/*
 * 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.freemarker.generator;

import java.nio.file.FileVisitResult;
import java.nio.file.Path;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Map;

import org.apache.maven.execution.MavenSession;

import freemarker.template.Configuration;

/**
 * FileVisitor designed to process json data files. The json file parsed into
 * a map and given to FreeMarker to 
 */
public class GeneratingFileVisitor extends SimpleFileVisitor<Path> {

  private final Configuration config;
  private final MavenSession session;
  private final long pomLastModifiedTimestamp;
  private final Map<String, OutputGeneratorPropertiesProvider > extensionToBuilder;

  private GeneratingFileVisitor(Configuration config, MavenSession session, Map<String, OutputGeneratorPropertiesProvider> extensionToBuilder) {
    this.config = config;
    this.session = session;
    this.extensionToBuilder = extensionToBuilder;
    this.pomLastModifiedTimestamp = session.getAllProjects().stream()
        .map(project->project.getFile().lastModified())
        .reduce(Long::max)
        .orElse(0L);
  }

  /**
   * Factory method that calls constructor, added to facilitate testing with jmockit.
   */
  public static GeneratingFileVisitor create(Configuration config, MavenSession session, Map<String, OutputGeneratorPropertiesProvider> extensionToBuilder) {
    return new GeneratingFileVisitor(config, session, extensionToBuilder);
  }

  @Override
  public FileVisitResult visitFile(Path path, BasicFileAttributes attrs) {
    if (attrs.isRegularFile()) {
      OutputGenerator.OutputGeneratorBuilder builder = OutputGenerator.builder()
          .addGeneratorLocation(path)
          .addPomLastModifiedTimestamp(pomLastModifiedTimestamp);
      String fileName = path.getFileName().toString();
      String extenstion = fileName.substring(fileName.lastIndexOf('.'));
      OutputGeneratorPropertiesProvider pathProcessor = extensionToBuilder.get(extenstion);
      if (pathProcessor == null) {
        throw new RuntimeException("Unknown file extension: " + path);
      }
      pathProcessor.providePropertiesFromFile(path, builder);
      builder.addToDataModel("pomProperties", session.getCurrentProject().getProperties());
      builder.create().generate(config);
    }
    return FileVisitResult.CONTINUE;
  }
}