package euler;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;

/**
 * Euler proof engine wrapper
 * 
 * @author Jos De Roo
 */

public class ProofEngine {

	static boolean windows = System.getProperty("os.name").startsWith("Windows");
	static boolean linux = System.getProperty("os.name").startsWith("Linux");

	/**
	 * runProofEngine method
	 * 
	 * @param args
	 *      <options>* <data>* <query>*
	 * @param ops
	 *      output print stream
	 * @param eps
	 *      error print stream
	 * 
	 * @return the process
	 */
	public static Process runProofEngine(String[] args, PrintStream ops, PrintStream eps) {
		Process pr = createProofEngine(args, ops, eps);
		executeProofEngine(pr);
		return pr;
	}

	/**
	 * runProofEngine method
	 * 
	 * @param args
	 *      <options>* <data>* <query>*
	 * 
	 * @return the proof
	 */
	public static String runProofEngine(String[] args) {
		Process pr = runProofEngine(args, null, System.err);
		return pr.getOutput();
	}

	/**
	 * createProofEngine method
	 * 
	 * @param args
	 *      <options>* <data>* <query>*
	 * @param ops
	 *      output print stream
	 * @param eps
	 *      error print stream
	 * 
	 * @return the process
	 */
	public static Process createProofEngine(String[] args, PrintStream ops, PrintStream eps) {
		long ttl = Long.MAX_VALUE;
		String tmpdir = System.getProperty("java.io.tmpdir");
		if (!windows) {
			tmpdir = "/tmp/";
		}
		String sep = System.getProperty("file.separator");
		if (!tmpdir.endsWith(sep)) {
			tmpdir += sep;
		}
		int j;
		String[] cmd;
		if (windows) {
			j = 6;
			cmd = new String[j + args.length];
			cmd[0] = "swipl";
			cmd[1] = "-x";
			cmd[2] = "C:\\Program Files\\eye\\lib\\eye.pvm";
			cmd[3] = "--";
			cmd[4] = "--wget-path";
			cmd[5] = tmpdir + "eye\\windows\\bin\\";
		}
		else {
			j = 4;
			cmd = new String[j + args.length];
			cmd[0] = "swipl";
			cmd[1] = "-x";
			cmd[2] = "/opt/eye/lib/eye.pvm";
			cmd[3] = "--";
		}
		ArrayList<File> fl = new ArrayList<File>();
		for (int i = 0; i < args.length; i++) {
			if (args[i].startsWith("http://localhost/.context")) {
				try {
					File f = File.createTempFile("eye_", ".n3");
					fl.add(f);
					FileOutputStream fos = new FileOutputStream(f);
					OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF8");
					osw.write(Codd.urlDecode(args[i]).substring(26));
					osw.flush();
					osw.close();
					cmd[j++] = f.getAbsolutePath();
				}
				catch (Throwable t) {
					t.printStackTrace();
				}
			}
			else {
				cmd[j++] = args[i];
			}
		}
		Process pr = new Process(cmd, null, ops, eps);
		pr.setFileList(fl);
		return pr;
	}

	/**
	 * executeProofEngine method
	 * 
	 * @param pr
	 *      process
	 */
	public static void executeProofEngine(Process pr) {
		long ttl = Long.MAX_VALUE;
		ProcessHook ph = new ProcessHook(pr);
		Runtime rt = Runtime.getRuntime();
		rt.addShutdownHook(ph);
		int ev = pr.execute(ttl);
		rt.removeShutdownHook(ph);
		ArrayList<File> fl = pr.getFileList();
		for (File f : fl)
			f.delete();
		if (ev != 0) {
			throw new RuntimeException("Abnormal process termination");
		}
		if (pr.err != null) {
			throw new RuntimeException(pr.err);
		}
	}

	/**
	 * main method
	 * 
	 * @param args
	 *      &lt;options&gt;* &lt;data&gt;* &lt;query&gt;*
	 */
	public static void main(String[] args) {
		try {
			PrintStream ps = new PrintStream(System.out, true, "UTF8");
			runProofEngine(args, ps, System.err);
		}
		catch (Throwable e) {
			e.printStackTrace();
		}
	}
}