/*******************************************************************************
 * ============LICENSE_START====================================================
 * * org.onap.aaf
 * * ===========================================================================
 * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
 * * ===========================================================================
 * * 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.
 * * ============LICENSE_END====================================================
 * *
 * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
 * *
 ******************************************************************************/
package com.att.cadi.config;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Date;
import java.util.HashSet;

import com.att.cadi.AbsUserCache;
import com.att.cadi.lur.LocalLur;

public class UsersDump {

	/**
	 * @param args
	 */
	public static boolean write(OutputStream os, AbsUserCache<?> lur) {
		PrintStream ps;
		if(os instanceof PrintStream) {
			ps = (PrintStream)os;
		} else {
			ps = new PrintStream(os);
		}
		try {
			ps.println("<?xml version='1.0' encoding='utf-8'?>");
			ps.println("<!--");
			ps.print(  "     Code Generated Tomcat Users and Roles from AT&T LUR on ");
			ps.println(new Date());
			ps.println(  "-->");
			ps.println("<tomcat-users>");

			// We loop through Users, but want to write Groups first... therefore, save off print
			StringBuilder sb = new StringBuilder();
			
			// Obtain all unique role names
			HashSet<String> groups = new HashSet<String>();
			for(AbsUserCache<?>.DumpInfo di : lur.dumpInfo()) {
				sb.append("\n  <user username=\"");
				sb.append(di.user);
				sb.append("\" roles=\"");
				boolean first = true;
				for(String role : di.perms) {
					groups.add(role);
					if(first)first = false;
					else sb.append(',');
					sb.append(role);
				}
				sb.append("\"/>");

			}

			// Print roles
			for(String group : groups) {
				ps.print("  <role rolename=\"");
				ps.print(group);
				ps.println("\"/>");
			}
	
			ps.println(sb);

			ps.println("</tomcat-users>");
			ps.flush();
		} catch (Throwable t) {
			t.printStackTrace(ps);
			return false;
		}
		return true;
	}
	
	/**
	 * 
	 * Note: This method returns a String if there's an error, or null if ok.
	 * This unusual style is necessitated by the fact that any Exceptions thrown are likely to 
	 * be unlogged and hidden from view, making debugging almost impossible.
	 * 
	 * @param writeto
	 * @param up
	 * @return
	 */
	public static String updateUsers(String writeto, LocalLur up) {
		// Dump a Tomcat-user.xml lookalike (anywhere)
		if(writeto!=null) {
			// First read content
			ByteArrayOutputStream baos = new ByteArrayOutputStream();
			if(UsersDump.write(baos, up)) {
				byte[] postulate = baos.toByteArray();
				// now get contents of file
				File file = new File(writeto);
				boolean writeIt;
				if(file.exists()) {
					try {
						FileInputStream fis = new FileInputStream(file);
						byte[] orig = new byte[(int)file.length()];
						try {
							fis.read(orig);
						} finally {
							fis.close();
						}
						// Starting at third "<" (<tomcat-users> line)
						int startA=0, startB=0;
						for(int i=0;startA<orig.length && i<3;++startA) if(orig[startA]=='<')++i;
						for(int i=0;startB<orig.length && i<3;++startB) if(postulate[startB]=='<')++i;
						
						writeIt=orig.length-startA!=postulate.length-startB; // first, check if remaining length is the same
						while(!writeIt && startA<orig.length && startB<postulate.length) {
							if(orig[startA++]!=postulate[startB++])writeIt = true;
						}
					} catch (Exception e) {
						writeIt = true;
					}
				} else {
					writeIt = true;
				}
				
				if(writeIt) {
					try {
						FileOutputStream fos = new FileOutputStream(file);
						try {
							fos.write(postulate);
						} finally {
							fos.close();
						}
					} catch (IOException e) {
						return e.getMessage();
					}
				}
			}
		}
		return null; // no message means ok.
	}

}