/*
    * Copyright 2013-2020 the original author or authors.
    *
    * Licensed 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
    *
    *      https://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.springframework.cloud.contract.maven.verifier;
  
  import java.io.File;
  
  import org.apache.maven.execution.MavenSession;
  import org.apache.maven.plugin.MojoExecution;
  import org.apache.maven.plugin.MojoExecutionException;
  import org.apache.maven.shared.incremental.IncrementalBuildHelper;
  import org.apache.maven.shared.utils.io.DirectoryScanner;
  
  final class ChangeDetector {
  
  	private ChangeDetector() {
  	}
  
  	static boolean inputFilesChangeDetected(File contractsDirectory, MojoExecution mojoExecution, MavenSession session)
  			throws MojoExecutionException {
  		if (session.getGoals().contains("clean")) {
  			return true;
  		}
  		IncrementalBuildHelper incrementalBuildHelper = new IncrementalBuildHelper(mojoExecution, session);
  
  		DirectoryScanner scanner = incrementalBuildHelper.getDirectoryScanner();
  		scanner.setBasedir(contractsDirectory);
  		scanner.scan();
  		boolean changeDetected = incrementalBuildHelper.inputFileTreeChanged(scanner);
  		if (scanner.getIncludedFiles().length == 0) {
  			// at least one input file must exist to consider changed/unchanged
  			// return true to skip incremental build and make visible no input file at all
  			return true;
  		}
  		return changeDetected;
  	}
  
  }