/* 
 * JAVA PRESS Vol.5
 * "Scripting with ECMAScipt" example (List 3 / English Version)
 * Written by Summery Sardine <sardine@toyfish.net>
 */

import FESI.jslib.*;
import java.io.*;
import java.util.*;

/**
 * Simple pre-processor using FESI ECMAScript interpreter.
 */
class jpre {
	String source, result;
	Vector props;
	final char startingChar = '#';
	
	/**
	 * Construct a new preprocessor.
	 *
	 * @param	source	source file
	 * @param	result	output file
	 * @param	props	variables
	 */
	jpre(String source, String result, Vector props) {
		this.source = source;
		this.result = result;
		this.props = props;
	}
	
	// main procedure
	void process() throws IOException, JSException {
		BufferedReader reader = null;
		BufferedWriter writer = null;
		try {
			// prepare
			File temp = new File("temp.es");
			reader = new BufferedReader(new FileReader(source));
			writer = new BufferedWriter(new FileWriter(temp));
			
			// write to temporary file
			String s, t;
			while ((s = reader.readLine()) != null) {
				t = s.replace('\t', ' ').trim();
				if (t.equals("")) {
					writer.write("put(\"" + s + "\");");
				} else if (t.charAt(0) == startingChar) {
					int p = s.indexOf(startingChar);
					writer.write(s.substring(0, p) +
					             s.substring(p + 1));
				} else {
					writer.write("put(\"" + escape(s) + "\");");
				}
				writer.newLine();
			}
			reader.close();
			writer.close();
			
			// construct FESI interpreter
			JSGlobalObject global = null;
			try {
				global = JSUtil.makeEvaluator();
			} catch (JSException e) {
				System.err.println("Cannot initialize FESI.");
				System.exit(1);
			}
			writer = new BufferedWriter(new FileWriter(result));
			global.setMember("put", new PutFunction(writer));
			
			// define variables
			Enumeration e = props.elements();
			while (e.hasMoreElements()) {
				global.eval((String)e.nextElement());
			}
			
			// execute temporary script file
			global.eval(new BufferedReader(new FileReader(temp)),
			            "Temporary file");
		} finally {
			if (reader != null) reader.close();
			if (writer != null) writer.close();
		}
	}
	
	/**
	 * Replace doublequotes and backslashes with their escape sequences.
	 *
	 * @param	target string
	 * @return	result
	 */
	String escape(String s) {
		StringBuffer buf = new StringBuffer();
		char[] chars = s.toCharArray();
		int n = chars.length;
		for (int i = 0; i < n; i++) {
			switch (chars[i]) {
			case '"':
				buf.append("\\\"");
				break;
			case '\\':
				buf.append("\\\\");
				break;
			default:
				buf.append(chars[i]);
			}
		}
		return buf.toString();
	}
	
	/**
	 * An object defining the behavior of "put" function.
	 */
	class PutFunction extends JSFunctionAdapter {
		BufferedWriter writer = null;
		
		PutFunction(BufferedWriter writer) {
			this.writer = writer;
		}
		
		public Object doCall(JSObject thisObject, Object[] args)
			                throws JSException {
			try {
				writer.write(args[0].toString());
				writer.newLine();
			} catch (IOException e) {
				throw new JSException("Output failed.", e);
			}
			return null;
		}
	}
	
	public static void main(String[] args) {
		if (args.length >= 2) {
			try {
				Vector props = new Vector();
				int n = args.length;;
				for (int i = 2; i < n; i++) {
					if ((args[i].indexOf('=')) > -1) {
						props.addElement(args[i] + ";");
					} else {
						props.addElement(args[i] + " = true;");
					}
				}
				jpre jp = new jpre(args[0], args[1], props);
				jp.process();
			} catch (Exception e) {
				System.err.println(e.getMessage());
				e.printStackTrace();
			}
		} else {
			System.err.println("usage: jpre source outfile [property...]");
			System.err.println("   property: name[=value]");
		}
	}
}