/*
 *   Copyright 2014 Brian Rosenberger (Brutex Network)
 *
 *   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 net.brutex.svn;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;

/* Executes the svnadmin utility
 * 
 * @author Brian Rosenberger bru(at)brutex.de
 * @since 0.1

 */
public class SVNAdminExecutor {
	
	private Logger logger = Logger.getLogger(SVNAdminExecutor.class);
	private final File svnadmin;
	private final String repos;
	private String rev = null;
	private String message = null;
	private String locale = "de_DE.UTF-8";
	private String encoding = "UTF-8";
	private boolean useBypassHooks = true;
	
	/**
	 * Instantiates a new SVN admin executor.
	 *
	 * @param svnadmin the svnadmin
	 * @param repos the repos
	 */
	public SVNAdminExecutor(File svnadmin, String repos) {
		if(! svnadmin.exists() ) throw new IllegalArgumentException( String.format("The svnadmin executable at '%s' does not exist.", svnadmin.toString()));
		if(! svnadmin.isFile() ) throw new IllegalArgumentException( String.format("The svnadmin utility at'%s' is not a file.", svnadmin.toString()));
		logger.debug(String.format("Instantiating '%s' with svnadmin at '%s'.", this.getClass().getCanonicalName(), svnadmin.toString()));
		this.svnadmin = svnadmin;
		logger.debug(String.format("Working against svn repository at '%s'.", repos));
		this.repos = repos;
	}
	

	/**
	 * Execute svn admin.
	 *
	 * @param command the command
	 * @return the string
	 */
	public String executeSVNAdmin(SVNAdminCommand command) {
		StringBuilder sb = new StringBuilder();
		StringBuilder sberr = new StringBuilder();
		
		if(rev==null) {
			logger.error("The revision can not be 'null' for the svnadmin command.");
			return null;
		}
		
		if(message==null) {
			logger.error("The new log message can not be 'null' for the svnadmin command.");
			return null;
		}
		
		File logfile = null;
		try {
			logfile = File.createTempFile("~msg"+rev+"_", ".tmp");
			BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(logfile), encoding));
			out.write(message);
			out.flush();
			out.close();
		} catch (IOException e) {
			logger.error("Failed to write new log message to temporary file '"+logfile.getAbsolutePath()+"'.", e);
			return null;
		}

		
		
		try {
			List<String> cmdline =  new ArrayList<String>(5);
			cmdline.add(svnadmin.toString());
			cmdline.add(command.getValue());
			cmdline.add(repos);
			if(useBypassHooks) {
				cmdline.add("--bypass-hooks");
			}
			cmdline.add("-r");
			cmdline.add(rev);
			cmdline.add(logfile.getAbsolutePath());

			ProcessBuilder pf = new ProcessBuilder(cmdline);
			logger.debug(String.format("Executing svnadmin with commandline '%s'.", pf.command()));
			Map<String, String> env = pf.environment();
			env.put("LANG", locale);
			Process svnprocess = pf.start();
			BufferedReader stdin = new BufferedReader(new InputStreamReader(svnprocess.getInputStream(), encoding));
			BufferedReader stderr = new BufferedReader(new InputStreamReader(svnprocess.getErrorStream(), encoding));
			String s;
			 while( (s = stdin.readLine()) != null ) {
				 sb.append(s + '\n');
			 }
			 while( (s = stderr.readLine()) != null ) {
				 sberr.append(s + '\n');
			 }
			 stdin.close(); stderr.close();
		} catch (IOException e) {
			logger.error( String.format( "Error calling the svnadmin utility: '%s'", e.getMessage()));
			e.printStackTrace();
		} finally {
			logfile.deleteOnExit();
		}
		
		String error = sberr.toString();
		if( error.length()>0 ) {
			error = "Failed to call svnadmin. The STDERR was '"+error+"'";
			logger.error(error);
			throw new IllegalArgumentException(error);
		}
		String output = sb.toString().trim();
		logger.debug(String.format("Svnadmin output was '%s'", output));
		return output;		
	}
	
	
	public void setRev(String rev) {
		if(rev==null || rev.length()<=0) throw new IllegalArgumentException("Revision cannot be null or empty.");
		this.rev = rev;
	}
	
	public void setEncoding(String encoding) {
		this.encoding = encoding;
	}
	 /**
	  * Set the locale that will be pushed into
	  * 'LANG' environment variable.
	  * 
	  * @param locale i.e. de_DE.UTF-8
	  */
	public void setLocale(String locale) {
		this.locale = locale;
	}
	
	/**
	 * Set the new log message.
	 * 
	 * @param message new message
	 */
	public void setMessage(String message) {
		this.message = message;
	}
	
	/**
	 * Set this to true to bypass the pre-revprop-change and post-revprop-change
	 * hooks.
	 * 
	 * @param useBypassHooks defaults to true
	 */
	public void setUseBypassHooks(boolean useBypassHooks) {
		this.useBypassHooks = useBypassHooks;
	}

}