/*

 * Copyright 2009 Sun Microsystems, Inc.  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.

 *

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.classanalyzer;

import java.io.BufferedReader;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.Collection;

import java.util.LinkedList;

import java.util.List;

import java.util.Set;

import java.util.TreeSet;

import java.util.regex.Pattern;

/**

 *

 * @author Mandy Chung

 */

public class ModuleConfig {

    private static String baseModuleName = "base";

    private final Set<String> roots;

    private final Set<String> includes;

    private final Filter filter;

    private List<String> members;

    final String module;

    final boolean isBase;

    private ModuleConfig(String name) throws IOException {

        this.roots = new TreeSet<String>();

        this.includes = new TreeSet<String>();

        this.module = name;

        this.isBase = name.equals(baseModuleName);

        this.filter = new Filter(this);

    }

    List<String> members() {

        if (members == null) {

            members = new LinkedList<String>();

            for (String s : includes) {

                if (!s.contains("*") && Module.findModule(s) != null) {

                    // module member

                    members.add(s);

                }

            }

        }

        return members;

    }

    boolean matchesRoot(String name) {

        for (String pattern : roots) {

            if (matches(name, pattern)) {

                return true;

            }

        }

        return false;

    }

    boolean matchesIncludes(String name) {

        for (String pattern : includes) {

            if (matches(name, pattern)) {

                return true;

            }

        }

        return false;

    }

    boolean isExcluded(String name) {

        return filter.isExcluded(name);

    }

    boolean matchesPackage(String packageName, String pattern) {

        int pos = pattern.lastIndexOf('.');

        String pkg = pos > 0 ? pattern.substring(0, pos) : "<unnamed>";

        return packageName.equals(pkg);

    }

    boolean matches(String name, String pattern) {

        if (pattern.contains("**") && !pattern.endsWith("**")) {

            throw new UnsupportedOperationException("Not yet implemented");

        }

        String javaName = name;

        boolean isResourceFile = name.indexOf('/') >= 0;

        if (isResourceFile) {

            // it's a resource file; convert the name as a java

            javaName = name.replace('/', '.');

        }

        if (pattern.indexOf('/') < 0) {

            // if the pattern doesn't contain '/

            return matchesJavaName(javaName, pattern);

        } else {

            if (isResourceFile) {

                // the pattern is for matching resource file

                return matchesNameWithSlash(name, pattern);

            } else {

                return false;

            }

        }

    }

    boolean matchesJavaName(String name, String pattern) {

        int pos = name.lastIndexOf('.');

        String packageName = pos > 0 ? name.substring(0, pos) : "<unnamed>";

        if (pattern.endsWith("**")) {

            String p = pattern.substring(0, pattern.length() - 2);

            return name.startsWith(p);

        } else if (pattern.endsWith("*") && pattern.indexOf('*') == pattern.lastIndexOf('*')) {

            if (matchesPackage(packageName, pattern)) {

                // package name has to be exact match

                String p = pattern.substring(0, pattern.length() - 1);

                return name.startsWith(p);

            } else {

                return false;

            }

        } else if (pattern.contains("*")) {

            String basename = pos > 0 ? name.substring(pos + 1, name.length()) : name;

            pos = pattern.indexOf('*');

            String prefix = pattern.substring(0, pos);

            String suffix = pattern.substring(pos + 1, pattern.length());

            if (name.startsWith(prefix) && matchesPackage(packageName, prefix)) {

                // package name has to be exact match

                if (suffix.contains("*")) {

                    return name.matches(convertToRegex(pattern));

                } else {

                    return basename.endsWith(suffix);

                }

            } else {

                // we don't support wildcard be used in the package name

                return false;

            }

        } else {

            // exact match or inner class

            return name.equals(pattern) || name.startsWith(pattern + "$");

        }

    }

    boolean matchesNameWithSlash(String name, String pattern) {

        if (pattern.endsWith("**")) {

            String p = pattern.substring(0, pattern.length() - 2);

            return name.startsWith(p);

        } else if (pattern.contains("*")) {

            int pos = pattern.indexOf('*');

            String prefix = pattern.substring(0, pos);

            String suffix = pattern.substring(pos + 1, pattern.length());

            String tail = name.substring(pos, name.length());

            if (!name.startsWith(prefix)) {

                // prefix has to exact match

                return false;

            }

            if (pattern.indexOf('*') == pattern.lastIndexOf('*')) {

                // exact match prefix with no '/' in the tail string

                String wildcard = tail.substring(0, tail.length() - suffix.length());

                return tail.indexOf('/') < 0 && tail.endsWith(suffix);

            }

            if (suffix.contains("*")) {

                return matchesNameWithSlash(tail, suffix);

            } else {

                // tail ends with the suffix while no '/' in the wildcard matched string

                String any = tail.substring(0, tail.length() - suffix.length());

                return tail.endsWith(suffix) && any.indexOf('/') < 0;

            }

        } else {

            // exact match

            return name.equals(pattern);

        }

    }

    private String convertToRegex(String pattern) {

        StringBuilder sb = new StringBuilder();

        int i = 0;

        int index = 0;

        int plen = pattern.length();

        while (i < plen) {

            char p = pattern.charAt(i);

            if (p == '*') {

                sb.append("(").append(pattern.substring(index, i)).append(")");

                if (i + 1 < plen && pattern.charAt(i + 1) == '*') {

                    sb.append(".*");

                    index = i + 2;

                } else {

                    sb.append("[^\\.]*");

                    index = i + 1;

                }

            }

            i++;

        }

        if (index < plen) {

            sb.append("(").append(pattern.substring(index, plen)).append(")");

        }

        return sb.toString();

    }

    static class Filter {

        final ModuleConfig config;

        final Set<String> exclude = new TreeSet<String>();

        final Set<String> allow = new TreeSet<String>();

        Filter(ModuleConfig config) {

            this.config = config;

        }

        Filter exclude(String pattern) {

            exclude.add(pattern);

            return this;

        }

        Filter allow(String pattern) {

            allow.add(pattern);

            return this;

        }

        String allowedBy(String name) {

            String allowedBy = null;

            for (String pattern : allow) {

                if (config.matches(name, pattern)) {

                    if (name.equals(pattern)) {

                        return pattern;  // exact match

                    }

                    if (allowedBy == null) {

                        allowedBy = pattern;

                    } else {

                        if (pattern.length() > allowedBy.length()) {

                            allowedBy = pattern;

                        }

                    }

                }

            }

            return allowedBy;

        }

        String excludedBy(String name) {

            String allowedBy = allowedBy(name);

            String excludedBy = null;

            if (allowedBy != null && name.equals(allowedBy)) {

                return null;  // exact match

            }

            for (String pattern : exclude) {

                if (config.matches(name, pattern)) {

                    // not matched by allowed rule or exact match

                    if (allowedBy == null || name.equals(pattern)) {

                        return pattern;

                    }

                    if (excludedBy == null) {

                        excludedBy = pattern;

                    } else {

                        if (pattern.length() > excludedBy.length()) {

                            excludedBy = pattern;

                        }

                    }

                }

            }

            return excludedBy;

        }

        boolean isExcluded(String name) {

            String allowedBy = allowedBy(name);

            String excludedBy = excludedBy(name);

            if (excludedBy == null) {

                return false;

            }

            // not matched by allowed rule or exact match

            if (allowedBy == null || name.equals(excludedBy)) {

                return true;

            }

            if (allowedBy == null) {

                return true;

            }

            if (allowedBy != null &&

                    excludedBy.length() > allowedBy.length()) {

                return true;

            }

            return false;

        }

    }

    private static String trimComment(String line) {

        StringBuilder sb = new StringBuilder();

        int pos = 0;

        while (pos >= 0 && pos < line.length()) {

            int c1 = line.indexOf("//", pos);

            if (c1 > 0 && !Character.isWhitespace(line.charAt(c1-1))) {

                // not a comment

                c1 = -1;

            }

            int c2 = line.indexOf("/*", pos);

            if (c2 > 0 && !Character.isWhitespace(line.charAt(c2-1))) {

                // not a comment

                c2 = -1;

            }

            int c = line.length();

            int n = line.length();

            if (c1 >= 0 || c2 >= 0) {

                if (c1 >= 0) {

                    c = c1;

                }

                if (c2 >= 0 && c2 < c) {

                    c = c2;

                }

                int c3 = line.indexOf("*/", c2 + 2);

                if (c == c2 && c3 > c2) {

                    n = c3 + 2;

                }

            }

            if (c > 0) {

                if (sb.length() > 0) {

                    // add a whitespace if multiple comments on one line

                    sb.append(" ");

                }

                sb.append(line.substring(pos, c));

            }

            pos = n;

        }

        return sb.toString();

    }

    private static boolean beginBlockComment(String line) {

        int pos = 0;

        while (pos >= 0 && pos < line.length()) {

            int c = line.indexOf("/*", pos);

            if (c < 0) {

                return false;

            }

            if (c > 0 && !Character.isWhitespace(line.charAt(c-1))) {

                return false;

            }

            int c1 = line.indexOf("//", pos);

            if (c1 >= 0 && c1 < c) {

                return false;

            }

            int c2 = line.indexOf("*/", c + 2);

            if (c2 < 0) {

                return true;

            }

            pos = c + 2;

        }

        return false;

    }

    static void setBaseModule(String name) {

        baseModuleName = name;

    }

    // TODO: we shall remove "-" from the regex once we define

    // the naming convention for the module names without dashes

    static final Pattern classNamePattern = Pattern.compile("[\\w\\.\\*_$-/]+");

    static List<ModuleConfig> readConfigurationFile(String file) throws IOException {

        List<ModuleConfig> result = new ArrayList<ModuleConfig>();

        // parse configuration file

        FileInputStream in = new FileInputStream(file);

        try {

            BufferedReader reader = new BufferedReader(new InputStreamReader(in));

            String line;

            int lineNumber = 0;

            boolean inRoots = false;

            boolean inIncludes = false;

            boolean inAllows = false;

            boolean inExcludes = false;

            boolean inBlockComment = false;

            ModuleConfig config = null;

            while ((line = reader.readLine()) != null) {

                lineNumber++;

                if (inBlockComment) {

                    int c = line.indexOf("*/");

                    if (c >= 0) {

                        line = line.substring(c + 2, line.length());

                        inBlockComment = false;

                    } else {

                        // skip lines until end of comment block

                        continue;

                    }

                }

                inBlockComment = beginBlockComment(line);

                line = trimComment(line).trim();

                // ignore empty lines

                if (line.length() == 0) {

                    continue;

                }

                String values;

                if (inRoots || inIncludes || inExcludes || inAllows) {

                    values = line;

                } else {

                    String[] s = line.split("\\s+");

                    String keyword = s[0].trim();

                    if (keyword.equals("module")) {

                        if (s.length != 3 || !s[2].trim().equals("{")) {

                            throw new RuntimeException(file + ", line " +

                                    lineNumber + ", is malformed");

                        }

                        config = new ModuleConfig(s[1].trim());

                        result.add(config);

                        // switch to a new module; so reset the flags

                        inRoots = false;

                        inIncludes = false;

                        inExcludes = false;

                        inAllows = false;

                        continue;

                    } else if (keyword.equals("roots")) {

                        inRoots = true;

                    } else if (keyword.equals("include")) {

                        inIncludes = true;

                    } else if (keyword.equals("exclude")) {

                        inExcludes = true;

                    } else if (keyword.equals("allow")) {

                        inAllows = true;

                    } else if (keyword.equals("}")) {

                        if (config == null || s.length != 1) {

                            throw new RuntimeException(file + ", line " +

                                    lineNumber + ", is malformed");

                        } else {

                            // end of a module

                            config = null;

                            continue;

                        }

                    } else {

                        throw new RuntimeException(file + ", \"" + keyword + "\" on line " +

                                lineNumber + ", is not recognized");

                    }

                    values = line.substring(keyword.length(), line.length()).trim();

                }

                if (config == null) {

                    throw new RuntimeException(file + ", module not specified");

                }

                int len = values.length();

                if (len == 0) {

                    continue;

                }

                char lastchar = values.charAt(len - 1);

                if (lastchar != ',' && lastchar != ';') {

                    throw new RuntimeException(file + ", line " +

                            lineNumber + ", is malformed:" +

                            " ',' or ';' is missing.");

                }

                values = values.substring(0, len - 1);

                // parse the values specified for a keyword specified

                for (String s : values.split(",")) {

                    s = s.trim();

                    if (s.length() > 0) {

                        if (!classNamePattern.matcher(s).matches()) {

                            throw new RuntimeException(file + ", line " +

                                    lineNumber + ", is malformed: \"" + s + "\"");

                        }

                        if (inRoots) {

                            config.roots.add(s);

                        } else if (inIncludes) {

                            config.includes.add(s);

                        } else if (inExcludes) {

                            config.filter.exclude(s);

                        } else if (inAllows) {

                            config.filter.allow(s);

                        }

                    }

                }

                if (lastchar == ';') {

                    inRoots = false;

                    inIncludes = false;

                    inExcludes = false;

                    inAllows = false;

                }

            }

            if (inBlockComment) {

                throw new RuntimeException(file + ", line " +

                        lineNumber + ", missing \"*/\" to end a block comment");

            }

            if (config != null) {

                throw new RuntimeException(file + ", line " +

                        lineNumber + ", missing \"}\" to end module definition" +

                        " for \"" + config.module + "\"");

            }

        } finally {

            in.close();

        }

        return result;

    }

    private String format(String keyword, Collection<String> values) {

        if (values.size() == 0) {