/*

 * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package build.tools.spp;

import java.util.*;

import java.util.regex.*;

/*

 * Spp: A simple regex-based stream preprocessor based on Mark Reinhold's

 *      sed-based spp.sh

 *

 * Usage: java build.tools.spp.Spp [-be] [-nel] [-Kkey] -Dvar=value ... <in >out

 *

 * If -nel is declared then empty lines will not be substituted for lines of

 * text in the template that do not appear in the output.

 *

 *   Meaningful only at beginning of line, works with any number of keys:

 *

 *    #if[key]              Includes text between #if/#end if -Kkey specified,

 *    #else[key]            otherwise changes text to blank lines; key test

 *    #end[key]             may be negated by prefixing !, e.g., #if[!key]

 *

 *    #begin                If -be is specified then lines up to and including

 *    #end                  #begin, and from #end to EOF, are deleted

 *

 *    #warn                 Changed into warning that file is generated

 *

 *    // ##                 Changed into blank line

 *

 *  Meaningful anywhere in line

 *

 *    {#if[key]?yes}        Expands to yes if -Kkey specified

 *    {#if[key]?yes:no}     Expands to yes if -Kkey, otherwise no

 *    {#if[!key]?yes}       Expands to yes if -Kother

 *    {#if[!key]?yes:no}    Expands to yes if -Kother, otherwise no

 *    $var$                 Expands to value if -Dvar=value given

 *

 *    yes, no must not contain whitespace

 *

 * @author Xueming Shen

 */

public class Spp {

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

        Map<String, String> vars = new HashMap<>();

        Set<String> keys = new HashSet<>();

        boolean be = false;

        boolean el = true;

        for (String arg:args) {

            if (arg.startsWith("-D")) {

                int i = arg.indexOf('=');

                vars.put(arg.substring(2, i),arg.substring(i+1));

            } else if (arg.startsWith("-K")) {

                keys.add(arg.substring(2));

            } else if ("-be".equals(arg)) {

                be = true;

            } else if ("-nel".equals(arg)) {

                el = false;

            } else {

                System.err.println("Usage: java build.tools.spp.Spp [-be] [-nel] [-Kkey] -Dvar=value ... <in >out");

                System.exit(-1);

            }

        }

        StringBuffer out = new StringBuffer();

                      out, "",

                      keys, vars, be, el,

                      false);

    }

    static final String LNSEP = System.getProperty("line.separator");

    static final String KEY = "([a-zA-Z0-9]+)";

    static final String VAR = "([a-zA-Z0-9_\\-]+)";

    static final String TEXT = "([a-zA-Z0-9&;,.<>/#() \\?\\[\\]\\$]+)"; // $ -- hack embedded $var$

    static final int GN_NOT = 1;

    static final int GN_KEY = 2;

    static final int GN_YES = 3;

    static final int GN_NO  = 5;

    static final int GN_VAR = 6;

    final Matcher   ifkey = Pattern.compile("^#if\\[(!)?" + KEY + "\\]").matcher("");

    final Matcher elsekey = Pattern.compile("^#else\\[(!)?" + KEY + "\\]").matcher("");

    final Matcher  endkey = Pattern.compile("^#end\\[(!)?" + KEY + "\\]").matcher("");

    final Matcher  vardef = Pattern.compile("\\{#if\\[(!)?" + KEY + "\\]\\?" + TEXT + "(:"+ TEXT + ")?\\}|\\$" + VAR + "\\$").matcher("");

    final Matcher vardef2 = Pattern.compile("\\$" + VAR + "\\$").matcher("");

    void append(StringBuffer buf, String ln,

                Set<String> keys, Map<String, String> vars) {

        vardef.reset(ln);

        while (vardef.find()) {

            String repl = "";

            if (vardef.group(GN_VAR) != null)

                repl = vars.get(vardef.group(GN_VAR));

            else {

                boolean test = keys.contains(vardef.group(GN_KEY));

                if (vardef.group(GN_NOT) != null)

                    test = !test;

                repl = test?vardef.group(GN_YES):vardef.group(GN_NO);

                if (repl == null)

                    repl = "";

                else {  // embedded $var$

                    while (vardef2.reset(repl).find()) {

                        repl = vardef2.replaceFirst(vars.get(vardef2.group(1)));

                    }

                }

            }

            vardef.appendReplacement(buf, repl);

        }

        vardef.appendTail(buf);

    }

    // return true if #end[key], #end or EOF reached

    boolean spp(Scanner in, StringBuffer buf, String key,

                Set<String> keys, Map<String, String> vars,

                boolean be, boolean el, boolean skip) {

        while (in.hasNextLine()) {

            String ln = in.nextLine();

            if (be) {

                if (ln.startsWith("#begin")) {

                    buf.setLength(0);      //clean up to this line

                    continue;

                }

                if (ln.equals("#end")) {

                    while (in.hasNextLine())

                        in.nextLine();

                    return true;           //discard the rest to EOF

                }

            }

            if (ifkey.reset(ln).find()) {

                String k = ifkey.group(GN_KEY);

                boolean test = keys.contains(k);

                if (ifkey.group(GN_NOT) != null)

                    test = !test;

                if (el) buf.append(LNSEP);

                if (!spp(in, buf, k, keys, vars, be, el, skip || !test)) {

                    spp(in, buf, k, keys, vars, be, el, skip || test);

                }

                continue;

            }

            if (elsekey.reset(ln).find()) {

                if (!key.equals(elsekey.group(GN_KEY))) {

                    throw new Error("Mis-matched #if-else-end at line <" + ln + ">");

                }

                if (el) buf.append(LNSEP);

                return false;

            }

            if (endkey.reset(ln).find()) {

                if (!key.equals(endkey.group(GN_KEY))) {

                    throw new Error("Mis-matched #if-else-end at line <" + ln + ">");

                }

                if (el) buf.append(LNSEP);

                return true;

            }

            if (ln.startsWith("#warn")) {

                ln = "// -- This file was mechanically generated: Do not edit! -- //";

            } else if (ln.trim().startsWith("// ##")) {

                ln = "";

            }

            if (!skip) {

                append(buf, ln, keys, vars);

                if (!el) buf.append(LNSEP);

            }

            if (el) buf.append(LNSEP);

        }

        return true;

    }

}