *
   */
  @Named
  public class DefaultToolchainsBuilder implements ToolchainsBuilder {
  
      private final MavenToolchainsMerger toolchainsMerger = new MavenToolchainsMerger();
  
      private final Interpolator interpolator;
  
      private final ToolchainsXmlFactory toolchainsXmlFactory;
  
      public DefaultToolchainsBuilder() {
          this(new DefaultInterpolator(), new DefaultToolchainsXmlFactory());
      }
  
      @Inject
      public DefaultToolchainsBuilder(Interpolator interpolator, ToolchainsXmlFactory toolchainsXmlFactory) {
          this.interpolator = interpolator;
          this.toolchainsXmlFactory = toolchainsXmlFactory;
      }
  
      @Override
      public ToolchainsBuilderResult build(ToolchainsBuilderRequest request) throws ToolchainsBuilderException {
          List<BuilderProblem> problems = new ArrayList<>();
  
          Source installationSource = request.getInstallationToolchainsSource().orElse(null);
          PersistedToolchains installation = readToolchains(installationSource, request, problems);
  
          Source userSource = request.getUserToolchainsSource().orElse(null);
          PersistedToolchains user = readToolchains(userSource, request, problems);
  
          PersistedToolchains effective = toolchainsMerger.merge(user, installation, false, null);
  
          if (hasErrors(problems)) {
              throw new ToolchainsBuilderException("Error building toolchains", problems);
          }
  
          return new DefaultToolchainsBuilderResult(effective, problems);
      }
  
      private boolean hasErrors(List<BuilderProblem> problems) {
          if (problems != null) {
              for (BuilderProblem problem : problems) {
                  if (BuilderProblem.Severity.ERROR.compareTo(problem.getSeverity()) >= 0) {
                      return true;
                  }
              }
          }
  
          return false;
     }
 
     private PersistedToolchains readToolchains(
             Source toolchainsSource, ToolchainsBuilderRequest request, List<BuilderProblem> problems) {
         if (toolchainsSource == null) {
             return PersistedToolchains.newInstance();
         }
 
         PersistedToolchains toolchains;
 
         try {
             try {
                 InputStream is = toolchainsSource.openStream();
                 if (is == null) {
                     return PersistedToolchains.newInstance();
                 }
                 toolchains = toolchainsXmlFactory.read(XmlReaderRequest.builder()
                         .inputStream(is)
                         .location(toolchainsSource.getLocation())
                         .strict(true)
                         .build());
             } catch (XmlReaderException e) {
                 InputStream is = toolchainsSource.openStream();
                 if (is == null) {
                     return PersistedToolchains.newInstance();
                 }
                 toolchains = toolchainsXmlFactory.read(XmlReaderRequest.builder()
                         .inputStream(is)
                         .location(toolchainsSource.getLocation())
                         .strict(false)
                         .build());
                 Location loc = e.getCause() instanceof XMLStreamException xe ? xe.getLocation() : null;
                 problems.add(new DefaultBuilderProblem(
                         toolchainsSource.getLocation(),
                         loc != null ? loc.getLineNumber() : -1,
                         loc != null ? loc.getColumnNumber() : -1,
                         e,
                         e.getMessage(),
                         BuilderProblem.Severity.WARNING));
             }
         } catch (XmlReaderException e) {
             Location loc = e.getCause() instanceof XMLStreamException xe ? xe.getLocation() : null;
             problems.add(new DefaultBuilderProblem(
                     toolchainsSource.getLocation(),
                     loc != null ? loc.getLineNumber() : -1,
                     loc != null ? loc.getColumnNumber() : -1,
                     e,
                     "Non-parseable toolchains " + toolchainsSource.getLocation() + ": " + e.getMessage(),
                     BuilderProblem.Severity.FATAL));
             return PersistedToolchains.newInstance();
         } catch (IOException e) {
             problems.add(new DefaultBuilderProblem(
                     toolchainsSource.getLocation(),
                     -1,
                     -1,
                     e,
                     "Non-readable toolchains " + toolchainsSource.getLocation() + ": " + e.getMessage(),
                     BuilderProblem.Severity.FATAL));
             return PersistedToolchains.newInstance();
         }
 
         toolchains = interpolate(toolchains, request, problems);
 
         return toolchains;
     }
 
     private PersistedToolchains interpolate(
             PersistedToolchains toolchains, ToolchainsBuilderRequest request, List<BuilderProblem> problems) {
         Map<String, String> userProperties = request.getSession().getUserProperties();
         Map<String, String> systemProperties = request.getSession().getSystemProperties();
         Function<String, String> src = Interpolator.chain(userProperties::get, systemProperties::get);
         return new MavenToolchainsTransformer(value -> value != null ? interpolator.interpolate(value, src) : null)
                 .visit(toolchains);
     }
 
     /**
      * Collects the output of the toolchains builder.
      *
      */
     static class DefaultToolchainsBuilderResult implements ToolchainsBuilderResult {
 
         private final PersistedToolchains effectiveToolchains;
 
         private final List<BuilderProblem> problems;
 
         DefaultToolchainsBuilderResult(PersistedToolchains effectiveToolchains, List<BuilderProblem> problems) {
             this.effectiveToolchains = effectiveToolchains;
             this.problems = (problems != null) ? problems : new ArrayList<>();
         }
 
         @Override
         public PersistedToolchains getEffectiveToolchains() {
             return effectiveToolchains;
         }
 
         @Override
         public List<BuilderProblem> getProblems() {
             return problems;
         }
     }
 }