/*
    * 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.myfaces.tobago.ant.sniplet;
  
  import org.apache.tools.ant.BuildException;
  import org.apache.tools.ant.DirectoryScanner;
  import org.apache.tools.ant.Task;
  import org.apache.tools.ant.Project;
  import org.apache.tools.ant.types.FileSet;
  
  import java.util.regex.Pattern;
  import java.util.regex.Matcher;
  import java.util.List;
  import java.util.ArrayList;
  import java.io.File;
  import java.io.LineNumberReader;
  import java.io.FileReader;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.io.FileOutputStream;
  
  /**
   * This task extracts lines from source fileSets marked with a tag. Such a sniplet starts with
   * <p/>
   * code-sniplet-start id="id"
   * <p/>
   * and ends with
   * <p/>
   * code-sniplet-end id="id"
   * <p/>
   * Its allowed to have nested and even entangled tags. Each sniplet gets ist own output file
   * in the output directory. The name of the file is [id].txt.
   * <p/>
   * The fileSets to process are specified by a fileset.
   * <p/>
   * Example:
   * <pre>
   * &lt;target name="code-extract">
   *   &lt;taskdef name="code-extract" classname="org.apache.myfaces.tobago.ant.sniplet.CodeSnipletExtractTask"/>
   *   &lt;code-extract outputDir="build/sniplets">
   *     &lt;fileset dir="src">
   *       &lt;include name="*.java"/>
   *     &lt;/fileset>
   *   &lt;/code-extract>
   * &lt;/target>
   * </pre>
   */
  public class CodeSnipletExtractTask extends Task {
  
    private List<CodeSniplet> sniplets;
    private List<FileSet> fileSets;
    private Pattern startPattern;
    private Pattern endPattern;
    private File outputDir;
    private String outputFileNamePattern;
    private boolean stripLeadingSpaces;
  
    public void init() throws BuildException {
      startPattern = Pattern.compile(".*code-sniplet-start\\s*id\\s*=\\s*\"(\\w*)\".*");
      endPattern = Pattern.compile(".*code-sniplet-end\\s*id\\s*=\\s*\"(\\w*)\".*");
      this.sniplets = new ArrayList<CodeSniplet>();
      this.fileSets = new ArrayList<FileSet>();
    }
  
    public String getOutputFileNamePattern() {
      return outputFileNamePattern;
    }
  
    public void setOutputFileNamePattern(String outputFileNamePattern) {
      this.outputFileNamePattern = outputFileNamePattern;
    }
  
    public File getOutputDir() {
      return outputDir;
    }
  
    public void setOutputDir(File outputDir) {
      this.outputDir = outputDir;
    }
  
    public void addConfiguredFileSet(FileSet fileSet) {
     this.fileSets.add(fileSet);
   }
 
   public boolean isStripLeadingSpaces() {
     return stripLeadingSpaces;
   }
 
   public void setStripLeadingSpaces(boolean stripLeadingSpaces) {
     this.stripLeadingSpaces = stripLeadingSpaces;
   }
 
   public void execute() throws BuildException {
     for (int k = 0; k < fileSets.size(); k++) {
       FileSet fileSet = fileSets.get(k);
       DirectoryScanner dirScanner = fileSet.getDirectoryScanner(getProject());
       dirScanner.scan();
       String[] includedFiles = dirScanner.getIncludedFiles();
       for (int i = 0; i < includedFiles.length; i++) {
         String fileS = includedFiles[i];
         LineNumberReader in = null;
         try {
           in = new LineNumberReader(new FileReader(fileSet.getDir(getProject())
               + File.separator + fileS));
           String line = in.readLine();
           while (line != null) {
             Matcher startMatcher = startPattern.matcher(line);
             if (startMatcher.matches()) {
               startSniplet(startMatcher.group(1), fileS, in.getLineNumber());
             } else {
               Matcher endMatcher = endPattern.matcher(line);
               if (endMatcher.matches()) {
                 endSniplet(endMatcher.group(1), fileS, in.getLineNumber());
               } else {
                 addLine(line);
               }
             }
             line = in.readLine();
           }
           for (int j = 0; j < sniplets.size(); j++) {
             CodeSniplet codeSniplet = (CodeSniplet) sniplets.get(j);
             if (codeSniplet.getLineEnd() == 0) {
               codeSniplet.setLineEnd(in.getLineNumber());
               log("Unclosed sniplet '" + codeSniplet.getId() + "' in file '" + codeSniplet.getFileName() + "' at line '"
                   + codeSniplet.getLineStart() + "'. Forcing close", Project.MSG_WARN);
             }
           }
           createOutput();
           sniplets = new ArrayList<CodeSniplet>();
         } catch (IOException e) {
           throw new BuildException(e);
         } finally {
           if (in != null) {
             try {
               in.close();
             } catch (IOException e) {
               throw new BuildException(e);
             }
           }
         }
       }
     }
   }
 
   private void createOutput() throws FileNotFoundException {
     for (int i = 0; i < sniplets.size(); i++) {
       CodeSniplet codeSniplet = (CodeSniplet) sniplets.get(i);
       String fileName = codeSniplet.getId() + ".snip";
       File file = new File(outputDir, fileName);
       PrintWriter out = new PrintWriter(new FileOutputStream(file));
       StringBuffer code = codeSniplet.getCode(stripLeadingSpaces);
       out.print(code);
       out.close();
       log("Wrote: " + file.getName(), Project.MSG_INFO);
     }
   }
 
   private void startSniplet(String id, String fileName, int lineNumber) {
     for (int i = 0; i < sniplets.size(); i++) {
       CodeSniplet codeSniplet = (CodeSniplet) sniplets.get(i);
       if (codeSniplet.getId().equals(id)) {
         throw new BuildException("Duplicate sniplet declaration '" + id + "' in file '" + fileName + "' at line '"
             + lineNumber + "'. First declaration was in file '" + codeSniplet.getFileName() + "' at line '"
             + codeSniplet.getLineStart() + "'.");
       }
     }
     CodeSniplet codeSniplet = new CodeSniplet(id, fileName, lineNumber);
     sniplets.add(codeSniplet);
   }
 
   private void endSniplet(String id, String fileName, int lineNumber) {
     for (int i = 0; i < sniplets.size(); i++) {
       CodeSniplet codeSniplet = (CodeSniplet) sniplets.get(i);
       if (codeSniplet.getId().equals(id)) {
         codeSniplet.setLineEnd(lineNumber);
         return;
       }
     }
     throw new BuildException("No start of sniplet '" + id + "' in file '" + fileName + "' at line '" + lineNumber
         + "' found.");
   }
 
   private void addLine(String line) {
     for (int i = 0; i < sniplets.size(); i++) {
       CodeSniplet codeSniplet = (CodeSniplet) sniplets.get(i);
       if (codeSniplet.getLineEnd() == 0) {
         codeSniplet.addLine(line);
         log("Adding: " + line + " -> " + codeSniplet.getFileName() + ":" + codeSniplet.getId(), Project.MSG_DEBUG);
       }
     }
   }
 
 }