/**
 * Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.opengamma.util.annotation;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Set;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.Reference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Scans for annotations and writes the names of classes using them to a file.
 */
public class AnnotationScannerTask extends Task {
  
  private static final Logger s_logger = LoggerFactory.getLogger(AnnotationScannerTask.class);
  
  private String _outputFile;
  private String _annotationClassName;
  
  private String[] _classpath;
  
  private String getOutputFile() {
    return _outputFile;
  }
  
  public void setOutputFile(String outputFile) {
    _outputFile = outputFile;
  }
  
  public String getAnnotationClassName() {
    return _annotationClassName;
  }
  
  public void setAnnotationClassName(String annotationClassName) {
    _annotationClassName = annotationClassName;
  }
    
  public void setClasspathref(Reference classpathref) {
    Path classpath = new Path(getProject());
    classpath.setRefid(classpathref);
    _classpath = classpath.list();
  }
  
  //-------------------------------------------------------------------------
  
  @Override
  public void execute() throws BuildException {
    if (getOutputFile() == null) {
      throw new BuildException("outputFile must be set");
    }
    File outputFile = new File(getOutputFile());
    if (outputFile.exists() && !outputFile.canWrite()) {
      throw new BuildException("Cannot write to file '" + outputFile + "'");
    }
    if (getAnnotationClassName() == null) {
      throw new BuildException("annotationClassName must be set");
    }
    Set<String> classNames;
    try {
      classNames = ClassNameAnnotationScannerUtils.scan(_classpath, getAnnotationClassName());
    } catch (Exception e) {
      throw new BuildException("Error scanning for annotated classes", e);
    }
    try {
      PrintWriter writer = new PrintWriter(outputFile);
      for (String className : classNames) {
        writer.println(className);
      }
      writer.close();
    } catch (IOException e) {
      s_logger.error("Error writing to output file", e);
      throw new BuildException("Error writing to output file", e);
    }

  }
  
}