package org.daisy.pipeline.zip.calabash.impl;
   
   /**
    * Unzip extension for non-XML files
    *
    * @author Lars Wittmar -- le-tex publishing services GmbH
    * @date   2012-03-08
    * 
    * A Java unzip for XProc, particularly useful 
   * if you want to access zip contents as extracted files
   * (and don't want to retrieve single files recursively, and
   * potentially base64 encoded).
   * 
   * Written by Lars Wittmar, le-tex publishing services GmbH
   * (small portions also by Gerrit Imsieke)
   * 
   * Configure letex:unzip step by passing options to it:
   * zip (required):      file name (not URI) of a zip file
   * dest-dir (required): directory (relative or absolute; not an URI)
   * overwrite ('yes'/'no', optional, default 'no'): overwrite individual files even if they already exist
   * file (optional):     file name relative to zip root. If omitted, extract complete zip file
   * 
   * The directory (and missing subdirectories) will be created if
   * missing. 
   * 
   * CAVEAT: If overwrite='yes' and, e.g., dest-dir='/', it will attempt to remove the root directory.
   * 
   * DO NOT USE THIS AS A USER WITH ADMIN PRIVILEGES.
   * 
   *
   * 2015-02-27, Jostein Austvik Jacobsen (NLB - Norwegian library of talking books and braille):
   *     - Wrapped into a org.daisy.common.xproc.calabash.XProcStepProvider
   *     - removed Apache Commons dependency
   *     - Use file URIs instead of OS-specific paths for options
   * 2016-02-10, Jostein Austvik Jacobsen (NLB - Norwegian library of talking books and braille):
   *     - slightly changed the meaning of the 'overwrite' option
   */
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.PrintWriter;
  import java.io.StringReader;
  import java.io.StringWriter;
  import java.net.URI;
  import java.util.Map;
  import java.util.zip.ZipEntry;
  import java.util.zip.ZipInputStream;
  
  import javax.xml.transform.Source;
  import javax.xml.transform.stream.StreamSource;
  
  import com.xmlcalabash.core.XProcException;
  import com.xmlcalabash.core.XProcRuntime;
  import com.xmlcalabash.io.WritablePipe;
  import com.xmlcalabash.library.DefaultStep;
  import com.xmlcalabash.model.RuntimeValue;
  import com.xmlcalabash.runtime.XAtomicStep;
  
  import net.sf.saxon.s9api.DocumentBuilder;
  import net.sf.saxon.s9api.SaxonApiException;
  import net.sf.saxon.s9api.XdmNode;
  import net.sf.saxon.s9api.QName;
  
  import org.daisy.common.xproc.calabash.XProcStep;
  import org.daisy.common.xproc.calabash.XProcStepProvider;
  import org.daisy.common.xproc.XProcMonitor;
  
  import org.osgi.service.component.annotations.Component;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @Component(
  	name = "letex:unzip",
  	service = { XProcStepProvider.class },
  	property = { "type:String={http://www.le-tex.de/namespace}unzip" }
  )
  public class UnZipProvider implements XProcStepProvider {
  
      /** The logger. */
      Logger logger = LoggerFactory.getLogger(this.getClass());
  
      /* (non-Javadoc)
       * @see org.daisy.common.xproc.calabash.XProcStepProvider#newStep(com.xmlcalabash.core.XProcRuntime, com.xmlcalabash.runtime.XAtomicStep)
       */
      @Override
      public XProcStep newStep(XProcRuntime runtime, XAtomicStep step, XProcMonitor monitor, Map<String,String> properties) {
          return new UnZip(runtime, step);
      }
  
      /**
       * Activate (OSGI)
       */
      public void activate() {
          logger.trace("Activating letex:unzip provider");
      }
     
     public static class UnZip
             extends DefaultStep implements XProcStep
     {
         public UnZip(XProcRuntime runtime, XAtomicStep step)
         {
             super(runtime,step);
         }
 
         @Override
         public void setOutput(String port, WritablePipe pipe)
         {
             myResult = pipe;
         }
 
         @Override
         public void reset()
         {
             myResult.resetWriter();
         }
 
         @Override
         public void run()
             throws SaxonApiException
         {
             super.run();
             
             String result = null;
             File folder = null, source = null;
             try {
                 RuntimeValue href = getOption(new QName("zip"));
                 URI sourceUri = href.getBaseURI().resolve(href.getString());
                 href = getOption(new QName("dest-dir"));
                 URI destinationUri = href.getBaseURI().resolve(href.getString());
     			
     			if (!"file".equals(sourceUri.getScheme())) {
     				throw new XProcException(step, "Only file: scheme URIs are supported by zip URI.");
     			} else {
     				source = new File(sourceUri.getPath());
     				if (!source.isFile()) {
     					throw new XProcException(step, "The zip URI must refer to a file.");
     				}
     			}
     			
     			if (!"file".equals(destinationUri.getScheme())) {
     				throw new XProcException(step, "Only file: scheme URIs are supported by dest-dir URI.");
     			} else {
     				folder = new File(destinationUri.getPath());
     				if (!folder.exists()) {
     					folder.mkdirs();
     				}
     				if (!folder.isDirectory()) {
     					throw new XProcException(step, "The dest-dir URI must refer to a directory.");
     				}
     				if (folder.getParentFile() == null || folder.getParentFile().getParentFile() == null) {
     					// Basic safety valve; should catch stuff like "/", "/home/", "C:\", "C:\Windows\" etc.
     					// Mainly aimed at catching typos or bugs in scripts during developent;
     					// running without admin-privileges is the only fairly safe option here 
     					throw new XProcException(step, "The dest-dir URI must not be the file system root directory (or any of its children) (was: \""+folder.getCanonicalPath()+"\").");
     				}
     			}
     			
                 String overwriteS = getOption(new QName("overwrite")).getString();
                 boolean overwrite = false; 
                 if (overwriteS != null) {
                     if (overwriteS.matches("yes")) {
                         overwrite = true;
                     }
                 }
 
     			String filename = "";
     			if (getOption(new QName("file"))!=null) {
                     filename = getOption(new QName("file")).getString();
     			}
     			
                 if(! folder.exists()) { 
                     folder.mkdirs(); 
                 }
     			
     			final int BUFFER = 2048;
     			BufferedOutputStream dest = null;
     			FileInputStream fis = new FileInputStream(source);
     			ZipInputStream zis = new ZipInputStream(new BufferedInputStream(fis));
     			ZipEntry entry;
 
                 int numFiles = 0;
     			result = "<c:files xmlns:c=\"http://www.w3.org/ns/xproc-step\" xml:base=\"" + folder.toURI() + "\">";
     			//without given fileNode extract everything
     			if(filename.equals("")) {
                     while((entry = zis.getNextEntry()) != null) {
                         int count;
                         byte data[] = new byte[BUFFER];
                         
                         if(entry.isDirectory()) {
                         	File dir = new File(folder, entry.getName());
                             if (!dir.exists()) { dir.mkdirs(); }
                         } else {
                             numFiles++;
                             result += "<c:file name=\"" + entry.getName() + "\"/>";
                             File destFile = new File(folder, entry.getName());
                             if (destFile.exists()) {
                                 if (overwrite) {
                                     deleteDirectory(destFile);
                                 } else {
                                     continue;
                                 }
                             }
                             File destdir = destFile.getParentFile();
                             if (!destdir.exists()) { destdir.mkdirs(); }
                             FileOutputStream fos = new FileOutputStream(destFile);
                             dest = new BufferedOutputStream(fos, BUFFER);
                             while ((count = zis.read(data, 0, BUFFER)) != -1) {
                                 dest.write(data, 0, count);
                             }
                             dest.flush();
                             dest.close();
                         }
                     }
     			} else {
                     while((entry = zis.getNextEntry()) != null) {
                         if(filename.equals(entry.getName())) {
                             int count;
                             byte data[] = new byte[BUFFER];
                             
                             numFiles++;
                             result += "<c:file name=\"" + entry.getName() + "\"/>";
                             File destFile = new File(folder, entry.getName());
                             if (destFile.exists()) {
                                 if (overwrite) {
                                     deleteDirectory(destFile);
                                 } else {
                                     continue;
                                 }
                             }
                             File destdir = destFile.getParentFile();
                             if (!destdir.exists()) { destdir.mkdirs(); }
                             FileOutputStream fos = new FileOutputStream(destFile);
                             dest = new BufferedOutputStream(fos, BUFFER);
                             while ((count = zis.read(data, 0, BUFFER)) != -1) {
                                 dest.write(data, 0, count);
                             }
                             dest.flush();
                             dest.close();
                         }							 
                     }
     			}
     			
     			zis.close();
     			if (numFiles == 0) {
     			  result = "<c:error xmlns:c=\"http://www.w3.org/ns/xproc-step\" xmlns:letex=\"http://www.le-tex.de/namespace\" code=\"zip-error\" href=\""+folder.toURI()+source.toURI()+"\">No content processed. Zip file may empty or corrupted.</c:error>";
     			} else {
     			  result += "</c:files>";
     			}
                 
     		  } catch(Exception e) {
     			  StringWriter stackTraceWriter = new StringWriter();
     			  e.printStackTrace(new PrintWriter(stackTraceWriter));
     			  String stackTrace = stackTraceWriter.toString().replaceAll("-", " - "); // just to be sure that the comment is valid
     			  result = "<c:error xmlns:c=\"http://www.w3.org/ns/xproc-step\" xmlns:letex=\"http://www.le-tex.de/namespace\" code=\"zip-error\" href=\""+folder.toURI()+source.toURI()+"\">Zip file seems to be corrupted: "+e.getMessage()+"<!-- "+stackTrace+" --></c:error>";
     		  }
             DocumentBuilder builder = runtime.getProcessor().newDocumentBuilder();
             Source src = new StreamSource(new StringReader(result));
             XdmNode doc = builder.build(src);
 
             myResult.write(doc);
         }
         
         /** http://stackoverflow.com/a/3775718/281065 */
         public static boolean deleteDirectory(File directory) {
             if(directory.exists()){
                 File[] files = directory.listFiles();
                 if(null!=files){
                     for(int i=0; i<files.length; i++) {
                         if(files[i].isDirectory()) {
                             deleteDirectory(files[i]);
                         }
                         else {
                             files[i].delete();
                         }
                     }
                 }
             }
             return(directory.delete());
         }
 
         private WritablePipe myResult = null;
     }
     
 }