/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.maven.plugin;
   
   import org.apache.maven.plugin.MojoExecutionException;
   import org.apache.maven.plugins.annotations.LifecyclePhase;
  import org.apache.maven.plugins.annotations.Mojo;
  import org.apache.maven.plugins.annotations.Parameter;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import dev.metaschema.core.model.IModule;
  import dev.metaschema.core.util.ObjectUtils;
  import dev.metaschema.databind.codegen.IProduction;
  import dev.metaschema.databind.codegen.JavaGenerator;
  import dev.metaschema.databind.codegen.config.DefaultBindingConfiguration;
  import dev.metaschema.databind.io.BindingException;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * Goal which generates Java source files for a given set of Metaschema modules.
   */
  @Mojo(name = "generate-sources", defaultPhase = LifecyclePhase.GENERATE_SOURCES)
  public class GenerateSourcesMojo
      extends AbstractMetaschemaMojo {
    private static final String STALE_FILE_NAME = "generateSourcesStaleFile";
  
    /**
     * A set of binding configurations.
     */
    @Parameter
    protected File[] configs;
  
    /**
     * <p>
     * Gets the last part of the stale filename.
     * </p>
     * <p>
     * The full stale filename will be generated by pre-pending
     * {@code "." + getExecution().getExecutionId()} to this staleFileName.
     *
     * @return the stale filename postfix
     */
    @Override
    protected String getStaleFileName() {
      return STALE_FILE_NAME;
    }
  
    /**
     * Retrieve a list of binding configurations.
     *
     * @return the collection of binding configurations
     */
    protected List<File> getConfigs() {
      List<File> retval;
      if (configs == null) {
        retval = Collections.emptyList();
      } else {
        retval = Arrays.asList(configs);
      }
      return retval;
    }
  
    /**
     * Generate the Java source files for the provided Metaschemas.
     *
     * @param modules
     *          the collection of Metaschema modules to generate sources for
     * @return the list of generated Java source files
     * @throws MojoExecutionException
     *           if an error occurred while generating sources
     */
    @Override
    @NonNull
    protected List<File> generate(@NonNull Set<IModule> modules) throws MojoExecutionException {
      DefaultBindingConfiguration bindingConfiguration = new DefaultBindingConfiguration();
      for (File config : getConfigs()) {
        try {
          if (getLog().isInfoEnabled()) {
            getLog().info("Loading binding configuration: " + config.getPath());
          }
          bindingConfiguration.load(config);
        } catch (IOException | BindingException ex) {
          throw new MojoExecutionException(
              String.format("Unable to load binding configuration from '%s'.", config.getPath()), ex);
        }
      }
  
      IProduction production;
      try {
       if (getLog().isInfoEnabled()) {
         getLog().info("Generating Java classes in: " + getOutputDirectory().getPath());
       }
       production = JavaGenerator.generate(
           modules,
           ObjectUtils.notNull(getOutputDirectory().toPath()),
           bindingConfiguration);
     } catch (IOException ex) {
       throw new MojoExecutionException("Creation of Java classes failed.", ex);
     }
 
     // add generated sources to Maven
     try {
       getMavenProject().addCompileSourceRoot(getOutputDirectory().getCanonicalFile().getPath());
     } catch (IOException ex) {
       throw new MojoExecutionException("Unable to add output directory to maven sources.", ex);
     }
 
     return ObjectUtils.notNull(production.getGeneratedClasses()
         .map(gen -> gen.getClassFile().toFile())
         .collect(Collectors.toUnmodifiableList()));
   }
 }