/*******************************************************************************
* Copyright (c) 2009-2012 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Vector;

import org.luaj.vm2.Globals;
import org.luaj.vm2.Lua;
import org.luaj.vm2.LuaTable;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Print;
import org.luaj.vm2.Varargs;
import org.luaj.vm2.lib.jse.JsePlatform;
import org.luaj.vm2.luajc.LuaJC;

/**
 * lua command for use in JSE environments.
 */
public class lua {
	private static final String version = Lua._VERSION + " Copyright (c) 2012 Luaj.org.org";

	private static final String usage = "usage: java -cp luaj-jse.jar lua [options] [script [args]].\n"
		+ "Available options are:\n" + "  -e stat  execute string 'stat'\n" + "  -l name  require library 'name'\n"
		+ "  -i       enter interactive mode after executing 'script'\n" + "  -v       show version information\n"
		+ "  -b      	use luajc bytecode-to-bytecode compiler (requires bcel on class path)\n"
		+ "  -n      	nodebug - do not load debug library by default\n" + "  -p      	print the prototype\n"
		+ "  -c enc  	use the supplied encoding 'enc' for input files\n" + "  --       stop handling options\n"
		+ "  -        execute stdin and stop handling options";

	private static void usageExit() {
		System.out.println(usage);
		System.exit(-1);
	}

	private static Globals globals;
	private static boolean print    = false;
	private static String  encoding = null;

	public static void main(String[] args) throws IOException {

		// process args
		boolean interactive = args.length == 0;
		boolean versioninfo = false;
		boolean processing = true;
		boolean nodebug = false;
		boolean luajc = false;
		Vector libs = null;
		try {
			// stateful argument processing
			for (int i = 0; i < args.length; i++) {
				if (!processing || !args[i].startsWith("-")) {
					// input file - defer to last stage
					break;
				} else if (args[i].length() <= 1) {
					// input file - defer to last stage
					break;
				} else {
					switch (args[i].charAt(1)) {
					case 'e':
						if (++i >= args.length)
							usageExit();
						// input script - defer to last stage
						break;
					case 'b':
						luajc = true;
						break;
					case 'l':
						if (++i >= args.length)
							usageExit();
						libs = libs != null? libs: new Vector();
						libs.addElement(args[i]);
						break;
					case 'i':
						interactive = true;
						break;
					case 'v':
						versioninfo = true;
						break;
					case 'n':
						nodebug = true;
						break;
					case 'p':
						print = true;
						break;
					case 'c':
						if (++i >= args.length)
							usageExit();
						encoding = args[i];
						break;
					case '-':
						if (args[i].length() > 2)
							usageExit();
						processing = false;
						break;
					default:
						usageExit();
						break;
					}
				}
			}

			// echo version
			if (versioninfo)
				System.out.println(version);

			// new lua state
			globals = nodebug? JsePlatform.standardGlobals(): JsePlatform.debugGlobals();
			if (luajc)
				LuaJC.install(globals);
			for (int i = 0, n = libs != null? libs.size(): 0; i < n; i++)
				loadLibrary((String) libs.elementAt(i));

			// input script processing
			processing = true;
			for (int i = 0; i < args.length; i++) {
				if (!processing || !args[i].startsWith("-")) {
					processScript(new FileInputStream(args[i]), args[i], args, i);
					break;
				} else if ("-".equals(args[i])) {
					processScript(System.in, "=stdin", args, i);
					break;
				} else {
					switch (args[i].charAt(1)) {
					case 'l':
					case 'c':
						++i;
						break;
					case 'e':
						++i;
						processScript(new ByteArrayInputStream(args[i].getBytes()), "string", args, i);
						break;
					case '-':
						processing = false;
						break;
					}
				}
			}

			if (interactive)
				interactiveMode();

		} catch (IOException ioe) {
			System.err.println(ioe.toString());
			System.exit(-2);
		}
	}

	private static void loadLibrary(String libname) throws IOException {
		LuaValue slibname = LuaValue.valueOf(libname);
		try {
			// load via plain require
			globals.get("require").call(slibname);
		} catch (Exception e) {
			try {
				// load as java class
				LuaValue v = (LuaValue) Class.forName(libname).newInstance();
				v.call(slibname, globals);
			} catch (Exception f) {
				throw new IOException("loadLibrary(" + libname + ") failed: " + e + "," + f);
			}
		}
	}

	private static void processScript(InputStream script, String chunkname, String[] args, int firstarg)
		throws IOException {
		try {
			LuaValue c;
			try {
				script = new BufferedInputStream(script);
				c = encoding != null? globals.load(new InputStreamReader(script, encoding), chunkname)
					: globals.load(script, chunkname, "bt", globals);
			} finally {
				script.close();
			}
			if (print && c.isclosure())
				Print.print(c.checkclosure().p);
			Varargs scriptargs = setGlobalArg(chunkname, args, firstarg, globals);
			c.invoke(scriptargs);
		} catch (Exception e) {
			e.printStackTrace(System.err);
		}
	}

	private static Varargs setGlobalArg(String chunkname, String[] args, int i, LuaValue globals) {
		if (args == null)
			return LuaValue.NONE;
		LuaTable arg = LuaValue.tableOf();
		for (int j = 0; j < args.length; j++)
			arg.set(j-i, LuaValue.valueOf(args[j]));
		arg.set(0, LuaValue.valueOf(chunkname));
		arg.set(-1, LuaValue.valueOf("luaj"));
		globals.set("arg", arg);
		return arg.unpack();
	}

	private static void interactiveMode() throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		while ( true ) {
			System.out.print("> ");
			System.out.flush();
			String line = reader.readLine();
			if (line == null)
				return;
			processScript(new ByteArrayInputStream(line.getBytes()), "=stdin", null, 0);
		}
	}
}