/**
 *******************************************************************************
 * Copyright (C) 2001-2002, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
package com.ibm.icu.impl;

import com.ibm.icu.util.VersionInfo;

public final class ICUDebug {
    private static String params;
    static {
	try {
	    params = System.getProperty("ICUDebug");
	}
	catch (SecurityException e) {
	}
    }
    private static boolean debug = params != null;
    private static boolean help = debug && (params.equals("") || params.indexOf("help") != -1);

    static {
	if (debug) {
	    System.out.println("\nICUDebug=" + params);
	}
    }

    public static final String javaVersionString = System.getProperty("java.version");
    public static final boolean isJDK14OrHigher;
    public static final VersionInfo javaVersion;

    public static VersionInfo getInstanceLenient(String s) {
	// clean string
	// preserve only digits, separated by single '.' 
	// ignore over 4 digit sequences
	// does not test < 255, very odd...

	char[] chars = s.toCharArray();
	int r = 0, w = 0, count = 0;
	boolean numeric = false; // ignore leading non-numerics
	while (r < chars.length) {
	    char c = chars[r++];
	    if (c < '0' || c > '9') {
		if (numeric) {
		    if (count == 3) {
			// only four digit strings allowed
			break;
		    }
		    numeric = false;
		    chars[w++] = '.';
		    ++count;
		}
	    } else {
		numeric = true;
		chars[w++] = c;
	    }
	}
	while (w > 0 && chars[w-1] == '.') {
	    --w;
	}
	
	String vs = new String(chars, 0, w);

	return VersionInfo.getInstance(vs);
    }

    static {
	javaVersion = getInstanceLenient(javaVersionString);

        VersionInfo java14Version = VersionInfo.getInstance("1.4.0");

        isJDK14OrHigher = javaVersion.compareTo(java14Version) >= 0;
    }

    public static boolean enabled() {
	return debug;
    }

    public static boolean enabled(String arg) {
	if (debug) {
	    boolean result = params.indexOf(arg) != -1;
	    if (help) System.out.println("\nICUDebug.enabled(" + arg + ") = " + result);
	    return result;
	}
	return false;
    }

    public static String value(String arg) {
	String result = "false";
	if (debug) {
	    int index = params.indexOf(arg);
	    if (index != -1) {
		index += arg.length();
		if (params.length() > index && params.charAt(index) == '=') {
		    index += 1;
		    int limit = params.indexOf(",", index);
		    result = params.substring(index, limit == -1 ? params.length() : limit);
		}
		result = "true";
	    }

	    if (help) System.out.println("\nICUDebug.value(" + arg + ") = " + result);
	}
	return result;
    }

    static public void main(String[] args) {
	// test
	String[] tests = {
	    "1.3.0",
	    "1.3.0_02",
	    "1.3.1ea",
	    "1.4.1b43",
	    "___41___5",
	    "x1.4.51xx89ea.7f"
	};
	for (int i = 0; i < tests.length; ++i) {
	    System.out.println(tests[i] + " => " + getInstanceLenient(tests[i]));
	}
    }
}