package de.spiritscorp.datasync.model;
   
   /*-
    * 		Data Sync
    *
    * 		Copyright ©   2022    The Spirit
    * 		@email                        thespirit@spiritscorp.network
    *
    * 		This program is free software; you can redistribute it and/or modify
   * 		it under the terms of the GNU General Public License as published by
   * 		the Free Software Foundation; either version 3 of the License, or
   * 		(at your option) any later version.
   *
   * 		This program is distributed in the hope that it will be useful,
   * 		but WITHOUT ANY WARRANTY; without even the implied warranty of
   * 		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   * 		See the GNU General Public License for more details.
   *
   * 		You should have received a copy of the GNU General Public License
   * 		along with this program. If not, see <http://www.gnu.org/licenses/>.
   */
  
  import java.io.BufferedInputStream;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.StandardOpenOption;
  import java.nio.file.attribute.BasicFileAttributes;
  import java.nio.file.attribute.FileTime;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  import java.time.ZoneId;
  import java.time.format.DateTimeFormatter;
  import java.util.Map;
  
  import de.spiritscorp.datasync.ScanType;
  import de.spiritscorp.datasync.io.Debug;
  
  class FileScan implements Runnable {
  
  	private final Path path;
  	private final Path startPath;
  	private final Map<Path, FileAttributes> map;
  	private final ScanType scanType;
  	private final BasicFileAttributes bfa;
  
  	/**
  	 * Scan the attributes of one file
  	 *
  	 * @param path
  	 * @param startPath
  	 * @param map
  	 * @param scanType
  	 */
  	FileScan( Path path, Path startPath, Map<Path, FileAttributes> map, ScanType scanType, BasicFileAttributes bfa ) {
  		this.path = path;
  		this.startPath = startPath;
  		this.map = map;
  		this.scanType = scanType;
  		this.bfa = bfa;
  	}
  
  	@Override
  	public void run() {
  		final FileAttributes fileAttributes = new FileAttributes(
  				relativePath(),
  				fileTimeToString( bfa.creationTime() ),
  				bfa.creationTime(),
  				fileTimeToString( bfa.lastModifiedTime() ),
  				bfa.lastModifiedTime(),
  				bfa.size(),
  				deepScan() );
  		map.put( path, fileAttributes );
  	}
  
  	private String getSha256() {
  		final StringBuilder builder = new StringBuilder();
  		try( BufferedInputStream bis = new BufferedInputStream( Files.newInputStream( path, StandardOpenOption.READ ) ) ) {
  			final MessageDigest messageDigest = MessageDigest.getInstance( "SHA-256" );
  			byte[] input;
  			while( bis.available() != 0 ) {
  				input = bis.readNBytes( 8192 );
  				messageDigest.update( input );
  			}
  			final byte[] digestByte = messageDigest.digest();
  			for( final byte b : digestByte ) {
  				builder.append( Integer.toString( ( b & 0xff ) + 0x100, 16 ).substring( 1 ) );
  			}
  		}catch( IOException | NoSuchAlgorithmException e ) {
  			builder.delete( 0, builder.length() );
  			builder.append( "Failed" );
  			Debug.printDebug( "[FileScan] Failed: %s Message: %s", path, e.getMessage() );
  			Debug.printException( this.getClass(), e );
  		}
  		return builder.toString();
  	}
  
  	private String fileTimeToString( final FileTime fileTime ) {
  		return fileTime.toInstant().atZone( ZoneId.systemDefault() ).toLocalDateTime().format( DateTimeFormatter.ofPattern( "dd.MM.yyyy  HH:mm:ss" ) );
 	}
 
 	private Path relativePath() {
 		return startPath.relativize( path );
 	}
 
 	private String deepScan() {
 		return switch( scanType ) {
 			case DEEP_SCAN, DUBLICATE_SCAN -> getSha256();
 			case FLAT_SCAN, SYNCHRONIZE -> "null";
 			default -> "null";
 		};
 	}
 }