/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * Licensed 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.argeo.cms.ui.workbench.useradmin;
  
  import java.text.DateFormat;
  import java.text.SimpleDateFormat;
  import java.util.Arrays;
  import java.util.Date;
  import java.util.LinkedList;
  import java.util.List;
  
  import org.argeo.node.ArgeoLogListener;
  import org.eclipse.jface.viewers.ILazyContentProvider;
  import org.eclipse.jface.viewers.TableViewer;
  import org.eclipse.jface.viewers.Viewer;
  import org.eclipse.swt.widgets.Table;
  import org.eclipse.swt.widgets.TableItem;
  
  /** A content provider maintaining an array of lines */
  class LogContentProvider implements ILazyContentProvider, ArgeoLogListener {
  	private static final long serialVersionUID = -2084872367738339721L;
  
  	private DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
  
  	private final Long start;
  	/** current - start = line number. first line is number '1' */
  	private Long current;
  
  	// TODO make it configurable
  	private final Integer maxLineBufferSize = 10 * 1000;
  
  	private final TableViewer viewer;
  	private LinkedList<LogLine> lines;
  
  	public LogContentProvider(TableViewer viewer) {
  		this.viewer = viewer;
  		start = System.currentTimeMillis();
  		lines = new LinkedList<LogLine>();
  		current = start;
  	}
  
  	public synchronized void dispose() {
  		lines.clear();
  		lines = null;
  	}
  
  	@SuppressWarnings("unchecked")
  	public synchronized void inputChanged(Viewer viewer, Object oldInput,
  			Object newInput) {
  		List<String> lin = (List<String>) newInput;
  		if (lin == null)
  			return;
  		for (String line : lin) {
  			addLine(line);
  		}
  		this.viewer.setItemCount(lines.size());
  	}
  
  	public void updateElement(int index) {
  		viewer.replace(lines.get(index), index);
  	}
  
  	public synchronized void appendLog(String username, Long timestamp,
  			String level, String category, String thread, Object msg,
  			String[] exception) {
  		// check if valid
  		if (lines == null)
  			return;
  
  		String message = msg.toString();
  		int count = 0;
  		String prefix = prefix(username, timestamp, level, category, thread)
  				.toString();
  		// String suffix = suffix(username, timestamp, level, category, thread);
  		for (String line : message.split("\n")) {
  			addLine(count == 0 ? prefix + line : line);
  			count++;
  		}
  
  		if (exception != null) {
  			for (String ste : exception) {
  				addLine(ste);
  			}
  		}
  
  		viewer.getTable().getDisplay().asyncExec(new Runnable() {
 			public void run() {
 				if (lines == null)
 					return;
 				viewer.setItemCount(lines.size());
 				// doesn't work with syncExec
 				scrollToLastLine();
 			}
 		});
 	}
 
 	protected StringBuffer prefix(String username, Long timestamp,
 			String level, String category, String thread) {
 		StringBuffer buf = new StringBuffer("");
 		buf.append(dateFormat.format(new Date(timestamp))).append(" ");
 		// buf.append(level).append(" ");
 		return buf;
 	}
 
 	/** Normalize string to the given size */
 	protected String norm(String str, Integer size) {
 		int length = str.length();
 		if (length == size)
 			return str;
 		else if (length > size)
 			return str.substring(0, size);
 		else {
 			char[] arr = new char[size - length];
 			Arrays.fill(arr, ' ');
 			return str + new String(arr);
 		}
 	}
 
 	// protected String suffix(String username, Long timestamp, String level,
 	// String category, String thread) {
 	// return "";
 	// }
 
 	/** Scroll to the last line */
 	protected synchronized void scrollToLastLine() {
 		// we try to show last line with two methods
 		// viewer.reveal(lines.peekLast());
 
 		Table table = viewer.getTable();
 		TableItem ti = table.getItem(table.getItemCount() - 1);
 		table.showItem(ti);
 	}
 
 	protected synchronized LogLine addLine(String line) {
 		// check for maximal size and purge if necessary
 		while (lines.size() >= maxLineBufferSize) {
 			for (int i = 0; i < maxLineBufferSize / 10; i++) {
 				lines.poll();
 			}
 		}
 
 		current++;
 		LogLine logLine = new LogLine(current, line);
 		lines.add(logLine);
 		return logLine;
 	}
 
 	private class LogLine {
 		private Long linenumber;
 		private String message;
 
 		public LogLine(Long linenumber, String message) {
 			this.linenumber = linenumber;
 			this.message = message;
 		}
 
 		@Override
 		public int hashCode() {
 			return linenumber.intValue();
 		}
 
 		@Override
 		public boolean equals(Object obj) {
 			if (obj instanceof LogLine)
 				return ((LogLine) obj).linenumber.equals(linenumber);
 			else
 				return false;
 		}
 
 		@Override
 		public String toString() {
 			return message;
 		}
 	}
 }