package org.argeo.slc.core.execution.tasks;

import java.io.File;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.ExecuteException;
import org.apache.commons.exec.ExecuteResultHandler;
import org.apache.commons.exec.ExecuteWatchdog;
import org.apache.commons.exec.Executor;
import org.apache.commons.exec.LogOutputStream;
import org.apache.commons.exec.PumpStreamHandler;
import org.apache.commons.exec.ShutdownHookProcessDestroyer;
import org.apache.commons.lang.NotImplementedException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.argeo.slc.SlcException;

/** Execute and OS system call. */
public class SystemCall implements Runnable {
	private final Log log = LogFactory.getLog(getClass());

	private String execDir;

	private String cmd = null;
	private List<String> command = null;

	private Boolean synchronous = true;

	private String stdErrLogLevel = "ERROR";
	private String stdOutLogLevel = "INFO";

	private Map<String, List<String>> osCommands = new HashMap<String, List<String>>();
	private Map<String, String> osCmds = new HashMap<String, String>();
	private Map<String, String> environmentVariables = new HashMap<String, String>();

	private Long watchdogTimeout = 24 * 60 * 60 * 1000l;

	public void run() {
		try {
			if (log.isTraceEnabled()) {
				log.debug("os.name=" + System.getProperty("os.name"));
				log.debug("os.arch=" + System.getProperty("os.arch"));
				log.debug("os.version=" + System.getProperty("os.version"));
			}

			// Execution directory
			File dir = null;
			if (execDir != null) {
				// Replace '/' by local file separator, for portability
				execDir.replace('/', File.separatorChar);
				dir = new File(execDir).getCanonicalFile();
			}

			// Check if an OS specific command overrides
			String osName = System.getProperty("os.name");
			List<String> commandToUse = null;
			if (osCommands.containsKey(osName))
				commandToUse = osCommands.get(osName);
			else
				commandToUse = command;
			String cmdToUse = null;
			if (osCmds.containsKey(osName))
				cmdToUse = osCmds.get(osName);
			else
				cmdToUse = cmd;

			// Prepare executor
			if (dir == null)
				dir = new File(getUsedDir(dir));
			if (!dir.exists())
				dir.mkdirs();

			Executor executor = new DefaultExecutor();
			executor.setWatchdog(new ExecuteWatchdog(watchdogTimeout));
			PumpStreamHandler pumpStreamHandler = new PumpStreamHandler(
					new LogOutputStream() {
						protected void processLine(String line, int level) {
							log(stdOutLogLevel, line);
						}
					}, new LogOutputStream() {
						protected void processLine(String line, int level) {
							log(stdErrLogLevel, line);
						}
					}, null);
			executor.setStreamHandler(pumpStreamHandler);
			executor.setProcessDestroyer(new ShutdownHookProcessDestroyer());
			executor.setWorkingDirectory(dir);
			final CommandLine commandLine;

			// Which command definition to use
			if (commandToUse == null && cmdToUse == null)
				throw new SlcException("Please specify a command.");
			else if (commandToUse != null && cmdToUse != null)
				throw new SlcException(
						"Specify the command either as a line or as a list.");
			else if (cmdToUse != null) {
				if (log.isTraceEnabled())
					log.trace("Execute '" + cmdToUse + "' in "
							+ getUsedDir(dir));

				commandLine = CommandLine.parse(cmdToUse);
			} else if (commandToUse != null) {
				if (log.isTraceEnabled())
					log.trace("Execute '" + commandToUse + "' in "
							+ getUsedDir(dir));
				if (commandToUse.size() == 0)
					throw new SlcException("Command line is empty.");

				commandLine = new CommandLine(commandToUse.get(0));
				for (int i = 1; i < commandToUse.size(); i++)
					commandLine.addArgument(commandToUse.get(i));
			} else {
				// all cases covered previously
				throw new NotImplementedException();
			}

			// Env variables
			Map<String, String> environmentVariablesToUse = environmentVariables
					.size() > 0 ? environmentVariables : null;

			// Execute
			ExecuteResultHandler executeResultHandler = new ExecuteResultHandler() {

				public void onProcessComplete(int exitValue) {
					if (log.isDebugEnabled())
						log.debug("Process " + commandLine
								+ " properly completed.");
				}

				public void onProcessFailed(ExecuteException e) {
					throw new SlcException("Process " + commandLine
							+ " failed.", e);
				}
			};

			if (synchronous)
				try {
					int exitValue = executor.execute(commandLine,
							environmentVariablesToUse);
					executeResultHandler.onProcessComplete(exitValue);
				} catch (ExecuteException e1) {
					executeResultHandler.onProcessFailed(e1);
				}
			else
				executor.execute(commandLine, environmentVariablesToUse,
						executeResultHandler);
		} catch (Exception e) {
			throw new SlcException("Could not execute command " + cmd, e);
		}

	}

	/**
	 * Shortcut method returning the current exec dir if the specified one is
	 * null.
	 */
	private String getUsedDir(File dir) {
		if (dir == null)
			return System.getProperty("user.dir");
		else
			return dir.getPath();
	}

	protected void log(String logLevel, String line) {
		if ("ERROR".equals(logLevel))
			log.error(line);
		else if ("WARN".equals(logLevel))
			log.warn(line);
		else if ("INFO".equals(logLevel))
			log.info(line);
		else if ("DEBUG".equals(logLevel))
			log.debug(line);
		else if ("TRACE".equals(logLevel))
			log.trace(line);
		else
			throw new SlcException("Unknown log level " + logLevel);
	}

	public void setCmd(String command) {
		this.cmd = command;
	}

	public void setExecDir(String execdir) {
		this.execDir = execdir;
	}

	public void setStdErrLogLevel(String stdErrLogLevel) {
		this.stdErrLogLevel = stdErrLogLevel;
	}

	public void setStdOutLogLevel(String stdOutLogLevel) {
		this.stdOutLogLevel = stdOutLogLevel;
	}

	public void setSynchronous(Boolean synchronous) {
		this.synchronous = synchronous;
	}

	public void setCommand(List<String> command) {
		this.command = command;
	}

	public void setOsCommands(Map<String, List<String>> osCommands) {
		this.osCommands = osCommands;
	}

	public void setOsCmds(Map<String, String> osCmds) {
		this.osCmds = osCmds;
	}

	public void setEnvironmentVariables(Map<String, String> environmentVariables) {
		this.environmentVariables = environmentVariables;
	}

	public void setWatchdogTimeout(Long watchdogTimeout) {
		this.watchdogTimeout = watchdogTimeout;
	}

}