package de.funfried.netbeans.plugins.external.formatter.eclipse.mechanic;
   
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.IOException;
   import java.net.URL;
   import java.util.ArrayList;
   import java.util.List;
   import java.util.Map;
  import java.util.Properties;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.commons.validator.routines.UrlValidator;
  import org.netbeans.api.annotations.common.NonNull;
  
  import de.funfried.netbeans.plugins.external.formatter.eclipse.xml.EclipseFormatterUtils;
  
  /**
   * A parser for Workspace Mechanic configuration files.
   */
  public class WorkspaceMechanicConfigParser {
  	private static final Logger log = Logger.getLogger(WorkspaceMechanicConfigParser.class.getName());
  
  	private static final String MULTI_FILE_SETUP_PREFIX = "/instance/com.google.eclipse.mechanic/mechanicSourceDirectories";
  
  	/**
  	 * Parses and returns properties of the given {@code path} into a key value {@link Map}. If an optional
  	 * {@code prefix} is specified, only the properties where the key starts with the given {@code prefix}
  	 * are returned and the {@code prefix} will be removed from the keys in the returned {@link Map}.
  	 *
  	 * @param path a configuration file path or URL
  	 * @param prefix an optional key prefix
  	 *
  	 * @return properties of the given {@code path} as a key value {@link Map}
  	 *
  	 * @throws IOException if there is an issue accessing the given configuration file
  	 */
  	@NonNull
  	public static Map<String, String> readPropertiesFromConfiguration(String path, String prefix) throws IOException {
  		Properties properties = createPropertiesFromPath(path);
  		if (properties.containsKey(MULTI_FILE_SETUP_PREFIX)) {
  			parseAdditionalFiles((String) properties.get(MULTI_FILE_SETUP_PREFIX)).stream().forEach(p -> properties.putAll(p));
  
  			properties.remove(MULTI_FILE_SETUP_PREFIX);
  		}
  
  		return EclipseFormatterUtils.toMap(properties, prefix);
  	}
  
  	@NonNull
  	private static List<Properties> parseAdditionalFiles(String pathStruct) throws IOException {
  		// the pathStruct looks as follows:
  		// ["/path/to/additional/mechanic/files","/path/to/origin/mechanic/file"]
  		pathStruct = StringUtils.trimToEmpty(pathStruct);
  		pathStruct = StringUtils.removeStart(pathStruct, "[");
  		pathStruct = StringUtils.removeEnd(pathStruct, "]");
  
  		List<Properties> result = new ArrayList<>();
  		String[] additionalFilesPaths = StringUtils.split(pathStruct, ",");
  		for (String additionalFilesPath : additionalFilesPaths) {
  			additionalFilesPath = StringUtils.removeStart(additionalFilesPath, "\"");
  			additionalFilesPath = StringUtils.removeEnd(additionalFilesPath, "\"");
  
  			Properties additionalProperties = createPropertiesFromPath(additionalFilesPath);
  			result.add(additionalProperties);
  		}
  
  		return result;
  	}
  
  	@NonNull
  	private static Properties createPropertiesFromPath(String path) throws IOException {
  		if (StringUtils.isBlank(path)) {
  			return new Properties();
  		}
  
  		if (UrlValidator.getInstance().isValid(path)) {
  			try {
  				URL url = new URL(path);
  
  				Properties properties = new Properties();
  				properties.load(url.openStream());
  
  				return properties;
  			} catch (IOException ex) {
  				log.log(Level.WARNING, "Could not read given path as URL, fallback to local file reading", ex);
  			}
  		}
  
  		return createPropertiesFromFile(new File(path));
  	}
  
  	@NonNull
  	private static Properties createPropertiesFromFile(File file) throws IOException {
  		Properties properties = new Properties();
  
  		if (file != null && file.exists()) {
 			if (file.isFile()) {
 				try (FileInputStream is = new FileInputStream(file)) {
 					properties.load(is);
 				}
 			} else if (file.isDirectory()) {
 				File[] files = file.listFiles();
 				for (File f : files) {
 					if (file.isDirectory() || (file.isFile() && StringUtils.endsWith(file.getName(), EclipseFormatterUtils.EPF_FILE_EXTENSION))) {
 						Properties additionalProperties = createPropertiesFromFile(f);
 						properties.putAll(additionalProperties);
 					}
 				}
 			}
 		}
 
 		return properties;
 	}
 }